Radio resource control messaging

Abstract

A wireless device in a radio resource control (RRC) idle or RRC inactive state communicates via a first cell of a first base station. Based on a failure of the communication of the first cell, the wireless device in the RRC idle or RRC inactive state sends a RRC request message to a second base station. The RRC request message includes a cell radio network temporary identifier (C-RNTI) of the first cell.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application 63 / 040,111, filed June 17, 2020, the contents of which are incorporated herein by reference in their entirety. Attached Figure Description

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

[0004] Figure 1A and Figure 1B An exemplary mobile communication network in which embodiments of the present disclosure may be implemented is shown.

[0005] Figure 2A and Figure 2B The new radio (NR) user plane and control plane protocol stacks are shown respectively.

[0006] Figure 3 It shows in Figure 2A An example of the services provided between the protocol layers of the NR user plane protocol stack.

[0007] Figure 4A It shows the flow through Figure 2A An example downlink data stream of the NR user plane protocol stack.

[0008] Figure 4B An exemplary format of the MAC subheader in a MAC PDU is shown.

[0009] Figure 5A and Figure 5B The mappings between logical channels, transport channels, and physical channels used for downlink and uplink are shown respectively.

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

[0011] Figure 7 An exemplary configuration is shown in which OFDM symbols are grouped into NR frames.

[0012] Figure 8 An exemplary configuration of time slots in the time and frequency domains of an NR carrier is shown.

[0013] Figure 9 An example of bandwidth adaptation using three configured BWPs with an NR carrier is shown.

[0014] Figure 10A Three carrier aggregation configurations with two component carriers are shown.

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

[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 The four-step contention-based random access procedure, the 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 for the bandwidth portion is shown.

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

[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 An exemplary structure for uplink and downlink transmission is shown.

[0024] Figure 17 An example of the RRC connection reconstruction process is shown.

[0025] Figure 18 An example of the RRC connection recovery process is shown.

[0026] Figure 19 An example of small data transfer is shown.

[0027] Figure 20 An example of Early Data Transmission (EDT) is shown.

[0028] Figure 21 Example diagrams of UP EDT and CP EDT are shown.

[0029] Figure 22 An example of UP PUR is shown.

[0030] Figure 23 Examples of UP PUR and CP PUR are shown.

[0031] Figure 24A An example of the RRC procedure is shown when a failure is detected in an inactive or idle state of RRC.

[0032] Figure 24B An example of the RRC procedure is shown when a failure in the RRC connection state is detected.

[0033] Figure 25 An example of the process for restoring communication in an inactive or idle RRC state is shown.

[0034] Figure 26 An example of the process for restoring communication in an inactive or idle RRC state is shown.

[0035] Figure 27 An example of re-suspending an RRC connection based on communication failures during an RRC inactive or idle state is shown.

[0036] Figure 28 An example of maintaining the UE context in the first base station is shown. Detailed Implementation

[0037] In this disclosure, various embodiments are presented as examples of how the disclosed technology and / or how the disclosed technology can be implemented in environments and scenarios. It will be apparent to those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention. Indeed, alternative embodiments will be apparent to those skilled in the art upon reading the specification. Embodiments of the invention should not be limited to any of the described exemplary embodiments. Embodiments of this disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed exemplary embodiments may be combined to create additional embodiments within the scope of this disclosure. Any diagrams highlighting functionality and advantages are given for illustrative purposes only. The disclosed architecture is flexible and configurable enough that it can be utilized in ways other than those shown. For example, actions listed in any flowchart may be reordered or optionally used only in certain embodiments.

[0038] The implementation scheme can be configured to operate as needed. The disclosed mechanisms can be executed when certain criteria are met, such as in wireless devices, base stations, radio environments, networks, combinations thereof, etc. Exemplary criteria may be based at least in part on, for example, wireless device or network node configuration, traffic load, initial system settings, packet size, service characteristics, combinations thereof, etc. Various exemplary implementation schemes can be applied when one or more criteria are met. Therefore, exemplary implementation schemes that selectively implement the disclosed protocols can be implemented.

[0039] A base station can communicate with a hybrid of wireless devices. The wireless devices and / or base stations can support multiple technologies and / or multiple versions of the same technology. Wireless devices may have certain specific capabilities, depending on the wireless device category and / or capabilities. When this disclosure refers to a base station communicating with multiple wireless devices, this disclosure may mean a subset of the total number of wireless devices in the coverage area. For example, this disclosure may mean multiple wireless devices having a given capability and in a given sector of a base station using a given LTE or 5G version. Multiple wireless devices in this disclosure may refer to a selected set of wireless devices, and / or a subset of the total number of wireless devices in the coverage area performing according to the disclosed method, etc. Multiple base stations or multiple wireless devices may exist in the coverage area that may not conform to the disclosed method; for example, these wireless devices or base stations may be based on older versions of LTE or 5G technology.

[0040] In this disclosure, “a” (“a” and “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 a suitable possibility among a number of suitable possibilities that may or may not be used in one or more embodiments of various embodiments. As used herein, the terms “comprising” and “including” enumerate one or more parts of the element being described. The terms “comprising” and “including” are interchangeable and do not exclude the inclusion of unlisted parts in the element being described. In contrast, “including” provides a complete enumeration of the one or more parts 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, “based on only”. As used herein, the term “and / or” indicates any possible combination of the enumerated elements. For example, "A, B and / or C" can mean A; B; C; A and B; A and C; B and C; or A, B and C.

[0041] 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, possible subsets of B = {cell1, cell2} are: {cell1}, {cell2}, and {cell1, 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 a variety of suitable possibilities that may or may not be used in one or more embodiments in different implementations. The phrase “in response to” (or equivalently “at least in response to”) indicates that the phrase following the phrase “in response to” is an example of one of a variety of suitable possibilities that may or may not be used in one or more embodiments in different implementations. The phrase “depends on” (or equivalently “at least depends on”) indicates that the phrase following the phrase “depends on” is an example of one of a variety of suitable possibilities that may or may not be used in one or more embodiments in different implementations. The phrase “adopt / use” (or equivalently “at least adopt / use”) indicates that the phrase following “adopt / use” is an example of a suitable possibility among a number of suitable possibilities that may or may not be used in one or more different implementation schemes.

[0042] The term "configured" can refer to the capabilities of a device, whether the device is in an operational or non-operational state. "Configured" can also refer to specific settings within the device that affect its operational characteristics, regardless of whether the device is in an operational or non-operational state. In other words, hardware, software, firmware, registers, memory values, etc., can be "configured" within the device to provide specific characteristics to that device, whether the device is in an operational or non-operational state. For example, the term "control message generated in the device" can mean that the control message has parameters that can be used to configure specific characteristics in the device or to perform certain actions in the device, regardless of whether the device is in an operational or non-operational state.

[0043] In this disclosure, a parameter (or equivalently referred to as a field or information element: IE) may include one or more information objects, and an information object may include one or more other objects. For example, if parameter (IE)N includes parameter (IE)M, and parameter (IE)M includes parameter (IE)K, and parameter (IE)K includes parameter (information element)J, then, for example, N includes K, and N includes J. In an exemplary embodiment, when one or more messages include multiple parameters, it means that a parameter among the multiple parameters is in at least one of the one or more messages, but not necessarily in every one of the one or more messages.

[0044] Many of the proposed features are described as optional using the word "may" or parentheses. For brevity and readability, this disclosure does not explicitly describe every permutation that can be obtained by selecting from this set of optional features. This disclosure should be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features can be embodied in seven different ways: having only one of the three possible features, having any two of the three possible features, or having three of the three possible features.

[0045] Many elements described in the disclosed embodiments can be implemented as modules. A module is defined herein as an element that performs the defined function and has defined interfaces to other elements. Modules described in this disclosure can be implemented in hardware, software combined with hardware, firmware, wet hardware (e.g., hardware with biological elements), or combinations thereof, all of which may 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 modules 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++, etc. FPGAs, ASICs, and CPLDs are frequently programmed using hardware description languages ​​(HDLs), such as VHSIC Hardware Description Language (VHDL) or Verilog. These languages ​​configure connections between limited internal hardware modules on a programmable device. The aforementioned techniques are often combined to achieve the desired functional module results.

[0046] Figure 1A An example of a mobile communication network 100 in which embodiments of the present disclosure may be implemented is shown. The mobile communication network 100 may, for example, be a Public Land Mobile Network (PLMN) operated by a network operator. Figure 1A As shown, the mobile communication network 100 includes a core network (CN) 102, a radio access network (RAN) 104, and a wireless device 106.

[0047] CN 102 can provide the wireless device 106 with an interface to one or more data networks (DNs) (such as public DNs (e.g., the Internet), private DNs, and / or carrier-internal DNs). As part of the interface functionality, 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 charging functionality.

[0048] RAN 104 can connect CN 102 to radio device 106 via radio communication through an air interface. As part of the radio communication, RAN 104 can provide scheduling, radio resource management, and retransmission protocols. The communication direction from RAN 104 to radio device 106 via the air interface is referred to as the downlink, while the communication direction from radio device 106 to RAN 104 via the air interface is referred to as the uplink. Downlink transmissions can be separated from uplink transmissions using Frequency Division Duplex (FDD), Time Division Duplex (TDD), and / or some combination of these two duplex technologies.

[0049] The term "wireless device" may be used throughout this disclosure to mean and cover any mobile or fixed (non-mobile) device that requires or can use wireless communication. For example, a wireless device can be a telephone, smartphone, tablet, computer, laptop, sensor, instrument, wearable device, Internet of Things (IoT) device, roadside unit (RSU) of a vehicle, relay node, automobile, and / or any combination thereof. The term "wireless device" also encompasses other terms including user equipment (UE), user terminal (UT), access terminal (AT), mobile station, handheld device, wireless transmit and receive unit (WTRU), and / or wireless communication device.

