Secondary cell group configuration

Abstract

A method may include receiving, by a wireless device, a radio resource control (RRC) reconfiguration message from a primary base station associated with a primary cell group. The message may include a conditional configuration of a secondary cell group (SCG) associated with a secondary base station of one or more secondary base stations, and one or more counters for the secondary base station. The RRC reconfiguration message may indicate that the one or more counters are associated with the SCG; and / or the one or more counters are used for subsequent cell group changes. The method may also include applying a configuration of the conditional configuration of the SCG based on an execution condition satisfying the conditional configuration. The method may further include transmitting an RRC reconfiguration complete message indicating the conditional configuration to the secondary base station based on the configuration to which the SCG is applied.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 410,179, filed on September 26, 2022, which is hereby incorporated by reference in its entirety. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Examples of several embodiments of the present disclosure are described herein with reference to the drawings.

[0004] Figure 1A and Figure 1B show an example mobile communication network in which embodiments of the present disclosure may be implemented.

[0005] Figure 2A and Figure 2B show a New Radio (NR) user plane and control plane protocol stack, respectively.

[0006] Figure 3 show an example of a service provided between protocol layers of the NR user plane protocol stack in Figure 2A

[0007] Figure 4A show an example of a downlink data stream flowing through the NR user plane protocol stack in Figure 2A

[0008] Figure 4B show an example format of a MAC sub - header in a MAC PDU.

[0009] Figure 5A and Figure 5B show the mapping between logical channels, transport channels, and physical channels for downlink and uplink, respectively.

[0010] Figure 6 is an example diagram showing the RRC state transition of a UE.

[0011] Figure 7 show an example configuration of an NR frame into which OFDM symbols are grouped.

[0012] Figure 8 show an example configuration of time slots in the time and frequency domains of an NR carrier.

[0013] Figure 9 show an example of bandwidth adaptation using three configured Bandwidth Parts (BWPs) of an NR carrier.

[0014] Figure 10A show three carrier aggregation configurations with two component carriers.

[0015] Figure 10B An example of how an aggregated cell can be configured into one or more PUCCH groups is shown.

[0016] Figure 11A An example of the SS / PBCH block structure and location is shown.

[0017] Figure 11B An example of CSI-RS mapped in the time and frequency domains is shown.

[0018] Figure 12A and Figure 12B Examples of three downlink and uplink beam management procedures are shown respectively.

[0019] Figure 13A 、 Figure 13B and Figure 13C Examples of a four-step contention-based random access procedure, a two-step contention-free random access procedure, and another two-step random access procedure are shown respectively.

[0020] Figure 14A An example of the CORESET configuration of a bandwidth part is shown.

[0021] Figure 14B An example of the CCE-to-REG mapping for DCI transmission on CORESET and PDCCH processing is shown.

[0022] Figure 15 An example of a wireless device communicating with a base station is shown.

[0023] Figure 16A 、 Figure 16B 、 Figure 16C and Figure 16D Examples of structures for uplink and downlink transmissions are shown.

[0024] Figure 17 An example of an RRC connection reestablishment procedure is shown.

[0025] Figure 18 An example of an RRC connection resume procedure is shown.

[0026] Figure 19 An example of a conditional handover procedure is shown.

[0027] Figure 20 An example of a connection restoration procedure with a conditional handover configuration is shown.

[0028] Figure 21 An example of a conditional PSCell addition / change procedure is shown.

[0029] Figure 22 An example of an MCG failure information procedure is shown.

[0030] Figure 23 Shows an example of an RRC connection reestablishment procedure.

[0031] Figure 24 Shows an example of the security parameters of a secondary base station.

[0032] Figure 25 Shows an example of the security parameters of a secondary base station and SCG configuration parameters.

[0033] Figure 26 Shows an example of the security parameters of a secondary base station and conditional SCG configuration parameters.

[0034] Figure 27 Shows an example of a subsequent SCG change.

[0035] Figure 28 Shows an example of a subsequent SCG change.

[0036] Figure 29 Shows an example of additional security parameters of a secondary base station.

[0037] Figure 30 Shows an example of additional counters and wireless devices.

[0038] Figure 31 Shows an example of an additional secondary key and a secondary base station.

[0039] Figure 32 Shows an example of additional security parameters, wireless devices and a secondary base station.

[0040] Figure 33 Shows an example of multiple additional security parameters.

[0041] Figure 34 Shows an example of additional security parameters with one or more configurations.

[0042] Figure 35 Shows an example of additional security parameters with one or more configurations.

[0043] Figure 36A Shows an example of additional counters included in a cell group configuration.

[0044] Figure 36B Shows an example of additional counters not included in a cell group configuration.

[0045] Figure 36C Shows an example of additional counters included in a configuration (re)configuration. Detailed Description

[0046] In the present disclosure, various embodiments are presented in the form of examples of how the disclosed technology can be implemented and / or how the disclosed technology can be practiced in environments and scenarios. It will be apparent to those skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope of the present invention. In fact, after reading the specification, it will be apparent to those skilled in the relevant art how to implement alternative embodiments. The embodiments of the present invention should not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed exemplary embodiments can be combined to create additional embodiments within the scope of the present disclosure. Any figures that highlight functionality and advantages are given for example purposes only. The disclosed architecture is flexible and configurable enough such that it can be utilized in ways different from the shown manner. For example, the actions listed in any flowchart can be reordered or used only optionally in certain embodiments.

[0047] Embodiments can be configured to operate as needed. For example, in a wireless device, a base station, a radio environment, a network, a combination of the above, etc., when certain criteria are met, the disclosed mechanisms can be executed. Example criteria can be at least partially based on, for example, wireless device or network node configuration, traffic load, initial system settings, packet size, traffic characteristics, a combination of the above, etc. When one or more criteria are met, various example embodiments can be applied. Thus, example embodiments that selectively implement the disclosed protocol can be implemented.

[0048] A base station can communicate with a mixture of wireless devices. The wireless devices and / or the base station can support multiple technologies and / or multiple versions of the same technology. A wireless device may have certain specific capabilities, depending on the wireless device category and / or capabilities. When the present disclosure refers to a base station communicating with multiple wireless devices, the present disclosure may mean a subset of the total wireless devices in the coverage area. For example, the present disclosure may mean multiple wireless devices with a given capability and a given LTE or 5G version in a given sector of the base station. The multiple wireless devices in the present disclosure can refer to a selected multiple of wireless devices, and / or a subset of the total wireless devices in the coverage area that execute according to the disclosed method, etc. There may be multiple base stations or multiple wireless devices in the coverage area that may not conform to the disclosed method. For example, these wireless devices or base stations may execute based on an older version of LTE or 5G technology.

[0049] In this disclosure, "a", "an", and similar phrases will be interpreted as "at least one" and "one or more". Similarly, any term ending with the suffix "(s)" will be interpreted as "at least one" and "one or more". In this disclosure, the term "may" is interpreted as "may, for example". In other words, the term "may" indicates that the phrase following the term "may" is an example of one of the various suitable possibilities that may or may not be used in one or more of the respective embodiments. As used herein, the terms "comprising" and "consisting of" enumerate one or more components of the element being described. The term "comprising" is interchangeable with "including" and does not exclude components not enumerated from being included in the element being described. In contrast, "consisting of" provides a complete enumeration of the one or more components of the element being described. As used herein, the term "based on" should be interpreted as "at least partially based on" rather than, for example, "only based on". As used herein, the term "and / or" represents any possible combination of the enumerated elements. For example, "A, B, and / or C" can represent A; B; C; A and B; A and C; B and C; or A, B, and C.

[0050] If A and B are sets and every element of A is also an element of B, then A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, the possible subsets of B = {cell 1, cell2} are: {cell 1}, {cell2}, and {cell 1, cell2}. The phrase "based on" (or equivalently "at least based on") indicates that the phrase following the term "based on" is an example of one of the various suitable possibilities that may or may not be used in one or more different embodiments. The phrase "in response to" (or equivalently "at least in response to") indicates that the phrase following the term "in response to" is an example of one of the various suitable possibilities that may or may not be used in one or more different embodiments. The phrase "depending on" (or equivalently "at least depending on") indicates that the phrase following the term "depending on" is an example of one of the various suitable possibilities that may or may not be used in one or more different embodiments. The phrase "employing / using" (or equivalently "at least employing / using") indicates that the phrase following the term "employing / using" is an example of one of the various suitable possibilities that may or may not be used in one or more different embodiments.

[0051] The term "configured" can relate to the capabilities of a device, whether the device is in an operating state or a non-operating state. "Configured" can refer to specific settings in a device that affect the operating characteristics of the device, whether the device is in an operating state or a non-operating state. In other words, hardware, software, firmware, registers, memory values, etc. can be "configured" within the device to provide the device with specific characteristics, whether the device is in an operating state or a non-operating state. The term such as "control message induced in a device" can mean that the control message has parameters that can be used to configure specific characteristics in the device or parameters that can be used to implement certain actions in the device, whether the device is in an operating state or a non-operating state.

[0052] In the present disclosure, a parameter (or equivalently referred to as a field or information element: IE) can contain one or more information objects, and an information object can contain one or more other objects. For example, if parameter (IE) N contains parameter (IE) M, and parameter (IE) M contains parameter (IE) K, and parameter (IE) K contains parameter (information element) J. Then, for example, N contains K, and N contains J. In an exemplary embodiment, when one or more messages contain multiple parameters, it means that the parameters among the multiple parameters are in at least one of the one or more messages, but not necessarily in each of the one or more messages.

[0053] Many of the features presented are described as optional by using "may" or by using parentheses. For the sake of brevity and readability, the present disclosure does not explicitly recite every permutation that can be obtained by making a selection from the group of optional features. The present disclosure should be construed as explicitly disclosing all such permutations. For example, a system described as having three optional features can be embodied in seven different ways, namely having only one of the three possible features, having any two of the three possible features, or having all three of the three possible features.

[0054] Many of the elements described in the disclosed embodiments can be implemented as modules. A module is defined herein as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure can be implemented in hardware, software in combination with hardware, firmware, wetware (e.g., hardware with biological elements), or combinations thereof, all of which can be behaviorally equivalent. For example, a module can be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab, etc.) or a modeling / simulation program (such as Simulink, Stateflow, GNU Octave, or LabVIEW MathScript). It is possible to implement a module using physical hardware incorporating discrete or programmable analog, digital, and / or quantum hardware. Examples of programmable hardware include: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field-programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++. FPGAs, ASICs, and CPLDs are often programmed using hardware description languages (HDLs), such as VHSIC hardware description language (VHDL) or Verilog, which configure connections between less-functional internal hardware modules on the programmable device. The technologies mentioned are often used in combination to achieve the results of functional modules.

[0055] Figure 1A An example of a mobile communication network 100 in which embodiments of the present disclosure can be implemented is shown. The mobile communication network 100 can be, for example, a public land mobile network (PLMN) operated by a network operator. As Figure 1A shown, the mobile communication network 100 includes a core network (CN) 102, a radio access network (RAN) 104, and a wireless device 106.

[0056] The CN 102 can provide the wireless device 106 with an interface to one or more data networks (DNs) (such as a public DN (e.g., the Internet), a private DN, and / or an operator-internal DN). As part of the interface function, the CN 102 can establish an end-to-end connection between the wireless device 106 and one or more DNs, authenticate the wireless device 106, and provide a charging function.

[0057] The RAN 104 can connect the CN 102 to the wireless device 106 via radio communication over the air interface. As part of the radio communication, the RAN 104 can provide scheduling, radio resource management, and retransmission protocols. The communication direction from the RAN 104 to the wireless device 106 over the air interface is referred to as the downlink, while the communication direction from the wireless device 106 to the RAN 104 over the air interface is referred to as the uplink. Frequency-division duplexing (FDD), time-division duplexing (TDD), and / or some combination of the two duplexing techniques can be used to separate downlink transmissions from uplink transmissions.

[0058] The term "wireless device" can be used throughout this disclosure to mean and encompass any mobile device or fixed (non-mobile) device that requires or can use wireless communication. For example, a wireless device can be a phone, smartphone, tablet, computer, laptop, sensor, meter, wearable device, Internet of Things (IoT) device, vehicle roadside unit (RSU), relay node, automobile, and / or any combination thereof. The term "wireless device" encompasses other terms, including user equipment (UE), user terminal (UT), access terminal (AT), mobile station, handset, wireless transmit and receive unit (WTRU), and / or wireless communication device.

[0059] The RAN 104 can include one or more base stations (not shown). The term "base station" can be used throughout this disclosure to mean and encompass: Node B (associated with UMTS and / or 3G standards); evolved Node B (eNB, associated with E-UTRA and / or 4G standards); remote radio head (RRH); a baseband processing unit coupled to one or more RRHs; a repeater node or relay node for extending the coverage area of a donor node; next-generation evolved Node B (ng-eNB); generation Node B (gNB, associated with NR and / or 5G standards); access point (AP, associated with, for example, WiFi or any other suitable wireless communication standard); and / or any combination thereof. A base station can include at least one gNB central unit (gNB-CU) and at least one gNB distributed unit (gNB-DU).

[0060] The base stations included in the RAN 104 can include one or more sets of antennas for communicating with the wireless device 106 over the air interface. For example, one or more of the base stations can include three sets of antennas to control three cells (or sectors) respectively. The size of a cell can be determined by the range within which a receiver (e.g., a base station receiver) can successfully receive transmissions from a transmitter (e.g., a wireless device transmitter) operating in the cell. The cells of the base stations can together provide radio coverage over a wide geographic area to support the movement of the wireless device 106.

[0061] In addition to three-sector sites, other implementations of the base station are possible. For example, one or more of the base stations in RAN 104 can be implemented as sectorized sites with more or fewer than three sectors. One or more of the base stations in RAN 104 can be implemented as access points, baseband processing units coupled to a number of remote radio heads (RRHs), and / or repeaters or relay nodes for extending the coverage area of a donor node. The baseband processing unit coupled to the RRH can be part of a centralized or cloud RAN architecture, where the baseband processing unit can be centralized in a pool of baseband processing units or virtualized. The repeater node can amplify and replay the radio signals received from the donor node. The relay node can perform the same / similar functions as the repeater node, but can decode the radio signals received from the donor node to eliminate noise before amplifying and replaying the radio signals.

[0062] RAN 104 can be deployed as a homogeneous network of macrocell base stations with similar antenna patterns and similar high-level transmission powers. RAN 104 can be deployed as a heterogeneous network. In a heterogeneous network, small cell base stations can be used to provide small coverage areas, such as coverage areas that overlap with the relatively large coverage areas provided by macrocell base stations. Small coverage areas can be provided in areas with high data traffic (or so-called "hotspots") or in areas with weak macrocell coverage. Examples of small cell base stations, in decreasing order of coverage area, include: microcell base stations, picocell base stations, and femtocell base stations or home base stations.

[0063] The 3rd Generation Partnership Project (3GPP) was established in 1998 to provide global specification standardization for mobile communication networks similar to the mobile communication network 100 in Figure 1A So far, 3GPP has developed specifications for three generations of mobile networks: the 3rd generation (3G) network known as the Universal Mobile Telecommunications System (UMTS), the 4th generation (4G) network known as Long Term Evolution (LTE), and the 5th generation (5G) network known as the 5G System (5GS). The embodiments of the present disclosure are described with reference to the RAN of the 3GPP 5G network known as the Next Generation RAN (NG-RAN). These embodiments can be applicable to the RANs of other mobile communication networks, such as Figure 1A the RAN 104 in

[0064] Figure 1BFIG. 0 shows another exemplary mobile communication network 150 in which embodiments of the present disclosure may be implemented. The mobile communication network 150 may be, for example, a PLMN operated by a network operator. As Figure 1B shown, the mobile communication network 150 includes a 5G Core Network (5G-CN) 152, an NG-RAN 154, and UEs 156A and 156B (collectively referred to as UEs 156). These components may be implemented and operated in the same or similar manner as the corresponding components described with respect to Figure 1A .

[0065] The 5G-CN 152 provides an interface to one or more DNs for the UEs 156, such as a public DN (e.g., the Internet), a private DN, and / or an operator-internal DN. As part of the interface function, the 5G-CN 152 may establish an end-to-end connection between the UEs 156 and the one or more DNs, authenticate the UEs 156, and provide a charging function. Compared with the CN of the 3GPP 4G network, the 5G-CN 152 may be based on a service-based architecture. This means that the architecture of the nodes that make up the 5G-CN 152 may be defined as network functions that provide services to other network functions via interfaces. The network functions of the 5G-CN 152 may be implemented in several ways, including as network elements on dedicated or shared hardware, as software instances running on dedicated or shared hardware, or as virtualized functions instantiated on a platform (e.g., a cloud-based platform).

[0066] As Figure 1B shown, the 5G-CN 152 includes an Access and Mobility Management Function (AMF) 158A and a User Plane Function (UPF) 158B, which are shown as one component AMF / UPF 158 for ease of illustration in Figure 1B . The UPF 158B may act as a gateway between the NG-RAN 154 and the one or more DNs. The functions that the UPF 158B may perform include: packet routing and forwarding, packet inspection, and enforcement of user plane policy rules, service usage reporting, support for uplink classification for routing traffic flows to the one or more DNs, quality of service (QoS) handling for the user plane (e.g., packet filtering, gating, uplink / downlink rate enforcement, and uplink traffic verification), downlink packet buffering, and triggering of downlink data notifications. The UPF 158B may act as an anchor for mobility within / across radio access technologies (RATs), an external protocol (or packet) data unit (PDU) session point for interconnecting with the one or more DNs, and / or a pivot for supporting multi-homed PDU sessions. The UEs 156 may be configured to receive services through PDU sessions, which are logical connections between the UEs and the DNs.

[0067] The functions that AMF 158A can perform include, for example, non-access stratum (NAS) signaling termination, NAS signaling security, access stratum (AS) security control, CN-inter node signaling for mobility between 3GPP access networks, idle mode UE reachability (e.g., control and execution of paging retransmission), registration area management, in-system and inter-system mobility support, access authentication, access authorization including roaming right verification, mobility management control (subscription and policy), network slice support, and / or session management function (SMF) selection. NAS can refer to the functions operating between the CN and the UE, and AS can refer to the functions operating between the UE and the RAN.

[0068] 5G-CN 152 may include one or more additional network functions not shown for clarity in Figure 1B For example, 5G-CN 152 may include one or more of the following: session management function (SMF), NR repository function (NRF), policy control function (PCF), network exposure function (NEF), unified data management (UDM), application function (AF), and / or authentication server function (AUSF).

[0069] NG-RAN 154 can connect 5G-CN 152 to UE 156 via radio communication over the air interface. NG-RAN 154 may include: one or more gNBs, shown as gNB 160A and gNB 160B (collectively gNB 160); and / or one or more ng-eNBs, shown as ng-eNB 162A and ng-eNB 162B (collectively ng-eNB 162). The gNB 160 and ng-eNB 162 can be more generally referred to as base stations. The gNB 160 and ng-eNB 162 may include one or more sets of antennas for communicating with UE 156 over the air interface. For example, one or more of the gNBs in gNB 160 and / or one or more of the ng-eNBs in ng-eNB 162 may include three sets of antennas to control three cells (or sectors) respectively. The cells of gNB 160 and ng-eNB 162 can together provide radio coverage over a wide geographical area to support UE mobility for UE 156.

[0070] As Figure 1BAs shown, gNB 160 and / or ng-eNB 162 can be connected to 5G-CN 152 via the NG interface and to other base stations via the Xn interface. The NG and Xn interfaces can be established using direct physical connections and / or indirect connections via an underlying transport network, such as an Internet Protocol (IP) transport network. gNB 160 and / or ng-eNB 162 can be connected to UE 156 via the Uu interface. For example, as Figure 1B shown, gNB 160A can be connected to UE156A via the Uu interface. The NG, Xn, and Uu interfaces are associated with protocol stacks. The protocol stacks associated with the interfaces can be used by Figure 1B the network elements in to exchange data and signaling messages and can include two planes: a user plane and a control plane. The user plane can handle data of interest to the user. The control plane can handle signaling messages of interest to the network elements.

[0071] gNB 160 and / or ng-eNB 162 can be connected to one or more AMF / UPF functions of 5G-CN 152, such as AMF / UPF 158, via one or more NG interfaces. For example, gNB 160A can be connected to UPF 158B of AMF / UPF 158 via the NG user plane (NG-U) interface. The NG-U interface can provide the delivery (e.g., non-guaranteed delivery) of user plane PDUs between gNB 160A and UPF 158B. gNB 160A can be connected to AMF 158A via the NG control plane (NG-C) interface. The NG-C interface can provide, for example, NG interface management, UE context management, UE mobility management, delivery of NAS messages, paging, PDU session management, and configuration delivery and / or warning message transmission.

[0072] gNB 160 can provide NR user plane and control plane protocol termination to UE 156 via the Uu interface. For example, gNB 160A can provide NR user plane and control plane protocol termination to UE 156A via the Uu interface associated with a first protocol stack. ng-eNB 162 can provide evolved UMTS terrestrial radio access (E-UTRA) user plane and control plane protocol termination to UE 156 via the Uu interface, where E-UTRA refers to the 3GPP 4G radio access technology. For example, ng-eNB 162B can provide E-UTRA user plane and control plane protocol termination to UE 156B via the Uu interface associated with a second protocol stack.

[0073] 5G-CN 152 is described as being configured to handle NR and 4G radio access. A person of ordinary skill in the art will understand that NR has the possibility of connecting to a 4G core network in a mode referred to as "non-standalone operation". In non-standalone operation, the 4G core network is used to provide (or at least support) control plane functions (e.g., initial access, mobility, and paging). Although Figure 1B only one AMF / UPF 158 is shown, a gNB or ng-eNB can be connected to multiple AMF / UPF nodes to provide redundancy and / or load sharing across the multiple AMF / UPF nodes.

[0074] As discussed, Figure 1B the interfaces between the network elements in (e.g., the Uu, Xn, and NG interfaces) can be associated with the protocol stacks used by the network elements to exchange data and signaling messages. The protocol stack can include two planes: the user plane and the control plane. The user plane can handle data of interest to the user, while the control plane can handle signaling messages of interest to the network elements.

[0075] Figure 2A and Figure 2B show examples of the NR user plane and NR control plane protocol stacks for the Uu interface located between the UE 210 and the gNB 220, respectively. Figure 2A and Figure 2B The protocol stacks shown in can be the same as or similar to those for the Uu interface between, for example, Figure 1B the UE156A and the gNB 160A shown in.

[0076] Figure 2A shows an NR user plane protocol stack including five layers implemented in the UE 210 and the gNB 220. At the bottom of the protocol stack, the physical layers (PHY) 211 and 221 can provide transport services to the higher layers of the protocol stack and can correspond to layer 1 of the Open Systems Interconnection (OSI) model. The next four protocols above the PHY 211 and 221 include the media access control layers (MAC) 212 and 222, the radio link control layers (RLC) 213 and 223, the packet data convergence protocol layers (PDCP) 214 and 224, and the service data application protocol layers (SDAP) 215 and 225. These four protocols can together constitute layer 2 or the data link layer of the OSI model.

[0077] Figure 3 shows an example of the services provided between the protocol layers of the NR user plane protocol stack. From Figure 2A and Figure 3Starting from the top, SDAP 215 and 225 can perform QoS flow processing. UE 210 can receive services through a PDU session, which can be a logical connection between UE 210 and the DN. A PDU session can have one or more QoS flows. The UPF in the CN (e.g., UPF 158B) can map IP packets to the one or more QoS flows of the PDU session based on QoS requirements (e.g., in terms of latency, data rate, and / or error rate). SDAP 215 and 225 can perform mapping / demapping between the one or more QoS flows and one or more data radio bearers. The mapping / demapping between the QoS flow and the data radio bearer can be determined by SDAP 225 at gNB 220. SDAP 215 at UE 210 can learn the mapping between the QoS flow and the data radio bearer through reflective mapping or control signaling received from gNB 220. For reflective mapping, SDAP 225 at gNB 220 can mark downlink packets with a QoS flow indicator (QFI), which can be observed by SDAP 215 at UE 210 to determine the mapping / demapping between the QoS flow and the data radio bearer.

[0078] PDCP 214 and 224 can perform header compression / decompression to reduce the amount of data that needs to be transmitted over the air interface, can perform encryption / decryption to prevent unauthorized decoding of data transmitted over the air interface, and can perform integrity protection to ensure that control messages originate from the expected source. PDCP 214 and 224 can perform retransmission of undelivered packets, in-order delivery and reordering of packets, and removal of packets that are repeatedly received due to, for example, handover within the gNB. PDCP 214 and 224 can perform packet duplication to increase the likelihood of a packet being received, and remove any duplicate packets at the receiver. Packet duplication can be applicable to services that require high reliability.

[0079] Although Figure 3 not shown in the figure, PDCP 214 and 224 can perform mapping / demapping between split radio bearers and RLC channels in a dual-connectivity scenario. Dual-connectivity is a technique that allows a UE to be connected to two cells or more generally to two cell groups: a master cell group (MCG) and a secondary cell group (SCG). A split bearer is a split bearer when a single radio bearer (such as one of the radio bearers provided by PDCP 214 and 224 as a service to SDAP 215 and 225) is handled by cell groups in a dual-connectivity. PDCP 214 and 224 can map / demap split radio bearers between RLC channels belonging to cell groups.

[0080] RLC 213 and 223 can perform segmentation, retransmission via automatic repeat request (ARQ), and removal of duplicate data units received from MAC 212 and 222, respectively. RLC 213 and 223 can support three transfer modes: transparent mode (TM); unacknowledged mode (UM); and acknowledged mode (AM). Based on the transfer mode in which the RLC is operating, the RLC can perform one or more of the functions. RLC configuration can be per logical channel, independent of the parameter set and / or transmission time interval (TTI) duration. As Figure 3 shown, RLC 213 and 223 can provide RLC channels as services to PDCP 214 and 224, respectively.

[0081] MAC 212 and 222 can perform multiplexing / demultiplexing of logical channels and / or mapping between logical channels and transport channels. Multiplexing / demultiplexing can include: multiplexing data units belonging to the one or more logical channels into / demultiplexing the data units from transport blocks (TBs) delivered to / from PHY 211 and 221. MAC 222 can be configured to perform scheduling, scheduling information reporting, and priority handling between UEs by means of dynamic scheduling. Scheduling can be performed in gNB 220 (at MAC 222) for both downlink and uplink. MAC 212 and 222 can be configured to perform error correction via hybrid automatic repeat request (HARQ) (e.g., one HARQ entity per carrier in the case of carrier aggregation (CA)), priority handling between logical channels of UE 210 by means of logical channel prioritization, and / or padding. MAC 212 and 222 can support one or more parameter sets and / or transmission timing. In one example, mapping restrictions in logical channel prioritization can control which parameter set and / or transmission timing a logical channel can use. As Figure 3 shown, MAC 212 and 222 can provide logical channels as services to RLC 213 and 223.

[0082] PHY 211 and 221 can perform mapping of transport channels to physical channels and digital and analog signal processing functions for transmitting and receiving information over the air interface. These digital and analog signal processing functions can include, for example, encoding / decoding and modulation / demodulation. PHY 211 and 221 can perform multi-antenna mapping. As Figure 3 shown, PHY 211 and 221 can provide one or more transport channels as services to MAC 212 and 222.

[0083] Figure 4A Shows an example downlink data flow through the NR user plane protocol stack. Figure 4Ashows the downlink data flow of three IP packets (n, n+1, and m) flowing through the NR user plane protocol stack to generate two transport blocks (TBs) at the gNB 220. The uplink data flow flowing through the NR user plane protocol stack can be similar to the Figure 4A depicted downlink data flow.

[0084] Figure 4A The downlink data flow of Figure 4A starts when the SDAP 225 receives three IP packets from one or more QoS flows and maps the three packets to radio bearers. In Figure 4A , the SDAP 225 maps IP packets n and n+1 to the first radio bearer 402, and maps IP packet m to the second radio bearer 404. An SDAP header (marked as "H" in Figure 4A ) is added to the IP packets. A data unit from / to a higher protocol layer is called a service data unit (SDU) of a lower protocol layer, and a data unit to / from a lower protocol layer is called a protocol data unit (PDU) of a higher protocol layer. As shown in Figure 4A , the data unit from the SDAP 225 is the SDU of the lower protocol layer PDCP 224 and the PDU of the SDAP 225.

[0085] Figure 4A The remaining protocol layers in Figure 4A can perform their associated functions (e.g., regarding Figure 3 ), add corresponding headers, and forward their respective outputs to the next lower layer. For example, the PDCP 224 can perform IP header compression and encryption and forward its output to the RLC 223. The RLC 223 can optionally perform segmentation (e.g., as shown for IP packet m in Figure 4A ) and forward its output to the MAC 222. The MAC 222 can multiplex a number of RLC PDUs and can attach a MAC sub-header to the RLC PDUs to form a transport block. In NR, the MAC sub-header can be distributed throughout the MAC PDU, as shown in Figure 4A . In LTE, the MAC sub-header can be entirely at the start of the MAC PDU. The NR MAC PDU structure can reduce processing time and associated latency because the MAC PDU sub-header can be calculated before assembling the complete MAC PDU.

[0086] Figure 4BShows an example format of a MAC sub-header in a MAC PDU. The MAC sub-header includes: an SDU length field for indicating the length (e.g., in bytes) of the MAC SDU corresponding to the MAC sub-header; a logical channel identifier (LCID) field for identifying the logical channel from which the MAC SDU originated to assist in the demultiplexing process; a flag (F) for indicating the size of the SDU length field; and a reserved bit (R) field for future use.

[0087] Figure 4B Further shows MAC control elements (CEs) inserted into the MAC PDU by the MAC (such as MAC 223 or MAC 222). For example, Figure 4B Shows two MAC CEs inserted into the MAC PDU. The MAC CEs can be inserted at the beginning of the downlink transmission of the MAC PDU (as Figure 4B shown) and at the end of the uplink transmission of the MAC PDU. The MAC CEs can be used for in-band control signaling. Example MAC CEs include: scheduling-related MAC CEs such as buffer status reports and power headroom reports; activation / deactivation MAC CEs such as those for PDCP duplicate detection, channel state information (CSI) reporting, sounding reference signal (SRS) transmission, and activation / deactivation of previously configured components; discontinuous reception (DRX)-related MAC CEs; timing advance MAC CEs; and random access-related MAC CEs. A MAC sub-header having a format similar to the format described for the MAC SDU can exist before the MAC CE, and the MAC CE can be identified with a reserved value in the LCID field indicating the type of control information included in the MAC CE.

[0088] Before describing the NR control plane protocol stack, first describe the logical channels, transport channels, and physical channels and the mapping between the channel types. One or more of these channels can be used to perform functions associated with the NR control plane protocol stack described later below.

[0089] Figure 5A and Figure 5BThe mapping between logical channels, transport channels, and physical channels is shown separately for the downlink and the uplink. Information transfer occurs through channels between the RLC, MAC, and PHY of the NR protocol stack. Logical channels can be used between the RLC and the MAC and can be classified as control channels that carry control and configuration information in the NR control plane or as traffic channels that carry data in the NR user plane. Logical channels can be classified as dedicated logical channels dedicated to a specific UE or as common logical channels that can be used by more than one UE. Logical channels can also be defined by the type of information they carry. The set of logical channels defined by NR includes, for example:

[0090] - Paging Control Channel (PCCH), which is used to carry paging messages for paging UEs whose location is unknown to the network at the cell level;

[0091] - Broadcast Control Channel (BCCH), which is used to carry system information messages in the form of a Master Information Block (MIB) and several System Information Blocks (SIBs), where the system information messages can be used by the UE to obtain information on how the cell is configured and how to operate within the cell;

[0092] - Common Control Channel (CCCH), which is used to carry control messages as well as random access;

[0093] - Dedicated Control Channel (DCCH), which is used to carry control messages to a specific UE / carry control messages from a specific UE to configure the UE; and

[0094] - Dedicated Traffic Channel (DTCH), which is used to carry user data to a specific UE / carry user data from a specific UE.

[0095] Transport channels are used between the MAC layer and the PHY layer and can be defined by how the information they carry is transmitted over the air interface. The set of transport channels defined by NR includes, for example:

[0096] - Paging Channel (PCH), which is used to carry paging messages originating from the PCCH;

[0097] - Broadcast Channel (BCH), which is used to carry the MIB from the BCCH;

[0098] - Downlink Shared Channel (DL-SCH), which is used to carry downlink data and signaling messages, including SIBs from the BCCH;

[0099] - Uplink Shared Channel (UL-SCH), which is used to carry uplink data and signaling messages; and

[0100] - Random Access Channel (RACH), which is used to allow the UE to access the network without any prior scheduling.

[0101] The PHY can use physical channels to transfer information between the processing levels of the PHY. A physical channel can have a set of associated time-frequency resources for carrying information of one or more transport channels. The PHY can generate control information to support the low-level operations of the PHY and provide the control information to the lower levels of the PHY via physical control channels (referred to as L1 / L2 control channels). The set of physical channels and physical control channels defined by NR includes, for example:

[0102] - Physical Broadcast Channel (PBCH), which is used to carry the Master Information Block (MIB) from the BCH;

[0103] - Physical Downlink Shared Channel (PDSCH), which is used to carry downlink data and signaling messages from the DL-SCH and paging messages from the PCH;

[0104] - Physical Downlink Control Channel (PDCCH), which is used to carry Downlink Control Information (DCI), and the downlink control information can include downlink scheduling commands, uplink scheduling grants, and uplink power control commands;

[0105] - Physical Uplink Shared Channel (PUSCH), which is used to carry uplink data and signaling messages from the UL-SCH and, in some cases, carry uplink control information (UCI) as described below;

[0106] - Physical Uplink Control Channel (PUCCH), which is used to carry UCI, and the UCI can include HARQ acknowledgments, Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), and Scheduling Request (SR); and

[0107] - Physical Random Access Channel (PRACH), which is used for random access.

[0108] Similar to physical control channels, the physical layer generates physical signals to support the low-level operations of the physical layer. As shown in Figure 5A and Figure 5B , the physical layer signals defined by NR include: Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), Channel State Information Reference Signal (CSI-RS), Demodulation Reference Signal (DMRS), Sounding Reference Signal (SRS), and Phase Tracking Reference Signal (PT-RS). These physical layer signals will be described in more detail below.

[0109] Figure 2B Shows an example NR control plane protocol stack. AsFigure 2B As shown, the NR control plane protocol stack may use the same / similar first four protocol layers as the example NR user plane protocol stack. These four protocol layers include PHY 211 and 221, MAC 212 and 222, RLC 213 and 223, and PDCP 214 and 224. Instead of having SDAP 215 and 225 at the top of the stack as in the NR user plane protocol stack, the NR control plane protocol stack has radio resource control (RRC) 216 and 226 and NAS protocol 217 and 237 at the top of the NR control plane protocol stack.

[0110] NAS protocol 217 and 237 may provide control plane functions between UE 210 and AMF 230 (e.g., AMF 158A) or more generally between UE 210 and the CN. NAS protocol 217 and 237 may provide control plane functions between UE 210 and AMF 230 via signaling messages called NAS messages. There is no direct path through which NAS messages can be transmitted between UE 210 and AMF 230. The AS of the Uu and NG interfaces may be used to transmit NAS messages. NAS protocol 217 and 237 may provide control plane functions such as authentication, security, connection setup, mobility management, and session management.

[0111] RRC 216 and 226 may provide control plane functions between UE 210 and gNB 220 or more generally between UE 210 and the RAN. RRC 216 and 226 may provide control plane functions between UE 210 and gNB 220 via signaling messages called RRC messages. The RRC messages may be transmitted between UE 210 and the RAN using signaling radio bearers and the same / similar PDCP, RLC, MAC, and PHY protocol layers. The MAC may multiplex control plane and user plane data into the same transport block (TB). The control plane functions that RRC 216 and 226 may provide include: broadcasting of system information related to the AS and NAS; paging initiated by the CN or the RAN; establishment, maintenance, and release of the RRC connection between UE 210 and the RAN; security functions including key management; establishment, configuration, maintenance, and release of signaling radio bearers and data radio bearers; mobility functions; QoS management functions; UE measurement reporting and control of the reporting; detection of radio link failure (RLF) and recovery from radio link failure; and / or NAS message transfer. As part of establishing the RRC connection, RRC 216 and 226 may establish an RRC context, which may involve configuring parameters for communication between UE 210 and the RAN.

[0112] Figure 6is an example diagram showing the RRC state transition of a UE. The UE may be the same as or similar to the wireless device 106 depicted in Figure 1A and the UE 210 depicted in Figure 2A and Figure 2B or any other wireless device described in the present disclosure. As shown in Figure 6 , the UE may be in at least one of three RRC states: RRC connected 602 (e.g., RRC_CONNECTED), RRC idle 604 (e.g., RRC_IDLE), and RRC inactive 606 (e.g., RRC_INACTIVE).

[0113] In RRC connected 602, the UE has an established RRC context and may have at least one RRC connection with a base station. The base station may be similar to one of the following: Figure 1A the one or more base stations included in the RAN 104 depicted in Figure 1B one of the gNB 160 or ng-eNB 162 depicted in Figure 2A and Figure 2B the gNB220 depicted in

[0114] or any other base station described in the present disclosure. The base station connected to the UE may have an RRC context for the UE. The RRC context, referred to as the UE context, may contain parameters for communication between the UE and the base station. These parameters may include, for example: one or more AS contexts; one or more radio link configuration parameters; bearer configuration information (e.g., related to data radio bearers, signaling radio bearers, logical channels, QoS flows, and / or PDU sessions); security information; and / or PHY, MAC, RLC, PDCP, and / or SDAP layer configuration information. When in RRC connected 602, the mobility of the UE may be managed by the RAN (e.g., RAN 104 or NG-RAN 154). The UE may measure the signal levels (e.g., reference signal levels) from the serving cell and neighboring cells and report these measurements to the base station currently serving the UE. The serving base station of the UE may request a handover to a cell of one of the neighboring base stations based on the reported measurements. The RRC state may transition from RRC connected 602 to RRC idle 604 through the connection release procedure 608 or to RRC inactive 606 through the connection deactivation procedure 610.

[0114] In RRC idle state 604, an RRC context may not be established for the UE. In RRC idle state 604, the UE may not have an RRC connection with the base station. When in RRC idle state 604, the UE may be in a sleep state most of the time (e.g., to save battery power). The UE may wake up periodically (e.g., once per discontinuous reception cycle) to monitor paging messages from the RAN. The mobility of the UE may be managed by the UE through a procedure called cell reselection. The RRC state may be transitioned from RRC idle state 604 to RRC connected state 602 through a connection establishment procedure 612, which may involve a random access procedure, as discussed in more detail below.

[0115] In RRC inactive state 606, the previously established RRC context is maintained in both the UE and the base station. This allows for a quick transition to RRC connected state 602 with reduced signaling overhead compared to the transition from RRC idle state 604 to RRC connected state 602. When in RRC inactive state 606, the UE may be in a sleep state, and the mobility of the UE may be managed by the UE through cell reselection. The RRC state may be transitioned from RRC inactive state 606 to RRC connected state 602 through a connection resume procedure 614, or to RRC idle state 604 through a connection release procedure 616, which may be the same as or similar to connection release procedure 608.

[0116] The RRC state may be associated with a mobility management mechanism. In RRC idle state 604 and RRC inactive state 606, the mobility is managed by the UE through cell reselection. The purpose of mobility management in RRC idle state 604 and RRC inactive state 606 is to allow the network to be able to notify the UE of events via paging messages without having to broadcast the paging messages across the entire mobile communication network. The mobility management mechanism used in RRC idle state 604 and RRC inactive state 606 may allow the network to track the UE at the cell group level, such that the paging messages can be broadcast on the cells within the cell group in which the UE is currently camped on rather than across the entire mobile communication network. The mobility management mechanisms for RRC idle state 604 and RRC inactive state 606 track the UE at the cell group level. These mobility management mechanisms may do so using different granularities of grouping. For example, there may be three levels of cell grouping granularity: individual cells; cells within a RAN area identified by a RAN area identifier (RAI); and cells within a group of RAN areas called a tracking area and identified by a tracking area identifier (TAI).

[0117] Tracking areas can be used to track UEs at the CN level. A CN (e.g., CN 102 or 5G-CN 152) can provide a list of TAIs associated with the UE's registered area to the UE. If the UE moves to a cell associated with a TAI that is not included in the list of TAIs associated with the UE's registered area through cell reselection, the UE can perform a registration update to the CN to allow the CN to update the UE's location and provide the UE with a new UE registered area.

[0118] RAN areas can be used to track UEs at the RAN level. For a UE in the RRC Inactive 606 state, a RAN notification area can be assigned to the UE. The RAN notification area can contain a list of one or more cell identities, RAI, or TAI. In one example, a base station can belong to one or more RAN notification areas. In one example, a cell can belong to one or more RAN notification areas. If the UE moves to a cell not included in the RAN notification area assigned to the UE through cell reselection, the UE can perform a notification area update to the RAN to update the UE's RAN notification area.

[0119] The base station that stores the RRC context for the UE or the UE's last serving base station can be referred to as the anchor base station. The anchor base station can maintain the RRC context for the UE at least during the period when the UE remains in the RAN notification area of the anchor base station and / or during the period when the UE remains in the RRC Inactive 606 state.

[0120] gNB, such as Figure 1B the gNB 160 in , can be divided into two parts: a central unit (gNB-CU) and one or more distributed units (gNB-DU). The gNB-CU can be coupled to one or more gNB-DUs using the F1 interface. The gNB-CU can include RRC, PDCP, and SDAP. The gNB-DU can include RLC, MAC, and PHY.

[0121] In NR, physical signals and physical channels (regarding Figure 5A and Figure 5Bcan be mapped onto an Orthogonal Frequency Division Multiplexing (OFDM) symbol. OFDM is a multi-carrier communication scheme that transmits data over F orthogonal sub-carriers (or tones). Before transmission, the data can be mapped onto a series of complex symbols called source symbols (e.g., M-Quadrature Amplitude Modulation (M-QAM) symbols or M-Phase Shift Keying (M-PSK) symbols), and divided into F parallel symbol streams. The F parallel symbol streams can be considered as if they were in the frequency domain and used as inputs to an Inverse Fast Fourier Transform (IFFT) block that transforms them into the time domain. The IFFT block can take F source symbols at a time (one source symbol from each of the F parallel symbol streams), and use each source symbol to modulate the amplitude and phase of one of the F sine basis functions corresponding to the F orthogonal sub-carriers. The output of the IFFT block can be F time-domain samples representing the sum of the F orthogonal sub-carriers. The F time-domain samples can form a single OFDM symbol. After some processing (e.g., addition of a cyclic prefix) and up-conversion, the OFDM symbol provided by the IFFT block can be transmitted over the air interface at the carrier frequency. The F parallel symbol streams can be scrambled using an FFT block before being processed by the IFFT block. This operation produces a Discrete Fourier Transform (DFT) precoded OFDM symbol and can be used by a UE in the uplink to reduce the Peak-to-Average Power Ratio (PAPR). The inverse processing of the OFDM symbol can be performed at the receiver using an FFT block to recover the data mapped onto the source symbols.

[0122] Figure 7 Fig. shows an example configuration of an NR frame into which OFDM symbols are grouped. The NR frame can be identified by a System Frame Number (SFN). The SFN can repeat with a period of 1024 frames. As shown, the duration of one NR frame can be 10 milliseconds (ms) and can include 10 sub-frames with a duration of 1 ms each. The sub-frames can be divided into time slots, which include, for example, 14 OFDM symbols per time slot.

[0123] The duration of a time slot can depend on the parameter set of the OFDM symbols used for the time slot. In NR, flexible parameter sets are supported to accommodate different cell deployments (e.g., cells with carrier frequencies below 1 GHz up to cells with carrier frequencies in the mmWave range). The parameter sets can be defined in terms of subcarrier spacing and cyclic prefix duration. For the parameter sets in NR, the subcarrier spacing can be scaled by a power of two from a baseline subcarrier spacing of 15 kHz, and the cyclic prefix duration can be scaled by a power of two from a baseline cyclic prefix duration of 4.7 microseconds. For example, NR defines parameter sets with the following subcarrier spacing / cyclic prefix duration combinations: 15 kHz / 4.7 microseconds; 30 kHz / 2.3 microseconds; 60 kHz / 1.2 microseconds; 120 kHz / 0.59 microseconds; and 240 kHz / 0.29 microseconds.

[0124] A time slot can have a fixed number of OFDM symbols (e.g., 14 OFDM symbols). Parameter sets with higher subcarrier spacing have shorter time slot durations and correspondingly more time slots per subframe. Figure 7 The transmission structure of the time slot duration and time slots per subframe related to the parameter set is shown (for ease of illustration, Figure 7 the parameter set with a subcarrier spacing of 240 kHz is not shown). The subframe in NR can be used as a time reference independent of the parameter set, while the time slot can be used as a unit for scheduling uplink and downlink transmissions. To support low latency, scheduling in NR can be decoupled from the time slot duration and start at any OFDM symbol and continue for as many symbols as required for transmission. These partial time slot transmissions can be referred to as mini-slot or sub-slot transmissions.

[0125] Figure 8 An example configuration of a time slot in the time and frequency domains of an NR carrier is shown. The time slot includes resource elements (REs) and resource blocks (RBs). The RE is the smallest physical resource in NR. The RE spans one OFDM symbol in the time domain by one subcarrier in the frequency domain, as Figure 8 shown. The RB spans twelve consecutive REs in the frequency domain, as Figure 8 shown. The NR carrier can be limited to a width of 275 RBs or 275×12 = 3300 subcarriers. If this limit is used, for subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, and 120 kHz, the NR carrier can be limited to 50 MHz, 100 MHz, 200 MHz, and 400 MHz respectively, where the 400 MHz bandwidth can be set based on a bandwidth limit of 400 MHz per carrier.

[0126] Figure 8Shows a single parameter set used across the entire bandwidth of an NR carrier. In other example configurations, multiple parameter sets can be supported on the same carrier.

[0127] NR can support wide carrier bandwidths (e.g., up to 400 MHz for a subcarrier spacing of 120 kHz). Not all UEs may be able to receive the full carrier bandwidth (e.g., due to hardware limitations). Also, in terms of UE power consumption, receiving the full carrier bandwidth may be prohibitive. In one example, to reduce power consumption and / or for other purposes, a UE can adapt the size of its receive bandwidth based on the traffic volume the UE is scheduled to receive. This is referred to as bandwidth adaptation.

[0128] NR defines a bandwidth part (BWP) to support UEs that cannot receive the full carrier bandwidth and to support bandwidth adaptation. In an example, a BWP can be defined by a subset of contiguous RBs on a carrier. A UE can be configured (e.g., via the RRC layer) with one or more downlink BWPs and one or more uplink BWPs per serving cell (e.g., up to four downlink BWPs and up to four uplink BWPs per serving cell). At a given time, one or more of the configured BWPs for a serving cell can be active. The one or more BWPs can be referred to as the active BWPs of the serving cell. When a serving cell is configured with a secondary uplink carrier, the serving cell can have one or more first active BWPs in the uplink carrier and one or more second active BWPs in the secondary uplink carrier.

[0129] For unpaired spectrum, if the downlink BWP index of a downlink BWP is the same as the uplink BWP index of an uplink BWP, the downlink BWP from the set of configured downlink BWPs can be linked to the uplink BWP from the set of configured uplink BWPs. For unpaired spectrum, a UE can expect the center frequency of the downlink BWP to be the same as the center frequency of the uplink BWP.

[0130] For a downlink BWP in the set of configured downlink BWPs on a primary cell (PCell), the base station can configure a UE with one or more control resource sets (CORESETs) for at least one search space. A search space is a set of positions in the time and frequency domain where a UE can look for control information. The search space can be a UE-specific search space or a common search space (potentially usable by multiple UEs). For example, the base station can configure a common search space for a UE on the PCell or a primary-secondary cell (PSCell) in the active downlink BWP.

[0131] For the uplink BWPs in the set of configured uplink BWPs, the BS may configure one or more resource sets for the UE for one or more PUCCH transmissions. The UE may receive downlink reception (e.g., PDCCH or PDSCH) in the downlink BWP according to the set of configured parameters for the downlink BWP (e.g., subcarrier spacing and cyclic prefix duration). The UE may transmit uplink transmission (e.g., PUCCH or PUSCH) in the uplink BWP according to the set of configured parameters (e.g., subcarrier spacing and cyclic prefix length of the uplink BWP).

[0132] One or more BWP indicator fields may be provided in the downlink control information (DCI). The value of the BWP indicator field may indicate which BWP in the set of configured BWPs is the active downlink BWP for one or more downlink receptions. The value of the one or more BWP indicator fields may indicate the active uplink BWP for one or more uplink transmissions.

[0133] The base station may semi-statically configure a default downlink BWP for the UE within the set of configured downlink BWPs associated with the PCell. If the base station does not provide a default downlink BWP for the UE, the default downlink BWP may be the initial active downlink BWP. The UE may determine which BWP is the initial active downlink BWP based on the CORESET configuration obtained using the PBCH.

[0134] The base station may configure a BWP inactivity timer value for the UE for the PCell. The UE may start or restart the BWP inactivity timer at any appropriate time. For example, the UE may start or restart the BWP inactivity timer when: (a) the UE detects DCI indicating an active downlink BWP other than the default downlink BWP for paired spectrum operation; or (b) the UE detects DCI indicating an active downlink BWP or an active uplink BWP other than the default downlink BWP or the uplink BWP for unpaired spectrum operation. If the UE does not detect DCI within a time interval (e.g., 1 ms or 0.5 ms), the UE may run the BWP inactivity timer towards expiration (e.g., incrementing from zero to the BWP inactivity timer value, or decrementing from the BWP inactivity timer value to zero). When the BWP inactivity timer expires, the UE may switch from the active downlink BWP to the default downlink BWP.

[0135] In one example, the base station may configure the UE semi-statically using one or more BWPs. The UE may switch the active BWP from the first BWP to the second BWP in response to receiving DCI indicating that the second BWP is the active BWP and / or in response to the expiration of the BWP inactivity timer (e.g., in the case where the second BWP is the default BWP).

[0136] Downlink and uplink BWP switching (where BWP switching refers to switching from the current active BWP to a non-current active BWP) may be performed independently in paired spectrum. In unpaired spectrum, downlink and uplink BWP switching may be performed simultaneously. Switching may occur between the configured BWPs based on RRC signaling, DCI, the expiration of the BWP inactivity timer, and / or the initiation of random access.

[0137] Figure 9 An example of bandwidth adaptation using three configured BWPs of an NR carrier is shown. The UE configured with the three BWPs may switch from one BWP to another at a handover point. In Figure 9 the example shown, the BWPs include: BWP 902, which has a bandwidth of 40 MHz and a subcarrier spacing of 15 kHz; BWP 904, which has a bandwidth of 10 MHz and a subcarrier spacing of 15 kHz; and BWP 906, which has a bandwidth of 20 MHz and a subcarrier spacing of 60 kHz. BWP 902 may be the initial active BWP, and BWP 904 may be the default BWP. The UE may switch between the BWPs at the handover point. In Figure 9 the example, the UE may switch from BWP 902 to BWP 904 at handover point 908. The handover at handover point 908 may occur for any suitable reason, such as in response to the expiration of the BWP inactivity timer (indicating a handover to the default BWP) and / or in response to receiving DCI indicating that BWP 904 is the active BWP. The UE may switch from the active BWP 904 to BWP 906 at handover point 910 in response to receiving DCI indicating that BWP 906 is the active BWP. The UE may switch from the active BWP 906 to BWP 904 at handover point 912 in response to the expiration of the BWP inactivity timer and / or in response to receiving DCI indicating that BWP 904 is the active BWP. The UE may switch from the active BWP 904 to BWP 902 at handover point 914 in response to receiving DCI indicating that BWP 902 is the active BWP.

[0138] If the UE is configured with a secondary cell having a default downlink BWP and timer value in a set of configured downlink BWPs, the UE procedures for switching the BWP on the secondary cell can be the same / similar to those on the primary cell. For example, the UE can use these values of the secondary cell in the same / similar way as the UE would use the timer value and default downlink BWP of the primary cell.

[0139] To provide a higher data rate, carrier aggregation (CA) can be used to aggregate two or more carriers and transmit to / from the same UE simultaneously. The aggregated carriers in CA can be referred to as component carriers (CCs). When CA is used, there are multiple serving cells for the UE, one serving cell per CC. The CCs can have three configurations in the frequency domain.

[0140] Figure 10A Three CA configurations with two CCs are shown. In the in-band contiguous configuration 1002, the two CCs are aggregated in the same frequency band (band A) and are positioned directly adjacent to each other within the band. In the in-band non-contiguous configuration 1004, the two CCs are aggregated in the same frequency band (band A) and are separated by a certain gap in the band. In the inter-band configuration 1006, the two CCs are in different frequency bands (band A and band B).

[0141] In one example, up to 32 CCs can be aggregated. The aggregated CCs can have the same or different bandwidths, subcarrier spacings, and / or duplex schemes (TDD or FDD). The serving cells for the UE using CA can have downlink CCs. For FDD, one or more uplink CCs can optionally be configured for the serving cell. For example, when the UE has more data traffic in the downlink than in the uplink, the ability to aggregate more downlink carriers than uplink carriers can be useful.

[0142] When using CA, one of the aggregated cells in the aggregated cells for a UE can be referred to as a primary cell (PCell). The PCell can be the serving cell to which the UE is initially connected at RRC connection establishment, re - establishment, and / or handover. The PCell can provide NAS mobility information and security input to the UE. The UE can have different PCells. In the downlink, the carrier corresponding to the PCell can be referred to as the downlink primary CC (DL PCC). In the uplink, the carrier corresponding to the PCell can be referred to as the uplink primary CC (UL PCC). Other aggregated cells for the UE can be referred to as secondary cells (SCells). In one example, an SCell can be configured after the PCell is configured for the UE. For example, an SCell can be configured through an RRC connection re - configuration procedure. In the downlink, the carrier corresponding to the SCell can be referred to as the downlink secondary CC (DL SCC). In the uplink, the carrier corresponding to the SCell can be referred to as the uplink secondary CC (UL SCC).

[0143] The configured SCell for the UE can be activated and de - activated based on, for example, traffic and channel conditions. The de - activation of an SCell can mean stopping PDCCH and PDSCH reception on the SCell, and stopping PUSCH, SRS, and CQI transmission on the SCell. MAC CE regarding Figure 4B can be used to activate and de - activate the configured SCell. For example, the MAC CE can use a bitmap (e.g., one bit per SCell) to indicate which SCells (e.g., in a subset of the configured SCells) for the UE are activated or de - activated. The configured SCell can be de - activated in response to the expiration of an SCell de - activation timer (e.g., one SCell de - activation timer per SCell).

[0144] The downlink control information of a cell (such as scheduling assignment and scheduling grant) can be transmitted on the cell corresponding to the assignment and grant, which is called self - scheduling. The DCI of a cell can be transmitted on another cell, which is called cross - carrier scheduling. The uplink control information for the aggregated cells (e.g., HARQ acknowledgments and channel state feedback such as CQI, PMI, and / or RI) can be transmitted on the PUCCH of the PCell. For a large number of aggregated downlink CCs, the PUCCH of the PCell may become overloaded. The cell can be divided into multiple PUCCH groups.

[0145] Figure 10B An example showing how the aggregated cells can be configured into one or more PUCCH groups is shown. PUCCH group 1010 and PUCCH group 1050 can each include one or more downlink CCs. In Figure 10BIn the example, PUCCH group 1010 includes three downlink CCs: PCell 1011, SCell 1012, and SCell 1013. PUCCH group 1050 includes three downlink CCs in this example: PCell 1051, SCell 1052, and SCell 1053. One or more uplink CCs can be configured as PCell 1021, SCell 1022, and SCell 1023. One or more other uplink CCs can be configured as a primary SCell (PSCell) 1061, SCell 1062, and SCell 1063. Uplink control information (UCI) related to the downlink CCs of PUCCH group 1010 (shown as UCI 1031, UCI 1032, and UCI 1033) can be transmitted on the uplink of PCell 1021. Uplink control information (UCI) related to the downlink CCs of PUCCH group 1050 (shown as UCI 1071, UCI 1072, and UCI 1073) can be transmitted on the uplink of PSCell 1061. In one example, if Figure 10B the aggregated cells depicted in

[0146] are not divided into PUCCH group 1010 and PUCCH group 1050, a single uplink PCell transmits UCI related to the downlink CCs, and the PCell may become overloaded. By dividing the transmission of UCI between PCell 1021 and PSCell 1061, overload can be prevented.

[0147] In CA, the multi-carrier nature of the PHY can be exposed to the MAC. In one example, the HARQ entity can operate on the serving cell. Transmission blocks can be generated according to the assignment / grant of each serving cell. The transmission block and the potential HARQ retransmission of this transmission block can be mapped to the serving cell.

[0148] In the downlink, the base station may transmit one or more reference signals (RS) (e.g., unicast, multicast, and / or broadcast) to the UE (e.g., PSS, SSS, CSI-RS, DMRS, and / or PT-RS, as Figure 5A shown). In the uplink, the UE may transmit one or more RS to the base station (e.g., DMRS, PT-RS, and / or SRS, as Figure 5B shown). The PSS and SSS may be transmitted by the base station and used by the UE to synchronize the UE with the base station. The PSS and SSS may be provided in a synchronization signal (SS) / physical broadcast channel (PBCH) block including the PSS, SSS, and PBCH. The base station may periodically transmit bursts of SS / PBCH blocks.

[0149] Figure 11A An example of the structure and location of the SS / PBCH block is shown. A burst of SS / PBCH blocks may include one or more SS / PBCH blocks (e.g., 4 SS / PBCH blocks, as Figure 11A shown). The bursts may be transmitted periodically (e.g., every 2 frames or 20 ms). The bursts may be limited to a half-frame (e.g., the first half-frame with a duration of 5 ms). It should be understood that Figure 11A are examples, and these parameters (the number of SS / PBCH blocks per burst, the period of the bursts, the burst position within the frame) may be configured based on, for example: the carrier frequency of the cell in which the SS / PBCH blocks are transmitted; the numerology or subcarrier spacing of the cell; the configuration by the network (e.g., using RRC signaling); or any other suitable factor. In one example, the UE may assume the subcarrier spacing of the SS / PBCH blocks based on the carrier frequency being monitored, unless the radio network configures the UE to assume a different subcarrier spacing.

[0150] The SS / PBCH block may span one or more OFDM symbols in the time domain (e.g., 4 OFDM symbols, as Figure 11A shown in the example), and may span one or more subcarriers in the frequency domain (e.g., 240 consecutive subcarriers). The PSS, SSS, and PBCH may have a common center frequency. The PSS may be transmitted first and may span, for example, 1 OFDM symbol and 127 subcarriers. The SSS may be transmitted after the PSS (e.g., after two symbols) and may span 1 OFDM symbol and 127 subcarriers. The PBCH may be transmitted after the PSS (e.g., spanning the next 3 OFDM symbols) and may span 240 subcarriers.

[0151] The UE may not know the position of the SS / PBCH block in the time domain and the frequency domain (e.g., in the case where the UE is searching for a cell). To search for and select a cell, the UE may monitor the carrier of the PSS. For example, the UE may monitor the frequency position within the carrier. If the PSS is not detected after a certain duration (e.g., 20 ms), the UE may search for the PSS at different frequency positions within the carrier, as indicated by the synchronization raster. If the PSS is detected at a certain position in the time domain and the frequency domain, the UE may determine the positions of the SSS and the PBCH respectively based on the known structure of the SS / PBCH block. The SS / PBCH block may be a cell-defined SS block (CD-SSB). In one example, the primary cell may be associated with the CD-SSB. The CD-SSB may be located on the synchronization raster. In one example, cell selection / search and / or reselection may be based on the CD-SSB.

[0152] The SS / PBCH block may be used by the UE to determine one or more parameters of the cell. For example, the UE may determine the physical cell identifier (PCI) of the cell respectively based on the sequences of the PSS and the SSS. The UE may determine the position of the frame boundary of the cell based on the position of the SS / PBCH block. For example, the SS / PBCH block may indicate that it has been transmitted according to a transmission pattern, where the SS / PBCH block in the transmission pattern is a known distance from the frame boundary.

[0153] The PBCH may use QPSK modulation and may use forward error correction (FEC). The FEC may use polar coding. One or more symbols spanned by the PBCH may carry one or more DMRSs for demodulating the PBCH. The PBCH may include an indication of the current system frame number (SFN) of the cell and / or the SS / PBCH block timing index. These parameters may assist the UE in time synchronization with the base station. The PBCH may include a master information block (MIB) for providing one or more parameters to the UE. The MIB may be used by the UE to locate the remaining minimum system information (RMSI) associated with the cell. The RMSI may include system information block type 1 (SIB1). The SIB1 may contain the information required for the UE to access the cell. The UE may use one or more parameters of the MIB to monitor the PDCCH that may be used to schedule the PDSCH. The PDSCH may include the SIB1. The parameters provided in the MIB may be used to decode the SIB1. The PBCH may indicate the absence of the SIB1. Based on the PBCH indicating the absence of the SIB1, the UE may point to a frequency. The UE may search for the SS / PBCH block at the frequency pointed to by the UE.

[0154] The UE may assume that one or more SS / PBCH blocks transmitted using the same SS / PBCH block index are quasi-co-located (QCLed) (e.g., having the same / similar Doppler spread, Doppler shift, average gain, average delay, and / or spatial Rx parameters). The UE may not assume QCL for SS / PBCH block transmissions with different SS / PBCH block indices.

[0155] SS / PBCH blocks (e.g., those within a half-frame) may be transmitted in a spatial direction (e.g., using different beams spanning the coverage area of the cell). In one example, a first SS / PBCH block may be transmitted in a first spatial direction using a first beam, and a second SS / PBCH block may be transmitted in a second spatial direction using a second beam.

[0156] In one example, within the frequency range of a carrier, the base station may transmit multiple SS / PBCH blocks. In one example, the first PCI of the first SS / PBCH block among the multiple SS / PBCH blocks may be different from the second PCI of the second SS / PBCH block among the multiple SS / PBCH blocks. The PCI of SS / PBCH blocks transmitted at different frequency positions may be different or the same.

[0157] CSI-RS may be transmitted by the base station and used by the UE to obtain channel state information (CSI). The base station may use one or more CSI-RS to configure the UE for channel estimation or any other suitable purpose. The base station may use one or more of the same / similar CSI-RS to configure the UE. The UE may measure the one or more CSI-RS. The UE may estimate the downlink channel state and / or generate a CSI report based on the measurement of the one or more downlink CSI-RS. The UE may provide the CSI report to the base station. The base station may perform link adaptation using the feedback provided by the UE (e.g., the estimated downlink channel state).