[0050] RAN 104 may include one or more base stations (not shown). The term base station may 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 Header (RRH); Baseband Processing Unit coupled to one or more RRHs; 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 may include at least one gNB Central Unit (gNB-CU) and at least one gNB Distributed Unit (gNB-DU).

[0051] The base stations included in RAN 104 may include one or more sets of antennas for communicating with wireless device 106 via an air interface. For example, one or more base stations may include three sets of antennas to control three cells (or sectors) respectively. The size of a cell may 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 within the cell. The cells of the base stations may together provide radio coverage over a wide geographical area to wireless device 106 to support wireless device mobility.

[0052] Besides three-sector sites, other implementations of base stations are also possible. For example, one or more base stations in RAN 104 can be implemented as sectorized sites with more or fewer than three sectors. One or more base stations in RAN 104 can be implemented as access points, baseband processing units coupled to several remote radio heads (RRHs), and / or repeater or relay nodes for extending the coverage area of ​​the 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. Repeater nodes can amplify and replay radio signals received from the donor node. Relay nodes can perform the same / similar functions as repeater nodes, but can decode radio signals received from the donor node to remove noise before amplifying and replaying the radio signals.

[0053] RAN 104 can be deployed as a homogeneous network of macrocell base stations with similar antenna configurations and similar high-level transmission power. RAN 104 can also 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 overlapping 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 "hot spots") or in areas where macrocell coverage is weak. Examples of small cell base stations, in descending order of coverage area, include: microcell base stations, picocell base stations, and femtocell base stations or home base stations.

[0054] The Third Generation Partnership Project (3GPP) was established in 1998 to facilitate collaboration with... Figure 1A The mobile communication network 100 in this disclosure provides global standardization for similar mobile communication networks. To date, 3GPP has defined specifications for three generations of mobile networks: the third-generation (3G) network known as Universal Mobile Telecommunications System (UMTS), the fourth-generation (4G) network known as Long Term Evolution (LTE), and the fifth-generation (5G) network known as 5G System (5GS). The embodiments of this disclosure are described with reference to the RAN of the 3GPP 5G network, known as Next Generation RAN (NG-RAN). These embodiments are applicable to the RAN of other mobile communication networks, such as... Figure 1A RAN 104, the RAN of early 3G and 4G networks, and those RANs of future networks that have not yet been specified (e.g., 3GPP 6G networks). NG-RAN implements 5G radio access technology known as New Radio (NR) and can be configured to implement 4G radio access technology or other radio access technologies, including non-3GPP radio access technologies.

[0055] Figure 1B Another exemplary mobile communication network 150 in which embodiments of the present disclosure may be implemented is shown. The mobile communication network 150 may be, for example, a PLMN operated by a network operator. Figure 1B As 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 UE 156). This can be compared with... Figure 1A These components are implemented and operated in the same or similar ways as the corresponding components described.

[0056] 5G-CN 152 provides UE 156 with an interface to one or more DNs, such as public DNs (e.g., the Internet), private DNs, and / or operator-internal DNs. As part of the interface functionality, 5G-CN 152 can establish end-to-end connections between UE 156 and one or more DNs, authenticate UE 156, and provide charging functions. Compared to the CNs in 3GPP 4G networks, the foundation of 5G-CN 152 can be a service-based architecture. This means that the architecture of the nodes constituting 5G-CN 152 can be defined as network functions that provide services to other network functions via the interface. The network functions of 5G-CN 152 can 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).

[0057] like Figure 1B As shown, 5G-CN 152 includes Access and Mobility Management Function (AMF) 158A and User Plane Function (UPF) 158B. For ease of explanation, in Figure 1BThese are shown as a single component, AMF / UPF 158. UPF 158B can act as a gateway between NG-RAN 154 and one or more DNs. Functions that UPF 158B can perform include: packet routing and forwarding, packet inspection and user plane policy rule enforcement, service usage reporting, uplink classification supporting the routing of service flows to the one or more DNs, user plane Quality of Service (QoS) processing (e.g., packet filtering, gating, uplink / downlink rate enforcement, and uplink service authentication), downlink packet buffering, and downlink data notification triggering. UPF 158B can act as an anchor point for intra / inter-Radio Access Technology (RAT) mobility, an external Protocol (or Packet) Data Unit (PDU) session point interconnected with the one or more DNs, and / or a pivot point supporting multihomed PDU sessions. UE 156 can be configured to receive services via a PDU session, which is a logical connection between the UE and the DN.

[0058] The AMF 158A can perform functions such as: Non-Access Layer (NAS) signaling termination, NAS signaling security, Access Layer (AS) security control, inter-CN node signaling for mobility between 3GPP access networks, idle mode UE reachability (e.g., control and execution of paging retransmission), registration area management, intra-system and inter-system mobility support, access authentication, access authorization including roaming rights checks, mobility management control (subscription and policies), network slicing support, and / or Session Management Function (SMF) selection. NAS can refer to functions operating between the CN and the UE, and AS can refer to functions operating between the UE and the RAN.

[0059] 5G-CN 152 may include, for clarity, not listed here. Figure 1B One or more additional network functions are shown in the diagram. 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 Openness Function (NEF), Unified Data Management (UDM), Application Function (AF), and / or Authentication Server Function (AUSF).

[0060] NG-RAN 154 can connect 5G-CN 152 to UE 156 via radio communication over an air interface. NG-RAN 154 may include: one or more gNBs, such as gNB 160A and gNB 160B (collectively referred to as gNB 160); and / or one or more ng-eNBs, such as ng-eNB 162A and ng-eNB 162B (collectively referred to as ng-eNB 162). gNB 160 and ng-eNB 162 may be more generally referred to as base stations. 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 gNBs in gNB 160 and / or one or more ng-eNBs in ng-eNB 162 may include three sets of antennas to control three cells (or sectors) respectively. The gNB 160 and ng-eNB 162 cells can work together to provide UE 156 with radio coverage over a wide geographical area to support UE mobility.

[0061] like Figure 1B As shown, gNB 160 and / or ng-eNB 162 can connect 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 a direct physical connection and / or an indirect connection via an underlying transport network (such as an Internet Protocol (IP) transport network). gNB 160 and / or ng-eNB 162 can connect to UE 156 via the Uu interface. For example, as... Figure 1B As shown, the gNB 160A can connect to the UE156A via the Uu interface. The NG, Xn, and Uu interfaces are associated with a protocol stack. The protocol stack associated with the interface can be... Figure 1B The network elements in the system are used to exchange data and signaling messages, and can include two planes: a user plane and a control plane. The user plane can handle data that is of interest to the user. The control plane can handle signaling messages that are of interest to the network elements.

[0062] The gNB 160 and / or ng-eNB 162 can connect to one or more AMF / UPF functions of the 5G-CN 152, such as AMF / UPF 158, via one or more NG interfaces. For example, the gNB 160A can connect to the UPF 158B of the AMF / UPF 158 via an NG user plane (NG-U) interface. The NG-U interface can provide user plane PDU delivery (e.g., non-guaranteed delivery) between the gNB 160A and the UPF 158B. The gNB 160A can connect to the AMF158A via an NG control plane (NG-C) interface. The NG-C interface can provide, for example, NG interface management, UE context management, UE mobility management, NAS message delivery, paging, PDU session management, and configuration delivery and / or warning message transmission.

[0063] The gNB 160 can provide NR user plane and control plane protocol termination to UE 156 via the Uu interface. For example, the gNB 160A can provide NR user plane and control plane protocol termination to UE 156A via the Uu interface associated with the first protocol stack. The 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 3GPP 4G radio access technology. For example, the ng-eNB 162B can provide E-UTRA user plane and control plane protocol termination to UE 156B via the Uu interface associated with the second protocol stack.

[0064] 5G-CN 152 is described as being configured to handle NR and 4G radio access. Those skilled in the art will understand that NR can potentially connect to the 4G core network in a mode known 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 The diagram shows only one AMF / UPF 158, but a gNB or ng-eNB can connect to multiple AMF / UPF nodes to provide redundancy and / or load sharing across those multiple AMF / UPF nodes.

[0065] As discussed, Figure 1B The interfaces between network elements (e.g., Uu, Xn, and NG interfaces) can be associated with the protocol stack used by the network elements to exchange data and signaling messages. The protocol stack can include two planes: a user plane and a control plane. The user plane handles data of interest to the user, while the control plane handles signaling messages of interest to the network elements.

[0066] Figure 2A and Figure 2B Examples of NR user plane and NR control plane protocol stacks for the Uu interface located between UE 210 and gNB 220 are shown respectively. Figure 2A and Figure 2B The protocol stack shown can be used with, for example, Figure 1B The protocol stacks of the Uu interface between UE156A and gNB 160A shown are the same or similar.

[0067] Figure 2A The diagram illustrates a five-layer NR user plane protocol stack implemented in UE 210 and gNB 220. At the bottom of the stack, the Physical Layer (PHY) 211 and 221 provide transport services to the higher layers and can correspond to Layer 1 of the Open Systems Interconnection (OSI) model. The next four protocols above PHY 211 and 221 include the Medium Access Control (MAC) layer 212 and 222, the Radio Link Control (RLC) layer 213 and 223, the Packet Data Convergence Protocol (PDCP) layer 214 and 224, and the Service Data Application Protocol (SDAP) layer 215 and 225. These four protocols together can constitute Layer 2 of the OSI model or the Data Link Layer.