[0158] The base station may semi-statically configure the UE using one or more CSI-RS resource sets. The CSI-RS resources may be associated with positions in the time domain and frequency domain and periodicity. The base station may selectively activate and / or deactivate the CSI-RS resources. The base station may indicate to the UE which CSI-RS resources in the CSI-RS resource set are activated and / or deactivated.

[0159] The base station may configure the UE to report CSI measurement values. The base station may configure the UE to provide CSI reports periodically, aperiodically, or semi-persistently. For periodic CSI reports, the UE may be configured with the timing and / or period of multiple CSI reports. For aperiodic CSI reports, the base station may request a CSI report. For example, the base station may command the UE to measure the configured CSI-RS resources and provide a CSI report related to the measurement values. For semi-persistent CSI reports, the base station may configure the UE to transmit periodically and selectively activate or deactivate the periodic report. The base station may configure the UE using CSI-RS resource sets and CSI reports using RRC signaling.

[0160] The CSI-RS configuration may include one or more parameters indicating, for example, up to 32 antenna ports. The UE may be configured to use the same OFDM symbol for the downlink CSI-RS and the control resource set (CORESET) when the downlink CSI-RS and the CORESET are spatially QCLed and the resource elements associated with the downlink CSI-RS are outside the physical resource blocks (PRBs) configured for the CORESET. The UE may be configured to use the same OFDM symbol for the downlink CSI-RS and the SS / PBCH block when the downlink CSI-RS and the SS / PBCH block are spatially QCLed and the resource elements associated with the downlink CSI-RS are outside the PRBs configured for the SS / PBCH block.

[0161] The downlink DMRS can be transmitted by the base station and used by the UE for channel estimation. For example, the downlink DMRS can be used for coherent demodulation of one or more downlink physical channels (e.g., PDSCH). The NR network can support one or more variable and / or configurable DMRS patterns for data demodulation. At least one downlink DMRS configuration can support the pre-loaded DMRS pattern. The pre-loaded DMRS can be mapped on one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). The base station can semi-statically configure the UE with the number of pre-loaded DMRS symbols (e.g., the maximum number) for the PDSCH. The DMRS configuration can support one or more DMRS ports. For example, for single-user MIMO, the DMRS configuration can support up to eight orthogonal downlink DMRS ports per UE. For multi-user MIMO, the DMRS configuration can support up to 4 orthogonal downlink DMRS ports per UE. The radio network can (e.g., at least for CP-OFDM) support a common DMRS structure for downlink and uplink, where the DMRS position, DMRS type, and / or scrambling sequence can be the same or different. The base station can transmit the downlink DMRS and the corresponding PDSCH using the same precoding matrix. The UE can use the one or more downlink DMRSs to perform coherent demodulation / channel estimation on the PDSCH.

[0162] In one example, a transmitter (e.g., a base station) can use a precoder matrix for a portion of the transmission bandwidth. For example, the transmitter can use a first precoder matrix for a first bandwidth and a second precoder matrix for a second bandwidth. The first precoder matrix and the second precoder matrix can be different based on the first bandwidth being different from the second bandwidth. The UE can assume the same precoding matrix is used throughout the set of PRBs. The set of PRBs can be represented as a precoding resource block group (PRG).

[0163] The PDSCH can contain one or more layers. The UE can assume that at least one symbol with DMRS exists on a layer among the one or more layers of the PDSCH. The higher layer can configure up to 3 DMRSs for the PDSCH.

[0164] The downlink PT-RS can be transmitted by the base station and used by the UE for phase noise compensation. The presence of the downlink PT-RS can depend on the RRC configuration. The presence and / or pattern of the downlink PT-RS can be configured on a UE-specific basis using a combination of RRC signaling and / or association with one or more parameters that can be indicated by DCI for other purposes (e.g., modulation and coding scheme (MCS)). When configured, the dynamic presence of the downlink PT-RS can be associated with one or more DCI parameters including at least the MCS. The NR network can support multiple PT-RS densities defined in the time and / or frequency domain. When present, the frequency domain density can be associated with at least one configuration of the scheduled bandwidth. The UE can employ the same precoding for the DMRS port and the PT-RS port. The number of PT-RS ports can be less than the number of DMRS ports in the scheduled resources. The downlink PT-RS can be restricted to the scheduled time / frequency duration of the UE. The downlink PT-RS can be transmitted on symbols to assist in phase tracking at the receiver.

[0165] The UE can transmit uplink DMRS to the base station for channel estimation. For example, the base station can use the uplink DMRS for coherent demodulation of one or more uplink physical channels. For example, the UE can transmit uplink DMRS with PUSCH and / or PUCCH. The uplink DM-RS can span a frequency range similar to the frequency range associated with the corresponding physical channel. The base station can configure the UE with one or more uplink DMRS configurations. At least one DMRS configuration can support the pre-loaded DMRS mode. The pre-loaded DMRS can be mapped on one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). One or more uplink DMRS can be configured to be transmitted at one or more symbols of PUSCH and / or PUCCH. The base station can semi-statically configure the UE with the number (e.g., maximum number) of pre-loaded DMRS symbols of PUSCH and / or PUCCH, and the UE can use the pre-loaded DMRS symbols to schedule single-symbol DMRS and / or double-symbol DMRS. The NR network can support (e.g., for cyclic prefix orthogonal frequency division multiplexing (CP-OFDM)) a common DMRS structure for downlink and uplink, where the DMRS position, DMRS pattern, and / or scrambling sequence of the DMRS can be the same or different.

[0166] The PUSCH can contain one or more layers, and the UE can transmit at least one symbol with DMRS on the layer(s) present in one or more layers of the PUSCH. In one example, the higher layer can configure up to three DMRS for the PUSCH.

[0167] Depending on the UE's RRC configuration, uplink PT-RS (which can be used by the base station for phase tracking and / or phase noise compensation) may or may not be present. The presence and / or pattern of the uplink PT-RS can be configured on a UE-specific basis through a combination of RRC signaling and / or one or more parameters that can be indicated by DCI for other purposes (e.g., modulation and coding scheme (MCS)). When configured, the dynamic presence of the uplink PT-RS can be associated with one or more DCI parameters including at least the MCS. The radio network may support multiple uplink PT-RS densities defined in the time / frequency domain. When present, the frequency-domain density can be associated with at least one configuration of the scheduled bandwidth. The UE may employ the same precoding for the DMRS port and the PT-RS port. The number of PT-RS ports may be less than the number of DMRS ports in the scheduled resources. For example, the uplink PT-RS may be restricted to the scheduled time / frequency duration of the UE.

[0168] The UE may transmit SRS to the base station for channel state estimation to support uplink channel-dependent scheduling and / or link adaptation. The SRS transmitted by the UE may allow the base station to estimate the uplink channel state at one or more frequencies. The scheduler at the base station may use the estimated uplink channel state to assign one or more resource blocks for uplink PUSCH transmission from the UE. The base station may configure the UE semi-statically with one or more SRS resource sets. For an SRS resource set, the base station may configure the UE with one or more SRS resources. The SRS resource set applicability may be configured by a higher layer (e.g., RRC) parameter. For example, when the higher layer parameter indicates beam management, the SRS resources in one or more SRS resource sets (e.g., having the same / similar time-domain behavior, being periodic, being aperiodic, etc.) may be transmitted at a certain time (e.g., simultaneously). The UE may transmit one or more SRS resources in the SRS resource set. The NR network may support aperiodic, periodic, and / or semi-persistent SRS transmission. The UE may transmit SRS resources based on one or more trigger types, where the one or more trigger types may include higher layer signaling (e.g., RRC) and / or one or more DCI formats. In one example, at least one DCI format may be employed for the UE to select at least one configured SRS resource set from one or more configured SRS resource sets. SRS trigger type 0 may refer to SRS triggered based on higher layer signaling. SRS trigger type 1 may refer to SRS triggered based on one or more DCI formats. In one example, when PUSCH and SRS are transmitted in the same time slot, the UE may be configured to transmit SRS after the transmission of PUSCH and the corresponding uplink DMRS.

[0169] The base station can semi-statically configure the UE using one or more SRS configuration parameters indicating at least one of the following: SRS resource configuration identifier; number of SRS ports; time-domain behavior of the SRS resource configuration (e.g., indication of periodic, semi-persistent, or aperiodic SRS); slot, mini-slot, and / or sub-frame level period; slot of the periodic and / or aperiodic SRS resource; number of OFDM symbols in the SRS resource; starting OFDM symbol of the SRS resource; SRS bandwidth; hopping bandwidth; cyclic shift; and / or SRS sequence ID.

[0170] An antenna port is defined such that a symbol on the antenna port through which it is conveyed can be inferred from the channel through which another symbol on the same antenna port is conveyed. If the first symbol and the second symbol are transmitted on the same antenna port, the receiver can infer the channel for conveying the second symbol on the antenna port from the channel for conveying the first symbol on the antenna port (e.g., fading gain, multipath delay, etc.). If one or more large-scale properties of the channel through which the first symbol on the first antenna port is conveyed can be inferred from the channel through which the second symbol on the second antenna port is conveyed, the first antenna port and the second antenna port can be referred to as quasi-co-located (QCLed). The one or more large-scale properties can include at least one of the following: delay spread; Doppler spread; Doppler shift; average gain; average delay; and / or spatial receive (Rx) parameters.

[0171] Channels using beamforming require beam management. Beam management can include beam measurement, beam selection, and beam indication. A beam can be associated with one or more reference signals. For example, a beam can be identified by one or more beamformed reference signals. The UE can perform downlink beam measurements based on downlink reference signals (e.g., channel state information reference signal (CSI-RS)) and generate a beam measurement report. After establishing an RRC connection with the base station, the UE can perform a downlink beam measurement procedure.

[0172] Figure 11B An example of a channel state information reference signal (CSI-RS) mapped in the time and frequency domains is shown. Figure 11BThe square shown in [Figure] can represent resource blocks (RBs) within the bandwidth of a cell. The base station may transmit one or more RRC messages containing CSI-RS resource configuration parameters indicating one or more CSI-RSs. One or more of the following parameters may be configured for the CSI-RS resource configuration by higher layer signaling (e.g., RRC and / or MAC signaling): CSI-RS resource configuration identity, number of CSI-RS ports, CSI-RS configuration (e.g., symbol and resource element (RE) positions in a subframe), CSI-RS subframe configuration (e.g., subframe position, offset, and periodicity in a radio frame), CSI-RS power parameters, CSI-RS sequence parameters, code division multiplexing (CDM) type parameters, frequency density, transmission comb, quasi co-location (QCL) parameters (e.g., QCL-scrambling identity, crs-portscount, mbsfn-subframeconfiglist, csi-rs-configZPid, qcl-csi-rs-configNZPid), and / or other radio resource parameters.

[0173] Figure 11B The three beams shown can be configured for a UE in a UE-specific configuration. Figure 11B Three beams (beam #1, beam #2, and beam #3) are shown, and more or fewer beams may be configured. CSI-RS1101 may be assigned to beam #1, which may be transmitted in one or more subcarriers in the RB of the first symbol. CSI-RS1102 may be assigned to beam #2, which may be transmitted in one or more subcarriers in the RB of the second symbol. CSI-RS1103 may be assigned to beam #3, which may be transmitted in one or more subcarriers in the RB of the third symbol. By using frequency division multiplexing (FDM), the base station may use other subcarriers in the same RB (e.g., those not used for transmitting CSI-RS1101) to transmit another CSI-RS associated with a beam of another UE. By using time division multiplexing (TDM), the beams for a UE may be configured such that the beams for a UE use symbols from the beams of other UEs.

[0174] CSI-RS, as Figure 11BThose shown in (e.g., CSI-RS 1101, 1102, 1103) can be transmitted by the base station and used by the UE for one or more measurements. For example, the UE can measure the reference signal received power (RSRP) of the configured CSI-RS resource. The base station can configure the UE using a reporting configuration, and the UE can report the RSRP measurement to the network (e.g., via one or more base stations) based on the reporting configuration. In an example, the base station can determine one or more transmission configuration indication (TCI) states including a plurality of reference signals based on the reported measurement results. In an example, the base station can indicate one or more TCI states to the UE (e.g., via RRC signaling, MAC CE, and / or DCI). The UE can receive a downlink transmission with a receive (Rx) beam determined based on the one or more TCI states. In an example, the UE may or may not have beam correspondence capabilities. If the UE has beam correspondence capabilities, the UE can determine the spatial domain filter of the transmission (Tx) beam based on the spatial domain filter of the corresponding Rx beam. If the UE does not have beam correspondence capabilities, the UE can perform an uplink beam selection procedure to determine the spatial domain filter of the Tx beam. The UE can perform the uplink beam selection procedure based on one or more sounding reference signal (SRS) resources configured by the base station for the UE. The base station can select and indicate the uplink beam of the UE based on the measurement of one or more SRS resources transmitted by the UE.

[0175] In a beam management procedure, the UE can assess (e.g., measure) the channel quality of one or more beam pairs, the beam pairs including the transmission beam transmitted by the base station and the receive beam received by the UE. Based on the assessment, the UE can transmit a beam measurement report indicating one or more beam pair quality parameters, the one or more beam pair quality parameters including, for example, one or more beam identifiers (e.g., beam index, reference signal index, etc.), RSRP, precoding matrix indicator (PMI), channel quality indicator (CQI), and / or rank indicator (RI).

[0176] Figure 12AIllustrates examples of three downlink beam management procedures: P1, P2, and P3. Procedure P1 can enable UE measurements of the transmission (Tx) beam of a transmission reception point (TRP) (or multiple TRPs), for example, to support the selection of one or more base station Tx beams and / or UE Rx beams (shown as ellipses in the top and bottom rows of P1 respectively). Beamforming at the TRP can include Tx beam sweeping for a set of beams (shown as ellipses rotating in the counterclockwise direction indicated by the dashed arrow in the top rows of P1 and P2). Beamforming at the UE can include Rx beam sweeping for a set of beams (shown as ellipses rotating in the clockwise direction indicated by the dashed arrow in the bottom rows of P1 and P3). Procedure P2 can be used to enable UE measurements of the Tx beam of the TRP (shown as an ellipse rotating in the counterclockwise direction indicated by the dashed arrow in the top row of P2). The UE and / or the base station can perform Procedure P2 using a smaller set of beams or beams that are narrower than the set of beams used in Procedure P1. This can be referred to as beam refinement. The UE can perform Procedure P3 for Rx beam determination by using the same Tx beam at the base station and sweeping the Rx beam at the UE.

[0177] Figure 12B Illustrates examples of three uplink beam management procedures: U1, U2, and U3. Procedure U1 can be used to enable the base station to perform measurements on the Tx beam of the UE, for example, to support the selection of one or more UE Tx beams and / or base station Rx beams (shown as ellipses in the top and bottom rows of U1 respectively). Beamforming at the UE can include, for example, Tx beam sweeping from a set of beams (shown as ellipses rotating in the clockwise direction indicated by the dashed arrow in the bottom rows of U1 and U3). Beamforming at the base station can include, for example, Rx beam sweeping from a set of beams (shown as ellipses rotating in the counterclockwise direction indicated by the dashed arrow in the top rows of U1 and U2). When the UE uses a fixed Tx beam, Procedure U2 can be used to enable the base station to adjust its Rx beam. The UE and / or the base station can perform Procedure U2 using a smaller set of beams or beams that are narrower than the set of beams used in Procedure P1. This can be referred to as beam refinement. The UE can perform Procedure U3 to adjust its Tx beam when the base station uses a fixed Rx beam.

[0178] The UE can initiate a Beam Failure Recovery (BFR) procedure based on detecting beam failure. The UE can transmit a BFR request (e.g., preamble, UCI, SR, MAC CE, etc.) based on the initiation of the BFR procedure. The UE can detect beam failure based on the determination that the quality of the beam pair link of the associated control channel is not satisfactory (e.g., having an error rate higher than the error rate threshold, a received signal power lower than the received signal power threshold, expiration of a timer, etc.).

[0179] The UE can measure the quality of the beam pair link using one or more reference signals (RS), the one or more reference signals including one or more SS / PBCH blocks, one or more CSI-RS resources, and / or one or more demodulation reference signals (DMRS). The quality of the beam pair link can be based on one or more of the following: block error rate (BLER), RSRP value, signal-to-interference-plus-noise ratio (SINR) value, reference signal received quality (RSRQ) value, and / or CSI value measured on the RS resource. The base station can indicate that the RS resource is quasi-co-located (QCLed) with one or more DM-RS of a channel (e.g., control channel, shared data channel, etc.). The one or more DMRS of the RS resource and the channel can be QCLed when the channel characteristics (e.g., Doppler shift, Doppler spread, average delay, delay spread, spatial Rx parameters, fading, etc.) from the transmission via the RS resource to the UE are similar or identical to the channel characteristics from the transmission via the channel to the UE.

[0180] The network (e.g., gNB and / or ng-eNB of the network) and / or the UE can initiate a random access procedure. A UE in the RRC_IDLE state and / or RRC_INACTIVE state can initiate a random access procedure to request connection setup to the network. The UE can initiate a random access procedure from the RRC_CONNECTED state. The UE can initiate a random access procedure to request uplink resources (e.g., uplink transmission for SR when there are no available PUCCH resources) and / or obtain uplink timing (e.g., when the uplink synchronization state is not synchronized). The UE can initiate a random access procedure to request one or more system information blocks (SIB) (e.g., other system information such as SIB2, SIB3, etc.). The UE can initiate a random access procedure for a beam failure recovery request. The network can initiate a random access procedure for handover and / or for establishing time alignment for SCell addition.

[0181] Figure 13A A four-step contention-based random access procedure is shown. Before initiating the procedure, the base station can transmit a configuration message 1310 to the UE. Figure 13AThe program shown includes the transmission of four messages: Msg 1 1311, Msg 2 1312, Msg 3 1313, and Msg 4 1314. Msg 1 1311 may include and / or be referred to as a preamble (or random access preamble). Msg 2 1312 may include and / or be referred to as a random access response (RAR).

[0182] The configuration message 1310 may be transmitted using, for example, one or more RRC messages. The one or more RRC messages may indicate to the UE one or more random access channel (RACH) parameters. The one or more RACH parameters may include at least one of the following: general parameters for one or more random access procedures (e.g., RACH-configGeneral); cell-specific parameters (e.g., RACH-ConfigCommon); and / or dedicated parameters (e.g., RACH-configDedicated). The base station may broadcast or multicast the one or more RRC messages to one or more UEs. The one or more RRC messages may be UE-specific (e.g., dedicated RRC messages transmitted to the UE in the RRC_CONNECTED state and / or the RRC_INACTIVE state). The UE may determine the time-frequency resources and / or uplink transmission power for transmitting Msg 1 1311 and / or Msg 3 1313 based on the one or more RACH parameters. Based on the one or more RACH parameters, the UE may determine the reception timing and downlink channel for receiving Msg 2 1312 and Msg 4 1314.

[0183] The one or more RACH parameters provided in the configuration message 1310 may indicate one or more physical RACH (PRACH) opportunities available for transmitting Msg 1 1311. The one or more PRACH opportunities may be predefined. The one or more RACH parameters may indicate one or more available sets of one or more PRACH opportunities (e.g., prach-ConfigIndex). The one or more RACH parameters may indicate the association between: (a) one or more PRACH opportunities, and (b) one or more reference signals. The one or more RACH parameters may indicate the association between: (a) one or more preambles, and (b) one or more reference signals. The one or more reference signals may be SS / PBCH blocks and / or CSI-RS. For example, the one or more RACH parameters may indicate the number of SS / PBCH blocks mapped to a PRACH opportunity and / or the number of preambles mapped to an SS / PBCH block.

[0184] The one or more RACH parameters provided in the configuration message 1310 can be used to determine the uplink transmission power of Msg 1 1311 and / or Msg3 1313. For example, the one or more RACH parameters can indicate a reference power for preamble transmission (e.g., the received target power and / or the initial power of preamble transmission). There can be one or more power offsets indicated by the one or more RACH parameters. For example, the one or more RACH parameters can indicate: a power ramp step; a power offset between SSB and CSI-RS; a power offset between the transmissions of Msg 1 1311 and Msg 3 1313; and / or a power offset value between preamble groups. The one or more RACH parameters can indicate one or more thresholds based on which the UE can determine at least one reference signal (e.g., SSB and / or CSI-RS) and / or an uplink carrier (e.g., a normal uplink (NUL) carrier and / or a supplementary uplink (SUL) carrier).

[0185] Msg 1 1311 can include one or more preamble transmissions (e.g., a preamble transmission and one or more preamble retransmissions). RRC messages can be used to configure one or more preamble groups (e.g., group A and / or group B). A preamble group can contain one or more preambles. The UE can determine a preamble group based on a path loss measurement value and / or the size of Msg 3 1313. The UE can measure the RSRP of one or more reference signals (e.g., SSB and / or CSI-RS) and determine at least one reference signal having an RSRP higher than an RSRP threshold (e.g., rsrp-ThresholdSSB and / or rsrp-ThresholdCSI-RS). For example, if the association between the one or more preambles and the at least one reference signal is configured by an RRC message, the UE can select at least one preamble associated with the one or more reference signals and / or the selected preamble group.

[0186] The UE can determine the preamble based on the one or more RACH parameters provided in the configuration message 1310. For example, the UE can determine the preamble based on path loss measurement, RSRP measurement, and / or the size of Msg 3 1313. As another example, the one or more RACH parameters can indicate: the preamble format; the maximum number of preamble transmissions; and / or one or more thresholds for determining one or more preamble groups (e.g., group A and group B). The base station can use the one or more RACH parameters to configure the association between one or more preambles and one or more reference signals (e.g., SSB and / or CSI-RS) for the UE. If the association is configured, the UE can determine the preamble included in Msg 1 1311 based on the association. Msg 1 1311 can be transmitted to the base station via one or more PRACH opportunities. The UE can use one or more reference signals (e.g., SSB and / or CSI-RS) for preamble selection and for determining the PRACH opportunity. One or more RACH parameters (e.g., ra-ssb-OccasionMskIndex and / or ra-OccasionList) can indicate the association between the PRACH opportunity and the one or more reference signals.

[0187] If no response is received after the preamble transmission, the UE can perform preamble retransmission. The UE can increase the uplink transmission power for preamble retransmission. The UE can select the initial preamble transmission power based on the path loss measurement value and / or the target received preamble power configured by the network. The UE can determine the retransmission preamble and can ramp up the uplink transmission power. The UE can receive one or more RACH parameters (e.g., PREAMBLE_POWER_RAMPING_STEP) indicating the ramp-up step size for preamble retransmission. The ramp-up step size can be the amount of incremental increase in the uplink transmission power for retransmission. If the UE determines the same reference signal (e.g., SSB and / or CSI-RS) as the previous preamble transmission, the UE can ramp up the uplink transmission power. The UE can count the number of preamble transmissions and / or retransmissions (e.g., PREAMBLE_TRANSMISSION_COUNTER). For example, if the number of preamble transmissions exceeds the threshold (e.g., preambleTransMax) configured by the one or more RACH parameters, the UE can determine that the random access procedure has not been successfully completed.

[0188] Msg 2 1312 received by the UE may include a RAR. In some scenarios, Msg 2 1312 may include multiple RARs corresponding to multiple UEs. Msg 2 1312 may be received after the transmission of Msg 1 1311 or in response to the transmission. Msg 2 1312 may be scheduled on the DL-SCH and indicated on the PDCCH using a random access RNTI (RA-RNTI). Msg 2 1312 may indicate that Msg 1 1311 has been received by the base station. Msg 2 1312 may include a timing alignment command that can be used by the UE to adjust the transmission timing of the UE, a scheduling grant for transmitting Msg 3 1313, and / or a temporary cell RNTI (TC-RNTI). After transmitting a preamble, the UE may start a time window (e.g., ra-ResponseWindow) to monitor the PDCCH of Msg 2 1312. The UE may determine when to start the time window based on the PRACH occasion used by the UE to transmit the preamble. For example, the UE may start a time window of one or more symbols after the last symbol of the preamble (e.g., at the first PDCCH occasion starting from the end of the preamble transmission). The one or more symbols may be determined based on the parameter set. The PDCCH may be in a common search space configured by an RRC message (e.g., Type1-PDCCH common search space). The UE may identify the RAR based on a radio network temporary identifier (RNTI). The RNTI may be used depending on one or more events that initiate the random access procedure. The UE may use a random access RNTI (RA-RNTI). The RA-RNTI may be associated with the PRACH occasion in which the UE transmits the preamble. For example, the UE may determine the RA-RNTI based on the following: OFDM symbol index; slot index; frequency domain index; and / or UL carrier indicator of the PRACH occasion. An example of the RA-RNTI may be as follows:

[0189] RA-RNTI = 1 + s_id + 14×t_id + 14×80×f_id + 14×80×8×ul_carrier_id

[0190] where s_id may be the index of the first OFDM symbol of the PRACH occasion (e.g., 0 ≤ s_id < 14), t_id may be the index of the first slot of the PRACH occasion in the system frame (e.g., 0 ≤ t_id < 80), f_id may be the index of the PRACH occasion in the frequency domain (e.g., 0 ≤ f_id < 8), and ul_carrier_id may be the UL carrier used for preamble transmission (e.g., 0 for the NUL carrier and 1 for the SUL carrier).

[0191] The UE may transmit Msg 3 1313 in response to successfully receiving Msg 2 1312 (e.g., using the resources identified in Msg 2 1312). Msg 3 1313 may be used for, e.g., Figure 13A contention resolution in a contention-based random access procedure as shown in Figure 13A . In some scenarios, multiple UEs may transmit the same preamble to the base station, and the base station may provide a RAR corresponding to the UE. If the multiple UEs interpret the RAR as corresponding to themselves, a conflict may occur. Contention resolution (e.g., using Msg 3 1313 and Msg 4 1314) may be used to increase the likelihood that a UE does not incorrectly use the identity of another UE. To perform contention resolution, the UE may include a device identifier in Msg 3 1313 (e.g., the TC-RNTI included in Msg 2 1312 and / or any other suitable identifier if a C-RNTI is assigned).

[0192] Msg 4 1314 may be received after or in response to the transmission of Msg 3 1313. If a C-RNTI is included in Msg 3 1313, the base station will address the UE on the PDCCH using the C-RNTI. If the unique C-RNTI of the UE is detected on the PDCCH, it is determined that the random access procedure has been successfully completed. If a TC-RNTI is included in Msg 3 1313 (e.g., if the UE is in the RRC_IDLE state or is not otherwise connected to the base station), Msg 4 1314 will be received using the DL-SCH associated with the TC-RNTI. If the MAC PDU is successfully decoded and the MAC PDU contains a UE contention resolution identity MAC CE that matches or otherwise corresponds to the CCCH SDU transmitted (e.g., sent) in Msg 3 1313, the UE may determine that contention resolution is successful and / or the UE may determine that the random access procedure has been successfully completed.

[0193] The UE can be configured with a supplementary uplink (SUL) carrier and a normal uplink (NUL) carrier. Initial access (e.g., random access procedure) can be supported on the uplink carrier. For example, the base station can configure two separate RACH configurations for the UE: one for the SUL carrier and the other for the NUL carrier. To perform random access in a cell configured with an SUL carrier, the network can indicate which carrier (NUL or SUL) to use. For example, if the measured quality of one or more reference signals is below a broadcast threshold, the UE can determine the SUL carrier. The uplink transmission of the random access procedure (e.g., Msg 1 1311 and / or Msg 3 1313) can be retained on the selected carrier. In one or more cases, the UE can switch the uplink carrier during the random access procedure (e.g., between Msg 1 1311 and Msg 3 1313). For example, the UE can determine and / or switch the uplink carrier for Msg 1 1311 and / or Msg 3 1313 based on a clear channel assessment (e.g., listen-before-talk).

[0194] Figure 13B A two-step contention-free random access procedure is shown. Similar to Figure 13A the four-step contention-based random access procedure shown, the base station can transmit a configuration message 1320 to the UE before the procedure is initiated. The configuration message 1320 can be similar to the configuration message 1310 in some aspects. Figure 13B The procedure shown includes the transmission of two messages: Msg 1 1321 and Msg 2 1322. Msg 1 1321 and Msg 2 1322 can be similar to Figure 13A Msg 1 1311 and Msg 2 1312 shown respectively in some aspects. As can be understood from Figure 13A and Figure 13B the contention-free random access procedure may not include messages similar to Msg 3 1313 and / or Msg 4 1314.

[0195] The contention-free random access procedure shown can be initiated for beam failure recovery, other SI requests, SCell addition, and / or handover. For example, the base station can indicate or assign a preamble to be used for Msg 1 1321 to the UE. The UE can receive an indication of the preamble (e.g., ra-PreambleIndex) from the base station via PDCCH and / or RRC. Figure 13B

[0196] ​After transmitting a preamble, the UE may start a time window (e.g., ra-ResponseWindow) to monitor the PDCCH of the RAR. In the case of a beam failure recovery request, the base station may configure the UE with a separate time window and / or a separate PDCCH in a search space indicated by an RRC message (e.g., recoverySearchSpaceId). The UE may monitor PDCCH transmissions addressed to the Cell RNTI (C-RNTI) on the search space. In Figure 13B In the contention-free random access procedure shown, the UE may determine that the random access procedure is successfully completed after the transmission of Msg 1 1321 and the reception of the corresponding Msg 2 1322 or in response to the transmission and the reception. For example, if the PDCCH transmission is addressed to the C-RNTI, the UE may determine that the random access procedure is successfully completed. For example, if the UE receives an RAR that contains a preamble identifier corresponding to the preamble transmitted by the UE and / or the RAR contains a MAC sub-PDU with a preamble identifier, the UE may determine that the random access procedure is successfully completed. The UE may determine that the response is an indication of an acknowledgement of the SI request.

[0197] Figure 13C Another two-step random access procedure is shown. Similar to Figure 13A and Figure 13B the random access procedure shown, the base station may transmit a configuration message 1330 to the UE before the procedure is initiated. The configuration message 1330 may be similar to the configuration message 1310 and / or the configuration message 1320 in some aspects. Figure 13C The procedure shown involves the transmission of two messages: Msg A 1331 and Msg B 1332.

[0198] Msg A 1331 may be transmitted by the UE in an uplink transmission. Msg A 1331 may contain one or more transmissions of a preamble 1341 and / or one or more transmissions of a transport block 1342. The transport block 1342 may contain content similar and / or equivalent to the content of Figure 13A the Msg3 1313 shown. The transport block 1342 may contain UCI (e.g., SR, HARQ ACK / NACK, etc.). The UE may receive Msg B 1332 after transmitting Msg A 1331 or in response to the transmission. Msg B 1332 may contain content similar and / or equivalent to the content of Figure 13A and Figure 13B the Msg 2 1312 (e.g., RAR) shown and / or Figure 13A the content of the Msg 4 1314 shown.

[0199] The UE may initiate a two-step random access procedure for licensed spectrum and / or unlicensed spectrum. The UE may determine whether to initiate the two-step random access procedure based on one or more factors. The one or more factors may be: the radio access technology being used (e.g., LTE, NR, etc.); whether the UE has a valid TA; the cell size; the RRC state of the UE; the type of spectrum (e.g., licensed vs. unlicensed); and / or any other suitable factors. Figure 13C The UE may determine the radio resources and / or uplink transmission power of the preamble 1341 and / or the transport block 1342 included in Msg A 1331 based on the two-step RACH parameters included in configuration message 1330. The RACH parameters may indicate the modulation and coding scheme (MCS), time-frequency resources, and / or power control of the preamble 1341 and / or the transport block 1342. Time-frequency resources (e.g., PRACH) for the transmission of the preamble 1341 and time-frequency resources (e.g., PUSCH) for the transmission of the transport block 1342 may be multiplexed using FDM, TDM, and / or CDM. The RACH parameters may enable the UE to determine the reception timing and downlink channel for monitoring and / or receiving Msg B1332.

[0200] The RACH parameters may indicate the modulation and coding scheme (MCS), time-frequency resources, and / or power control of the preamble 1341 and / or the transport block 1342. Time-frequency resources (e.g., PRACH) for the transmission of the preamble 1341 and time-frequency resources (e.g., PUSCH) for the transmission of the transport block 1342 may be multiplexed using FDM, TDM, and / or CDM. The RACH parameters may enable the UE to determine the reception timing and downlink channel for monitoring and / or receiving Msg B1332.

[0201] The transport block 1342 may contain data (e.g., delay-sensitive data), an identifier of the UE, security information, and / or device information (e.g., International Mobile Subscriber Identity (IMSI)). The base station may transmit Msg B 1332 as a response to Msg A 1331. Msg B 1332 may contain at least one of the following: a preamble identifier; a timing advance command; a power control command; an uplink grant (e.g., radio resource assignment and / or MCS); a UE identifier for contention resolution; and / or an RNTI (e.g., C-RNTI or TC-RNTI). The UE may determine that the two-step random access procedure has been successfully completed if any of the following conditions are met: the preamble identifier in Msg B 1332 matches the preamble transmitted by the UE; and / or the UE identifier in Msg B 1332 matches the UE identifier in Msg A 1331 (e.g., the transport block 1342).

[0202] The UE and the base station may exchange control signaling. The control signaling may be referred to as L1 / L2 control signaling and may originate from the PHY layer (e.g., layer 1) and / or the MAC layer (e.g., layer 2). The control signaling may contain downlink control signaling transmitted from the base station to the UE and / or uplink control signaling transmitted from the UE to the base station.

[0203] Downlink control signaling may include: downlink scheduling assignment; uplink scheduling authorization indicating uplink radio resources and / or transmission format; slot format information; preemption indication; power control command; and / or any other suitable signaling. The UE may receive downlink control signaling in the payload transmitted by the base station on the physical downlink control channel (PDCCH). The payload transmitted on the PDCCH may be referred to as downlink control information (DCI). In some scenarios, the PDCCH may be a group common PDCCH (GC-PDCCH) common to a group of UEs.

[0204] The base station may append one or more cyclic redundancy check (CRC) parity bits to the DCI to facilitate detection of transmission errors. When the DCI is intended for a UE (or a group of UEs), the base station may scramble the CRC parity bits with the identifier of the UE (or the identifier of the group of UEs). Scrambling the CRC parity bits with an identifier may include modulo-2 addition (or exclusive OR operation) of the identifier value and the CRC parity bits. The identifier may include a 16-bit value of a radio network temporary identifier (RNTI).

[0205] The DCI may be used for different purposes. The purpose may be indicated by the type of RNTI used to scramble the CRC parity bits. For example, a DCI with CRC parity bits scrambled with a paging RNTI (P-RNTI) may indicate paging information and / or a system information change notification. The P-RNTI may be predefined as hexadecimal "FFFE". A DCI with CRC parity bits scrambled with a system information RNTI (SI-RNTI) may indicate broadcast transmission of system information. The SI-RNTI may be predefined as hexadecimal "FFFF". A DCI with CRC parity bits scrambled with a random access RNTI (RA-RNTI) may indicate a random access response (RAR). A DCI with CRC parity bits scrambled with a cell RNTI (C-RNTI) may indicate a dynamically scheduled unicast transmission and / or trigger for PDCCH-ordered random access. A DCI with CRC parity bits scrambled with a temporary cell RNTI (TC-RNTI) may indicate contention resolution (e.g., similar to Figure 13AMsg 3 as shown (Msg 3 of 1313). Other RNTIs configured by the base station for the UE may include: the configured scheduling RNTI (CS-RNTI), the transmission power control PUCCH RNTI (TPC-PUCCH-RNTI), the transmission power control PUSCH RNTI (TPC-PUSCH-RNTI), the transmission power control SRS RNTI (TPC-SRS-RNTI), the interruption RNTI (INT-RNTI), the time slot format indication RNTI (SFI-RNTI), the semi-persistent CSI RNTI (SP-CSI-RNTI), the modulation and coding scheme cell RNTI (MCS-C-RNTI), etc.

[0206] Depending on the purpose and / or content of the DCI, the base station may transmit DCI with one or more DCI formats. For example, DCI format 0_0 may be used for the scheduling of PUSCH in the cell. DCI format 0_0 may be a fallback DCI format (e.g., with a compact DCI payload). DCI format 0_1 may be used for the scheduling of PUSCH in the cell (e.g., with a larger DCI payload than DCI format 0_0). DCI format 1_0 may be used for the scheduling of PDSCH in the cell. DCI format 1_0 may be a fallback DCI format (e.g., with a compact DCI payload). DCI format 1_1 may be used for the scheduling of PDSCH in the cell (e.g., with a larger DCI payload than DCI format 1_0). DCI format 2_0 may be used to provide a time slot format indication to a UE group. DCI format 2_1 may be used to notify a UE group of physical resource blocks and / or OFDM symbols, where the UE may assume that no transmission is expected for the UE. DCI format 2_2 may be used to transmit a transmission power control (TPC) command for PUCCH or PUSCH. DCI format 2_3 may be used to transmit a set of TPC commands for SRS transmission by one or more UEs. DCI formats with new functions may be defined in future releases. The DCI formats may have different DCI sizes or may share the same DCI size.

[0207] After scrambling the DCI with an RNTI, the base station may process the DCI with channel coding (e.g., polar coding), rate matching, scrambling, and / or QPSK modulation. The base station may map the coded and modulated DCI on resource elements used for and / or configured for the PDCCH. Based on the payload size of the DCI and / or the coverage of the base station, the base station may transmit the DCI via a PDCCH that occupies multiple consecutive control channel elements (CCEs). The number of consecutive CCEs (referred to as the aggregation level) may be 1, 2, 4, 8, 16, and / or any other suitable number. A CCE may contain a number of resource element groups (REGs) (e.g., 6). A REG may contain resource blocks in an OFDM symbol. The mapping of the coded and modulated DCI on resource elements may be based on the mapping of CCEs and REGs (e.g., CCE-to-REG mapping).

[0208] Figure 14A An example of a CORESET configuration for a bandwidth part is shown. The base station may transmit the DCI via a PDCCH on one or more control resource sets (CORESETs). A CORESET may contain time-frequency resources in which the UE attempts to decode the DCI using one or more search spaces. The base station may configure the CORESET in the time-frequency domain. In Figure 14A the example, a first CORESET 1401 and a second CORESET 1402 appear at the first symbol in a time slot. The first CORESET 1401 overlaps with the second CORESET 1402 in the frequency domain. A third CORESET 1403 appears at the third symbol in the time slot. A fourth CORESET 1404 appears at the seventh symbol in the time slot. The CORESETs may have different numbers of resource blocks in the frequency domain.

[0209] Figure 14B An example of a CCE-to-REG mapping for DCI transmission on a CORESET and PDCCH processing is shown. The CCE-to-REG mapping may be an interleaved mapping (e.g., for the purpose of providing frequency diversity) or a non-interleaved mapping (e.g., for the purpose of facilitating interference coordination and / or frequency-selective transmission of the control channel). The base station may perform different or the same CCE-to-REG mapping for different CORESETs. The CORESET may be associated with the CCE-to-REG mapping through RRC configuration. The CORESET may be configured with antenna port quasi-co-location (QCL) parameters. The antenna port QCL parameters may indicate the QCL information of the demodulation reference signal (DMRS) for PDCCH reception in the CORESET.

[0210] The base station may transmit an RRC message to the UE, which contains configuration parameters of one or more CORESETs and one or more search space sets. The configuration parameters may indicate the association between the search space set and the CORESET. The search space set may contain a set of PDCCH candidates formed by CCEs at a given aggregation level. The configuration parameters may indicate: the number of PDCCH candidates to be monitored at each aggregation level; the PDCCH monitoring period and the PDCCH monitoring pattern; one or more DCI formats to be monitored by the UE; and / or whether the search space set is a common search space set or a UE-specific search space set. The set of CCEs in the common search space set may be predefined and known to the UE. The set of CCEs in the UE-specific search space set may be configured based on the identity of the UE (e.g., C-RNTI).

[0211] As Figure 14B shown, the UE may determine the time-frequency resources of the CORESET based on the RRC message. The UE may determine the CCE-to-REG mapping (e.g., interleaved or non-interleaved and / or mapping parameters) of the CORESET based on the configuration parameters of the CORESET. The UE may determine the number of search space sets configured on the CORESET (e.g., up to 10) based on the RRC message. The UE may monitor the set of PDCCH candidates according to the configuration parameters of the search space set. The UE may monitor the set of PDCCH candidates in one or more CORESETs for detecting one or more DCIs. The monitoring may include decoding one or more PDCCH candidates in the set of PDCCH candidates according to the monitored DCI format. The monitoring may include decoding the DCI content of one or more PDCCH candidates, which has possible (or configured) PDCCH positions, possible (or configured) PDCCH formats (e.g., the number of CCEs, the number of PDCCH candidates in the common search space, and / or the number of PDCCH candidates in the UE-specific search space), and possible (or configured) DCI formats. The decoding may be referred to as blind decoding. The UE may determine that the DCI is valid for the UE in response to a CRC check (e.g., the scrambled bits of the CRC parity bits of the DCI that match the RNTI value). The UE may process the information contained in the DCI (e.g., scheduling assignment, uplink grant, power control, slot format indication, downlink preemption, etc.).

[0212] The UE can transmit uplink control signaling (e.g., uplink control information (UCI)) to the base station. The uplink control signaling transmission can include a hybrid automatic repeat request (HARQ) acknowledgment for the received DL-SCH transport block. The UE can transmit the HARQ acknowledgment after receiving the DL-SCH transport block. The uplink control signaling can include channel state information (CSI) indicating the channel quality of the physical downlink channel. The UE can transmit the CSI to the base station. Based on the received CSI, the base station can determine transmission format parameters for downlink transmission (e.g., including multi-antenna and beamforming schemes). The uplink control signaling can include a scheduling request (SR). The UE can transmit an SR indicating that uplink data is available for transmission to the base station. The UE can transmit UCI (e.g., HARQ acknowledgment (HARQ-ACK), CSI report, SR, etc.) via the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH). The UE can transmit uplink control signaling via the PUCCH using one of several PUCCH formats.

[0213] There can be five PUCCH formats, and the UE can determine the PUCCH format based on the size of the UCI (e.g., the number of uplink symbols for UCI transmission and the number of UCI bits). PUCCH format 0 can have a length of one or two OFDM symbols and can include two or fewer bits. If the transmission is more than one or two symbols and the number of HARQ-ACK information bits (HARQ-ACK / SR bits) with a positive or negative SR is one or two, the UE can transmit the UCI in the PUCCH resource using PUCCH format 0. PUCCH format 1 can occupy a number between four and fourteen OFDM symbols and can include two or fewer bits. If the transmission is four or more symbols and the number of HARQ-ACK / SR bits is one or two, the UE can use PUCCH format 1. PUCCH format 2 can occupy one or two OFDM symbols and can include more than two bits. If the transmission is more than one or two symbols and the number of UCI bits is two or more, the UE can use PUCCH format 2. PUCCH format 3 can occupy a number between four and fourteen OFDM symbols and can include more than two bits. If the transmission is four or more symbols, the number of UCI bits is two or more, and the PUCCH resource does not include an orthogonal cover code, the UE can use PUCCH format 3. PUCCH format 4 can occupy a number between four and fourteen OFDM symbols and can include more than two bits. If the transmission is four or more symbols, the number of UCI bits is two or more, and the PUCCH resource includes an orthogonal cover code, the UE can use PUCCH format 4.

[0214] The base station may transmit the configuration parameters of multiple PUCCH resource sets to the UE using, for example, RRC messages. The multiple PUCCH resource sets (e.g., up to four sets) may be configured on the uplink BWP of the cell. The PUCCH resource set may be configured with: a PUCCH resource set index; multiple PUCCH resources having PUCCH resources identified by PUCCH resource identifiers (e.g., pucch-Resourceid); and / or multiple (e.g., maximum number of) UCI information bits that the UE may transmit using one of the multiple PUCCH resources in the PUCCH resource set. When multiple PUCCH resource sets are configured, the UE may select one PUCCH resource set (e.g., HARQ-ACK, SR, and / or CSI) from the multiple PUCCH resource sets based on the total bit length of the UCI information bits. If the total bit length of the UCI information bits is two or less, the UE may select the first PUCCH resource set having a PUCCH resource set index equal to "0". If the total bit length of the UCI information bits is greater than two and less than or equal to a first configured value, the UE may select the second PUCCH resource set having a PUCCH resource set index equal to "1". If the total bit length of the UCI information bits is greater than the first configured value and less than or equal to a second configured value, the UE may select the third PUCCH resource set having a PUCCH resource set index equal to "2". If the total bit length of the UCI information bits is greater than the second configured value and less than or equal to a third value (e.g., 1406), the UE may select the fourth PUCCH resource set having a PUCCH resource set index equal to "3".

[0215] After determining the PUCCH resource set from the multiple PUCCH resource sets, the UE may determine the PUCCH resource for UCI (HARQ-ACK, CSI, and / or SR) transmission from the PUCCH resource set. The UE may determine the PUCCH resource based on the PUCCH resource indicator in the DCI (e.g., DCI format 1_0 or DCI for 1_1) received on the PDCCH. The three-bit PUCCH resource indicator in the DCI may indicate one of the eight PUCCH resources in the PUCCH resource set. Based on the PUCCH resource indicator, the UE may use the PUCCH resource indicated by the PUCCH resource indicator in the DCI to transmit UCI (HARQ-ACK, CSI, and / or SR).

[0216] Figure 15 An example of a wireless device 1502 communicating with a base station 1504 in accordance with an embodiment of the present disclosure is shown. The wireless device 1502 and the base station 1504 may be part of a mobile communication network, such as Figure 1A the mobile communication network 100 shown,Figure 1B The mobile communication network 150 or any other communication network shown. Figure 15 Only one wireless device 1502 and one base station 1504 are shown, but it should be understood that the mobile communication network may include more than one UE and / or more than one base station, which have the same or similar configurations as Figure 15 those shown.

[0217] The base station 1504 can connect the wireless device 1502 to the core network (not shown) through radio communication via the air interface (or radio interface) 1506. The communication direction from the base station 1504 to the wireless device 1502 through the air interface 1506 is called the downlink, while the communication direction from the wireless device 1502 to the base station 1504 through the air interface is called the uplink. The downlink transmission and the uplink transmission can be separated using FDD, TDD, and / or some combination of the two duplexing techniques.

[0218] In the downlink, the data to be sent from the base station 1504 to the wireless device 1502 can be provided to the processing system 1508 of the base station 1504. The data can be provided to the processing system 1508 through, for example, the core network. In the uplink, the data to be sent from the wireless device 1502 to the base station 1504 can be provided to the processing system 1518 of the wireless device 1502. The processing system 1508 and the processing system 1518 can implement layer 3 and layer 2 OSI functions to process the data for transmission. Layer 2 can include, for example, the SDAP layer, PDCP layer, RLC layer, and MAC layer regarding Figure 2A , Figure 2B , Figure 3 and Figure 4A . Layer 3 can include the RRC layer regarding Figure 2B .

[0219] After being processed by the processing system 1508, the data to be sent to the wireless device 1502 can be provided to the transmission processing system 1510 of the base station 1504. Similarly, after being processed by the processing system 1518, the data to be sent to the base station 1504 can be provided to the transmission processing system 1520 of the wireless device 1502. The transmission processing system 1510 and the transmission processing system 1520 can implement layer 1 OSI functions. Layer 1 can include the PHY layer regarding Figure 2A , Figure 2B , Figure 3 and Figure 4A . For transmission processing, the PHY layer can perform, for example, forward error correction coding of the transport channel, interleaving, rate matching, mapping of the transport channel to the physical channel, modulation of the physical channel, multiple input multiple output (MIMO) or multi-antenna processing, etc.

[0220] At base station 1504, the receive processing system 1512 may receive an uplink transmission from wireless device 1502. At wireless device 1502, the receive processing system 1522 may receive a downlink transmission from base station 1504. The receive processing system 1512 and the receive processing system 1522 may implement layer 1 OSI functions. Layer 1 may include the PHY layer with respect to Figure 2A , Figure 2B , Figure 3 and Figure 4A . For receive processing, the PHY layer may perform, for example, error detection, forward error correction decoding, deinterleaving, demapping of transport channels to physical channels, demodulation of physical channels, MIMO or multi-antenna processing, etc.

[0221] As Figure 15 shown, wireless device 1502 and base station 1504 may include multiple antennas. The multiple antennas may be used to perform one or more MIMO or multi-antenna techniques, such as spatial multiplexing (e.g., single-user MIMO or multi-user MIMO), transmit / receive diversity, and / or beamforming. In other examples, wireless device 1502 and / or base station 1504 may have a single antenna.

[0222] Processing system 1508 and processing system 1518 may be associated with memory 1514 and memory 1524, respectively. Memory 1514 and memory 1524 (e.g., one or more non-transitory computer-readable media) may store computer program instructions or code that may be executed by processing system 1508 and / or processing system 1518 to perform one or more of the functions discussed in this application. Although Figure 15 not shown, the transmit processing system 1510, the transmit processing system 1520, the receive processing system 1512, and / or the receive processing system 1522 may be coupled to a memory (e.g., one or more non-transitory computer-readable media) storing computer program instructions or code that may be executed to perform one or more of their respective functions.

[0223] Processing system 1508 and / or processing system 1518 may include one or more controllers and / or one or more processors. The one or more controllers and / or one or more processors may include, for example, general-purpose processors, digital signal processors (DSPs), microcontrollers, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and / or other programmable logic devices, discrete gates and / or transistor logic, discrete hardware components, on-board units, or any combination thereof. Processing system 1508 and / or processing system 1518 may perform at least one of the following: signal encoding / processing, data processing, power control, input / output processing, and / or any other function that enables wireless device 1502 and base station 1504 to operate in a wireless environment.

[0224] Processing system 1508 and / or processing system 1518 may be respectively connected to one or more peripheral devices 1516 and one or more peripheral devices 1526. The one or more peripheral devices 1516 and the one or more peripheral devices 1526 may include software and / or hardware that provides features and / or functions, such as speakers, microphones, keyboards, displays, touchpads, power supplies, satellite transceivers, universal serial bus (USB) ports, hands-free headsets, frequency modulation (FM) radio units, media players, Internet browsers, electronic control units (e.g., for motor vehicles), and / or one or more sensors (e.g., accelerometers, gyroscopes, temperature sensors, radar sensors, lidar sensors, ultrasonic sensors, light sensors, cameras, etc.). Processing system 1508 and / or processing system 1518 may receive user input data from the one or more peripheral devices 1516 and / or the one or more peripheral devices 1526 and / or may provide user output data to the one or more peripheral devices described above. The processing system 1518 in the wireless device 1502 may receive power from a power supply and / or may be configured to distribute power to other components in the wireless device 1502. The power supply may include one or more power sources, such as batteries, solar cell units, fuel cell units, or any combination thereof. Processing system 1508 and / or processing system 1518 may be respectively connected to GPS chipset 1517 and GPS chipset 1527. GPS chipset 1517 and GPS chipset 1527 may be configured to provide the geographical location information of wireless device 1502 and base station 1504 respectively.

[0225] Figure 16Aillustrates an example structure for uplink transmission. The baseband signal representing the physical uplink shared channel may perform one or more functions. The one or more functions may include at least one of the following: scrambling; modulating the scrambled bits to generate complex-valued symbols; mapping the complex-valued modulated symbols to one or more transport layers; transform precoding to generate complex-valued symbols; precoding of complex-valued symbols; mapping of precoded complex-valued symbols to resource elements; generating a complex-valued time-domain single-carrier frequency-division multiple access (SC-FDMA) or CP-OFDM signal for an antenna port; and so on. In one example, when transform precoding is enabled, an SC-FDMA signal for uplink transmission may be generated. In an example, when transform precoding is not enabled, a CP-OFDM signal for uplink transmission may be generated by Figure 16A These functions are shown as examples, and it is expected that other mechanisms may be implemented in various embodiments.

[0226] Figure 16B illustrates an example structure for modulating and upconverting a baseband signal to a carrier frequency. The baseband signal may be a complex-valued SC-FDMA or CP-OFDM baseband signal of an antenna port and / or a complex-valued physical random access channel (PRACH) baseband signal. Filtering may be employed before transmission.

[0227] Figure 16C illustrates an example structure for downlink transmission. The baseband signal representing the physical downlink channel may perform one or more functions. The one or more functions may include: scrambling the coded bits in the codeword to be transmitted on the physical channel; modulating the scrambled bits to generate complex-valued modulated symbols; mapping the complex-valued modulated symbols to one or more transport layers; precoding of the complex-valued modulated symbols on the layer for transmission on an antenna port; mapping the complex-valued modulated symbols for an antenna port to resource elements; generating a complex-valued time-domain OFDM signal for an antenna port; and so on. These functions are shown as examples, and it is expected that other mechanisms may be implemented in various embodiments.

[0228] Figure 16D illustrates another example structure for modulating and upconverting a baseband signal to a carrier frequency. The baseband signal may be a complex-valued OFDM baseband signal of an antenna port. Filtering may be employed before transmission.

[0229] A wireless device may receive one or more messages (e.g., RRC messages) from a base station that contain configuration parameters for multiple cells (e.g., a primary cell, a secondary cell). The wireless device may communicate with at least one base station (e.g., two or more base stations in dual connectivity) via the multiple cells. One or more messages (e.g., as part of the configuration parameters) may contain parameters for configuring the wireless device for the physical layer, MAC layer, RLC layer, PCDP layer, SDAP layer, and RRC layer. For example, the configuration parameters may include parameters for configuring physical layer and MAC layer channels, bearers, etc. For example, the configuration parameters may include parameters indicating values of timers for the physical layer, MAC layer, RLC layer, PCDP layer, SDAP layer, RRC layer, and / or communication channels.

[0230] Once started, a timer may begin running and continue to run until it is stopped or until it expires. If the timer is not running, it may be started, or if it is running, it may be restarted. A timer may be associated with a value (e.g., the timer may start or restart from a certain value, or may start from zero and expire once it reaches the value). The duration of the timer may not be updated until the timer is stopped or expires (e.g., due to a BWP switch). Timers may be used to measure the time period / window of a process. When the specification refers to embodiments and procedures related to one or more timers, it should be understood that there are multiple ways to implement the one or more timers. For example, it should be understood that one or more of the multiple ways to implement a timer may be used to measure the time period / window of a program. For example, a random access response window timer may be used to measure the time window for receiving a random access response. In one example, instead of starting and expiring a random access response window timer, the time difference between two timestamps may be used. When the timer is restarted, the measurement process of the time window may be restarted. Other example embodiments may be provided to restart the measurement of the time window.

[0231] When an RRC connection has been established, the UE may be in the RRC connected state or the RRC inactive state. When no RRC connection is established, the UE is in the RRC idle state.

[0232] When the UE is in the RRC idle state, the UE (RRC layer) or the base station can support PLMN selection; broadcast of system information; cell reselection mobility; paging for mobile-terminated data initiated by the 5GC; DRX for paging by the core network (CN) configured by the non-access stratum (NAS). When the UE is in the RRC idle state, UE-specific DRX can be configured by the upper layer; and / or the UE controls mobility based on network configuration. When the UE is in the RRC idle state, the UE (RRC layer) can: monitor short messages transmitted with P-RNTI via DCI; monitor the paging channel for CN paging using the serving temporary mobile subscriber identity (S-TMSI) (e.g., 5G-S-TMSI); perform neighbor cell measurements and cell (re)selection; obtain system information; send SI requests; perform recording of available measurements and record the location and time of the UE for the recorded measurements.

[0233] When the UE is in the RRC inactive state, the UE (RRC layer) or the base station can support PLMN selection; broadcast of system information; cell reselection mobility; paging initiated by the NG-RAN (RAN paging); management of RAN-based notification area (RNA) by the NG-RAN; DRX for RAN paging configured by the NG-RAN; the core network (e.g., 5G Core, 5GC) - establish a RAN (e.g., base station) connection (control plane and / or user plane) for the UE; store the UE AS context in the RAN and the UE; the RAN is aware of the RNA to which the UE belongs. For example, when the UE (RRC layer) is in the RRC inactive state, UE-specific DRX can be configured by the upper layer or the RRC layer; the UE can perform / support UE-controlled mobility based on network configuration; the UE can store the UE inactive AS context; the RAN-based notification area (RNA) can be configured by the RRC layer. When the UE is in the RRC inactive state, the UE (RRC layer) can: monitor short messages transmitted with P-RNTI via DCI; monitor the paging channel for CN paging using the S-TMSI and monitor the paging channel for RAN paging using the fully inactive RNTI (I-RNTI) (or fully restored identity); perform neighbor cell measurements and cell (re)selection; perform RAN-based notification area (RNA) updates periodically and when moving out of the configured RAN-based notification area; obtain system information; send SI requests; perform recording of available measurements and record the location and time of the UE for the recorded measurements.

[0234] When the UE is in the RRC connected state, the UE (RRC layer) or the base station can support: the 5GC to establish an NG-RAN connection for the UE (both the C-plane / U-plane); store the UE AS context in the RAN (e.g., the base station) and the UE; the RAN to be aware of the cell to which the UE belongs; transfer unicast data to / from the UE; network-controlled mobility, including measurements. For example, when the UE is in the RRC connected state, the UE (RRC layer) can: store the AS context; transfer / receive unicast data; at the lower layer, be configured with UE-specific DRX; for a CA-capable UE, use one or more SCell aggregated with the SpCell to increase the bandwidth; for a DC-capable UE, use one SCG aggregated with the MCG to increase the bandwidth; perform / support network-controlled mobility within NR and to / from E-UTRA; when the UE is in the RRC connected state, the UE can: monitor short messages transmitted with P-RNTI via DCI; monitor the control channel associated with the shared data channel to determine whether data is scheduled for this control channel; provide channel quality and feedback information; perform neighbor cell measurements and measurement reports; obtain system information; perform immediate minimization of drive test (MDT) measurements and available location reports.

[0235] Radio bearers can be divided into two groups: data radio bearers (DRB) for user plane data and signaling radio bearers (SRB) for control plane data.

[0236] A "Signalling Radio Bearer" (SRB) can be defined as a Radio Bearer (RB) that is only used for the transmission of RRC and NAS messages. The following SRBs can be defined: SRB0 can be used for RRC messages using the Common Control Channel (CCCH) logical channel; SRB1 can be used for RRC messages (which can include the piggybacked NAS messages) and for NAS messages before the establishment of SRB2, all of these messages using the Dedicated Control Channel (DCCH) logical channel; SRB2 can be used for NAS messages and RRC messages, the RRC messages of which can include the recorded measurement information, all of these messages using the DCCH logical channel. SRB2 can have a lower priority than SRB1 and can be configured by the network after the activation of the Access Stratum (AS) security; when the UE is in dual connectivity (e.g., (NG) EN-DC or NR-DC), SRB3 can be used for specific RRC messages, all specific RRC messages using the DCCH logical channel. In the downlink, the piggybacking of NAS messages can be used for a related (e.g., having joint success / failure) procedure: bearer establishment / modification / release. In the uplink, the piggybacking of NAS messages can be used to transfer the initial NAS messages during (RRC) connection setup and (RRC) connection re-establishment. The NAS messages transmitted via SRB2 can be contained in an RRC message that may not include any RRC protocol control information. Once AS security is activated, all RRC messages (including those containing NAS messages) on SRB1, SRB2, and SRB3 can be integrity protected and encrypted by PDCP. NAS can independently apply integrity protection and encryption to NAS messages. Split SRB can be supported in both SRB1 and SRB2 to enable dual connectivity (e.g., Multi-Radio (MR)-DC option). SRB0 and SRB3 may not support split SRB. For operations utilizing shared spectrum channel access, SRB0, SRB1, and SRB3 can be assigned the highest priority Channel Access Priority Class (CAPC) (e.g., CAPC = 1), while the CAPC for SRB2 is configurable.

[0237] The MAC layer of the UE or the base station can provide different types of data transfer services. Each logical channel type can be defined by the type of information being transferred. Logical channels can be divided into two groups: control channels and traffic channels. Control channels can be used to transfer control plane information: Broadcast Control Channel (BCCH), which is a downlink channel for broadcasting system control information; Paging Control Channel (PCCH), which is a downlink channel carrying paging messages; Common Control Channel (CCCH), which is a channel for transmitting control information between the UE and the network. This channel is used for UEs that do not have an RRC connection with the network; and Dedicated Control Channel (DCCH), which is a point-to-point two-way channel for transmitting dedicated control information between the UE and the network. It is used by UEs with an RRC connection. Traffic channels can be used to transfer user plane information: Dedicated Traffic Channel (DTCH), which is a point-to-point channel dedicated to one UE for transferring user information. DTCH can exist in both the uplink and the downlink.

[0238] When establishing or resuming an RRC connection, the UE can transition to the RRC connected state. When the RRC connection is released or suspended, the UE can transition to the RRC idle state. When the RRC connection is suspended, the UE can transition to the RRC inactive state. When the UE is in the RRC idle state, the UE can have a suspended RRC connection. Based on the suspended RRC connection in the RRC idle state, the UE is in the RRC idle state with a suspended RRC connection.

[0239] The establishment of the RRC connection can include the establishment of SRB1. The base station can complete the RRC connection establishment before establishing a connection with the core network (e.g., N2 / N3 connection) (e.g., before receiving UE context information from a core network entity (e.g., AMF)). During the initial phase of the RRC connection, access stratum (AS) security may not be activated. During the initial phase of the RRC connection, the base station can configure the UE to perform measurement reporting. After successful activation of AS security, the UE can send the corresponding measurement report. When AS security is activated, the UE can receive or accept handover messages (e.g., handover commands).

[0240] When receiving the UE context from the core network (e.g., AMF), the RAN (base station) can use the initial security activation procedure to activate AS security (both encryption protection and integrity protection). The RRC messages (commands and successful responses) used to activate AS security can be integrity protected while encryption starts after the process is completed. The response to the RRC message used to activate AS security can be unencrypted, while subsequent messages (e.g., for establishing SRB2 and DRB) can be both integrity protected and encrypted. After the initial AS security activation procedure has been initiated, the network (e.g., base station) can initiate the establishment of SRB2 and DRB. For example, the network can do so before receiving the confirmation of the initial AS security activation from the UE. The network can apply both encryption and integrity protection to the RRC reconfiguration messages used to establish SRB2 and DRB. If the initial AS security activation and / or the radio bearer establishment fails, the network shall release the RRC connection. Configurations with SRB2 without a DRB or DRB without an SRB2 may not be supported (i.e., SRB2 and at least one DRB must be configured in the same RRC reconfiguration message, and it may not be allowed to release all DRBs without releasing the RRC connection). For integrated access and backhaul mobile terminals (IAB-MTs), configurations with SRB2 but without a DRB may be supported.

[0241] The release of the RRC connection can be initiated by the network. The release procedure can be used to redirect the UE to an NR frequency or an E-UTRA carrier frequency.

[0242] The suspension of the RRC connection can be initiated by the network. When the RRC connection is suspended, the UE can store the UE inactive AS context and any configuration received from the network and transition to the RRC inactive state. The RRC message used to suspend the RRC connection can be integrity protected and encrypted.