[0068] Figure 3 This illustrates an example of services provided between protocol layers in the NR user plane protocol stack. From Figure 2A and Figure 3 Starting from the top, SDAPs 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. The PDU session can have one or more QoS flows. The CN's UPF (e.g., UPF 158B) can map IP packets to these 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). SDAPs 215 and 225 can perform mapping / demapping between these one or more QoS flows and one or more data radio bearers. The mapping / demapping between QoS flows and data radio bearers can be determined by SDAP 225 at gNB 220. SDAP 215 at UE 210 can learn the mapping between QoS flows and data radio bearers through reflected mapping or control signaling received from gNB 220. For reflective mapping, the SDAP 225 at gNB 220 can mark downlink packets with a QoS Flow Indicator (QFI), which can be observed by the SDAP 215 at UE 210 to determine the mapping / demapping between QoS flows and data radio bearers.

[0069] 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 their intended source. PDCP 214 and 224 can perform retransmission of undelivered packets, reordering and repackaging of packets, and removal of duplicate packets received due to, for example, intra-gNB handover. PDCP 214 and 224 can perform packet duplication to increase the likelihood of packet reception and remove any duplicate packets at the receiver. Packet duplication can be suitable for services requiring high reliability.

[0070] although Figure 3 Although not shown, 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 connect to two cells or more generally to two cell groups: a primary cell group (MCG) and a secondary cell group (SCG). Split bearers are those that are handled by 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) when handled by a cell group in dual connectivity. PDCP 214 and 224 can map / demapping split radio bearers between RLC channels belonging to a cell group.

[0071] RLCs 213 and 223 can respectively perform segmentation, retransmission via Automatic Repeat Request (ARQ), and removal of duplicate data units received from MACs 212 and 222. RLCs 213 and 223 can support three transmission modes: Transparent Mode (TM); Unacknowledged Mode (UM); and Acknowledged Mode (AM). Based on the transmission mode the RLC is operating in, the RLC can perform one or more of these functions. RLC configuration can be based on each logical channel, independent of parameter sets and / or Transmission Time Interval (TTI) duration. Figure 3 As shown, RLC 213 and 223 can provide RLC channels as services to PDCP 214 and 224, respectively.

[0072] MACs 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 one or more logical channels into / from a transport block (TB) delivered to / from PHYs 211 and 221. MAC 222 can be configured to perform scheduling, scheduling information reporting, and priority processing between UEs via dynamic scheduling. Scheduling can be performed for downlink and uplink in gNB 220 (at MAC 222). MACs 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 processing between logical channels of UE 210 via logical channel priority ordering, and / or filling. MACs 212 and 222 can support one or more parameter sets and / or transmission timings. In one example, mapping constraints in logical channel priority ordering can control which parameter set and / or transmission timing a logical channel can use. like Figure 3 As shown, MAC 212 and 222 can provide logical channels as services to RLC 213 and 223.

[0073] PHYs 211 and 221 can perform transport-to-physical channel mapping and digital and analog signal processing functions for transmitting and receiving information over the air interface. These digital and analog signal processing functions may include, for example, encoding / decoding and modulation / demodulation. PHYs 211 and 221 can perform multi-antenna mapping. For example... Figure 3 As shown, PHYs 211 and 221 can provide one or more transport channels as services to MACs 212 and 222.

[0074] Figure 4A An exemplary downlink data flow through the NR user plane protocol stack is shown. Figure 4A The diagram illustrates the downlink data flow through the NR user plane protocol stack to generate three IP packets (n, n+1, and m) of two TB at the gNB 220. The uplink data flow through the NR user plane protocol stack can be compared with... Figure 4A The downlink data flow described in the text is similar.

[0075] Figure 4A The downlink data flow begins when SDAP 225 receives three IP packets from one or more QoS flows and maps those three packets to a radio bearer. Figure 4A In SDAP 225, IP packets n and n+1 are mapped to the first radio bearer 402, and IP packet m is mapped to the second radio bearer 404. The SDAP header (in...) Figure 4AData units marked with "H" are added to IP packets. Data units originating from / going to higher protocol layers are called lower protocol layer Service Data Units (SDUs), and data units originating from / going to lower protocol layers are called higher protocol layer Protocol Data Units (PDUs). Figure 4A As shown, the data unit from SDAP225 is the SDU of the lower protocol layer PDCP 224 and the PDU of SDAP 225.

[0076] Figure 4A The remaining protocol layers can perform their associated functions (e.g., regarding...). Figure 3 This involves adding the corresponding headers and forwarding their output to the next lower layer. For example, PDCP 224 can perform IP header compression and encryption, and forward its output to RLC 223. RLC 223 can optionally perform fragmentation (e.g., as...). Figure 4A (As shown in the image regarding IP packet m) and forwards its output to MAC 222. MAC 222 can multiplex many RLC PDUs and can attach MAC subheaders to RLC PDUs to form transport blocks. In NR, MAC subheaders can be distributed throughout MAC PDUs, such as... Figure 4A As shown in the diagram. In LTE, the MAC sub-header can be located entirely at the beginning of the MAC PDU. The NR MAC PDU structure can reduce processing time and associated latency because the MAC PDU sub-header can be computed before the complete MAC PDU is assembled.

[0077] Figure 4B An exemplary format of the MAC subheader in a MAC PDU is shown. The MAC subheader includes: an SDU length field indicating the length (e.g., in bytes) of the MAC SDU to which the MAC subheader corresponds; a Logical Channel Identifier (LCID) field identifying the logical channel from which the MAC SDU originates to assist in the demultiplexing process; a flag (F) indicating the size of the SDU length field; and a reserved bit (R) field for future use.

[0078] Figure 4B The diagram further illustrates a MAC control element (CE) inserted into the MAC PDU by a MAC (such as MAC 223 or MAC 222). For example, Figure 4B This shows two MAC CEs inserted into the MAC PDU. These can be used at the beginning of downlink transmissions within the MAC PDU (e.g., ...). Figure 4B(As shown in the diagram) and a MAC CE is inserted at the end of the uplink transmission of the MAC PDU. The MAC CE can be used for in-band control signaling. Exemplary 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 repeated detection, channel state information (CSI) reports, 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 subheader with a format similar to that described with respect to the MAC SDU may precede the MAC CE, and the MAC CE may be identified by a reserved value in the LCID field indicating the type of control information included in the MAC CE.

[0079] Before describing the NR control plane protocol stack, we will first describe the mapping between logical channels, transport channels, and physical channels, as well as channel types. One or more of these channels can be used to perform functions associated with the NR control plane protocol stack, which will be described later below.

[0080] Figure 5A and Figure 5B The mappings between logical channels, transport channels, and physical channels are shown for both downlink and uplink. Information is transmitted through channels between the RLC, MAC, and PHY of the NR protocol stack. Logical channels can be used between the RLC and MAC and can be classified as control channels carrying control and configuration information in the NR control plane, or as service channels carrying data in the NR user plane. Logical channels can be classified as dedicated logical channels for 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:

[0081] - Paging control channel (PCCH), which carries paging messages for paging UEs whose location is unknown to the network at the cell level;

[0082] - Broadcast Control Channel (BCCH), which carries system information messages in the form of a Master Information Block (MIB) and several System Information Blocks (SIB), wherein the system information messages can be used by the UE to obtain information about how the cell is configured and how to operate within the cell;

[0083] - Common Control Channel (CCCH), which is used to carry control messages and random access;

[0084] - Dedicated Control Channel (DCCH), used to carry control messages to a specific UE / carry control messages from a specific UE to configure that UE; and

[0085] - Dedicated Service Channel (DTCH), which is used to carry user data to a specific UE or carry user data from a specific UE.

[0086] 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:

[0087] - Paging Channel (PCH), which is used to carry paging messages originating from PCCH;

[0088] - Broadcast channel (BCH), which is used to carry MIBs from the BCCH;

[0089] - Downlink Shared Channel (DL-SCH), which is used to carry downlink data and signaling messages, including SIBs from BCCH;

[0090] - Uplink Shared Channel (UL-SCH), used to carry uplink data and signaling messages; and

[0091] - Random Access Channel (RACH), which is used to allow a UE to access the network without any prior scheduling.

[0092] The PHY can use physical channels to transfer information between processing levels of the PHY. A physical channel can be a set of associated time-frequency resources used to carry information from one or more transport channels. The PHY can generate control information to support lower-level PHY operations and provide this control information to 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:

[0093] - Physical Broadcast Channel (PBCH), which is used to carry MIBs from the BCH;

[0094] - The Physical Downlink Shared Channel (PDSCH) is used to carry downlink data and signaling messages from the DL-SCH and paging messages from the PCH;

[0095] - The Physical Downlink Control Channel (PDCCH) carries downlink control information (DCI), which may include downlink scheduling commands, uplink scheduling authorizations, and uplink power control commands;

[0096] - The Physical Uplink Shared Channel (PUSCH) is used to carry uplink data and signaling messages from the UL-SCH, and in some cases, uplink control information (UCI) as described below.

[0097] - The Physical Uplink Control Channel (PUCCH), which carries the UCI, including HARQ acknowledgments, Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), and Scheduling Request (SR); and

[0098] - Physical Random Access Channel (PRACH), which is used for random access.

[0099] Similar to the physical control channel, the physical layer generates physical signals to support low-level physical layer operations. For example... Figure 5A and Figure 5B As shown, 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.

[0100] Figure 2B An exemplary NR control plane protocol stack is shown. Figure 2B As shown, the NR control plane protocol stack can use the same / similar first four protocol layers as the exemplary 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 protocols 217 and 237 at the top of the NR control plane protocol stack.

[0101] NAS protocols 217 and 237 can provide control plane functions between UE 210 and AMF 230 (e.g., AMF 158A) or more generally between UE 210 and CN. NAS protocols 217 and 237 can provide control plane functions between UE 210 and AMF 230 via signaling messages known as NAS messages. There is no direct path through which NAS messages can be transmitted between UE 210 and AMF 230. NAS messages can be transmitted using the AS of the Uu and NG interfaces. NAS protocols 217 and 237 can provide control plane functions such as authentication, security, connection establishment, mobility management, and session management.

[0102] RRC 216 and 226 can provide control plane functionality between UE 210 and gNB 220, or more generally between UE 210 and RAN. RRC 216 and 226 can provide control plane functionality between UE 210 and gNB 220 via signaling messages known as RRC messages. RRC messages can be transmitted between UE 210 and RAN using signaling radio bearers and the same / similar PDCP, RLC, MAC, and PHY protocol layers. MAC can multiplex control plane and user plane data into the same transport block (TB). RRC 216 and 226 can provide control plane functions such as: broadcasting system information related to AS and NAS; paging initiated by CN or RAN; establishment, maintenance, and release of RRC connections between UE 210 and RAN; security functions including key management; establishment, configuration, maintenance, and release of signaling and data radio bearers; mobility functions; QoS management functions; UE measurement reporting and control of such reporting; detection and recovery of radio link failures (RLFs); and / or NAS messaging. As part of establishing an RRC connection, RRC 216 and 226 can establish an RRC context, which may involve configuring parameters for communication between UE 210 and RAN.

[0103] Figure 6 This is an example diagram illustrating the RRC state transition of the UE. The UE can interact with... Figure 1A The wireless device 106 described in the document Figure 2A and Figure 2B The UE 210 depicted herein is the same as or similar to any other wireless device described in this disclosure. Figure 6 As shown, the UE can 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).

[0104] In RRC connection 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 One or more base stations included in RAN 104 as depicted in the document; Figure 1B One of gNB 160 or ng-eNB 162 described herein; Figure 2A and Figure 2BThe gNB220 depicted in this disclosure; or any other base station described herein. A base station connected to a UE may have an RRC context for that UE. The RRC context, referred to as the UE context, may include 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., relating 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 connection 602, the UE's mobility may be managed by the RAN (e.g., RAN 104 or NG-RAN 154). The UE may measure 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 UE's serving base station may request a cell transfer to one of the neighboring base stations based on the reported measurements. The RRC state can be changed from RRC connection 602 to RRC idle 604 through connection release procedure 608, or to RRC inactive 606 through connection deactivation procedure 610.

[0105] In RRC Idle 604, an RRC context may not have been established for the UE. The UE may not have an RRC connection with the base station in RRC Idle 604. While in RRC Idle 604, the UE may be in sleep mode most of the time (e.g., to conserve battery power). The UE may wake up periodically (e.g., once in each discontinuous reception cycle) to monitor paging messages from the RAN. UE mobility can be managed by the UE through a process known as cell reselection. The RRC state can be transitioned from RRC Idle 604 to RRC Connection 602 via Connection Establishment Procedure 612, which may involve a random access procedure, as discussed in more detail below.

[0106] In RRC inactivity 606, the previously established RRC context is maintained in both the UE and the base station. This allows for a faster transition to RRC connection 602 with reduced signaling overhead compared to the transition from RRC idle 604 to RRC connected 602. While in RRC inactivity 606, the UE can be in a sleep state, and the UE's mobility can be managed by the UE through cell reselection. The RRC state can transition from RRC inactivity 606 to RRC connected 602 via connection recovery procedure 614, or to RRC idle 604 via connection release procedure 616, which can be the same as or similar to connection release procedure 608.

[0107] RRC states can be associated with mobility management mechanisms. In RRC Idle 604 and RRC Inactive 606, mobility is managed by the UE through cell reselection. The purpose of mobility management in RRC Idle 604 and RRC Inactive 606 is to allow the network to notify the UE of events via paging messages without having to broadcast paging messages across the entire mobile network. The mobility management mechanisms used in RRC Idle 604 and RRC Inactive 606 allow the network to track the UE at the cell group level, so that paging messages can be broadcast on the cells in the cell group where the UE is currently camped, rather than across the entire mobile network. Mobility management mechanisms for RRC Idle 604 and RRC Inactive 606 track the UE at the cell group level. These mobility management mechanisms can do this using groupings of different granularities. For example, there can be three levels of cell grouping granularity: a single cell; cells within a RAN area identified by a RAN Area Identifier (RAI); and cells within a group of RAN areas called tracking areas and identified by a Tracking Area Identifier (TAI).

[0108] A tracking area can be used to track the UE at the CN level. The CN (e.g., CN 102 or 5G-CN 152) can provide the UE with a list of TAIs associated with the UE's registration area. If the UE moves to a cell associated with a TAI not included in the list of TAIs associated with the UE's registration area via cell reselection, the UE can perform a registration update with the CN to allow the CN to update the UE's location and provide the UE with a new UE registration area.

[0109] RAN areas can be used to track UEs at the RAN level. For a UE in an RRC inactive 606 state, a RAN notification area can be assigned to that UE. A RAN notification area can include one or more cell identifiers, a list of RAIs, or a list of TAIs. In one example, a base station can belong to one or more RAN notification areas. In another example, a cell can belong to one or more RAN notification areas. If a UE moves via cell reselection to a cell not included in its assigned RAN notification area, the UE can perform a notification area update to update its RAN notification area.

[0110] 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 may maintain the RRC context for the UE at least during the period when the UE remains in the anchor base station's RAN notification area and / or during the period when the UE remains in RRC inactivity 606.

[0111] gNB, such as Figure 1BThe gNB 160 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 an F1 interface. The gNB-CU may include RRC, PDCP, and SDAP. The gNB-DU may include RLC, MAC, and PHY.

[0112] In NR, physical signals and physical channels (about Figure 5A and Figure 5B The concepts discussed can be mapped onto Orthogonal Frequency Division Multiplexing (OFDM) symbols. OFDM is a multi-carrier communication scheme that transmits data via F orthogonal subcarriers (or tones). Before transmission, the data can be mapped to a series of complex symbols called source symbols (e.g., M-QAM or M-PSK symbols) and divided into F parallel symbol streams. These F parallel symbol streams can be treated as if they were in the frequency domain and used as input to an Inverse Fast Fourier Transform (IFFT) block that transforms them into the time domain. The IFFT block takes F source symbols at a time (one source symbol from each of the F parallel symbol streams) and uses each source symbol to modulate the amplitude and phase of one of the F sinusoidal basis functions corresponding to the F orthogonal subcarriers. The output of the IFFT block can be F time-domain samples representing the sum of the F orthogonal subcarriers. These F time-domain samples can form a single OFDM symbol. After some processing (e.g., addition of a cyclic prefix) and upsampling, the OFDM symbols provided by the IFFT block can be transmitted over the air interface at the carrier frequency. The F parallel symbol streams can be mixed using an FFT block before being processed by the IFFT block. This operation produces OFDM symbols precoded with Discrete Fourier Transform (DFT) and can be used by the UE in the uplink to reduce the peak-to-average power ratio (PAPR). The inverse processing of the OFDM symbols at the receiver can be performed using the FFT block to recover the data mapped to the source symbols.

[0113] Figure 7 An exemplary configuration of NR frames in which OFDM symbols are grouped is shown. NR frames can be identified by a System Frame Number (SFN). An SFN can repeat for a period of 1024 frames. As shown, the duration of an NR frame can be 10 milliseconds (ms) and can include 10 subframes with a duration of 1 ms. Subframes can be divided into time slots, which include, for example, 14 OFDM symbols per time slot.

[0114] The duration of a time slot can depend on the parameter set of the OFDM symbols used for that time slot. NR supports flexible parameter sets to accommodate different cell deployments (e.g., cells with carrier frequencies below 1 GHz, up to cells with carrier frequencies in the mmWave range). Parameter sets can be defined in terms of subcarrier spacing and cyclic prefix duration. For parameter sets in NR, subcarrier spacing can be scaled up from a baseline subcarrier spacing of 15 kHz by powers of two, and cyclic prefix duration can be scaled down from a baseline cyclic prefix duration of 4.7 μs by powers of two. For example, NR defines parameter sets with the following combinations of subcarrier spacing / cyclic prefix duration: 15 kHz / 4.7 μs; 30 kHz / 2.3 μs; 60 kHz / 1.2 μs; 120 kHz / 0.59 μs; and 240 kHz / 0.29 μs.

[0115] A time slot can have a fixed number of OFDM symbols (e.g., 14 OFDM symbols). A parameter set with a higher subcarrier spacing has a shorter time slot duration and correspondingly more time slots per subframe. Figure 7 This illustrates the transmission structure of the time slot duration and per subframe time slot related to the parameter set (for ease of explanation). Figure 7 (The parameter set with a subcarrier spacing of 240 kHz is not shown in the diagram). Subframes in NR can be used as a time reference independent of the parameter set, while time slots can be used as units for scheduling uplink and downlink transmissions. To support low latency, scheduling in NR can be separated from the time slot duration and begin at any OFDM symbol, continuing to transmit as many symbols as needed. These partial time slot transmissions can be referred to as micro-time slots or sub-time slot transmissions.