[0243] The recovery of the suspended RRC connection can be initiated by the upper layer when the UE needs to transition from the RRC inactive state to the RRC connected state, or it can be initiated by the RRC layer to perform RNA update, or it can be initiated by RAN paging from the RAN (e.g., base station). When the RRC connection is recovered, the network can configure the UE according to the RRC connection recovery procedure based on the stored UE inactive AS context and any RRC configuration received from the network. The RRC connection recovery procedure reactivates AS security and reconstructs the SRB and DRB.

[0244] In response to a request to resume an RRC connection, the network may resume a suspended RRC connection and cause the UE to enter / transition to the RRC connected state, or reject the resume request and cause the UE to enter the RRC inactive state (using a wait timer), or directly re-suspend the RRC connection and cause the UE to enter RRC_INACTIVE, or directly release the RRC connection and cause the UE to enter / transition to the RRC idle state, or instruct the UE to initiate NAS-level restoration (in which case the network sends an RRC setup message). For user data (DRB), encryption may provide user data confidentiality, and integrity protection may provide user data integrity. For RRC signaling (SRB), encryption may provide signaling data confidentiality and integrity protection for signaling data integrity. In addition to RRC signaling for which integrity protection may always be configured, encryption and integrity protection may also be optionally configured. Encryption and integrity protection may be configured for each DRB.

[0245] For key management and data processing, network entities or UEs that process plaintext may be protected from physical attacks and be located in a secure environment. Base station (e.g., gNB or eNB) (AS) keys may be separated from (NAS) keys in an encrypted manner. Separate AS and NAS-level security mode command (SMC) procedures may be used. A sequence number (COUNT) may be used as an input for encryption and integrity protection, and a given sequence number may be used once for a given key on the same radio bearer in the same direction (except for the same retransmission).

[0246] Keys for security can be organized and exported as follows. Keys for core network entities (e.g., keys for AMF or keys for Mobility Management Entity (MME)) can include KAMF (or KMME). Keys for core network entities can be keys derived by the UE's Mobile Equipment (ME) and the Security Anchor Function (SEAF) from the key for SEAF (KSEAF). Keys for NAS signaling can include: KNASint is a key derived by the UE's Mobile Equipment (ME) and the core network from the key for the core network entity, and this key can be used to protect NAS signaling using a specific integrity algorithm; and KNASenc is a key derived by the ME and the core network entity from the key for the core network entity (e.g., KAMF / KMME), and this key can be used to protect NAS signaling using a specific encryption algorithm. Keys for the base station (e.g., gNB or eNB) can include KgNB (or KeNB), and this KgNB is a key derived by the ME and the core network entity (e.g., AMF / MME) from the key for the core network entity (e.g., KAMF / KMME). When performing horizontal or vertical key derivation, the ME and the source base station can further derive the key for the base station. Keys for UP traffic can include: KUPenc is a key derived by the ME and the base station from the key for the base station, and this key can be used to protect the UP traffic between the ME and the base station using a specific encryption algorithm; KUPint can be a key derived by the ME and the base station from the key for the base station, and this key can be used to protect the UP traffic between the ME and the base station using a specific integrity algorithm. Keys for RRC signaling can include: KRRCint is a key derived by the ME and the base station from the key for the base station, and this key can be used to protect RRC signaling using a specific integrity algorithm; KRRCenc is a key derived by the ME and the base station from the key for the base station, and this key can be used to protect RRC signaling using a specific encryption algorithm. Intermediate keys can include: The Next Hop Parameter (NH) can be a key derived by the ME and the core network entity (e.g., AMF / MME) for providing forward security; KgNB* (or KeNB*) is a key derived by the ME and the base station when performing horizontal or vertical key derivation.

[0247] Mutual authentication between the UE and the network can be achieved in primary authentication and the anchor key called KSEAF can be provided. Based on KSEAF, keys for core network entities (e.g., KAMF / KMME) can be created during, for example, primary authentication or NAS key re - setting key and key refresh events. Based on the keys for core network entities, when a successful NAS SMC process is running, KNASint and KNASenc can be derived.

[0248] Whenever an initial AS security context needs to be established between the UE and the base station, the core network entity (e.g., AMF / MME) and the UE can derive keys and next-hop parameters (NH) for the base station (e.g., KgNB / KeNB). The keys for the base station and NH can be derived from the keys for the core network entity. A next-hop link counter (NCC) can be associated with each key and NH parameter for the base station. The key for the base station can be associated with the NCC corresponding to the NH value from which the key is derived. At initial setup, the key for the base station can be directly derived from the key for the core network entity and subsequently considered to be associated with a virtual NH parameter with an NCC value equal to zero. At initial setup, the derived NH value can be associated with an NCC value of one. At handover, the basis for the key for the base station (referred to as KgNB* (or KeNB*)) to be used between the UE and the target base station can be derived from the current active key or NH parameter for the base station. If KgNB* (or KeNB*) can be derived from the current active key for the base station, this is referred to as horizontal key derivation and is indicated to the UE with an NCC that does not increase. If KgNB* (or KeNB*) is derived from the NH parameter, the derivation is referred to as vertical key derivation and is indicated to the UE with an NCC increase. After deriving a new key for the base station, KRRCint, KRRCenc, KUPint, and KUPenc can be derived based on the key for the base station.

[0249] Based on key derivation, a base station that knows the key for the base station (e.g., KgNB / KeNB) shared with the UE may not be able to compute any previous KgNB that has been used between the same UE and a previous base station, thus providing backward security. A base station that knows the key for the base station shared with the UE may not be able to predict any future keys for the base station that will be used between the same UE and another base station after n or more handovers (since the NH parameter can only be computed by the UE and the core network entity (e.g., AMF / MME)).

[0250] The AS SMC procedure can be used for RRC and UP security algorithm negotiation and RRC security activation. When establishing an AS security context in the base station, the AMF (or MME) can send the UE's security capabilities to the base station. The base station can select an encryption algorithm. The selected encryption algorithm can have the highest priority from its configuration list and also exist in the security capabilities. The base station can select an integrity algorithm. The selected integrity algorithm can have the highest priority from its configuration list and also exist in the security capabilities. The selected algorithms can be indicated to the UE in the AS SMC, and integrity protection can be applied to this message. RRC downlink ciphering (encryption) at the base station can start after sending the AS SMC message. RRC uplink deciphering (decryption) at the base station can start after receiving and successfully verifying the integrity protection of the AS security mode completion message from the UE. The UE can verify the validity of the AS SMC message from the base station by verifying the integrity of the received message. RRC uplink encryption (encryption) at the UE can start after sending the AS security mode completion message. RRC downlink decryption (decryption) at the UE can start after receiving and successfully verifying the AS SMC message. The RRC connection reconfiguration procedure for adding a DRB can be performed only after RRC security has been activated as part of the AS SMC procedure.

[0251] The UE can support integrity-protected DRBs. In case of integrity check failure (e.g., the message authentication code (MAC-I) for integrity has an error or is missing), the relevant packet data unit (PDU) can be discarded by the receiving PDCP entity. Key refresh is possible for the keys for the base station (K gNB / K eNB ), K RRC-enc , K RRC-int , K UP-enc and K UP-int , and can be initiated by the base station when the PDCP COUNT will be reused with the same radio bearer identity and the same K gNB . Key re-setting is possible for the keys for the base station (K gNB / K eNB ), K RRC-enc , K RRC-int , K UP-enc and K UP-int , and can be initiated by the core network entity (e.g., AMF / MME) when a different AS security context from the currently active security context is activated.

[0252] When the UE transitions from the RRC idle state to the RRC connected state, RRC protection keys and UP protection keys can be generated, assuming that keys for NAS protection and higher layer keys are already available. These higher layer keys may have been established as a result of authentication and key agreement (AKA), or as a result of being passed from another AMF during handover or idle mode mobility. When the UE transitions from the RRC connected state to the RRC idle state, the base station can delete the keys it stores for that UE, such that the state information for the idle mode UE only has to be maintained in core network entities (such as AMF / MME). The base station can no longer store the state information for the corresponding UE and delete the current keys from its memory (e.g., when transitioning the RRC connected state to the RRC idle state): the base station and the UE can delete NH, the key for the base station, KgNB, KRRCint, KRRCenc, KUPint, and KUPenc, and the associated NCC; the core network entity (such as AMF / MME) and the UE can save the key for the core network entity (such as KAMF / KMME), the stored KNASint, and KNASenc.

[0253] In mobility with vertical key derivation, NH can be further bound to the target physical cell identifier (PCI) and its frequency absolute radio frequency channel number - downlink (ARFCN-DL) before being used as the key for the base station in the target base station. In mobility with horizontal key derivation, the current active key for the base station can be further bound to the target PCI (PCI of the target cell) and its frequency ARFCN-DL, and then this current active key is used as the key for the base station in the target gNB. In both cases, the ARFCN-DL can be the absolute frequency of the SSB of the target primary cell (PCell). During the handover of the central unit (CU) within the gNB, it may not be necessary to change the AS security algorithm. If the UE does not receive an indication of a new AS security algorithm during the handover within the gNB-CU, the UE can continue to use the same algorithm as before the handover.

[0254] AS security can include integrity protection and encryption of RRC signaling (SRB) and user data (DRB). The AS can apply four different security keys: a security key for integrity protection of RRC signaling (KRRCint), a security key for encryption of RRC signaling (KRRCenc), a security key for integrity protection of user data (KUPint), and a security key for encryption of user data (KUPenc). The four AS keys can be derived from keys for the base station (e.g., KgNB / KgNB). The keys for the base station can be based on keys for core network entities (KAMF / KMME), which can be processed by an upper layer (e.g., the NAS layer). The integrity protection and encryption algorithms can be changed using reconfiguration with synchronization (e.g., handover command). The AS keys (KgNB, KRRCint, KRRCenc, KUPint, and KUPenc) can be changed during reconfiguration with synchronization and during connection re-establishment and connection recovery. For each radio bearer, independent counters (counts) can be maintained for each direction. For each radio bearer, the counts can be used as inputs for encryption and integrity protection.

[0255] Paging can allow the base station to reach UEs in the RRC idle state and RRC inactive state via paging messages, and to notify UEs in the RRC idle state, RRC inactive state, and RRC connected state of changes in UE system information, and to notify of earthquake and tsunami warning system (ETWS) or commercial mobile alert service (CMAS) indications via short messages. Both paging messages and short messages can be addressed using the P-RNTI on the PDCCH. Paging messages can be sent on the PCCH, and short messages can be sent directly via the PDCCH.

[0256] When the UE is in the RRC idle state, the UE can monitor the paging channel for paging initiated by the core network (CN). When the UE is in the RRC inactive state, the UE can monitor the paging channel for paging initiated by the RAN. However, the UE may not need to continuously monitor the paging channel. Paging DRX is defined as where a UE in the RRC idle state or RRC inactive state may only need to monitor the paging channel during one paging occasion (PO) of each DRX cycle. The paging DRX cycle can be configured by the network (such as a base station or a core network entity such as an AMF / MME): for CN-initiated paging, the default cycle can be broadcast in the system information; for CN-initiated paging, the UE-specific cycle can be configured via NAS signaling; for RAN-initiated paging, the UE-specific cycle can be configured via RRC signaling; the UE can use the shortest DRX cycle among the available DRX cycles. For example, a UE in the RRC idle state can use the shortest cycle among the first two cycles above. A UE in RRC_INACTIVE can use the shortest cycle among the three cycles above.

[0257] The POs for a UE for CN-initiated paging and RAN-initiated paging can be based on the same UE identifier (ID), resulting in PO overlap for both. The number of different POs in a DRX cycle can be configured via the system information, and the network can distribute UEs to those POs based on the UE's ID.

[0258] When in RRC_CONNECTED, the UE can monitor the paging channel in any PO signaled in the system information for SI change indication and PWS notification. A UE in the RRC connected state can only monitor the paging channel on the active BWP configured with a common search space. For operations using shared spectrum channel access, the UE can be configured with an additional number of PDCCH monitoring occasions in its PO to monitor paging. When the UE detects a PDCCH transmission within the PO of the UE addressed with the P-RNTI, the UE may not need to monitor subsequent PDCCH monitoring occasions within this PO.

[0259] The network (such as a base station) can initiate the paging process by transmitting a paging message at the paging occasion of the UE. The network can address multiple UEs in the paging message by including a paging record for each UE. The paging message can contain a list of paging records. The list of paging records can contain one or more paging records. Each paging record can contain at least one of the following: UE identifier (ID) and access type. The UE identity can contain the S-TMSI or I-RNTI (recovered identity). The access type can indicate whether the paging message is initiated due to a PDU session from a non-3GPP access.

[0260] Transitions from Registration Management (RM)-Deregistered to RM-Registered, from CM-Idle to CM-Connected, and from CM-Connected to CM-Idle may require cell selection. In the RM-DEREGISTERED state, the UE may not be registered with the network. The UE context in the core network entity (e.g., AMF / MME) may not hold valid location or routing information for the UE. The UE may not be reachable by the AMF. In the RM-REGISTERED state, the UE is registered with the network. In the RM-REGISTERED state, the UE can receive services that require registration with the network. A UE in the CM-IDLE state may not have an NAS signaling connection established (e.g., via the N1 / S1 interface) with a core network entity (e.g., AMF / MME). The UE can perform cell selection / cell reselection and PLMN selection. A UE in the CM-CONNECTED state may have an NAS signaling connection (e.g., via the N1 / S1 interface) with a core network entity. The NAS signaling connection can utilize the RRC connection between the UE and the base station (e.g., RAN) and the Next Generation Application Protocol (NGAP) / S1AP UE association between the access network (AN) (e.g., the AN of the base station) and the core network entity (e.g., AMF / MME).

[0261] Cell selection can be based on the following principles. The UE NAS layer can identify the selected PLMN and equivalent PLMNs. Cell selection can be based on Cell Definition SSBs (CD-SSBs) located on the synchronization raster: The UE can search the frequency (NR) band, and for each carrier frequency, it can identify the strongest cell based on the CD-SSB. The UE can then read the cell system information broadcast to identify its PLMN: The UE can search each carrier in sequence ("initial cell selection") or use the stored information to shorten the search ("stored information cell selection"). The UE can seek to identify a suitable cell; if the UE cannot identify a suitable cell, it seeks to identify an acceptable cell. When a suitable cell or only an acceptable cell is found, the UE can camp on that cell and start the cell reselection process: A suitable cell is a cell where the measured cell attributes meet the cell selection criteria; the cell PLMN is the selected PLMN, a registered or equivalent PLMN; the cell is not barred or reserved, and the cell is not part of a tracking area in the "forbidden tracking area for roaming" list; an acceptable cell is a cell where the measured cell attributes meet the cell selection criteria and is not barred.

[0262] When transitioning from the RRC connected state or the RRC inactive state to the RRC idle state, the UE can camp on a cell as a result of cell selection based on the frequency assigned by the RRC in the state transition message. The UE can attempt to find a suitable cell in the manner described above for the stored information or initial cell selection. If no suitable cell is found on any frequency or RAT, the UE can attempt to find an acceptable cell. In multi-beam operation, cell quality can be derived between beams corresponding to the same cell.

[0263] A UE in RRC idle can perform cell reselection. The principles of this process are as follows. Cell reselection can be based on CD-SSBs located on the synchronization raster. The UE can measure the attributes of the serving cell and neighboring cells to enable the reselection procedure: For the search and measurement of inter-frequency neighboring cells, the carrier frequency needs to be indicated. Cell reselection can identify the cell on which the UE should camp. Cell reselection can be based on cell reselection criteria involving measurements of the serving cell and neighboring cells: Intra-frequency reselection is based on the ranking of cells; Inter-frequency reselection is based on absolute priorities, where the UE attempts to camp on the highest priority available frequency; The neighbor cell list (NCL) can be provided by the serving cell to handle specific cases of intra-frequency and inter-frequency neighboring cells; A blacklist can be provided to prevent the UE from reselecting to specific intra-frequency and inter-frequency neighboring cells; A whitelist can be provided to request the UE to only reselect to specific intra-frequency and inter-frequency neighboring cells; Cell reselection can depend on speed; Serving-specific priorities. In multi-beam operation, cell quality can be derived between beams corresponding to the same cell.

[0264] The UE can perform one of two processes, such as initial cell selection and cell selection by using the stored information. When the UE has not stored cell information for the selected PLMN, the UE can perform initial cell selection. Otherwise, the UE can perform cell selection by using the stored information. For initial cell selection, the UE can scan all RF channels in the (NR) band according to its ability to find a suitable cell. Based on the results of the scan, the UE can search for the strongest cell on each frequency. The UE can select the cell as a suitable cell. For cell selection by using the stored information, the UE may require the stored frequency information, and optionally also information about cell parameters from previously received measurement control information elements or from previously detected cells. Based on the stored information, if the UE finds a suitable cell, the UE can search for and select a suitable cell. If the UE does not find a suitable cell, the UE can perform initial cell selection.

[0265] The base station can configure cell selection criteria for cell selection. The UE can seek to identify a cell suitable for cell selection. A suitable cell is a cell that meets the following conditions: (1) the measured cell attributes meet the cell selection criteria, (2) the cell PLMN is the selected PLMN, a registered or equivalent PLMN, (3) the cell is not prohibited or reserved, and (4) the cell is not part of a tracking area in the "roaming prohibited tracking area" list. The RRC layer in the UE can notify the NAS layer in the UE of cell selection and reselection results based on changes in the received system information related to the NAS. For example, the cell selection and reselection results can be cell identity, tracking area code, and PLMN identity.

[0266] The UE-RRC layer can initiate an RRC connection establishment procedure, an RRC connection resume procedure, or an RRC connection reestablishment procedure. Based on initiating the RRC connection establishment procedure or the RRC connection resume procedure, the UE can perform one or more procedures, where the one or more procedures include at least one of the following: perform a unified access control procedure (e.g., access prohibition check) on the access attempt for the RRC establishment / resume procedure on the serving cell; apply default configuration parameters and the configuration / parameters provided by SIB1 (e.g., based on the allowed access attempt, apply the default configuration and the configuration / parameters provided by SIB1); for example, based on the allowed access attempt, perform sending a random access preamble to the serving cell; send an RRC request message to the serving cell (e.g., based on determining the successful reception of a random access response, send an RRC request message to serving cell 0; start a timer based on sending the RRC request message; receive an RRC response message or an RRC rejection message from the serving cell (e.g., in response to the RRC request message); or send an RRC completion message (e.g., in response to receiving the RRC response message, send an RRC completion message). For the RRC connection reestablishment procedure, the UE may not perform a unified access procedure (e.g., access prohibition check) on the access attempt for the RRC reestablishment procedure.

[0267] A base station (e.g., NG-RAN) may support overload and access control functions such as RACH backoff, RRC connection rejection, RRC connection release, and UE-based access prohibition mechanisms. The unified access control framework applies to all UE states (e.g., RRC idle, inactive, and connected states). The base station may broadcast prohibition control information associated with access categories and access identifiers (in the case of network sharing, the prohibition control information may be set separately for each PLMN). The UE may determine whether an access attempt is authorized based on the prohibition information broadcast for the selected PLMN, the selected access category, and the access identifier of the access attempt. For NAS-triggered requests, the UE-NAS layer may determine the access category and access identifier. For AS-triggered requests, the UE-RRC layer determines the access category, and the NAS determines the access identifier. The base station may process access attempts with high-priority establishment reasons "emergency", "mps priority access", and "mcs priority access" (e.g., emergency calls, MPS, MCS subscribers) and respond to these access attempts with an RRC rejection only under extreme network load conditions that may threaten the stability of the base station.

[0268] Based on initiating an RRC connection establishment procedure or an RRC connection resume procedure, a UE in the RRC inactive or idle state may perform or initiate an access prohibition check (or unified access control procedure) for an access attempt of the RRC connection establishment procedure or the RRC connection resume procedure. Based on performing or initiating the access prohibition check, the UE may determine the access category and access identifier of the access attempt. The UE may determine that the access attempt is prohibited based on at least one of the following: the timer T309 is running for the access category of the access attempt; and the timer T302 is running and the access category is neither '2' nor '0'. The UE may determine an allowed access attempt based on at least one of the following: the access category is '0'; and the system information block (system information block type 25) containing the unified access control (UAC) prohibition parameter is not broadcast by the serving cell. The UE may determine that the access attempt is prohibited based on at least one of the following: the establishment reason (e.g., for the access attempt) is not an emergency; the access prohibition of each RSRP parameter of the system information block contains (or is set to) the threshold 0 and the radio device is in enhanced coverage; the access prohibition of each RSRP parameter of the system information block contains (or is set to) the threshold 1 and the measured RSRP is less than the first entry in the RSRP threshold PRACH information list; the access prohibition parameter of each RSRP of the system information block contains (or is set to) the threshold 2 and the measured RSRP is less than the second entry in the RSRP threshold PRACH information list; and the access prohibition of each RSRP parameter of the system information block contains (or is set to) the threshold 3 and the measured RSRP is less than the third entry in the RSRP threshold PRACH information list.

[0269] The UE may determine that an access attempt is allowed based on that the system information block does not contain UAC prohibition parameters for the access attempt. For example, the UE may determine that an access attempt is allowed based on that the system information block does not contain the UAC prohibition parameter of the PLMN selected by the UE and the public UAC prohibition parameter. The UE may determine that an access attempt is allowed based on that the public UAC prohibition parameter does not contain the access category of the access attempt. The UAC prohibition parameter may include at least one of the following: the UAC prohibition parameter per PLMN; and the UAC prohibition parameter. The UE may perform an access prohibition check on the access category of the access attempt based on the UAC prohibition parameter in the system information block. The UE may determine that an access attempt is allowed based on that at least one corresponding bit of the access identifiers in the UAC prohibition parameter is zero. The UE may extract a first random number uniformly distributed within a range, where the range is greater than or equal to 0 and less than 1.

[0270] The UE may determine that an access attempt is allowed based on that the first random number is lower than the UAC prohibition factor in the UAC prohibition parameter. The UE may determine that an access attempt is prohibited based on that the first random number is greater than the UAC prohibition factor in the UAC prohibition parameter. In response to determining that an access attempt is prohibited, the UE may extract a second random number uniformly distributed within a range, where the range is greater than or equal to 0 and less than 1. The UE may start a prohibition timer T309 for the access category based on the second random number. When the prohibition timer T309 is running, the access attempt associated with the access category is prohibited (for example, transmission is not allowed). Based on the expiration of the prohibition timer T309, the UE may consider that the prohibition on the access category is alleviated. Based on the alleviation of the prohibition on the access category, if the UE has an access attempt for the access category, the UE may perform an access prohibition check on the access category.

[0271] Based on initiating the RRC connection reestablishment procedure, if one or more prohibition timers T309 are running, the UE may stop one or more prohibition timers T309 for all access categories. Based on stopping one or more prohibition timers T309, the UE may determine that the prohibition on all access categories is being alleviated. The UE may perform the RRC connection reestablishment procedure based on the alleviation of the prohibition on all access categories. For example, based on the alleviation of the prohibition for all access categories, the UE may send an RRC reestablishment request without prohibition.

[0272] To initiate the RRC connection establishment / resumption / re - establishment process, the UE - RRC layer can use the parameters in the received SIB1. The UE - RRC layer can use the L1 parameter values and the timing alignment timer in SIB1. The UE - RRC layer can use the UAC prohibition information in SIB1 to perform the unified access control process. Based on the unified access control process, the UE - RRC layer can determine whether the access attempt for these RRC processes is prohibited or allowed. Based on determining that the access attempt is allowed, the UE - RRC layer can determine to send an RRC request message to the base station, where the RRC request message can be an RRC establishment request message, an RRC resume request message, or an RRC re - establishment message. The UE - NAS layer may or may not provide the S - TMSI as the UE identity. The UE - RRC layer can set the UE identity in the RRC request message.

[0273] For the RRC setup request message, a UE in the RRC idle state can initiate the RRC connection establishment process. Based on initiating the RRC connection establishment process, if the UE - NAS layer provides the S - TMSI, the UE - RRC layer in the RRC idle state can set the UE identity to the S - TMSI. Otherwise, the UE - RRC layer in the RRC idle state can extract a 39 - bit random value and set the UE identity to this random value. For the RRC resume request message, the UE - RRC layer in the RRC inactive or idle state can set the UE identity to the restored stored identity. For the RRC re - establishment request message, the UE - RRC layer in the RRC connected state can set the UE identity to the C - RNTI used in the source PCell. The UE - NAS layer can provide the establishment cause (e.g., the UE - NAS layer). The UE - RRC layer can set the establishment cause of the RRC request message.

[0274] For an RRC Resume Request message, a UE in RRC Inactive can initiate an RRC connection resume procedure. A UE in RRC Idle state with a suspended RRC connection can initiate an RRC connection resume procedure. A UE in RRC Inactive state or RRC Idle state can initiate an RRC connection procedure based on at least one of the following: resume (suspend) the RRC connection; and perform / initiate UP small data transfer. Based on initiating the RRC connection resume procedure, the UE-RRC layer can restore the stored configuration parameters and the stored security keys from the stored UE Inactive AS context. Based on the security key, the UE-RRC layer in RRC Inactive or Idle state can set the resumed MAC-I value to the 16 least significant bits of the MAC-I calculated based on a variable resume MAC input, the security key for integrity protection of the RRC layer in the UE Inactive AS context, the previously configured integrity protection algorithm, and other security parameters (e.g., count, bearer, and direction). The variable resume MAC input can include at least one of the following: the physical cell identity of the source cell; the C-RNTI of the source cell; and the cell identity of the target cell (e.g., the selected cell), where the cell identity is the cell identity in the system information block (e.g., SIB1) of the target cell (e.g., the selected cell). Based on the security key and the next-hop link count (NCC) value, the UE-RRC layer in RRC Inactive or Idle state derives new security keys for integrity protection and encryption and configures the lower layer (e.g., the UE-PDCP layer) to apply them. The UE can have a stored NCC value and a resume identity. The UE can receive an RRC Release message with a suspend indication (or suspend configuration parameters), where the RRC Release message includes at least one of the following: a resume identity; and an NCC value. The UE-RRC layer in RRC Inactive or Idle state can reconstruct the PDCP entities for one or more bearers. The UE-RRC layer can resume one or more bearers. For example, based on resuming the RRC connection, the UE-RRC layer can resume SRB1. Based on performing UP small data transfer, the UE-RRC layer can resume one or more SRBs and DRBs. The UE-RRC layer in RRC Inactive or Idle state can send an RRC Resume Request message to the base station, where the RRC Resume Request message can include at least one of the following: a resume identity; a resumed MAC-I; and a resume reason.

[0275] For an RRC reestablishment request message, a UE in the RRC connected state may initiate an RRC connection reestablishment procedure. Based on initiating the RRC connection reestablishment procedure, the UE-RRC layer in the RRC connected state may include the physical cell identity of the source PCell and the short MAC-I in the RRC reestablishment message. The UE-RRC layer in the RRC connected state may set the short MAC-I to the 16 least significant bits of the MAC-I calculated based on a variable short MAC input, the security key for integrity protection of the RRC layer, and the integrity protection algorithm (which is used in the source PCell or the PCell where the reestablishment trigger occurred), and other security parameters (such as count, bearer, and direction). The variable short MAC input may include at least one of the following: the physical cell identity of the source cell; the C-RNTI of the source cell; and the cell identity of the target cell (e.g., the selected cell), where the cell identity is the cell identity in the system information block (e.g., SIB1) of the target cell (e.g., the selected cell). The UE-RRC layer in the RRC connected state may re-establish the PDCP entity and the RLC entity for SRB1 and apply the default SRB1 configuration parameters for SRB1. The UE-RRC layer in the RRC connected state may configure the lower layer (e.g., the PDCP layer) to suspend the integrity protection and encryption of SRB1 and resume SRB1.

[0276] The UE-RRC layer may send an RRC request message for transmission to the lower layer (e.g., the PDCP layer, the RLC layer, the MAC layer, and / or the PHY layer), where the RRC request message may be an RRC setup request message, an RRC resume request message, or an RRC reestablishment message.

[0277] The UE-RRC layer may receive an RRC setup message in response to an RRC resume request message or an RRC reestablishment request message. Based on the RRC setup message, the UE-RRC layer may discard any stored AS context, suspended configuration parameters, and the current AS security context. The UE-RRC layer may release the radio resources of all established RBs except SRB0, including releasing the associated PDCP entity and the RLC entity of the SDAP. The UE-RRC layer may release the RRC configuration except for the default L1 parameter values, the default MAC cell group configuration, and the CCCH configuration. The UE-RRC layer may indicate a fallback of the RRC connection to the upper layer (e.g., the NAS layer). If operating in the case where the timer T380 is a periodic RAN-based notification area (RNA) update timer, the UE-RRC layer may stop the timer T380.

[0278] The UE-RRC layer may receive an RRC setup message in response to an RRC setup request message, an RRC resume request message, or an RRC reestablishment request message. The RRC setup message may include cell group configuration parameters and radio bearer configuration parameters. The radio bearer configuration parameters may include at least one of signaling radio bearer configuration parameters, data radio bearer configuration parameters, and / or security configuration parameters. The security configuration parameters may include security algorithm configuration parameters and a key usage indication that indicates whether the radio bearer configuration parameters are to use the master key or the secondary key. The signaling radio bearer configuration parameters may include one or more signaling radio bearer configuration parameters. Each signaling radio configuration parameter may include at least one of an SRB identifier, PDCP configuration parameters, a reestablish PDCP indication, and / or a discard PDCP indication. The data radio bearer configuration parameters may include one or more data radio bearer configuration parameters. Each data radio configuration parameter may include at least one of a DRB identifier, PDCP configuration parameters, SDAP configuration parameters, a reestablish PDCP indication, and / or a resume PDCP indication. The radio bearer configuration in the RRC setup message may include signaling radio configuration parameters for SIB1. Based on the RRC setup message, the UE-RRC layer may establish SRB1. Based on the RRC setup message, the UE-RRC layer may perform cell group configuration or radio bearer configuration. The UE-RRC layer may stop the prohibit timer and the wait timer to facilitate the cell to send the RRC setup message. Based on receiving the RRC setup message, the UE-RRC layer may perform one or more of the following: transition to the RRC connected state; stop the cell reselection process; consider the current cell that sent the RRC setup message as the PCell and / or send an RRC establishment complete message by setting the content of the RRC establishment complete message.

[0279] The UE-RRC layer can receive an RRC resume message in response to an RRC resume request message. Based on the RRC resume message, the UE-RRC layer can discard the UE inactive AS context and release the suspended configuration parameters except for the RNA notification area information. The RRC resume message can include at least one of the following: radio bearer configuration parameters; cell group configuration parameters; measurement configuration parameters; sk counters for AS security; a first indication to request idle / inactive measurement results; a second indication to resume secondary cells (SCells) of the master cell group (MCG); a third indication to resume the secondary cell group (SCG); and SCG configuration parameters; Based on the RRC resume message, the UE-RRC layer can perform processes for configuring or resuming configuration parameters (such as cell group configuration, radio bearer configuration, and / or SCG configuration); a security key update process; and / or a measurement (configuration) process. Based on receiving the RRC resume message, the UE-RRC layer can perform one or more of the following: indicate to the upper layer (e.g., the NAS layer) that the suspended RRC connection has been resumed; resume SRB2, all DRBs, and measurements; enter the RRC connected state; stop the cell reselection process; consider the current cell that sent the RRC resume message as the PCell and / or send an RRC resume complete message by setting the content of the RRC resume complete message.