[0116] Figure 8 An exemplary configuration of a time slot in the time and frequency domains of an NR carrier is shown. This time slot includes a resource element (RE) and a resource block (RB). An RE is the smallest physical resource in NR. An RE spans one OFDM symbol in the time domain via a subcarrier in the frequency domain, such as... Figure 8 As shown. RB spans twelve consecutive REs in the frequency domain, as... Figure 8 As shown. NR carriers can be limited to a width of 275RB or 275×12=3300 subcarriers. If this limitation is used, the NR carriers can be limited to 50MHz, 100MHz, 200MHz, and 400MHz for subcarrier spacing of 15kHz, 30kHz, 60kHz, and 120kHz, respectively, where the 400MHz bandwidth can be set based on the limitation of 400MHz bandwidth per carrier.

[0117] Figure 8This illustrates a single set of parameters used across the entire bandwidth of an NR carrier. In other exemplary configurations, multiple sets of parameters can be supported on the same carrier.

[0118] NR can support wide carrier bandwidths (e.g., up to 400MHz for a subcarrier spacing of 120kHz). Not all UEs can receive the full carrier bandwidth (e.g., due to hardware limitations). Moreover, receiving the full carrier bandwidth can be prohibitively expensive in terms of UE power consumption. In one example, to reduce power consumption and / or for other purposes, the UE can adjust the size of its receive bandwidth based on the amount of traffic it plans to receive. This is called bandwidth adaptation.

[0119] NR defines Bandwidth Components (BWPs) to support UEs that cannot receive the full carrier bandwidth and to support bandwidth adaptation. In one example, a BWP can be defined by a subset of consecutive Relay Buses (RBs) on a carrier. A UE can be configured (e.g., via the RRC layer) to have 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 the serving cell can be active. These one or more BWPs can be referred to as the active BWPs of the serving cell. When the serving cell is configured with a secondary uplink carrier, the serving cell can have one or more first active BWPs on the uplink carrier and one or more second active BWPs on the secondary uplink carrier.

[0120] For unpaired spectrum, if the downlink BWP index of the downlink BWP is the same as the uplink BWP index of the uplink BWP, then the downlink BWP from the set of configured downlink BWPs can be linked with the uplink BWP from the set of configured uplink BWPs. For unpaired spectrum, the UE can expect the center frequency of the downlink BWP to be the same as the center frequency of the uplink BWP.

[0121] For a set of downlink BWPs configured on the 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 time-domain and frequency-domain locations where a UE can locate control information. The search space can be a UE-specific search space or a common search space (which may be used by multiple UEs). For example, the base station can configure a common search space for the UE on the PCell or primary / secondary cell (PSCell) within an active downlink BWP.

[0122] For an uplink BWP in the configured set of uplink BWPs, the BS can configure one or more resource sets for the UE for one or more PUCCH transmissions. The UE can receive downlink reception (e.g., PDCCH or PDSCH) in the downlink BWP according to the configured set of parameters (e.g., subcarrier spacing and cyclic prefix duration) for the downlink BWP. The UE can transmit uplink transmissions (e.g., PUCCH or PUSCH) in the uplink BWP according to the configured set of parameters (e.g., subcarrier spacing and cyclic prefix length of the uplink BWP).

[0123] One or more BWP indicator fields can be provided in the downlink control information (DCI). The value of the BWP indicator field can 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 can indicate the active uplink BWP for one or more uplink transmissions.

[0124] The base station can 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 to the UE, the default downlink BWP can be the initial active downlink BWP. The UE can determine which BWP is the initial active downlink BWP based on the CORESET configuration obtained using the PBCH.

[0125] The base station can configure the BWP inactivity timer value for the UE for the PCell. The UE can start or restart the BWP inactivity timer at any appropriate time. For example, the UE can start or restart the BWP inactivity timer when: (a) the UE detects a DCI indicating an active downlink BWP other than the default downlink BWP for paired spectrum operation; or (b) the UE detects a DCI indicating an active downlink BWP or active uplink BWP other than the default downlink BWP or uplink BWP for unpaired spectrum operation. If the UE does not detect a DCI within a time interval (e.g., 1 ms or 0.5 ms), the UE can run the BWP inactivity timer toward its expiration (e.g., an increment from zero to the BWP inactivity timer value, or a decrement from the BWP inactivity timer value to zero). When the BWP inactivity timer expires, the UE can switch from the active downlink BWP to the default downlink BWP.

[0126] In one example, the base station can semi-statically configure the UE using one or more BWPs. The UE can switch the active BWP from the first BWP to the second BWP in response to receiving a 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 that the second BWP is the default BWP).

[0127] Downlink and uplink BWP handovers can be performed independently in paired spectrum (where BWP handover refers to switching from the currently active BWP to a non-currently active BWP). In unpaired spectrum, downlink and uplink BWP handovers can be performed simultaneously. Handovers between configured BWPs can occur based on RRC signaling, DCI, the expiration of a BWP inactivity timer, and / or the initiation of random access.

[0128] Figure 9 An example of bandwidth adaptation using three configured BWPs on an NR carrier is shown. A UE configured with these three BWPs can switch from one BWP to another at a handover point. Figure 9 In the example shown, the BWPs include: BWP902 with a bandwidth of 40MHz and a subcarrier spacing of 15kHz; BWP904 with a bandwidth of 10MHz and a subcarrier spacing of 15kHz; and BWP906 with a bandwidth of 20MHz and a subcarrier spacing of 60kHz. BWP902 can be the initial active BWP, and BWP904 can be the default BWP. The UE can switch between BWPs at a handover point. Figure 9 In the example, the UE can switch from BWP 902 to BWP 904 at handover point 908. The handover at handover point 908 can occur for any suitable reason, such as in response to the expiration of a BWP inactivity timer (indicating a switch to the default BWP) and / or in response to receiving a DCI indicating that BWP 904 is the active BWP. The UE can switch from active BWP 904 to BWP 906 at handover point 910 in response to receiving a DCI indicating that BWP 906 is the active BWP. The UE can switch from active BWP 906 to BWP 904 at handover point 912 in response to the expiration of a BWP inactivity timer and / or in response to receiving a DCI indicating that BWP 904 is the active BWP. The UE can switch from active BWP 904 to BWP 902 at handover point 914 in response to receiving a DCI indicating that BWP 902 is the active BWP.

[0129] If a UE is configured for a secondary cell with a default downlink BWP and timer values ​​from a set of configured downlink BWPs, the UE procedure for switching BWPs on the secondary cell can be the same as / similar to those on the primary cell. For example, the UE can use these values ​​on the secondary cell in the same / similar way as the UE would use the timer values ​​and default downlink BWP of the primary cell.

[0130] To provide higher data rates, carrier aggregation (CA) can be used to combine two or more carriers and transmit them simultaneously to / from the same UE. The aggregated carriers in CA can be referred to as component carriers (CCs). When using CA, there are multiple serving cells for the UE, with one serving cell per CC. A CC can have three configurations in the frequency domain.

[0131] Figure 10A Three CA configurations with two CCs are shown. In the intra-band contiguous configuration 1002, the two CCs are aggregated in the same frequency band (band A) and located directly adjacent to each other within the band. In the intra-band discontinuous configuration 1004, the two CCs are aggregated in the same frequency band (band A) and separated by a certain gap within the band. In the inter-band configuration 1006, the two CCs are located in frequency bands (band A and band B).

[0132] In one example, up to 32 CCs can be aggregated. Aggregated CCs can have the same or different bandwidths, subcarrier spacing, and / or duplex schemes (TDD or FDD). The serving cell 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, the ability to aggregate more downlink carriers than uplink carriers can be useful when the UE has more data traffic in the downlink than in the uplink.

[0133] When using CA, one of the aggregated cells used for the UE can be referred to as the primary cell (PCell). The PCell can be the serving cell to which the UE initially connects during RRC connection establishment, re-establishment, and / or handover. The PCell provides the UE with NAS mobility information and security input. 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 used for the UE can be referred to as secondary cells (SCells). In one example, the SCell can be configured after the PCell is configured for the UE. For example, the SCell can be configured through the RRC connection reconfiguration process. 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).

[0134] The SCell configured for the UE can be activated and deactivated based on factors such as traffic and channel conditions. Deactivating an SCell can mean stopping PDCCH and PDSCH reception on the SCell, and stopping PUSCH, SRS, and CQI transmissions on the SCell. Information about... Figure 4B The MAC CE is used to activate and deactivate configured SCells. For example, the MAC CE can use a bitmap (e.g., one bit per SCell) to indicate which SCells for the UE (e.g., a subset of configured SCells) are activated or deactivated. Configured SCells can be deactivated in response to the expiration of a SCell deactivation timer (e.g., one SCell deactivation timer per SCell).

[0135] Downlink control information for a cell (such as scheduling assignments and scheduling grants) can be transmitted on the cell corresponding to the assignment and grant, a process known as self-scheduling. A cell's DCI can be transmitted on another cell, a process known as cross-carrier scheduling. Uplink control information used for aggregation cells (e.g., HARQ acknowledgments and channel state feedback, such as CQI, PMI, and / or RI) can be transmitted on the PCell's PUCCH. For a large number of aggregation downlink CCs, the PCell's PUCCH may become overloaded. Cells can be divided into multiple PUCCH groups.

[0136] Figure 10B This illustrates an example of how aggregated cells can be configured into one or more PUCCH groups. PUCCH group 1010 and PUCCH group 1050 can each include one or more downlink CCs. Figure 10BIn the example, PUCCH group 1010 includes three downlink CCs: PCell 1011, SCell 1012, and SCell 1013. PUCCH group 1050 in this example includes three downlink CCs: 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 primary SCells (PSCells) 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 in the uplink of PCell 1021. Uplink control information (UCI) related to the downlink CC of PUCCH group 1050 (shown as UCI1071, UCI1072, and UCI1073) can be transmitted in the uplink of PSCell 1061. In one example, if Figure 10B If the aggregated cell depicted is not divided into PUCCH group 1010 and PUCCH group 1050, then a single uplink PCell will transmit UCIs associated with the downlink CC, and the PCell may become overloaded. Overload can be prevented by allocating UCI transmissions between PCell 1021 and PSCell 1061.

[0137] A physical cell ID and a cell index can be assigned to a cell that includes a downlink carrier and an optional uplink carrier. The physical cell ID or cell index can identify the cell's downlink carrier and / or uplink carrier, for example, depending on the context in which the physical cell ID is used. The physical cell ID can be determined using synchronization signals transmitted on the downlink component carrier. The cell index can be determined using RRC messages. In this disclosure, the physical cell ID can be referred to as a carrier ID, and the cell index can be referred to as a carrier index. For example, when this disclosure relates to a first physical cell ID for a first downlink carrier, this disclosure can mean that the first physical cell ID is used for a cell that includes the first downlink carrier. The same / similar concepts can be applied, for example, to carrier activation. When this disclosure indicates that a first carrier is activated, this specification can mean that a cell including that first carrier is activated.

[0138] In CA, the multi-carrier nature of the PHY can be exposed to the MAC. In one example, a HARQ entity can operate on the serving cell. Transport blocks can be generated based on the assignment / authorization of each serving cell. Transport blocks and their potential HARQ retransmissions can be mapped to the serving cell.

[0139] In the downlink, the base station can 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, such as...). Figure 5A (As shown). In the uplink, the UE can transmit one or more RSs to the base station (e.g., DMRS, PT-RS, and / or SRS, such as...). Figure 5B (As shown). PSS and SSS can be transmitted by the base station and used by the UE to synchronize the UE with the base station. PSS and SSS can be provided in a synchronization signal (SS) / physical broadcast channel (PBCH) block that includes PSS, SSS, and PBCH. The base station can periodically transmit bursts of SS / PBCH blocks.

[0140] Figure 11A An example of the structure and location of SS / PBCH blocks is shown. A burst of SS / PBCH blocks can include one or more SS / PBCH blocks (e.g., 4 SS / PBCH blocks, such as...). Figure 11A (As shown). Bursts can be transmitted periodically (e.g., every 2 frames or 20 ms). Bursts can be limited to half-frames (e.g., the first half-frame lasting 5 ms). It should be understood that... Figure 11A This is an example, and these parameters (the number of SS / PBCH blocks per burst, the burst period, the burst location within a frame) can be configured based on, for example, the carrier frequency of the cell in which the SS / PBCH blocks are transmitted; the cell's parameter set or subcarrier spacing; configuration performed 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.

[0141] SS / PBCH blocks can span one or more OFDM symbols in the time domain (e.g., 4 OFDM symbols, such as...). Figure 11A As shown in the example, and can span one or more subcarriers in the frequency domain (e.g., 240 consecutive subcarriers). PSS, SSS, and PBCH can have a common center frequency. PSS can be transmitted first and can span, for example, 1 OFDM symbol and 127 subcarriers. SSS can be transmitted after PSS (e.g., after two symbols) and can span 1 OFDM symbol and 127 subcarriers. PBCH can be transmitted after PSS (e.g., spanning the next 3 OFDM symbols) and can span 240 subcarriers.

[0142] The UE may not know the location of the SS / PBCH block in the time and frequency domains (e.g., when the UE is searching for a cell). To find and select a cell, the UE can monitor the carrier of the PSS. For example, the UE can monitor the frequency location within the carrier. If the PSS is not found after a certain duration (e.g., 20 ms), the UE can search for the PSS at different frequency locations within the carrier, as indicated by the synchronization grating. If the PSS is found at a certain location in the time and frequency domains, the UE can determine the location of the SSS and PBCH based on the known structure of the SS / PBCH block, respectively. The SS / PBCH block can be a cell-defined SS block (CD-SSB). In one example, the primary cell can be associated with a CD-SSB. The CD-SSB can be located on a synchronization grating. In one example, cell selection / search and / or reselection can be based on the CD-SSB.

[0143] The SS / PBCH block can be used by the UE to determine one or more parameters of the cell. For example, the UE can determine the Physical Cell Identifier (PCI) of the cell based on the sequence of the PSS and SSS, respectively. The UE can determine the location of the cell's frame boundary based on the location of the SS / PBCH block. For example, the SS / PBCH block can indicate that it has been transmitted according to a transmission mode in which the SS / PBCH block is at a known distance from the frame boundary.

[0144] The PBCH can use QPSK modulation and forward error correction (FEC). FEC can use polarity coding. One or more symbols spanned by the PBCH can carry one or more DMRS for PBCH demodulation. The PBCH can include an indication of the cell's current system frame number (SFN) and / or an SS / PBCH block timing index. These parameters can help the UE synchronize time with the base station. The PBCH can include a Master Information Block (MIB) to provide one or more parameters to the UE. The MIB can be used by the UE to locate the Residual Minimum System Information (RMSI) associated with the cell. The RMSI can include System Information Block Type 1 (SIB1). SIB1 can contain information required by the UE to access the cell. The UE can use one or more parameters of the MIB to monitor the PDCCH that can be used to schedule the PDSCH. The PDSCH can include SIB1. SIB1 can be decoded using the parameters provided in the MIB. The PBCH can indicate that SIB1 does not exist. Based on the PBCH indicating that SIB1 does not exist, the UE can point to a frequency. The UE can search for SS / PBCH blocks at the frequency pointed to by the UE.

[0145] 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 blocks transmitted with different SS / PBCH block indices.

[0146] SS / PBCH blocks (e.g., those within a half-frame) can be transmitted in spatial directions (e.g., using different beams across the coverage area of ​​the cell). In one example, a first SS / PBCH block can be transmitted in a first spatial direction using a first beam, and a second SS / PBCH block can be transmitted in a second spatial direction using a second beam.

[0147] In one example, within the carrier's frequency range, the base station can transmit multiple SS / PBCH blocks. In another example, the first PCI of the first SS / PBCH block of the multiple SS / PBCH blocks can be different from the second PCI of the second SS / PBCH block of the multiple SS / PBCH blocks. The PCIs of SS / PBCH blocks transmitted at different frequency locations can be different or the same.

[0148] CSI-RS can be transmitted by the base station and used by the UE to acquire Channel State Information (CSI). The base station can utilize one or more CSI-RS to configure the UE for channel estimation or any other suitable purpose. The base station can utilize one or more of the same / similar CSI-RS to configure the UE. The UE can measure the one or more CSI-RS. The UE can estimate the downlink channel state and / or generate a CSI report based on the measurements of the one or more downlink CSI-RS. The UE can provide the CSI report to the base station. The base station can use the feedback provided by the UE (e.g., the estimated downlink channel state) to perform link adaptation.

[0149] The base station can semi-statically configure the UE using one or more CSI-RS resource sets. CSI-RS resources can be associated with location and periodicity in the time and frequency domains. The base station can selectively activate and / or deactivate CSI-RS resources. The base station can instruct the UE that CSI-RS resources in the CSI-RS resource set are activated and / or deactivated.

[0150] The base station can configure the UE to report CSI measurements. The base station can configure the UE to provide CSI reports periodically, aperiodically, or semi-persistently. For periodic CSI reporting, the UE can be configured with multiple CSI report timings and / or periods. For aperiodic CSI reporting, the base station can request CSI reports. For example, the base station can command the UE to measure configured CSI-RS resources and provide CSI reports related to the measurements. For semi-persistent CSI reporting, the base station can configure the UE to transmit periodically and selectively activate or deactivate periodic reports. The base station can configure the UE using CSI-RS resource sets and CSI reports using RRC signaling.

[0151] CSI-RS configuration may include one or more parameters indicating, for example, up to 32 antenna ports. The UE can be configured to use the same OFDM symbols for both the downlink CSI-RS and the control resource set (CORESET) when the downlink CSI-RS and CORESET are spatially QCLed and the resource elements associated with the downlink CSI-RS are outside the physical resource block (PRB) configured for the CORESET. The UE can also be configured to use the same OFDM symbols for both the downlink CSI-RS and the SS / PBCH block when the downlink CSI-RS and SS / PBCH block are spatially QCLed and the resource elements associated with the downlink CSI-RS are outside the PRB configured for the SS / PBCH block.

[0152] Downlink DMRS can be transmitted by the base station and used by the UE for channel estimation. For example, downlink DMRS can be used for consistent demodulation of one or more downlink physical channels (e.g., PDSCH). The NR network can support one or more variable and / or configurable DMRS modes for data demodulation. At least one downlink DMRS configuration can support a frontload DMRS mode. Frontload 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 using the number (e.g., maximum number) of frontload DMRS symbols used for PDSCH. A DMRS configuration can support one or more DMRS ports. For example, for single-user MIMO, a DMRS configuration can support up to eight orthogonal downlink DMRS ports per UE. For multi-user MIMO, a DMRS configuration can support up to four orthogonal downlink DMRS ports per UE. Radio networks can (e.g., at least for CP-OFDM) support a common DMRS structure for both downlink and uplink, where the DMRS location, DMRS type, and / or scrambling sequence can be the same or different. Base stations can transmit downlink DMRS and corresponding PDSCHs using the same precoding matrix. UEs can use one or more downlink DMRSs to perform consistent demodulation / channel estimation of the PDSCH.