[0280] Cell group configuration parameters can be used to configure the master cell group (MCG) or the secondary cell group (SCG). If the cell group configuration parameters are used to configure the MCG, the cell group configuration parameters are master cell group configuration parameters. If the cell group configuration parameters are used to configure the SCG, the cell group configuration parameters are secondary cell group configuration parameters. A cell group contains one MAC entity, a set of logical channels with associated RLC entities and the serving cell (SpCell) as well as one or more secondary cells (SCells). The cell group configuration parameters (e.g., master cell group configuration parameters or secondary cell group configuration parameters) can include at least one of the RLC bearer configuration parameters of the cell group, the MAC cell group configuration parameters of the cell group, the physical cell group configuration parameters of the cell group, the SpCell configuration parameters of the cell group, or the SCell configuration parameters of the cell group. The MAC cell group configuration parameters can include the MAC parameters of the cell group, where the MAC parameters can include at least DRX parameters. The physical cell group configuration parameters can include cell group-specific L1 (layer 1) parameters.

[0281] The special cell (SpCell) may include the primary cell (PCell) of the MCG or the primary SCG cell (PSCell) of the SCG. The SpCell configuration parameters may include the serving cell-specific MAC and PHY parameters of the SpCell. The MR-DC configuration parameters may include at least one of the SRB3 configuration parameters, the measurement configuration parameters of the SCG, and the SCG configuration parameters.

[0282] The cell group configuration parameters may include at least one of the RLC bearer configuration parameters of the first cell group, the MAC cell group configuration parameters, the physical cell group configuration parameters, the SpCell configuration parameters, or the SCell configuration parameters of other cells of the second base station. The SpCell configuration parameters may include at least one of the radio link failure timer and constraints, radio link monitoring of the synchronization out-of-synchronization threshold, and / or the serving cell configuration parameters of the first cell. The serving cell configuration parameters may include at least one of the following: downlink BWP configuration parameters; uplink configuration parameters; uplink configuration parameters for supplementary uplink carriers (SUL); PDCCH parameters applicable to all BWPs of the serving cell; PDSCH parameters applicable to all BWPs of the serving cell; CSI measurement configuration parameters; SCell deactivation timer; cross-carrier scheduling configuration parameters of the serving cell; timing advance group (TAG) identification (ID) of the serving cell; path loss reference link indicating whether the UE should use the downlink of the SpCell or the SCell as the path loss reference for the uplink; serving cell measurement configuration parameters; channel access configuration parameters of the access procedure for shared spectrum channel access operations;

[0283] The CSI measurement configuration parameters may be to configure the CSI-RS (reference signal) belonging to the serving cell, configure the channel state information report of the CSI-RS (reference signal) belonging to the serving cell, and the channel state information report on the PUSCH triggered by DCI received on the serving cell.

[0284] In an example, the downlink BWP configuration parameters can be used to configure dedicated (UE-specific) parameters for one or more downlink BWPs. One or more downlink BWPs can include at least one of an initial downlink BWP, a default downlink BWP, and a first active downlink BWP. The downlink BWP configuration parameters can include at least one of the following: configuration parameters for one or more downlink BWPs; one or more downlink BWP IDs for one or more downlink BWPs; and a BWP inactivity timer. The configuration parameters for a downlink BWP can include at least one of the following: PDCCH configuration parameters for the downlink BWP; PDSCH configuration parameters for the downlink BWP; semi-persistent scheduling (SPS) configuration parameters for the downlink BWP; beam failure recovery SCell configuration parameters for candidate RSs; and / or radio link monitoring configuration parameters for detecting cell and beam radio link failure instances of the downlink BWP. One or more downlink BWP IDs can include at least one of an initial downlink BWP ID, a default downlink BWP identification (ID), and a first active downlink BWP ID.

[0285] In an example, the uplink configuration parameters can be uplink configuration parameters for a normal uplink carrier (not a supplementary uplink carrier). The uplink configuration parameters (or uplink configuration parameters for SUL) can be used to configure dedicated (UE-specific) parameters for one or more uplink BWPs. One or more uplink BWPs can include at least one of an initial uplink BWP and a first active uplink BWP. The uplink BWP configuration parameters can include at least one of the following: configuration parameters for one or more uplink BWPs; one or more uplink BWP IDs for one or more uplink BWPs; PUSCH parameters common to the BWPs of the UE in the serving cell; SRS carrier switching information; and power control configuration parameters. The configuration parameters for an uplink BWP can include at least one of the following: one or more PUCCH configuration parameters for the uplink BWP; PUSCH configuration parameters for the uplink BWP; one or more configured uplink grant configuration parameters for the uplink BWP; SRS configuration parameters for the uplink BWP; beam failure recovery configuration parameters for the uplink BWP; and / or cyclic prefix (CP) extension parameters for the uplink BWP.

[0286] One or more uplink BWP IDs may include at least one of an initial uplink BWP ID (e.g., initial uplink BWP ID = 0) and / or a first active uplink BWP ID. SRS carrier switching information can be used to configure SRS carrier switching when PUSCH is not configured, and SRS power control independent of PUSCH. The power control configuration parameters may include at least one of the power control configuration parameters for PUSCH, the power configuration control parameters for PUCCH, and the power control parameters for SRS.

[0287] The UE-RRC layer in the RRC inactive or idle state may receive an RRC reject message in response to an RRC establishment request message or an RRC resume request message. The RRC reject message may include a wait timer. Based on the wait timer, the UE-RRC layer may start timer T302, where the timer value is set to the wait timer. Based on the RRC reject message, the UE-RRC layer may notify the upper layer (e.g., the UE-NAS layer) of the failure to establish or resume an RRC connection. The UE-RRC layer may reset the MAC and release the default MAC cell group configuration. Based on the RRC reject received in response to a request from the upper layer, the UE-RRC layer may notify the upper layer (e.g., the NAS layer) that access prohibition applies to all access categories except categories '0' and '2'.

[0288] The UE-RRC layer in the RRC inactive or idle state may receive an RRC reject message in response to an RRC resume request message. Based on the RRC reject message, the UE-RRC layer may discard the current security key. The UE-RRC layer may re-suspend the RRC connection. If the resume is triggered due to RNA update, the UE-RRC layer may set the pending rna update value to true.

[0289] The UE-RRC layer in the RRC inactive or idle state may perform a cell (re)selection process while performing an RRC process to establish an RRC connection. Based on the cell selection or cell reselection, the UE-RRC layer may change the cell on which the UE camps and stop the RRC process. The UE-RRC layer may notify the upper layer (e.g., the NAS layer) of the failure of the RRC process.

[0290] A UE in the RRC connected state can detect a connection failure with the base station. The UE in the RRC connected state can activate AS security with the base station before detecting the failure. The failure includes at least one of the following: radio link failure (RLF); reconfiguration failure with synchronization; mobility failure from New Radio (NR); integrity check failure indication for Signaling Radio Bearer 1 (SRB1) or Signaling Radio Bearer 2 (SRB2) from a lower layer (e.g., the PDCP layer); or RRC connection reconfiguration failure.

[0291] The radio link failure can be a radio link failure of the primary cell of the base station. The base station can send a reconfiguration with synchronization to the UE in the RRC connected state in an RRC message. The reconfiguration with synchronization can include a reconfiguration timer (e.g., T304). Based on receiving the reconfiguration with synchronization, the UE can start the reconfiguration timer and perform the reconfiguration with synchronization (e.g., handover). Based on the expiration of the reconfiguration timer, the UE determines that the reconfiguration synchronization has failed. The base station can send mobility from an NR command message to the UE in the RRC connected state. Based on receiving the mobility from the NR command message, the UE can perform a handover from NR to a cell using another RAT (e.g., E-UTRA). The UE can determine a mobility failure from NR based on meeting at least one of the conditions: if the UE does not successfully establish a connection to the target radio access technology; or if the UE cannot comply with any part of the configuration included in the mobility from the NR command message; or if there is a protocol error in the inter-RAT information included in the mobility from the NR message.

[0292] Based on detecting the failure, the UE in the RRC connected state can initiate an RRC connection reestablishment procedure. Based on initiating the RRC connection reestablishment procedure, the UE can start timer T311, suspend all radio bearers except SRB0, and reset the MAC (layer). Based on initiating the RRC connection reestablishment procedure, the UE in the RRC connected state can release the MCG SCell, release the special cell (SpCell) configuration parameters and the multi-radio dual connectivity (MR-DC) related configuration parameters. For example, based on initiating the RRC connection reestablishment procedure, the UE can release the primary cell group configuration parameters.

[0293] Based on initiating the RRC connection reestablishment procedure, a UE in the RRC connected state can perform a cell selection procedure. Based on the cell selection procedure, the UE can select a cell based on the signal quality of the cell exceeding a threshold. A UE in the RRC connected state can select a cell based on the signal quality of the cell exceeding a threshold. The UE can determine that the selected cell exceeds the threshold based on the cell selection procedure. The signal quality includes at least one of the following: reference signal received power; received signal strength indicator; reference signal received quality or signal-to-interference plus noise ratio.

[0294] Based on selecting a suitable cell, a UE in the RRC connected state can stop timer 311 and start timer T301. Based on selecting a suitable cell, a UE in the RRC connected state can stop the barring timer T390 for all access categories. Based on stopping the barring timer T390, a UE in the RRC connected state can consider alleviating the barring for all access categories for the cell. Based on selecting a cell, a UE in the RRC connected state can apply default L1 parameter values other than the parameters provided in SIB1, apply the default MAC cell group configuration, apply the CCCH configuration, apply the timing alignment timer in SIB1, and initiate the transmission of an RRC reestablishment request message.

[0295] A UE in the RRC connected state can stop timer T301 based on receiving an RRC response message in response to the RRC reestablishment request message. The RRC response message can include at least one of an RRC reestablishment message, an RRC setup message, or an RRC reestablishment rejection message. When the selected cell becomes inappropriate, a UE in the RRC connected state can stop timer T301.

[0296] Based on the cell selection procedure triggered by initiating the RRC connection reestablishment procedure, a UE in the RRC connected state can select an inter-RAT cell. Based on selecting an inter-RAT cell, a UE in the RRC connected state (UE-AS layer) can transition to the RRC IDLE state and can provide the release cause 'RRC connection failure' to the upper layer (UE-NAS layer) of the UE.

[0297] Based on initiating the transmission of an RRC reestablishment request message, a UE in the RRC connected state can send an RRC reestablishment request message. The RRC reestablishment request message can include at least one of the C-RNTI used in the source PCell, the physical cell identifier (PCI) of the source PCell, the short MAC-I, or the reestablishment cause. The reestablishment cause can include at least one of reconfiguration failure, handover failure, or other failures.

[0298] Based on the transmission of the RRC Reestablishment Request message, a UE (RRC layer) in the RRC connected state can reestablish the PDCP of SRB1, reestablish the RLC of SRB1, apply the default SRB configuration of SRB1, configure the lower layer (PDCP layer) to suspend the integrity protection and encryption of SRB1, resume SRB1 and submit the RRC Reestablishment Request message to the lower layer (PDCP layer) for transmission. Based on submitting the RRC Reestablishment Request message to the lower layer, a UE in the RRC connected state can send the RRC Reestablishment Request message to the target base station via the cell selected based on the cell selection procedure, where the target base station may or may not be the source base station.

[0299] Based on the expiration of timer T311 or T301, a UE (UE-AS layer) can transition to the RRC idle state and can provide the release cause 'RRC connection failure' to the upper layer (UE-NAS layer) of the UE.

[0300] Based on receiving the release cause "RRC connection failure", when the UE does not have outstanding signaling and user data pending, a UE (UE-NAS layer) in the RRC idle state can perform the NAS signaling connection restoration procedure. Based on performing the NAS signaling connection restoration procedure, a UE in the RRC idle state can initiate the registration procedure by sending a registration request message to the AMF.

[0301] Based on receiving the release cause "RRC connection failure", when the UE has outstanding signaling or outstanding user data, a UE (UE-NAS layer) in the RRC idle state can perform the service request procedure by sending a service request message to the AMF.

[0302] Based on receiving the RRC Reestablishment Request message, the target base station can check whether the UE context of the UE is locally available. Based on the UE context not being locally available, the target base station can perform the UE context retrieval procedure by sending a UE context retrieval request message to the source base station (the last serving base station) of the UE.

[0303] For the RRC connection reestablishment procedure, the UE context retrieval request message may include at least one of a UE context ID, integrity protection parameters, or a new cell identifier. The UE context ID may include at least one of the following: the C-RNTI containing the RRC Reestablishment Request message; and the PCI of the source PCell (the last serving PCell). The integrity protection parameters for the RRC connection reestablishment procedure may be the short MAC-I. The new cell identifier may be the identifier of the target cell, where the target cell is the cell for which the RRC connection has been requested to be reestablished. The new cell identifier is the cell identity in the system information block (e.g., SIB1) of the target cell (e.g., the selected cell).

[0304] For the RRC connection reestablishment procedure, based on receiving a Retrieve UE Context Request message, the source base station may check the Retrieve UE Context Request message. If the source base station can identify the UE context by means of the UE context ID, and can successfully authenticate the UE by means of the integrity protection included in the Retrieve UE Context Request message, and decides to provide the UE context to the target base station, the source base station may respond to the target base station with a Retrieve UE Context Response message. If the source base station cannot identify the UE context by means of the UE context ID, or if the integrity protection included in the Retrieve UE Context Request message is not valid, the source base station may respond to the target base station with a Retrieve UE Context Failure message.

[0305] For the RRC connection reestablishment procedure, the Retrieve UE Context Response message may include at least one of the Xn Application Protocol (XnAP) ID of the target base station, the XnAP ID of the source base station, the Globally Unique AMF Identifier (GUAMI), or UE context information (e.g., UE context information Retrieve UE Context Response). The UE context information may include at least one of the NG-C UE association signaling reference, UE security capabilities, AS security information, UE aggregate maximum bitrate, PDU session list to be set, RRC context, mobility restriction list, or index to RAT / frequency selection priority. The NG-C UE association signaling reference may be the NG application protocol ID assigned at the AMF of the UE on the NG-C connection with the source base station. The AS security information may include the security key (K gNB ) of the base station and the Next Hop Link Count (NCC) value. The PDU session list to be set may include PDU session resource related information used at the UE context in the source base station. The PDU session resource related information may include the PDU session ID, PDU session resource aggregate maximum bitrate, security indication, PDU session type, or QoS flow list to be set. The security indication may include a user plane integrity protection indication and a confidentiality protection indication, which respectively indicate the requirements for user plane (UP) integrity protection and encryption for the corresponding PDU session. The security indication may also include an indication of whether to apply UP integrity protection to the PDU session, an indication of whether to apply UP encryption to the PDU session, and at least one of the maximum integrity protection data rate values (uplink and downlink) for each UE for integrity protection DRB. The PDU session type may indicate at least one of Internet Protocol version 4 (IPv4), IPv6, IPv4v6, Ethernet, or unstructured. The QoS flow list to be set may include at least one of the QoS flow identifier, QoS flow level QoS parameters (QoS parameters to be applied to the QoS flow), or bearer identifier.

[0306] For the RRC connection reestablishment procedure, the UE context retrieval failure message may include at least the XnAP ID of the target base station and a cause value.

[0307] For the RRC connection reestablishment procedure, based on receiving the UE context retrieval response message, the target base station may send an RRC reestablishment message to the UE. The RRC reestablishment message may include at least a network hop link count (NCC) value.

[0308] Based on receiving the RRC reestablishment message, the UE may derive a new security key (K gNB of the base station based on at least one of the current K gNB associated with the NCC value or the next hop (NH) parameter. Based on the new security key of the base station and the previously configured integrity protection algorithm, the UE may derive a security key (K RRCint ) for RRC signaling integrity protection and a security key (K UPint ) for integrity protection of user plane (UP) data. Based on the new security key of the base station and the previously configured encryption algorithm, the UE may derive a security key (K RRCenc ) for encrypting RRC signaling and a security key (K UPenc ) for encrypting user plane (UP) data. Based on K RRCint and the previously configured integrity protection algorithm, the UE may verify the integrity protection of the RRC reestablishment message. Based on a verification failure, the UE (UE-AS layer) may enter the RRC IDLE state and may provide a release cause "RRC connection failure" to the upper layer (UE-NAS layer) of the UE. Based on a verification success, the UE may be configured to resume the integrity protection of SRB1 based on the previously configured integrity protection algorithm and K RRCint , and configured to resume the encryption of SRB1 based on the previously configured encryption algorithm and K RRCenc . The UE may send an RRC reestablishment complete message to the target base station.

[0309] Based on receiving the UE context retrieval failure message, the target base station may send an RRC release message to the UE. For example, based on the UE context retrieval failure message containing the RRC release message, the target base station may send an RRC release message to the UE. Based on receiving the UE context retrieval failure message, the target base station may send an RRC setup message or an RRC reject message. Based on receiving the UE context retrieval failure message, the target base station may not send any response message to the UE.

[0310] Figure 17An example of an RRC connection reestablishment procedure is shown. A UE in the RRC connected state can send and receive data to / from a first base station (e.g., a source base station) via a cell, where the cell includes the primary cell (PCell) of the first base station. The UE can detect a failure of the connection to the first base station. Based on this failure, the UE can initiate an RRC reestablishment procedure.

[0311] In Figure 17 the example, based on initiating the RRC connection reestablishment procedure, the UE can start timer T311, suspend all radio bearers except SRB0, and / or reset the MAC (layer). Based on initiating the RRC connection reestablishment procedure, the UE can release the MCG SCell, release the special cell (SpCell) configuration parameters and the multi-radio dual connection (MR-DC) related configuration parameters. Based on initiating the RRC connection reestablishment procedure, the UE can perform a cell selection procedure. Based on the cell selection procedure, the UE can select cell 2 of a second base station (e.g., a target base station), where cell 2 is a suitable cell. Based on selecting the suitable cell, the UE can stop timer T311 and start timer T301. Based on selecting the suitable cell, if one or more barred timers T309 are running, the UE can stop one or more barred timers T309 for all access categories. Based on stopping one or more barred timers T309, the UE can consider alleviating the barring for all access categories for this cell. Based on selecting the cell, the UE can apply default L1 parameter values other than those provided in SIB1, apply the default MAC cell group configuration, apply the CCCH configuration, apply the timer alignment timer in SIB1, and initiate the transmission of an RRC reestablishment request message.

[0312] In Figure 17 the example, the RRC reestablishment message can include at least one of the C-RNTI used in the source PCell (e.g., cell 1), the physical cell identifier (PCI) of the source PCell, the short MAC-I, or the reestablishment cause. Based on initiating the transmission of the RRC reestablishment request message, the UE (RRC layer) can reestablish the PDCP of SRB1, reestablish the RLC of SRB1, apply the default SRB configuration of SRB1, configure the lower layer (PDCP layer) to suspend the integrity protection and encryption of SRB1, resume SRB1 and submit the RRC reestablishment request message to the lower layer (PDCP layer) for transmission. Based on initiating the transmission of the RRC reestablishment request message, the UE can send the RRC reestablishment request message to the second base station via cell 2.

[0313] In Figure 17In the example, based on receiving the RRC Reestablishment Request message, the second base station may check whether the UE context of the UE is locally available. Based on the UE context not being locally available, the second base station may perform a UE context retrieval procedure by sending a UE context retrieval request message to the source base station of the UE. The UE context retrieval request message may include at least one of the following: a UE context ID; an integrity protection parameter or a new cell identifier. The UE context ID may include at least one of the following: the C-RNTI containing the RRC Reestablishment Request message; and the PCI of the source PCell (the last serving PCell). The integrity protection parameter for the RRC reestablishment procedure may be the short MAC-I. The new cell identifier may be the identifier of the target cell, where the target cell is the cell for which the RRC connection reestablishment has been requested. The new cell identifier is the cell identifier in the system information block (e.g., SIB1) of the target cell (e.g., the selected cell).

[0314] In Figure 17 the example, based on receiving the UE context retrieval request message, the source base station may check the UE context retrieval request message. If the source base station successfully identifies the UE context by means of the C-RNTI, and successfully authenticates the UE by means of the short MAC-I, and decides to provide the UE context to the second base station, the source base station may respond to the second base station with a UE context retrieval response message. The UE context retrieval response message may include at least the GUAMI or the UE context information. Based on receiving the UE context retrieval response message, the second base station may send an RRC reestablishment message to the UE. The RRC reestablishment message may include a network hop link count (NCC) value.

[0315] In Figure 17 the example, based on receiving the RRC reestablishment message, the UE may derive a new security key (K gNB of the base station based on at least one of the current K gNB associated with the NCC value or the next hop (NH) parameter. Based on the new security key (K gNB ) of the base station and the previously configured security algorithm, the UE may derive the security keys for the integrity protection and encryption of the RRC signaling (e.g., K RRCint and K RRCenc ) respectively, and the security keys for the integrity protection and encryption of the user plane (UP) data (e.g., K UPint and K UPenc ). Based on the security key (K RRCint ) for the integrity protection of the RRC signaling, the UE may verify the integrity protection of the RRC reestablishment message. Based on successful verification, the UE may be configured to be based on the previously configured integrity protection algorithm and K RRCintTo resume integrity protection for one or more bearers (e.g., signaling radio bearers or RRC messages) and configured based on a previously configured encryption algorithm and K RRCenc To resume encryption for one or more bearers.

[0316] In Figure 17 's example, the second base station may send a first RRC reconfiguration message. The RRC first reconfiguration message may include SpCell configuration parameters. Based on the received SpCell configuration parameters, the UE may initiate transmitting and receiving data to / from the second base station. The UE may send an RRC reestablishment complete message to the second base station. The RRC reestablishment complete message may include a measurement report. Based on the received measurement report, the second base station may determine to configure an SCell and / or a secondary cell group (e.g., SCG or PSCell). Based on this determination, the second base station may send a second RRC reconfiguration message including SCell configuration parameters and / or MR-DC related configuration parameters. Based on the received second RRC reconfiguration message, the UE may transmit and receive data via the SCell and / or SCG.

[0317] In Figure 17 's example, the RRC reconfiguration message may include at least one of cell group configuration parameters of the MCG and / or SCG, radio bearer configuration parameters, or AS security key parameters.

[0318] The base station may initiate an RRC connection release procedure to transition the UE's RRC state from the RRC connected state to the RRC idle state, from the RRC connected state to the RRC inactive state, from the RRC inactive state to the RRC inactive state when the UE attempts to resume, or from the RRC inactive state to the RRC idle state when the UE attempts to resume. The RRC connection procedure may also be used to release the UE's RRC connection and redirect the UE to another frequency. The base station may send an RRC release message including suspension configuration parameters to the UE. Based on the RRC release message, the UE may suspend the RRC connection. The UE may transition the UE's RRC state to the RRC inactive state or the RRC idle state. The suspension configuration parameters may include at least one of the following: resume identity, RNA configuration, RAN paging cycle, or network hop link count (NCC) value, where the RNA configuration may include RNA notification area information or a periodic RNA update timer value (e.g., T380 value). When the UE is in the RRC inactive state, the base station may use a resume identity (e.g., inactive RNTI (I-RNTI)) to identify the UE context.

[0319] If the base station has a new and unused {NCC, Next Hop (NH)} pair, the base station may include the NCC in the suspension configuration parameters. Otherwise, the base station may include the same NCC associated with the current K gNB in the suspension configuration parameters. The NCC is used for AS security. After sending an RRC Release message containing the suspension configuration parameters to the UE, the base station may delete the current AS keys (e.g., K RRCenc , K UPenc ) and K Upint , but may keep the current AS key K RRCint . If the sent NCC value is new and belongs to an unused {NCC, NH} pair, the base station may save the {NCC, NH} pair in the current UE AS security context and may delete the current AS key K gNB . If the sent NCC value is equal to the NCC value associated with the current K gNB , the base station may keep the current AS key K gNB and the NCC. The base station may store the sent resume identity together with the current UE context, which includes the remainder of the AS security context.

[0320] After receiving an RRC Release message containing the suspension configuration parameters from the base station, the UE may verify that the integrity of the received RRC Release message containing the suspension configuration parameters is correct by checking the PDCP MAC-I. If this verification is successful, the UE may obtain the received NCC value and save it as the stored NCC with the current UE context. The UE may delete the current AS keys K RRCenc , K Upenc and K Upint , but keep the current AS key K RRCint key. If the stored NCC value is different from the NCC value associated with the current K gNB , the UE may delete the current AS key K gNB . If the stored NCC is equal to the NCC value associated with the current K gNB , the UE will keep the current AS key KgNB. The UE may store the received resume identity together with the current UE context including the remainder of the AS security context for the next state transition.

[0321] Upon receiving an RRC release message containing suspension configuration parameters, the UE may reset the MAC, release the default MAC cell group configuration, and re-establish the RLC entities for one or more bearers. Upon receiving an RRC release message containing suspension configuration parameters, the UE may store the current configuration parameters and the current security keys in the UE inactive AS context. For example, the UE may store some current configuration parameters. The stored current configuration parameters may include the robust header compression (ROHC) state, the QoS flow to DRB mapping rule, the C-RNTI used in the source PCell, the global cell identity and physical cell identity of the source PCell, and all other parameters configured except for the parameters within the reconfiguration with synchronization and the common parameters of the serving cell configuration in the SIB. The stored security keys may include K gNB and K RRCint at least one of. The common parameters of the serving cell configuration in the SIB may be used to configure the cell-specific parameters of the serving cell of the UE in SIB1. Upon receiving an RRC release message containing suspension configuration parameters, the UE may suspend all SRBs and DRBs except SRB0. Upon receiving an RRC release message containing suspension configuration parameters, the UE may start timer T380, enter the RRC inactive state, and perform a cell selection procedure.

[0322] A UE in the RRC inactive state may initiate an RRC connection resume procedure. For example, based on having data or signaling to transmit or receive an RAN paging message, a UE in the RRC inactive state may initiate an RRC connection resume procedure. Based on initiating the RRC connection resume procedure, the UE may select an access category based on the trigger condition of the RRC connection resume procedure and perform a unified access control procedure based on the access category. Based on the unified access control procedure, the UE may consider the access attempt of the RRC connection resume procedure as permitted. Based on considering the access attempt as permitted, the UE may apply the default L1 parameter values specified in the corresponding physical layer specification, apply the default SRB1 configuration except for the parameters for which values are provided in SIB1, apply the CCCH configuration, apply the common timing alignment timer included in SIB1, apply the default MAC cell group configuration, start timer T319 and initiate the transmission of an RRC resume request message.

[0323] Based on initiating the transmission of an RRC resume request message, the UE may set the content of the RRC resume request message. The RRC resume request message may include at least one of a resume identity, a resume MAC-I, or a resume cause. The resume cause may include at least one of emergency, high-priority access, mt access, mo signaling, mo data, mo voice call, mo sms, ran update, mps priority access, mcs priority access.

[0324] Based on the transmission of the RRC Resume Request message, in addition to the master cell group configuration parameters, MR-DC related configuration parameters (e.g., secondary cell group configuration parameters) and PDCP configuration parameters, the UE can restore the stored configuration parameters and the stored security keys from the (stored) UE Inactive AS context. The configuration parameters can include at least one of the following: the C-RNTI used in the source PCell, the global cell identifier and the physical cell identifier of the source PCell, and all other parameters configured except for the parameters within the reconfiguration with synchronization and the common parameters of the serving cell configuration in the SIB. Based on the current (restored) K associated with the stored NCC value gNB or the next-hop (NH) parameter, the UE can derive a new key (K gNB ) of the base station. Based on the new key of the base station, the UE can derive the security keys for integrity protection and encryption of the RRC signaling (e.g., K RRCenc and K RRCint ) respectively, and the security keys for integrity protection and encryption of the user plane data (e.g., K Upint and K Upenc ) respectively. Based on the configured algorithm and K RRCint and K Upint , the UE can configure the lower layer (e.g., the PDCP layer) to apply integrity protection to all radio bearers except SRB0. Based on the configured algorithm and K RRCenc and K Upenc , the UE can configure the lower layer (e.g., the PDCP layer) to apply encryption to all radio bearers except SRB0.

[0325] Based on the transmission of the RRC Resume Request message, the UE can reconstruct the PDCP entity for one or more bearers, resume one or more bearers and submit the RRC Resume Request message to the lower layer, where the lower layer can include at least one of the PDCP layer, the RLC layer, the MAC layer or the physical (PHY) layer.

[0326] The target base station can receive the RRC Resume Request message. Based on receiving the RRC Resume Request message, the target base station can check whether the UE context of the UE is locally available. Based on the UE context not being locally available, the target base station can perform the UE context retrieval process by sending a UE context retrieval request message to the source base station (the last serving base station) of the UE. The UE context retrieval request message can include at least one of the UE context ID, the integrity protection parameter, the new cell identifier or the resume reason, where the resume reason is in the RRC Resume Request message.

[0327] For the RRC connection restoration procedure, based on receiving the Retrieve UE Context Request message, the source base station may check the Retrieve UE Context Request message. If the source base station can identify the UE context by means of the UE context ID, and can successfully authenticate the UE by means of the integrity protection included in the Retrieve UE Context Request message, and decides to provide the UE context to the target base station, the source base station may respond to the target base station with a Retrieve UE Context Response message. If the source base station cannot identify the UE context by means of the UE context ID, or if the integrity protection included in the Retrieve UE Context Request message is not valid, or if the source base station decides not to provide the UE context to the target base station, the source base station may respond to the target base station with a Retrieve UE Context Failure message.

[0328] For the RRC connection restoration procedure, the Retrieve UE Context Failure message may include at least the XnAP ID of the target base station, the RRC release message, or the cause value.

[0329] For the RRC connection restoration procedure, based on receiving the Retrieve UE Context Response message, the target base station may send an RRC Resume message to the UE. The RRC Resume message may include at least one of radio bearer configuration parameters, cell group configuration parameters of MCG and / or SCG, measurement configuration parameters, or the sk counter, where the sk counter is used to derive the security key of the secondary base station based on K gNB derived from the security key of the secondary base station.

[0330] Based on receiving the Retrieve UE Context Failure message, the target base station may send an RRC release message to the UE. For example, based on the Retrieve UE Context Failure message including the RRC release message, the target base station may send an RRC release message to the UE. Based on receiving the Retrieve UE Context Failure message, the target base station may send an RRC setup message or an RRC reject message. Based on receiving the Retrieve UE Context Failure message, the target base station may not send any response message to the UE.

[0331] Based on receiving the RRC Resume message, the UE may stop timers T319 and T380. Based on receiving the RRC Resume message, the UE may resume the master cell group configuration parameters, secondary cell group configuration parameters, and PDCP configuration parameters in the UE Inactive AS context. Based on resuming the master cell group configuration parameters and / or secondary cell group configuration parameters, the UE may configure the SCell of MCG and / or SCG by configuring the lower layer to consider the resumed MCG and / or SCG SCell as being in the deactivated state, discard the UE Inactive AS context, and release the suspended configuration parameters.

[0332] Based on the cell group configuration parameters received in the RRC resume message, the UE can perform the cell group configuration of the MCG and / or SCG. Based on the radio bearer configuration parameters received in the RRC resume message, the UE can perform the radio bearer configuration. Based on the sk counter in the RRC resume message, the UE can perform the update of the security key of the secondary base station.

[0333] The UE can remain in CM-CONNECTED and move within the area configured by the base station without notifying the base station when the UE is in the RRC inactive state with the area as the RNA. In the RRC inactive state, the last serving base station can maintain the UE context and the NG connection associated with the UE to the serving AMF and UPF. Based on the downlink data received from the UPF or the downlink UE-associated signaling received from the AMF when the UE is in the RRC inactive state, the last serving base station can page in the cell corresponding to the RNA and, in the case where the RNA includes the cells of neighboring base stations, send a RAN page to the neighboring base stations via the Xn interface.