[0153] In one example, the transmitter (e.g., a base station) may use a precoder matrix for a portion of the transmission bandwidth. For instance, the transmitter may use a first precoder matrix for a first bandwidth and a second precoder matrix for a second bandwidth. The first and second precoder matrices may differ based on the first and second bandwidths. The UE may assume that the same precoder matrix is ​​used across the set of PRBs. This set of PRBs may be represented as a Precoder Resource Block Group (PRG).

[0154] A PDSCH may include one or more layers. The UE may assume that at least one symbol with DMRS exists on one or more layers of the PDSCH. A higher layer may configure up to three DMRS for the PDSCH.

[0155] Downlink PT-RS can be transmitted by the base station and used by the UE for phase noise compensation. The presence of downlink PT-RS can depend on RRC configuration. The presence and / or type of downlink PT-RS can be configured based on the UE using a combination of RRC signaling and / or association with one or more parameters that can be indicated by the DCI for other purposes (e.g., modulation and coding scheme (MCS)). When configured, the dynamic presence of downlink PT-RS can be associated with one or more DCI parameters including at least one MCS. NR networks can support multiple 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 can use the same precoding for both DMRS ports and PT-RS ports. The number of PT-RS ports can be less than the number of DMRS ports in the scheduled resources. Downlink PT-RS can be restricted to the UE's scheduled time / frequency duration. Downlink PT-RS can be transmitted on symbols to facilitate phase tracking at the receiver.

[0156] The UE can transmit uplink DMRS to the base station for channel estimation. For example, the base station can use uplink DMRS to perform consistent demodulation of one or more uplink physical channels. For example, the UE can transmit uplink DMRS with PUSCH and / or PUCCH. Uplink DMRS can span a frequency range similar to the frequency range associated with the corresponding physical channel. The base station can configure the UE using one or more uplink DMRS configurations. At least one DMRS configuration can support a frontload DMRS mode. Frontload 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 frontload DMRS symbols for PUSCH and / or PUCCH, which the UE can use to schedule single-symbol DMRS and / or dual-symbol DMRS. NR networks can support (e.g., for Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM)) a common DMRS structure for both downlink and uplink, where the DMRS location, DMRS type, and / or scrambling sequence of the DMRS can be the same or different.

[0157] A PUSCH may include one or more layers, and a UE may transmit at least one symbol having DMRS on one or more layers present in the PUSCH. In one example, a higher layer may configure up to three DMRS for the PUSCH.

[0158] Depending on the UE's RRC configuration, the 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 type of the uplink PT-RS can be configured UE-specifically through a combination of RRC signaling and / or through one or more parameters indicated by the 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 one MCS. The radio network can 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 can use the same precoding for both DMRS ports and PT-RS ports. The number of PT-RS ports can be less than the number of DMRS ports in the scheduled resources. For example, the uplink PT-RS can be restricted to the UE's scheduled time / frequency duration.

[0159] The UE can 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 allows the base station to estimate the uplink channel state at one or more frequencies. The scheduler at the base station can use the estimated uplink channel state to assign one or more resource blocks for uplink PUSCH transmissions from the UE. The base station can semi-statically configure the UE using one or more SRS resource sets. For each SRS resource set, the base station can configure the UE using one or more SRS resources. SRS resource set suitability can be configured by higher-layer (e.g., RRC) parameters. For example, when higher-layer parameters indicate beam management, SRS resources in one or more SRS resource sets (e.g., having the same / similar time-domain behavior, periodic, aperiodic, etc.) can be transmitted at certain times (e.g., simultaneously). The UE can transmit one or more SRS resources from the SRS resource set. The NR network can support aperiodic, periodic, and / or semi-persistent SRS transmissions. The UE can transmit SRS resources based on one or more trigger types, where the 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 used 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.

[0160] 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; temporal behavior of SRS resource configuration (e.g., indication of periodic, semi-persistent, or aperiodic SRS); time slot, micro-time slot, and / or subframe level period; time slots of periodic and / or aperiodic SRS resources; number of OFDM symbols in SRS resources; initiating OFDM symbols for SRS resources; SRS bandwidth; frequency hopping bandwidth; cyclic shift; and / or SRS sequence ID.

[0161] An antenna port is defined such that a symbol on the antenna port, through the channel through which it is transmitted, can be inferred from another symbol on the same antenna port, through the same channel through which it is transmitted. If a first symbol and a second symbol are transmitted on the same antenna port, the receiver can infer the channel used to transmit the second symbol on the antenna port (e.g., fade gain, multipath delay, etc.) from the channel used to transmit the first symbol on the antenna port. A first antenna port and a second antenna port can be referred to as quasi-co-located (QCLed) if one or more large-scale properties can be inferred from the channel through which the second symbol on the second antenna port is transmitted, and the channel through which the first symbol on the first antenna port is transmitted. These 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 reception (Rx) parameters.

[0162] 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 beamforming reference signals. The UE can perform downlink beam measurements and generate a beam measurement report based on downlink reference signals (e.g., Channel State Information Reference Signal (CSI-RS)). After setting up an RRC connection with the base station, the UE can perform the downlink beam measurement procedure.

[0163] 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 may represent a resource block (RB) within the cell's bandwidth. The base station may transmit one or more RRC messages including CSI-RS resource configuration parameters indicating one or more CSI-RS. One or more of the following parameters can be configured for CSI-RS resource configuration via higher-layer signaling (e.g., RRC and / or MAC signaling): CSI-RS resource configuration identifier, number of CSI-RS ports, CSI-RS configuration (e.g., symbol and resource element (RE) positions in subframes), CSI-RS subframe configuration (e.g., subframe position, offset, and periodicity in radio frames), CSI-RS power parameters, CSI-RS sequence parameters, Code Division Multiplexing (CDM) type parameters, frequency density, transport comb, Quasi-Co-location (QCL) parameters (e.g., QCL-scramblingidentity, crs-portscount, mbsfn-subframeconfiglist, csi-rs-configZPid, qcl-csi-rs-configNZPid), and / or other radio resource parameters.

[0164] Figure 11B The three beams shown can be configured for use in a UE-specific configuration. Figure 11B The document describes three beams (beam #1, beam #2, and beam #3), with the possibility of configuring more or fewer beams. CSI-RS1101 can be assigned to beam #1, which can be transmitted on one or more subcarriers in the RB of the first symbol. CSI-RS1102 can be assigned to beam #2, which can be transmitted on one or more subcarriers in the RB of the second symbol. CSI-RS1103 can be assigned to beam #3, which can be transmitted on one or more subcarriers in the RB of the third symbol. By using frequency division multiplexing (FDM), the base station can use other subcarriers in the same RB (e.g., those not used to transmit CSI-RS 1101) to transmit another CSI-RS associated with a beam of another UE. By using time domain multiplexing (TDM), the beam for a UE can be configured such that the beam for the UE uses symbols from beams of other UEs.

[0165] CSI-RS, such as Figure 11BThose shown (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 a configured CSI-RS resource. The base station can configure the UE using a reporting configuration, and the UE can report RSRP measurements to the network (e.g., via one or more base stations) based on the reporting configuration. In one example, the base station can determine one or more Transmission Configuration Indication (TCI) states, including multiple reference signals, based on the reported measurement results. In one 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 downlink transmissions with a receive (Rx) beam determined based on the one or more TCI states. In one example, the UE may or may not have beam correspondence capability. If the UE has beam correspondence capability, the UE can determine the spatial domain filter for the transmit (Tx) beam based on the spatial domain filter corresponding to the Rx beam. If the UE does not have beam correspondence capability, the UE can perform an uplink beam selection procedure to determine the spatial domain filter for the Tx beam. The UE can perform the uplink beam selection procedure based on one or more Sounding Reference Signal (SRS) resources configured for the UE by the base station. The base station can select and indicate the UE's uplink beam based on measurements of one or more SRS resources transmitted by the UE.

[0166] During beam management, the UE can assess (e.g., measure) the channel quality of one or more beampup links, including beampup links containing transmit beams transmitted by the base station, and receive beams received by the UE. Based on this assessment, the UE can transmit a beam measurement report indicating one or more beampup 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).

[0167] Figure 12AExamples of three downlink beam management procedures are shown: P1, P2, and P3. Procedure P1 can enable UE measurement of the transmit (Tx) beams for a Transport Receive 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 the beam set (shown as an ellipse rotating counterclockwise in the top rows of P1 and P2, indicated by the dashed arrows). Beamforming at the UE can include Rx beam sweeping for the beam set (shown as an ellipse rotating clockwise in the bottom rows of P1 and P3, indicated by the dashed arrows). Procedure P2 can be used to enable UE measurement of the Tx beams for a TRP (shown as an ellipse rotating counterclockwise in the top row of P2, indicated by the dashed arrows). The UE and / or base station can perform process P2 using a smaller beam set than that used in process P1, or using a narrower beam than that used in process P1. This can be referred to as beam refinement. The UE can perform process P3 for Rx beam determination by using the same Tx beam at the base station and sweeping the Rx beam at the UE.

[0168] Figure 12B Examples of three uplink beam management procedures are shown: U1, U2, and U3. Procedure U1 can be used to enable the base station to perform measurements on the UE's Tx beam, 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, an Rx beam sweep from the beam set (shown as an ellipse rotating clockwise in the bottom rows of U1 and U3, indicated by the dashed arrow). Beamforming at the base station can include, for example, an Rx beam sweep from the beam set (shown as an ellipse rotating counterclockwise in the top rows of U1 and U2, indicated by the dashed arrow). 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 base station can perform procedure U2 using a smaller beam set than that used in procedure P1, or using a narrower beam than that used in procedure P1. This can be called beam refinement. The UE can execute procedure U3 to adjust its Tx beam when the base station is using a fixed Rx beam.