[0334] The AMF can provide core network assistance information to the base station to assist the base station in deciding whether the UE can be sent to the RRC inactive state. The core network assistance information can include the registered area configured for the UE, the periodic registration update timer, the UE identity index value, UE-specific DRX, an indication of whether the UE is configured with the mobile-initiated connection only (MICO) mode by the AMF; or the expected UE behavior. The base station can use the UE-specific DRX and the UE identity index value to determine the paging occasion for RAN paging. The base station can use the periodic registration update timer to configure the periodic RNA update timer (e.g., timer T380). The base station can use the expected UE behavior to assist in the UE RRC state transition decision.

[0335] Figure 18 An example of the RRC connection resume procedure is shown. The UE in the RRC connected state can transmit and receive data to / from the first base station (source base station) via cell 1. The first base station can determine to transition the UE in the RRC connected state to the RRC inactive state. Based on this determination, the base station can send an RRC release message containing the suspension configuration parameters.

[0336] In Figure 18In the example, based on receiving an RRC release message containing suspension configuration parameters, the UE may store the current security keys (e.g., KgNB and KRRCint keys) and the current configuration parameters in the UE inactive AS context. For example, the UE may store some current configuration parameters. The stored (current) configuration parameters may be at least one of the following: Robust Header Compression (ROHC) status; QoS flow to DRB mapping rule; C-RNTI used in the source PCell; global cell identity and physical cell identity of the source PCell; and all other parameters configured except for the parameters within the reconfiguration with synchronization and the common service cell configuration parameters in the SIB. The Robust Header Compression (ROHC) status may include the ROHC status of all PDCP entities (or all bearers), where each PDCP entity (or each bearer) of each bearer may have an ROHC status. The QoS flow to DRB mapping rule may be the QoS flow to DRB mapping rule for all data radio bearers (DRBs), where each DRB may have a QoS flow to DRB mapping rule.

[0337] In Figure 18 the example, based on receiving an RRC release message containing suspension configuration parameters, the UE may suspend all SRBs and DRBs except SRB0. Based on receiving an RRC release message containing suspension configuration parameters, the UE may start timer T380, enter the RRC inactive state, and perform a cell selection procedure. Based on the cell selection procedure, the UE may select cell 2 of the second base station (target base station). The UE in the RRC inactive state may initiate an RRC connection resume procedure. The UE may perform a unified access control procedure. Based on the unified access control procedure, the UE may consider the access attempt of the RRC connection resume procedure as permitted. The UE may apply the default L1 parameter values specified in the corresponding physical layer specification, apply the default SRB1 configuration except for the parameters for which values are provided in SIB1, apply the CCCH configuration, apply the common timing alignment timer included in SIB1, apply the default MAC cell group configuration, start timer T319, and initiate the transmission of an RRC resume request message.

[0338] In Figure 18 the example, based on initiating the transmission of an RRC resume request message, the UE may recover the stored configuration parameters and the stored security keys from the (stored) UE inactive AS context. For example, except for the primary cell group configuration parameters, MR-DC related configuration parameters (e.g., secondary cell group configuration parameters), and PDCP configuration parameters, the UE may recover the stored configuration parameters and the stored security keys (e.g., K gNB and K RRCint)。Based on the current (recovered) K associated with the stored NCC value gNB or the next-hop (NH) parameter, the UE can derive a new key (K gNB ) for the base station. Based on the new key for the base station, the UE can derive security keys for integrity protection and encryption of RRC signaling (e.g., K RRCenc and K RRCint ) and security keys for integrity protection and encryption of user plane data (e.g., K Upint and K Upenc ). Based on the configured algorithm and K RRCint and K Upint , the UE (RRC layer) can configure the lower layer (e.g., PDCP layer) to apply integrity protection to all radio bearers except SRB0. Based on the configured algorithm and K RRCenc and K Upenc , the UE can configure the lower layer (e.g., PDCP layer) to apply encryption to all radio bearers except SRB0. For communication between the UE and the base station, integrity protection and / or encryption may be required. Based on integrity protection and / or encryption, the UE may be able to transmit and receive data to / from a second base station. The UE can use the recovered configuration parameters to transmit and receive data to / from the second base station.

[0339] In Figure 18 's example, based on the transmission of the RRC resume request message, the UE can reconstruct PDCP entities for one or more bearers, resume one or more bearers, and submit the RRC resume request message to the lower layer. Based on receiving the RRC resume request message, the second base station can check whether the UE context is locally available. Based on the UE context not being locally available, the second base station can perform a UE context retrieval process by sending a UE context retrieval request message to the UE's first base station (the last serving base station). The UE context retrieval request message can include at least one of the following: resume identity; resume MAC-I; or resume reason.

[0340] In Figure 18In an example, based on receiving a Retrieve UE Context Request message, the first base station may check the Retrieve UE Context Request message. If the first base station can identify the UE context by means of the UE context ID, and can successfully authenticate the UE by means of the recovered MAC-I, and decides to provide the UE context to the second base station, the first base station may respond to the second base station with a Retrieve UE Context Response message. Based on receiving the Retrieve UE Context Response message, the second base station may send an RRC Resume message to the UE. Based on receiving the RRC Resume message, the UE may resume the master cell group configuration parameters, the secondary cell group configuration parameters, and the PDCP configuration parameters in the UE Inactive AS context. Based on resuming the master cell group configuration parameters and / or the secondary cell group configuration parameters, the UE may configure the SCell of the MCG and / or SCG by configuring the lower layer to consider the resumed MCG and / or SCG SCell as being in the deactivated state, discard the UE Inactive AS context, and release the suspended configuration parameters. The UE may transmit and receive data via the SCell and / or SCG.

[0341] The base station may send an RRC Release message to the UE to release the RRC connection of the UE. Based on the RRC Release message, the UE may release the established radio bearers and all radio resources.

[0342] The base station may send an RRC Release message to the UE to suspend the RRC connection. Based on the RRC Release message, the UE may suspend all radio bearers except the signaling radio bearer 0 (SRB0). The RRC Release message may contain suspended configuration parameters. The suspended configuration parameters may include the next-hop link count (NCC) and the resume identifier (e.g., ID or identifier).

[0343] The base station may send an RRC Release message to transition a UE in the RRC connected state to the RRC idle state; or transition a UE in the RRC connected state to the RRC inactive state; or transition a UE in the RRC inactive state back to the RRC inactive state when the UE attempts to resume; or transition a UE in the RRC inactive state to the RRC idle state when the UE attempts to resume.

[0344] The base station may send an RRC Release message to redirect the UE to another frequency.

[0345] The UE can receive an RRC release message from the base station of the serving cell (or Pcell). Based on the RRC release message, the UE can perform UE actions for the RRC release message from the base station. From the moment the RRC release message is received or when the reception of the RRC release message is successfully confirmed, the UE can delay the UE actions for the RRC release message for a period of time (e.g., 60 ms). The UE can send a HARQ acknowledgment to the base station to confirm the RRC release message. Based on the RLC protocol data unit (PDU) containing the RRC release message and the RLC PDU containing the polling bit, the UE can send an RLC message (e.g., a status report) to the base station to confirm the RRC release message.

[0346] The UE actions for the RRC release message from the base station can include at least one of the following: pausing the RRC connection; releasing the RRC connection; cell (re)selection process; and / or idle / inactive measurement.

[0347] The RRC release message from the base station can include suspension configuration parameters. Based on the suspension configuration parameters, the UE can perform pausing the RRC connection. Pausing the RRC connection can include at least one of the following: media access control (MAC) reset (or reset MAC); releasing the default MAC cell group configuration; reconstructing the RLC entity for one or more radio bearers; storing the current configuration parameters and the current security key; pausing one or more bearers, where the bearer includes a signaling radio bearer and a data radio bearer; and / or transitioning to the RRC idle state or the RRC inactive state.

[0348] For example, the suspension configuration parameters can also include RNA configuration parameters. Based on the RNA configuration parameters, the UE can transition to the RRC inactive state. For example, based on the suspension configuration parameters not including the RNA configuration parameters, the UE can transition to the RRC idle state. For example, the RRC release message containing the suspension configuration parameters can include an indication to transition to the RRC inactive state. Based on this indication, the UE can transition to the RRC inactive state. For example, based on the RRC release message not including this indication, the UE can transition to the RRC idle state.

[0349] Based on the MAC reset, the UE may perform at least one of the following: stop all timers running in the UE-MAC layer; consider all time alignment timers as expired; set the new data indicator (NDI) of all uplink HARQ processes to the value 0; stop ongoing RACH processes; discard explicitly signaled contention-free random access resources (if any); flush the Msg 3 buffer; cancel triggered scheduling request processes; cancel triggered buffer status report processes; cancel triggered power headroom report processes; flush the soft buffers of all DL HARQ processes; for each DL HARQ process, consider the next received transmission of the TB as the first transmission; and / or release the temporary C-RNTI.

[0350] Based on considering the time alignment timer as expired, the UE may perform at least one of the following: flush all HARQ buffers of all serving cells; notify the RRC to release the PUCCH for all serving cells, if configured; notify the RRC to release the SRS for all serving cells, if configured; clear any configured downlink assignments and configured uplink authorizations; clear any PUSCH resources for semi-persistent CSI reporting; and / or consider all running time calibration timers as expired.

[0351] The default MAC cell group configuration parameters may include the buffer status report (BSR) configuration parameters (e.g., BSR timer) of the cell group of the base station and the power headroom report (PHR) configuration parameters (e.g., PHR timer or PHR transmission power factor change parameter) of the cell group of the base station.

[0352] Reconstructing the RLC entity may include at least one of the following: discarding all RLC SDUs, RLC SDU segments, and RLCPDUs, if any; stopping and resetting the timers of all RLC entities; and resetting all state variables of the RLC entity to their initial values.

[0353] The RRC release message from the base station may not include the suspension configuration parameters. Based on the RRC message not including the suspension configuration parameters, the UE may perform releasing the RRC connection. Releasing the RRC connection may include at least one of the following: MAC reset (or reset MAC); discarding stored configuration parameters and stored security keys (or discarding the stored UE inactive AS context); releasing the suspension configuration parameters; releasing all radio resources, including releasing the RLC entities, MAC configurations, and associated PDCP entities and SDAPs for all established radio bearers; and / or transitioning to the RRC idle state.

[0354] The RRC release message may include an RRC early data completion message.

[0355] The layer may be associated with the Open Systems Interconnection (OSI) model of computer networking functionality. In the OSI model, layer 1 may correspond to the bottom layer, with higher layers on top of the bottom layer. Layer 1 may correspond to the physical layer, which is related to the physical infrastructure (such as cables, optical fibers, and / or radio frequency transceivers) for transmitting signals. In New Radio (NR), layer 1 may include the Physical Layer (PHY). Layer 2 may correspond to the data link layer. Layer 2 may be related to packaging data (such as into data frames) for transfer between nodes of the network using the physical infrastructure of layer 1. In NR, layer 2 may include the Media Access Control layer (MAC), the Radio Link Control layer (RLC), the Packet Data Convergence Protocol layer (PDCP), and the Service Data Application Protocol layer (SDAP).

[0356] Layer 3 may correspond to the network layer. Layer 3 may be related to routing the data encapsulated in layer 2. Layer 3 may handle prioritization of data and traffic avoidance. In NR, layer 3 may include the Radio Resource Control layer (RRC) and the Non-Access Stratum layer (NAS). Layers 4 through 7 may correspond to the transport layer, the session layer, the presentation layer, and the application layer. The application layer interacts with the end user to provide data associated with the application. In an example, the end user implementing the application may generate data associated with the application and initiate the transmission of the information to a target data network (such as the Internet, an application server, etc.). Starting at the application layer, each layer in the OSI model may manipulate and / or repackage the information and deliver it to the lower layer. At the lowest layer, the manipulated and / or repackaged information may be exchanged via the physical infrastructure (such as electrically, optically, and / or electromagnetically). As it approaches the target data network, the information will be unpackaged and provided to increasingly higher layers until it reaches the application layer again in a form usable by the target data network (such as the same form as when it was provided by the end user). In response to the end user, the data network may perform this procedure in reverse.

[0357] Figure 2B The user plane protocol stack shown may be the New Radio (NR) protocol stack for the Uu interface between the UE and the gNB. In layer 1 of the UP protocol stack, the UE may implement the PHY and the gNB may implement the PHY. In layer 2 of the UP protocol stack, the UE may implement the MAC, RLC, PDCP, and SDAP. The gNB may implement the MAC, RLC, PDCP, and SDAP.

[0358] Figure 2BThe control plane protocol stack shown may be an NR protocol stack for the Uu interface between the UE and the gNB and / or the N1 interface between the UE and the AMF. In layer 1 of the CP protocol stack, the UE 1901 may implement the PHY and the gNB may implement the PHY. In layer 2 of the CP protocol stack, the UE may implement MAC, RLC, PDCP, RRC, and NAS. The gNB may implement MAC, RLC, PDCP, and RRC. The AMF may implement NAS.

[0359] Figure 2B The NAS shown may be related to the non-access stratum, specifically, the communication between the UE and the core network (e.g., the AMF). The lower layers may be related to the access stratum, e.g., the communication between the UE and the gNB. Messages sent between the UE and the core network may be referred to as NAS messages. In an example, the NAS messages may be relayed by the gNB, but the content of the NAS messages (e.g., the information elements of the NAS messages) may be invisible to the gNB.

[0360] In Figure 3 , the UE may receive services via a PDU session, and the PDU session may be a logical connection between the UE and a data network (DN). The UE and the DN may exchange data packets associated with the PDU session. The PDU session may include one or more quality of service (QoS) flows. The SDAP may perform mapping and / or demapping between the one or more QoS flows of the PDU session and one or more radio bearers (e.g., data radio bearers). The mapping between the QoS flow and the data radio bearer may be determined by the gNB in the SDAP and the UE may be notified of the mapping (e.g., based on control signaling and / or reflective mapping). For reflective mapping, the SDAP of the gNB may mark the downlink packet with a QoS flow indicator (QFI) and deliver the downlink packet to the UE. The UE may determine the mapping based on the QFI of the downlink packet.

[0361] In Figure 3 , the PDCP may perform header compression and / or decompression. Header compression may reduce the amount of data transmitted on the physical layer. The PDCP and the PDCP may perform encryption and / or decryption. Encryption may reduce the unauthorized decoding of data transmitted on the physical layer (e.g., intercepted on the air interface) and protect data integrity (e.g., to ensure control messages from an established source). The PDCP may perform retransmission of undelivered packets, in-order delivery and reordering of packets, duplication of packets, and / or identification and removal of duplicate packets. In a dual connectivity scenario, the PDCP may perform mapping between split radio bearers and RLC channels.

[0362] In Figure 3In it, RLC can perform segmentation and retransmission via Automatic Repeat reQuest (ARQ). RLC can separately perform removal of duplicate data units received from and sent to MAC. RLC can separately provide RLC channels as services to PDCP.

[0363] In Figure 3 it, MAC can perform multiplexing and / or demultiplexing of logical channels. MAC and MAC can map logical channels to transport channels. In an example, the UE can multiplex data units of one or more logical channels into a transport block in MAC. The UE can use PHY to transmit the transport block to the gNB. The gNB can use PHY to receive the transport block and demultiplex the data units of the transport block back into logical channels. MAC can perform error correction via Hybrid Automatic Repeat reQuest (HARQ), logical channel prioritization, and / or padding.

[0364] In Figure 3 it, PHY can perform mapping of transport channels to physical channels. PHY and PHY can perform digital and analog signal processing functions (e.g., encoding / decoding and modulation / demodulation) for sending and receiving information (e.g., transmission via the air interface). PHY can perform multi-antenna mapping.

[0365] One or more of the base stations in the NG-RAN can be split into a Central Unit (CU) and one or more Distributed Units (DUs). The CU can be coupled to one or more DUs via the F1 interface. The CU can handle one or more upper layers in the protocol stack, and the DU can handle one or more lower layers in the protocol stack. For example, the CU can handle RRC, PDCP, and SDAP, and the DU can handle RLC, MAC, and PHY. The one or more DUs can be in geographically distinct locations relative to the CU and / or relative to each other. Accordingly, the CU / DU split architecture can allow for increased coverage and / or achieve better coordination.

[0366] The central unit can be referred to as and / or can be interchanged with: the base station central unit or the central unit of the base station or CU or gNB-CU. The distributed unit can be referred to as and / or can be interchanged with: the base station distributed unit or the distributed unit of the base station or DU or gNB-DU.

[0367] In the RRC connected state, the wireless device can measure multiple (at least one) beams of a cell and can average the measurement results (power values) to derive the cell quality. In doing so, the wireless device can be configured to consider a subset of the detected beams. Filtering can be performed at two different levels: at the physical layer for deriving the beam quality and subsequently at the RRC layer for deriving the cell quality from multiple beams. For the serving cell and non-serving cells, the cell quality from beam measurements can be derived in the same way. If the base station (e.g., gNB) configures the UE to do so, the measurement report can include the measurement results of the X best beams.

[0368] The layer 1 filtering can be an internal layer 1 filtering of the input measured at point A. The exact filtering depends on the implementation. How the measurement can be performed in the physical layer by the implementation (input A and layer 1 filtering). A is the measured value (beam-specific sample) inside the physical layer. A1 is the measured value reported by layer 1 to layer 3 after layer 1 filtering (e.g., beam-specific measurement value).

[0369] The layer 1 filtering may introduce a certain level of measurement averaging. How and when the UE precisely performs the required measurements can be implementation-specific at the point where the output at B meets the set of performance requirements. B is the measured value derived from the beam-specific measurement values reported to layer 3 after beam combining / selection (e.g., cell quality). Beam combining / selection is the beam-specific measurement value that is combined to derive the cell quality. The configuration of this module is provided by RRC signaling. The reporting period at B can be equal to one measurement period at A1.

[0370] The layer 3 filtering for cell quality can be the filtering performed on the measured values provided at point B. The configuration of the layer 3 filter can be provided by RRC signaling. The filtering reporting period at C can be equal to one measurement period at B. The layer 3 filtering for cell quality and the related parameters used may not introduce any delay in the sample availability between B and C. The measured value at point C, C1 is the input used in the event evaluation. C is the measured value after being processed in the layer 3 filter. The reporting rate is the same as the reporting rate at point B. This measured value is used as an input for one or more evaluations of the reporting criteria. The evaluation of the reporting criteria can check whether an actual measurement report is required at point D. D is the measurement report information (message) sent on the radio interface. The evaluation can be based on more than one measurement stream at reference point C, e.g., to compare between different measured values. This can be illustrated by inputs C and C1. The UE evaluates the reporting criteria at least each time a new measurement result is reported at points C, C1. The configuration can be provided by RRC signaling (UE measured values).

[0371] The L3 beam filtering and related parameters used may not introduce any delay in the sample availability between E and F. The L3 beam filtering is performed on the measurements provided at point A1 (such as beam-specific measurements). The configuration of the beam filter can be provided by RRC signaling. The L3 beam filtering can provide K beams. The K beams can correspond to the measurements on the SSB, or the CSI-RS resources configured by the base station (such as gNB) for L3 mobility and detected by the UE at L1. The filtering reporting period at E can be equal to one measurement period at A1. E is the measurement value (such as beam-specific measurement value) after being processed in the beam filter. The reporting rate can be the same as the reporting rate at point A1. This measurement value is used as the input for selecting X measurement values to be reported. The beam selection for beam reporting can select X measurement values from the measurement values provided at point E. The configuration of this module can be provided by RRC signaling. F is the beam measurement information included in the measurement report (sent) on the radio interface.

[0372] The measurement report can be characterized as follows: The measurement report includes the measurement identity of the associated measurement configuration that triggers the report; the cell and beam measurement quantities to be included in the measurement report are configured by the network; the network can limit the number of non-serving cells to be reported through configuration; the cells belonging to the blacklist configured by the network are not used in event evaluation and reporting, and conversely, when the network configures a whitelist, only the cells belonging to the whitelist are used in event evaluation and reporting; the beam measurement values to be included in the measurement report are configured by the network (only beam identifiers, measurement results, and beam identifiers, or no beam reporting).

[0373] Intra-frequency adjacent (cell) measurements and inter-frequency adjacent (cell) measurements can be defined as follows: Intra-frequency measurements based on SSB, where the measurement is defined as an intra-frequency measurement based on SSB provided that the center frequency of the SSB of the serving cell is the same as the center frequency of the SSB of the adjacent cell, and the subcarrier spacing of the two SSBs is also the same; Inter-frequency measurements based on SSB, where the measurement is defined as an inter-frequency measurement based on SSB provided that the center frequency of the SSB of the serving cell is different from the center frequency of the SSB of the adjacent cell, or the subcarrier spacing of the two SSBs is different; Intra-frequency measurements based on CSI-RS; and Inter-frequency measurements based on CSI-RS, where if the measurement is not an intra-frequency measurement based on CSI-RS, the measurement is defined as an inter-frequency measurement based on CSI-RS.

[0374] CSI-RS-based intra-frequency measurement is defined as a measurement based on CSI-RS-based intra-frequency measurement, provided that: the subcarrier spacing of the CSI-RS resources on the neighboring cell configured for measurement is the same as the SCS of the CSI-RS resources on the serving cell indicated for measurement; for a 60 kHz subcarrier spacing, the CP type of the CSI-RS resources on the neighboring cell configured for measurement is the same as the CP type of the CSI-RS resources on the serving cell indicated for measurement; and the center frequency of the CSI-RS resources on the neighboring cell configured for measurement is the same as the center frequency of the CSI-RS resources on the serving cell indicated for measurement.

[0375] For SSB-based measurement, one measurement object can correspond to one SSB, and the wireless device treats different SSBs as different cells.

[0376] Whether the measurement is non-gap-assisted or gap-assisted depends on the capabilities of the wireless device, the active BWP of the wireless device, and the current operating frequency. For inter-frequency measurement based on SSB, if the wireless device reports measurement gap requirement information, the measurement gap configuration can be provided according to this information. Otherwise, the measurement gap configuration is provided in the following cases: if the wireless device only supports per-device measurement gap; if the wireless device supports per-FR measurement gap and any serving cell in the serving cells is within the same frequency range as the measurement object. For intra-frequency measurement based on SSB, if the wireless device reports measurement gap requirement information, the measurement gap configuration can be provided according to this information. Otherwise, the measurement gap configuration is always provided in the following cases: if any of the BWPs configured for the wireless device, except for the initial BWP, does not contain the frequency domain resources of the SSB associated with the initial DL BWP.

[0377] In the non-gap-assisted scenario, the wireless device can perform such measurements without a measurement gap. In the gap-assisted scenario, the wireless device may not be considered capable of performing such measurements without a measurement gap.

[0378] In an example, a measurement timing configuration can be used to convey auxiliary information for measurement timing. The measurement timing configuration can include at least one of the following: measurement timing; camp on first SSB; PSCell on only the first SSB

[0379] (PScell only on first SSB); and CSI-RS configuration (CSI-RS-config). Measurement timing (meastiming) may include frequency and timing (frequencyandtiming); SSB for measurement (ssb-tomeasure); and physical cell identifier (physcellid). Frequency and timing (frequencyandtiming) may include at least one of the following: carrier frequency (carrierfreq); SSB subcarrier spacing (ssbSubcarrierSpacing); SSB measurement timing configuration (ssb-measurementtimingconfiguration); SS-RSSI measurement (ss-RSSI-Measurement).

[0380] In an example, the CSI-RS configuration may include at least one of the following: CSI-RS subcarrier spacing (csi-RS-subcarrierspacing); CSI-RS cell mobility (csi-RS-cellmobility); and reference SSB frequency (refSSBfreq). csi-RS-cellmobility may indicate the CSI-RS configuration of the cell including this message. The timing of the CSI-RS resource may be based on the SSB indicated by refSSBfreq. csi-RS-subcarrierspacing may indicate the subcarrier spacing of the CSI-RS resource included in csi-RS-cellmobility.

[0381] In an example, meastiming may be a list of SMTC information, SSB RSSI measurement information, and associated frequencies (e.g., NR frequencies) exchanged via the X2 interface (e.g., for X2 setup / update or DC configuration setup / update or Xn setup / update or node (e.g., base station) configuration update or F1 message) between a base station central unit and a base station distributed unit. Physcellid may be the physical cell identity of the SSB indicated by carrierfreq (carrier frequency) based on the ARFCN. CamponfirstSSB (e.g., indicated as value true) may indicate that the SSB indicated in the first meastiming instance in the meastiming list may be used for camping and PCell configuration. The meastiming list may contain one or more meastimings. ssb-tomeasure may be a set of SS blocks to be measured during the SMTC measurement duration.

[0382] In an example, carrierfreq (carrier frequency) and ssbSubcarrierSpacing (SSB subcarrier spacing) may indicate the frequency and subcarrier spacing of the SS block of the cell including this message or other SS blocks within the same carrier. ssb-measurementtimingconfiguration (SSB measurement timing configuration) may indicate the SMTC that can be used to search for the SSB of the cell including the message. SS-RSSI-measurement (SS-RSSI measurement) may provide the configuration for the RSSI measurement of the cell including the message.

[0383] The transmitter (radio transmitter) of a wireless device may be an electronic device that uses an antenna to generate radio waves. The transmitter may generate a radio frequency alternating current applied to the antenna. For example, the antenna may radiate radio waves. The term transmitter may be limited to devices that generate radio waves for communication purposes; or radio positioning (such as radar and navigation transmitters). The transmitter may be a separate piece of electronic equipment or may be a circuit within another electronic device. A transmitter and a receiver combined in one unit may be called a transceiver. In technical documents, the term transmitter is usually abbreviated as "XMTR" or "TX". The use of most transmitters may be for radio information communication over a certain distance. The information may be provided to the transmitter in the form of an electronic signal, such as an audio (sound) signal from a microphone, a video (TV) signal from a camera, or a digital signal from a computer in a wireless (network service) device. The transmitter may combine the information signal to be carried with a radio frequency signal that generates radio waves, and this radio frequency signal is called a carrier signal. This process may be called modulation. The radio signal from the transmitter may be applied to the antenna, which radiates energy in the form of radio waves. The antenna may be enclosed inside a housing or may be attached to the outside of the transmitter, as in a portable device (such as a cellular phone). The transmitter may be an antenna (group) or an antenna panel (group) or a MIMO layer (group) or a transmitter (group). Each antenna panel may have one or more antenna elements. For example, the first one or more antennas (or the first one or more antenna panels, or the first one or more MIMO layers) may be the first transmitter. The second one or more antennas (or the second one or more antenna panels, or the first one or more MIMO layers) may be the second transmitter. For example, a base station and / or a wireless device may have multiple antennas. Multiple antenna elements may be assembled into multiple antennas. Multi-panel MIMO (layers) may be used for communication between a wireless device and a base station.

[0384] In an example, a wireless device may receive a measurement configuration from a base station. The measurement configuration may indicate one or more frequencies and / or one or more cells on which the wireless device performs measurements. Based on the measurement configuration, the wireless device may perform measurements on the frequencies and / or cells indicated by the measurement configuration.

[0385] The wireless device may use the measurement configuration to perform measurements during a measurement gap, for example, indicated by the measurement configuration. In the present disclosure, a measurement gap may be referred to as a gap, a gap (period and / or interval), a measurement gap (period and / or interval), etc., and / or may be interchangeable with a gap, a gap (period and / or interval), a measurement gap (period and / or interval), etc.

[0386] A measurement gap may be a duration during which a wireless device can measure radio channel conditions associated with a cell of a specific base station (e.g., a network) and / or configured at a specific frequency using a specific RAT. For example, the specific base station (e.g., a network) may be the same base station (e.g., the same network) with which the wireless device maintains a connection (e.g., an RRC connection). For example, the specific base station (e.g., a network) may be different from the base station (e.g., a network) with which the wireless device maintains a connection (e.g., an RRC connection). For example, the specific RAT may be Wifi, LTE, NR, etc. For example, the specific RAT may be the same RAT used by the wireless device to maintain a connection (e.g., an RRC connection) with a first base station (e.g., a network). For example, the specific RAT may be different from the RAT used by the wireless device to maintain a connection (e.g., an RRC connection) with a first base station (e.g., a network).

[0387] For example, the wireless device may maintain a connection (e.g., an RRC connection) with the current base station (e.g., a network) during a measurement gap. The wireless device may not communicate with the current base station during the measurement gap. For example, the wireless device may not transmit to and / or receive data (e.g., messages, packets, SDUs, PDUs, and / or transport blocks) and / or reference signals (e.g., SRS and / or CSI-RS) from the current base station during the measurement gap. The wireless device may not monitor the downlink control channel configured by the current base station during the measurement gap. The current base station may not communicate with the wireless device during the measurement gap. For example, the current base station may not transmit to and / or receive data (e.g., messages, packets, SDUs, PDUs, and / or transport blocks) and / or reference signals (e.g., SRS and / or CSI-RS) from the wireless device during the measurement gap. The current base station may not monitor the uplink control channel configured for the wireless device during the measurement gap.

[0388] For example, a wireless device may communicate with a second device (e.g., a second wireless device, a second base station, a second network, etc.) during a measurement gap while maintaining a connection (e.g., an RRC connection) with a current base station (e.g., a network). For example, the communication with the second device may include monitoring a downlink channel (e.g., a paging channel, PDCCH, PDSCH, SSB, CSI-RS, etc.) of the second device during the measurement gap. For example, the communication with the second device may include receiving signals and / or data from the second device via a downlink channel (e.g., PDCCH, PDSCH, SSB, CSI-RS, etc.) during the measurement gap. For example, the communication with the second device may include receiving signals (e.g., reference signals, such as SSB, CSI-RS) and / or data (e.g., messages, packets, SDUs, PDUs, and / or transport blocks) from the second device via a downlink channel (e.g., PDCCH, PDSCH, SSB, CSI-RS, etc.) during the measurement gap. For example, the communication with the second device may include transmitting signals (e.g., reference signals, such as SRS, preambles, etc.) and / or data (e.g., messages, packets, SDUs, PDUs, Msg3, MsgB, and / or transport blocks) to the second device via an uplink channel (e.g., PRACH, PUSCH, PUCCH, and / or SRS, etc.) during the measurement gap.

[0389] The wireless device may not communicate with the current base station during the measurement gap. For example, the wireless device may not transmit to and / or receive data (e.g., packets, SDUs, PDUs, and / or transport blocks) and / or reference signals (e.g., SRS and / or CSI-RS) from the current base station during the measurement gap. The wireless device may not monitor a downlink control channel configured by the current base station during the measurement gap. The current base station may not communicate with the wireless device during the measurement gap. For example, the current base station may not transmit to and / or receive data (e.g., packets, SDUs, PDUs, and / or transport blocks) and / or reference signals (e.g., SRS and / or CSI-RS) from the wireless device during the measurement gap. The current base station may not monitor an uplink control channel configured for the wireless device during the measurement gap.

[0390] In an example, a wireless device may receive a measurement configuration from a base station. The measurement configuration may include a measurement gap configuration. The measurement gap configuration may include one or more configuration parameters. One or more configuration parameters of the measurement gap may indicate a period of time during which the wireless device can be used to perform measurements. One or more configuration parameters may indicate one or more measurement gaps. Each of the one or more measurement gaps may be associated with one or more frequency ranges in which the wireless device performs one or more measurements using the one or more configuration parameters. For example, each of the one or more measurement gaps may be based on a frequency or frequency range (e.g., FR1, FR2, and / or FR3) and / or the wireless device / UE. For example, a measurement gap based on a frequency range (e.g., FR1, FR2, and / or FR3) may be applied to measurements performed by the wireless device in the corresponding frequency range. A measurement gap based on the wireless device / UE may be applied to measurements performed by the wireless device at one or more (e.g., all) frequencies (e.g., FR1, FR2, and / or FR3). Each measurement gap may include at least one of the following: a measurement gap repetition period (mgrp) value, a measurement gap length (mgl) value, a gap offset value, and a serving cell identifier. The mgrp value may indicate the measurement gap repetition period (in ms) of the measurement gap. The mgl value may indicate the measurement gap length (in ms) of the measurement gap. The gap offset value may indicate the gap offset of the gap pattern using the mgrp indicated in the field mgrp.

[0391] During the measurement gap period / time, the wireless device may not transmit data to the base station. For example, the data may include at least one of the following: HARQ feedback, SR and CSI, SRS report, and UL-SCH. During the measurement gap, the wireless device may not monitor the downlink channel (e.g., PDCCH) of the serving cell of the base station. The wireless device may not receive (downlink data) on the DL-SCH.

[0392] In an example, during the measurement gap period / time, the base station may not transmit downlink data to the base station. For example, the downlink data may include at least one of the following: DCI, MAC CE, and data on the DL-SCH. During the measurement gap, the base station (of the serving cell) may not monitor the uplink channel (e.g., PUCCH / PUSCH) of the wireless device. The base station may not receive (uplink data) on the UL-SCH.

[0393] Multi-Radio Dual Connectivity (MR-DC or DC) is a dual connectivity between an E-UTRA (e.g., eNB, LTE base station) and an NR node (e.g., gNB, NR base station) or between two NR nodes. The SpCell is the primary cell of the Master Cell Group (MCG) or the primary cell of the Secondary Cell Group (SCG). The Pcell is the SpCell of the Master Cell Group. The PSCell is the SpCell of the Secondary Cell Group.

[0394] The Master Cell Group (MCG) can be in MR-DC and is a serving cell group associated with the Master Node, which contains the SpCell (Pcell) and optionally one or more SCells. The Master Node (MN) can be in DC and is a radio access node (e.g., base station) that provides a control plane connection to the core network. The MN can be a master eNB, a master ng-eNB, or a master gNB. The Secondary Cell Group (SCG) can be in MR-DC and is a serving cell group associated with the Secondary Node, which contains the SpCell (PSCell) and optionally one or more SCells. The Secondary Node can be in MR-DC and is a radio access node without a control plane connection to the core network, providing additional resources to the wireless device. The Secondary Node can be an en-gNB, a secondary ng-eNB, or a secondary gNB.

[0395] Conditional PSCell addition is a PSCell addition procedure that is only executed when the PSCell addition conditions are met. Conditional PSCell change is a PSCell change procedure that is only executed when the PSCell execution conditions are met.

[0396] Conditional Handover (CHO) can be defined as a handover (e.g., layer 3 handover) performed by a wireless device when one or more handover execution conditions are met. The wireless device can start evaluating the execution conditions after receiving the CHO configuration and stop evaluating the execution conditions immediately after performing the handover.

[0397] The following principles can apply to CHO: The CHO configuration can include the configuration of CHO candidate cells generated by a candidate gNB and the execution conditions generated by the source gNB. The execution conditions can consist of one or two trigger conditions (CHO events, e.g., A3 / A5). Only a single reference signal (RS) type can be supported, and at most two different trigger quantities (e.g., RSRP and RSRQ, RSRP and SINR, etc.) can be configured for the evaluation of the execution conditions of a CHO for a single candidate cell simultaneously. Before any CHO execution condition is met, when receiving a HO command (without a CHO configuration), the wireless device can perform a HO procedure (e.g., regardless of any previously received CHO configuration). When performing a CHO (e.g., starting from the time when the wireless device starts synchronizing with the target cell), the wireless device can stop monitoring the source cell.

[0398] For example, the CHO procedure (e.g., the CHO procedure within the AMF / UPF) may be as follows. The UE context within the source base station may include information related to roaming and access restrictions provided at connection establishment or during the last tracking area (TA) update. The source base station may configure a measurement procedure for the wireless device, and the wireless device may report according to the measurement configuration. The source base station may decide to use CHO. The source base station may request CHO for one or more candidate cells belonging to one or more candidate base stations. A CHO request message is sent for each candidate cell. Admission control may be performed by the target base station. If slice information is sent to the target base station, slice-aware admission control may be performed. If the PDU session is associated with an unsupported slice, the target base station may reject such a PDU session.

[0399] In an example of the CHO procedure, the candidate base station may send a CHO response (HO request confirmation) to the source base station, and the CHO response includes the configuration of the CHO candidate cell. A CHO response message may be sent for each candidate cell. The source base station may send an RRC reconfiguration message to the wireless device, and the RRC reconfiguration message includes the configuration of the CHO candidate cell and the CHO execution condition. The CHO configuration of the candidate cell may then be followed by other reconfigurations from the source base station.

[0400] In an example of the CHO procedure, the wireless device may send an RRC reconfiguration complete message to the source base station. If early data forwarding is applied, the source base station may send an early state transfer message to the target base station of the candidate cell. The wireless device may maintain a connection with the source base station after receiving the CHO configuration and start evaluating the CHO execution condition of the candidate cell. If at least one CHO candidate cell meets the corresponding CHO execution condition, the wireless device may detach from the source base station, apply the stored corresponding configuration for the selected candidate cell, synchronize with the candidate cell, and complete the RRC handover procedure by sending an RRC reconfiguration complete message to the target base station. The wireless device may release the stored CHO configuration after the RRC handover procedure is successfully completed. The target base station may send a handover success message to the source base station to notify that the wireless device has successfully accessed the target cell. The source base station may send an SN (PDCP sequence number) state transfer message. Once the source base station receives the handover success message, it may initiate late data forwarding. The source base station may send a handover cancellation message to other signaling connections or other candidate target base stations (if any) to cancel the CHO of the wireless device.

[0401] The characteristics of Conditional Handover (CHO) can lie in the configured execution conditions for determining when / whether to execute the corresponding HO command. The base station can send CHO configurations. Upon receiving a CHO configuration, the wireless device can start evaluating the execution conditions of CHO candidate cells. Once a CHO candidate cell meets the conditions, the wireless device can execute the HO command. During CHO execution, the wireless device can stop evaluating the execution conditions of other candidate cells. The CHO configuration can include the configuration of the CHO candidate cells generated by the candidate target base station and the execution conditions generated by the source base station. The execution conditions can consist of measurement events such as A3 and A5. Up to two different execution metrics (e.g., RSRP and RSRQ, RSRP and SINR, etc.) can be configured simultaneously for evaluating the CHO execution conditions of a single candidate cell. The wireless device can maintain the connection with the source base station until the wireless device meets the CHO execution conditions of the CHO candidate cell. The reception of a normal HO command (unconditional component) overrides any configured CHO configuration. After the source base station sends a CHO command to the wireless device, the network can be allowed to change the source base station configuration. The network can use RRC messages to add, modify, and release the configured CHO configuration (i.e., until the wireless device starts to perform CHO on the candidate cell). When performing CHO, the wireless device can stop monitoring the source cell.

[0402] Figure 19 An example of a conditional handover procedure is shown. The source base station can decide on a conditional handover based on a measurement report from the wireless device. The source base station can send a CHO request message to a CHO target base station candidate. Based on the received CHO request message, the target base station can send a CHO response message including the CHO configuration. Based on the received CHO response message, the source base station can send an RRC reconfiguration message containing the CHO configuration of the candidate cell to the wireless device. Based on the received RRC reconfiguration message, the wireless device can send an RRC reconfiguration complete message to the source base station. The wireless device can start evaluating the CHO execution conditions of the candidate cells in the CHO configuration while maintaining the connection with the source base station. Based on at least one CHO candidate cell meeting the corresponding CHO execution conditions, the wireless device can detach from the source base station, apply the stored configuration of the selected candidate cell, and synchronize with the candidate cell. Based on the synchronization, the wireless device can complete the handover procedure by sending an RRC reconfiguration complete message to the target base station via the candidate cell.

[0403] The base station may send a CHO configuration. Based on the received CHO configuration, once the CHO candidate cell meets the conditions, the wireless device may execute a HO command. The wireless device may detect a radio link failure (RLF) in the source base station (e.g., the primary cell (Pcell)). Based on the detected radio link failure, the wireless device may execute a cell selection procedure. Based on the cell selection procedure, the wireless device may select a cell. Based on the selected cell being a CHO candidate, then the wireless device may perform CHO execution on the selected cell. Otherwise, the wireless device may execute an RRC connection reestablishment procedure. Based on a traditional handover failure or a failure to access a CHO candidate cell, the wireless device may execute a cell selection procedure. Based on the selected cell being a CHO candidate cell, the wireless device may perform CHO execution. Otherwise, the wireless device may execute an RRC connection reestablishment procedure.

[0404] Figure 20 An example of a connection recovery procedure with a conditional handover configuration is shown. The source base station may decide on a conditional handover based on a measurement report from the wireless device. The source base station may send a CHO request message to a CHO target base station candidate. Based on the received CHO request message, the target base station may send a CHO response message including the CHO configuration. Based on the received CHO response message, the source base station may send an RRC reconfiguration message containing the CHO configuration of the candidate cell to the wireless device. Based on the received RRC reconfiguration message, the wireless device may send an RRC reconfiguration complete message to the source base station. The wireless device may start evaluating the CHO execution conditions of the candidate cells in the CHO configuration while maintaining the connection with the source base station. The wireless device may detect a radio link failure or a conditional handover failure in the source base station (e.g., the Pcell). The wireless device may execute a cell selection procedure. Based on the selected cell being a conditional handover candidate cell (e.g., Figure 21 Target 1 in), the wireless device may perform CHO execution. The CHO execution may include a random access procedure for the selected cell and, based on a successful completion of the random access procedure, send an RRC reconfiguration message to the selected cell.

[0405] Based on at least one CHO candidate cell meeting the corresponding CHO execution conditions, the wireless device may detach from the source base station, apply the stored configuration of the selected candidate cell, and synchronize with the candidate cell. Based on the synchronization, the wireless device may complete the handover procedure by sending an RRC reconfiguration complete message to the target base station via the candidate cell.

[0406] Conditional PSCell addition (CPA) may be defined as a PSCell addition performed by the wireless device when the execution conditions are met. The wireless device may start evaluating the execution conditions after receiving the CPA configuration and stop evaluating the execution conditions immediately after triggering a PSCell addition or a Pcell change.

[0407] The following principles apply to CPA: The CPA configuration can include the configuration of the candidate PSCell for CPA, the execution conditions, and can include the MCG configuration to be applied when triggering the CPA execution. The execution conditions can consist of one or two trigger conditions (e.g., CondEvents). Only a single RS type and at most two different trigger quantities (e.g., RSRP and RSRQ, RSRP and SINR, etc.) can be used to evaluate the CPA execution conditions of a single candidate PSCell. Before any CPA execution conditions are met, after receiving the PSCell addition command or Pcell change command, the wireless device can execute the PSCell addition procedure or Pcell change procedure (e.g., regardless of any previously received CPA configuration). After successfully completing the PSCell addition procedure or Pcell change procedure, the wireless device can release the stored CPA configuration. When executing CPA, the wireless device may not need to continue evaluating the execution conditions of other candidate PSCs. Once the CPA procedure is successfully executed, the wireless device can release all stored conditional reconfigurations (e.g., for CPA and for CHO).

[0408] The SN addition procedure can be initiated by the MN and is used to establish the UE context at the SN to provide resources from the SN to the wireless device. For bearers that require SCG radio resources, this procedure can be used to at least add the initial SCG serving cell of the SCG. This procedure can be used to configure the MCG bearer terminated by the SN (e.g., in the case where no SCG configuration is required). In the case of CPA, the conditional secondary node addition procedure can be used for CPA configuration and CPA execution.

[0409] In an example, the MN can decide to configure CPA for the wireless device. The MN can request the candidate SN to allocate resources for one or more specific PDU sessions / QoS flows, thereby indicating the QoS flow characteristics (QoS flow level QoS parameters, PDU session level TNL address information, and PDU session level network slice information), thereby indicating that the request is for CPA and providing an upper limit on the number of PSCs that the candidate SN can prepare. Additionally, for bearers that require SCG radio resources, the MN can indicate the requested SCG configuration information, which includes the overall UE capabilities and the coordination result of the wireless device capabilities. In this case, the MN can provide the MN-recommended candidate cells via the latest measurement results of the SCG cells selected and configured by the candidate SN. The MN can request the candidate SN to allocate radio resources for split SRB operations. In NR-DC, the MN can provide all required security information to the candidate SN (even if there is no bearer terminated by the SN) so that SRB3 can be set based on the SN decision.

[0410] In an example of the conditional SN addition procedure, for a bearer option terminated at the MN that requires an Xn-U resource between the MN and the candidate SN, the MN may provide the Xn-U UL TNL address information. For a bearer terminated at the SN, the MN may provide a list of available DRB IDs. The candidate SN may store this information and use it when establishing a bearer terminated at the SN. The candidate SN may reject the addition request. For a bearer option terminated at the SN that requires an Xn-U resource between the MN and the candidate SN, the MN may provide a list of QoS flows for each PDU session for which SCG resources may be requested to be set up, and based on the SCG resources, the candidate SN decides how to map the QoS flows to DRBs. For split bearers, such amounts of MCG and SCG resources may be requested such that the QoS of the corresponding QoS flow can be guaranteed by exactly the sum of the resources provided by the MCG and SCG together or even more resources. For a split bearer terminated at the MN, the MN decision may be reflected by the QoS flow parameters signaled to the candidate SN, which may be different from the QoS flow parameters received on the NG. For a particular QoS flow, the MN may request to directly establish an SCG and / or a split bearer (e.g., without first establishing an MCG bearer). It may be allowed that all QoS flows can be mapped to a bearer terminated at the SN (e.g., no QoS flow is mapped to a bearer terminated at the MN).

[0411] In an example of the conditional SN addition procedure, if the RRM entity in the candidate SN can grant the resource request, the SN can allocate the corresponding radio resources and, depending on the bearer type option, allocate the corresponding transport network resources, and provide the prepared PSCell ID to the MN. For a bearer that requires SCG radio resources, the candidate SN configures random access such that the synchronization of the SN radio resource configuration can be performed when the CPA is executed. Within the cell list indicated in the measurement results as indicated by the MN, the candidate SN can (taking into account the maximum number indicated by the MN) determine the list of PSCells to be prepared, and for each prepared PSCell, the candidate SN can determine other SCG SCells and provide the MN with a new corresponding SCG radio resource configuration in the NR RRC reconfiguration message (e.g., of the SN) included in the SN addition request confirmation message. The candidate SN can accept or reject each candidate cell listed in the measurement results indicated by the MN (e.g., the candidate SN may not be able to configure any alternative candidates). In the case of a bearer option that requires an Xn-U resource between the MN and the candidate SN, the candidate SN can provide the Xn-U TNL address information (e.g., tunnel address) for the corresponding DRB, the Xn-U UL TNL address information for the bearer terminated by the SN, and the Xn-U DL TNL address information for the bearer terminated by the MN. For the bearer terminated by the SN, the candidate SN can provide the NG-U DL TNL address information for the corresponding PDU session and security algorithm. If SCG radio resources have been requested, the SCG radio resource configuration can be provided. For the bearer terminated by the SN that uses MCG resources, the MN can provide the Xn-U DL TNL address information in the Xn-U address indication message. In the case of early data forwarding in the CPA, the MN can send an early status transfer message to the candidate SN.

[0412] In an example of the conditional SN addition procedure, the MN can send an RRC reconfiguration message (e.g., a series of RRC reconfiguration *messages and associated execution conditions) including the CPA configuration to the wireless device, where each RRC reconfiguration message *includes the SCG configuration in the RRC reconfiguration **received from the candidate SN and possibly the MCG configuration. The RRC reconfiguration message can also include the updated MCG configuration (e.g., to configure the required conditional measurements).

[0413] In an example of the conditional SN addition procedure, the wireless device may apply the RRC reconfiguration message, store the CPA configuration, and reply to the MN with an RRC reconfiguration complete message. If the wireless device cannot comply with the configuration (part of it) included in the RRC reconfiguration message, the wireless device may execute a reconfiguration failure procedure. The wireless device may start evaluating the execution conditions. If the execution conditions of a candidate PSCell are met, the wireless device may apply the RRC reconfiguration *message corresponding to the selected candidate PSCell, and send an MN RRC reconfiguration complete *message, the MN RRC reconfiguration complete *message including the RRC reconfiguration complete **message for the selected candidate PSCell and information enabling the MN to identify the SN of the selected candidate PSCell. The MN may notify the SN of the selected candidate PS...

Claims

1. A method, comprising: receiving, by a wireless device, a radio resource control (RRC) reconfiguration message from a primary base station associated with a primary cell group, the RRC reconfiguration message comprising: a conditional configuration of a secondary cell group (SCG) associated with a secondary base station among one or more secondary base stations; one or more counters for the secondary base station, wherein the RRC reconfiguration message indicates: The one or more counters are associated with the SCG; and / or the one or more counters are for subsequent cell group changes; a configuration for applying the conditional configuration of the SCG based on meeting an execution condition of the conditional configuration; and transmitting, based on applying the configuration of the SCG, an RRC reconfiguration complete message to the secondary base station indicating the conditional configuration, wherein the transmission comprises: a first transmission using a first security key derived based on a first counter among the one or more counters; and a second transmission using a second security key derived based on a second counter among the one or more counters.

2. A method, comprising: receiving, by a wireless device, a radio resource control (RRC) reconfiguration message from a primary base station associated with a primary cell group, the RRC reconfiguration message comprising: configuration parameters of a secondary cell group (SCG) associated with a secondary base station; and one or more counters for the secondary base station, wherein the RRC reconfiguration message indicates: the one or more counters are associated with the SCG; and / or the one or more counters are for subsequent cell group changes; transmitting an RRC reconfiguration complete message to the secondary base station based on applying the configuration parameters, wherein the transmission comprises: a first transmission using a first security key derived based on a first counter among the one or more counters; and a second transmission using a second security key derived based on a second counter among the one or more counters.

3. A method, comprising: receiving, by a wireless device, a radio resource control (RRC) reconfiguration message from a primary base station associated with a primary cell group, the RRC reconfiguration message comprising: configuration parameters of a secondary cell group (SCG) associated with a secondary base station; and one or more counters for the secondary base station; and transmitting, by the wireless device, an RRC reconfiguration complete message.

4. The method according to any one of claims 1 to 3, further comprising communicating with the secondary base station based on applying the configuration parameters.

5. The method according to claim 4, wherein the communication comprises: a first communication using a first security key derived based on a first counter among the one or more counters; and a second communication using a second security key derived based on a second counter among the one or more counters.

6. The method according to any one of claims 1 to 5, wherein the one or more counters comprise: the first counter for the first communication between the wireless device and the secondary base station; and the second counter for the second communication between the wireless device and the secondary base station.

7. The method according to claim 6, wherein communicating with the secondary base station includes transmitting the RRC reconfiguration complete message to the secondary base station.

8. The method according to claim 7, wherein: the first communication includes transmitting a first RRC reconfiguration complete message to the secondary base station; and / or the second communication includes transmitting a second RRC reconfiguration complete message to the secondary base station.

9. The method according to claim 7 or claim 8, wherein the RRC reconfiguration complete message indicates: the configuration parameters of the SCG; and / or the wireless device has applied the configuration parameters; and / or the primary SCG cell of the SCG; and / or the configuration identity of the configuration parameters.

10. The method according to claim 9, wherein the RRC reconfiguration complete message includes: an RRC reconfiguration complete message for the primary base station; and an RRC reconfiguration complete message for the secondary base station.

11. The method according to any one of claims 4 to 10, wherein applying the configuration parameters is based on: receiving the RRC reconfiguration message; or meeting an execution condition.

12. The method according to claim 11, wherein: the configuration parameters of the SCG are conditional configuration parameters of the SCG; and / or the conditional configuration parameters include the execution condition; and / or the conditional configuration parameters include the identity of the conditional configuration parameters.

13. The method according to claim 12, wherein: the configuration parameters of the SCG include one or more configuration parameters of one or more SCGs; and / or each of the one or more configuration parameters is associated with a corresponding one of the one or more SCGs; and / or each of the one or more SCGs is associated with a corresponding one of the one or more secondary base stations; and / or the SCG is one of the one or more SCGs; and / or the SCG is associated with the secondary base station among the one or more secondary base stations.

14. The method according to claim 13, wherein: the one or more counters are associated with a corresponding one of the one or more SCGs; and / or the one or more counters are associated with the SCG; and / or the one or more counters are associated with a corresponding one of the one or more secondary base stations; and / or the one or more counters are associated with the secondary base station among the one or more secondary base stations; and / or the one or more counters are associated with one or more security keys; and / or the one or more counters are associated with a corresponding one of the one or more security keys.

15. The method according to claim 13 or claim 14, wherein: the first communication includes a first communication based on applying a first configuration parameter among the one or more configuration parameters; and / or the second communication includes a second communication based on applying a second configuration parameter among the one or more configuration parameters.

16. The method according to any one of claims 4 to 15, wherein applying the configuration parameters includes: The configuration parameter is for a first application of the first communication; and The configuration parameter is for a second application of the second communication; and The second application is after the first application; and The second communication is after the first communication.

17. The method according to claim 16, further comprising, based on the first application, performing at least one of the following: Deriving the first security key based on the first counter; Using the first security key to perform the first communication; Maintaining / storing / keeping the configuration parameter; or Releasing the first counter from the one or more counters.

18. The method according to any one of claims 4 to 17, further comprising selecting a counter from the one or more counters based on applying the configuration parameter.

19. The method according to claim 18, wherein selecting the counter comprises: Selecting an unused counter from the one or more counters; and / or After excluding the first counter from the one or more counters, selecting the second counter from the one or more counters.

20. The method according to claim 19, wherein selecting the counter is based on: The counter has the lowest index; or The counter has the highest index.

21. The method according to any one of claims 1 to 20, wherein the RRC reconfiguration message indicates at least one of the following: The one or more counters are associated with the configuration parameter; The one or more counters are associated with the configuration identity of the configuration parameter; The one or more counters are associated with the primary SCG cell of the SCG; The one or more counters are associated with the secondary base station; The one or more counters are associated with the SCG; Or The one or more counters are for a subsequent cell group change.

22. The method according to claim 21, wherein: The configuration parameter of the SCG comprises one or more configuration parameters of one or more SCGs; and / or Each of the one or more configuration parameters is associated with a corresponding SCG of the one or more SCGs; and / or Each of the one or more SCGs is associated with a corresponding secondary base station of the one or more secondary base stations; and / or The SCG is one of the one or more SCGs; and / or The SCG is associated with the secondary base station of the one or more secondary base stations.

23. The method according to claim 22, wherein: The one or more counters are associated with a corresponding SCG of the one or more SCGs; and / or The one or more counters are associated with the SCG; And / or The one or more counters are associated with a corresponding secondary base station of the one or more secondary base stations; And / or The one or more counters are associated with the secondary base station of the one or more secondary base stations; And / or The one or more counters are associated with one or more security keys; And / or The one or more counters are associated with a corresponding security key of the one or more security keys.

24. The method according to claim 23, wherein the one or more security keys are secondary security keys for a secondary base station.

25. The method according to any one of claims 1 to 24, wherein the one or more counters are a plurality of counters.

26. The method according to any one of claims 1 to 25, wherein the receiving of the RRC reconfiguration message occurs when communicating with the primary base station using the security key of the primary base station.

27. The method according to claim 26, further comprising receiving, from the primary base station, security parameters for deriving the security of the primary base station, wherein the security parameters for deriving the security of the primary base station include a Next Link Count (NCC).

28. The method according to any one of claims 1 to 27, wherein the one or more counters include: a first counter for normal cell group change; and a second counter for subsequent cell group change.

29. A method, comprising: receiving, by a wireless device, an (RRC) reconfiguration message from a primary base station associated with a primary cell group, the RRC reconfiguration message indicating: Configuration parameters of the secondary cell group (SCG) of the secondary base station; and one or more counters for deriving one or more security keys for the secondary base station; deriving a first security key using a first counter among the one or more counters based on applying the configuration parameters; communicating with the secondary base station using the first security key; and after the communication, deriving a second security key using a second counter among the one or more counters.

30. The method according to claim 29, wherein deriving the second security key using the second counter based on the communication includes, after the communication with the secondary base station, deriving the second security key using the second counter based on applying the configuration parameters.

31. The method according to claim 1, wherein: the one or more security keys are a plurality of security keys; and the one or more counters are a plurality of counters.

32. A method, comprising: receiving, by a wireless device, an (RRC) reconfiguration message from a primary base station associated with a primary cell group, the RRC reconfiguration message indicating: configuration parameters of a secondary cell group (SCG) of a secondary base station; a first counter for deriving a first security key of the secondary base station; receiving a second counter from the primary base station, the second counter being used to derive a second security key of the secondary base station before deriving the first security key using the first counter; communicating with the secondary base station based on applying the configuration parameters, wherein the communication includes: a first communication using the first security key derived based on the first counter; and a second communication using the second security key derived based on the second counter.

33. The method according to claim 32, wherein the receiving of the second counter includes receiving the RRC reconfiguration message including the second counter.

34. A method, comprising: A request message for parameters of dual connectivity operation for a wireless device and a secondary cell group (SCG) associated with a secondary base station is transmitted from a primary base station associated with a primary cell group to the secondary base station in one or more secondary base stations, wherein the request message includes one or more security keys for the secondary base station of the wireless device; A response message is received from the secondary base station, the response message including a conditional configuration of the SCG associated with the secondary base station, wherein the conditional configuration of the SCG includes: Execution conditions; and Configuration parameters of the SCG; An RRC reconfiguration message is transmitted to the wireless device, the RRC reconfiguration message including: The conditional configuration of the SCG; And One or more counters, wherein each of the one or more counters is associated with a corresponding security key among the one or more security keys; And An RRC reconfiguration complete message indicating the conditional configuration of the SCG is received from the wireless device.

35. A method includes: A request message for transmitting parameters for dual connectivity operation of a wireless device and a secondary cell group (SCG) from a master base station to a secondary base station, where the request message includes one or more security keys of the secondary base station for the wireless device; And An RRC reconfiguration message is transmitted to the wireless device, the RRC reconfiguration message including: Configuration parameters of the SCG; And One or more counters, wherein each of the one or more counters is associated with a corresponding security key among the one or more security keys.

36. The method according to claim 34 or 35, further comprising receiving from the secondary base station a response message including the configuration parameters of the SCG, wherein the transmission of the RRC reconfiguration message occurs after the receipt of the response message.

37. The method according to claim 36, wherein the response message is: A secondary node (SN) addition request confirmation message; or An SN modification request confirmation message.

38. The method according to any one of claims 34 to 37, wherein: The one or more counters are associated with a corresponding SCG among the one or more SCGs; and / or The one or more counters are associated with the SCG; And / or The one or more counters are associated with a corresponding secondary base station among the one or more secondary base stations; And / or The one or more counters are associated with the secondary base station among the one or more secondary base stations; And / or The one or more counters are associated with one or more security keys; And / or The one or more counters are associated with a corresponding security key among the one or more security keys.

39. The method according to claim 38, wherein the one or more security keys include: A first security key for a first communication between the wireless device and the secondary base station; and A second security key for a second communication between the wireless device and the secondary base station.

40. The method according to claim 39, wherein: The first security key is associated with a first counter among the one or more counters; and The second security key is associated with a second counter among the one or more counters.

41. The method according to claim 39 or claim 40, wherein the request message is A secondary node (SN) addition request message; or SN modification request message.

42. The method according to any one of claims 39 to 41, wherein the one or more security keys are a plurality of security keys.

43. The method according to any one of claims 34 to 42, wherein the request message comprises: a first request message; and a second request message.

44. The method according to claim 43, transmitting the request message to the secondary base station comprises: transmitting the first request message to the secondary base station, the first request message comprising a first security key of the one or more security keys; and transmitting the second request message to the secondary base station, the second request message comprising a second security key of the one or more security keys.

45. The method according to claim 43 or claim 44, wherein transmitting the second request message to the secondary base station is: after receiving an RRC reconfiguration complete message from the wireless device; and / or and after transmitting the first request message.

46. The method according to claim 45, wherein transmitting the second request message to the secondary base station is based on receiving the RRC reconfiguration complete message.

47. The method according to claim 46, wherein the RRC reconfiguration complete message indicates: the configuration parameters of the SCG; and / or the wireless device has applied the configuration parameters; and / or the primary SCG cell of the SCG; and / or the configuration identity of the configuration parameters.

48. The method according to claim 46 or claim 47, wherein: the second request is a secondary node (SN) radio resource control (RRC) reconfiguration complete message; and / or the SN RRC reconfiguration complete message comprises the RRC reconfiguration complete message; and / or the SN RRC reconfiguration complete message indicates that the wireless device has successfully applied the configuration parameters of the SCG.

49. The method according to claim 48, wherein the first request message is a secondary node (SN) addition request message; or an SN modification request message.

50. The method according to any one of claims 34 to 49, wherein the request message indicates that the one or more security keys are for a subsequent cell group change.

51. A method, comprising: receiving, by a secondary base station among one or more secondary base stations, from a primary base station associated with a primary cell group, a request message for parameters for dual connectivity operation of a wireless device and a secondary cell group SCG associated with the secondary base station, wherein the request message comprises one or more security keys of the secondary base station for the wireless device; transmitting a response message to the primary base station, the response message comprising a conditional configuration of the SCG associated with the secondary base station, wherein the conditional configuration of the SCG comprises: execution conditions; and the configuration parameters of the SCG; and receiving from the primary base station a secondary node (SN) RRC reconfiguration complete message comprising an RRC reconfiguration complete message, wherein: the RRC reconfiguration complete message is transmitted by the wireless device; The RRC reconfiguration complete message indicates the conditional configuration of the SCG.

52. A method includes: receiving, by a secondary base station, from a primary base station, a request message for parameters for dual connectivity operation of a wireless device and a secondary cell group (SCG), wherein the request message includes one or more security keys for the secondary base station of the wireless device.

53. The method according to claim 51 or claim 52, further including: transmitting to the primary base station a response message including configuration parameters of the SCG; and receiving from the primary base station a secondary node (SN) radio resource control (RRC) reconfiguration complete message.

54. The method according to any one of claims 51 to 53, wherein the response message is: a secondary node (SN) addition request confirmation message; or an SN modification request confirmation message.

55. The method according to any one of claims 51 to 54, wherein: the one or more counters are associated with a respective SCG among the one or more SCGs; and / or the one or more counters are associated with the SCG; and / or the one or more counters are associated with a respective secondary base station among the one or more secondary base stations; and / or the one or more counters are associated with the secondary base station among the one or more secondary base stations; and / or the one or more counters are associated with one or more security keys; and / or the one or more counters are associated with a respective security key among the one or more security keys.

56. The method according to any one of claims 51 to 55, wherein the one or more security keys include: a first security key for a first communication between the wireless device and the secondary base station; and a second security key for a second communication between the wireless device and the secondary base station.

57. The method according to claim 56, wherein: the first security key is associated with a first counter among the one or more counters; and the second security key is associated with a second counter among the one or more counters.

58. The method according to claim 56 or claim 57, wherein the request message is a secondary node (SN) addition request message; or an SN modification request message.

59. An apparatus includes one or more processors and a memory storing instructions that, when executed by the one or more processors, cause the apparatus to perform at least the method according to any one of claims 1 to 58.

60. A non-transitory computer-readable medium includes instructions that, when executed by one or more processors of a device, cause the device to perform the method according to any one of claims 1 to 58.

61. An apparatus includes means for performing the method according to any one of claims 1 to 58.

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