[0169] The UE can initiate a beam failure recovery (BFR) procedure based on the detection of a beam failure. The UE can initiate a BFR procedure by transmitting a BFR request (e.g., preamble, UCI, SR, MAC CE, etc.). The UE can detect a beam failure based on the determination that the quality of the beam pair link in the associated control channel is unsatisfactory (e.g., an error rate higher than a threshold, received signal power lower than a threshold, timer expiration, etc.).

[0170] The UE can use one or more reference signals (RS) to measure the quality of the beamp-link, which may include 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 beamp-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 reception quality (RSRQ) value, and / or CSI value measured on the RS resources. The base station may indicate one or more DM-RS quasi-co-located (QCLed) RS resources and channels (e.g., control channels, shared data channels, etc.). The one or more DMRS of the RS resources and channels may be QCLed when the channel characteristics (e.g., Doppler shift, Doppler spread, average delay, delay spread, spatial Rx parameter, fading, etc.) from the transmission to the UE via the RS resources are similar to or the same as the channel characteristics from the transmission to the UE via the channels.

[0171] A network (e.g., a gNB and / or an ng-eNB of the network) and / or a 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 establishment to the network. A UE can initiate a random access procedure from the RRC_CONNECTED state. A UE can initiate a random access procedure to request uplink resources (e.g., for uplink transmission of SR when no PUCCH resources are available) and / or to acquire uplink timing (e.g., when the uplink synchronization state is not synchronized). A UE can initiate a random access procedure to request one or more System Information Blocks (SIBs) (e.g., other system information such as SIB2, SIB3, etc.). A UE can initiate a random access procedure for beam failure recovery requests. The network can initiate random access procedures for handover and / or for establishing time alignment for SCell additions.

[0172] Figure 13A A four-step contention-based random access procedure is illustrated. Before initiating this procedure, the base station may transmit configuration message 1310 to the UE. Figure 13AThe process shown involves 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).

[0173] Configuration message 1310 may be transmitted, for example, using one or more RRC messages. These one or more RRC messages may indicate one or more Random Access Channel (RACH) parameters to the UE. These 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 these one or more RRC messages to one or more UEs. These 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 RRC_INACTIVE state). The UE may determine the time and frequency resources and / or uplink transmission power for transmitting Msg 1 1311 and / or Msg3 1313 based on these one or more RACH parameters. Based on these one or more RACH parameters, the UE may determine the receive timing and downlink channel for receiving Msg 2 1312 and Msg 4 1314.

[0174] The one or more RACH parameters provided in configuration message 1310 may indicate one or more physical RACH (PRACH) timings available for transmitting Msg 11311. These one or more PRACH timings may be predefined. These one or more RACH parameters may indicate one or more available sets of one or more PRACH timings (e.g., prach-ConfigIndex). These one or more RACH parameters may indicate a relationship between (a) one or more PRACH timings and (b) one or more reference signals. These one or more RACH parameters may indicate a relationship between (a) one or more preambles and (b) one or more reference signals. These one or more reference signals may be SS / PBCH blocks and / or CSI-RS. For example, these one or more RACH parameters may indicate the number of SS / PBCH blocks mapped to PRACH timings and / or the number of preambles mapped to SS / PBCH blocks.

[0175] The one or more RACH parameters provided in 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 the preamble transmission). One or more power offsets indicated by the one or more RACH parameters may exist. For example, the one or more RACH parameters can indicate: power ramp step size; power offset between SSB and CSI-RS; power offset between transmissions of Msg 1 1311 and Msg 3 1313; and / or power offset values ​​between preamble groups. The one or more RACH parameters can indicate one or more thresholds upon which the UE can determine at least one reference signal (e.g., SSB and / or CSI-RS) and / or uplink carrier (e.g., normal uplink (NUL) carrier and / or supplementary uplink (SUL) carrier).

[0176] Msg 1 1311 may include one or more preamble transmissions (e.g., 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 may include one or more preambles. The UE may determine the preamble group based on path loss measurements and / or the magnitude of Msg 3 1313. The UE may measure the RSRP of one or more reference signals (e.g., SSB and / or CSI-RS) and determine at least one reference signal with 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.

[0177] The UE can determine the preamble based on one or more RACH parameters provided in 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 an 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 timings. The UE can use one or more reference signals (e.g., SSB and / or CSI-RS) for selecting the preamble and for determining the PRACH timing. One or more RACH parameters (e.g., ra-ssb-OccasionMskIndex and / or ra-OccasionList) can indicate the association between the PRACH timing and the one or more reference signals.

[0178] If no response is received after the preamble transmission, the UE may perform a preamble retransmission. The UE may increase the uplink transmission power used for the preamble retransmission. The UE may select the initial preamble transmission power based on path loss measurements and / or the target received preamble power configured by the network. The UE may determine the preamble to be retransmitted and may ramp up the uplink transmission power. The UE may receive one or more RACH parameters (e.g., PREAMBLE_POWER_RAMPING_STEP) indicating the ramp step size used for the preamble retransmission. The ramp step size may be the amount by which the uplink transmission power used for the retransmission is incrementally increased. If the UE determines that the same reference signal (e.g., SSB and / or CSI-RS) is used as in the previous preamble transmission, the UE may ramp up the uplink transmission power. The UE may count the number of preamble transmissions and / or retransmissions (e.g., PREAMBLE_TRANSMISSION_COUNTER). For example, if the number of preamble transmissions exceeds a threshold configured by one or more RACH parameters (e.g., preambleTransMax), the UE can determine that the random access procedure has not been successfully completed.

[0179] The 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 or in response to the transmission of Msg 1 1311. 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 was received by the base station. Msg 2 1312 may include a time alignment command that the UE may use 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 the preamble, the UE may initiate a time window (e.g., ra-ResponseWindow) to monitor the PDCCH of Msg 2 1312. The UE may determine when to initiate the time window based on the PRACH timing used by the UE to transmit the preamble. For example, a UE may initiate a time window of one or more symbols after the last symbol of the preamble (e.g., at the first PDCCH timing starting from the end of the preamble transmission). These one or more symbols may be determined based on a set of parameters. The PDCCH may be in a common search space configured by RRC messages (e.g., a Type 1-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 timing in which the UE transmits the preamble. For example, the UE may determine the RA-RNTI based on: the OFDM symbol index; the time slot index; the frequency domain index; and / or the UL carrier indicator of the PRACH timing. Examples of RA-RNTIs include:

[0180] RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id

[0181] Where s_id can be the index of the first OFDM symbol of the PRACH timing (e.g., 0 ≤ s_id < 14), t_id can be the index of the first slot of the PRACH timing in the system frame (e.g., 0 ≤ t_id < 80), f_id can be the index of the PRACH timing in the frequency domain (e.g., 0 ≤ f_id < 8), and ul_carrier_id can be the UL carrier used for preamble transmission (e.g., 0 for NUL carriers and 1 for SUL carriers).

[0182] The UE may transmit Msg 3 1313 in response to successful reception of Msg 2 1312 (e.g., using the resource identified in Msg 2 1312). Msg 3 1313 can be used for, for example... Figure 13A The diagram illustrates contention resolution in a contention-based random access procedure. In some scenarios, multiple UEs may transmit the same preamble to a base station, and the base station may provide a RAR corresponding to each UE. If these 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) can be used to increase the likelihood that a UE will not mistakenly use the identifier of another UE. To perform contention resolution, the UE may include the device identifier in Msg 3 1313 (e.g., the TC-RNTI included in Msg 2 1312 if a C-RNTI is assigned, and / or any other suitable identifier).

[0183] Msg 4 1314 can be received after or in response to the transmission of Msg 3 1313. If Msg 3 1313 includes a C-RNTI, the base station will use the C-RNTI to address the UE on the PDCCH. If the UE's unique C-RNTI is detected on the PDCCH, the random access procedure is determined to have been successfully completed. If Msg 3 1313 includes a TC-RNTI (e.g., if the UE is in RRC_IDLE state or 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 includes a UE contention resolution identifier MAC CE that matches (e.g., is transmitted) the CCCH SDU sent in Msg 3 1313, the UE can determine that contention resolution was successful and / or the UE can determine that the random access procedure was successfully completed.

[0184] The UE can be configured with Supplemental Uplink (SUL) carriers and Normal Uplink (NUL) carriers. Initial access (e.g., random access procedures) can be supported on the uplink carriers. For example, the base station can configure two separate RACH configurations for the UE: one for the SUL carrier and another for the NUL carrier. To enable random access in a cell configured with an SUL carrier, the network can indicate which carrier (NUL or SUL) to use. For example, the UE can determine the SUL carrier if the measured quality of one or more reference signals is below a broadcast threshold. Uplink transmissions during the random access procedure (e.g., Msg1 1311 and / or Msg 3 1313) can be preserved on the selected carrier. In one or more cases, the UE can switch uplink carriers during the random access procedure (e.g., between Msg 1 1311 and Msg 3 1313). For example, the UE can determine and / or switch uplink carriers for Msg 1 1311 and / or Msg 3 1313 based on channel clarity assessment (e.g., listen before speaking).

[0185] Figure 13B This illustrates a two-step contention-free random access procedure. Figure 13A The four-step contention-based random access procedure shown is similar, and the base station can transmit configuration message 1320 to the UE before the procedure is initiated. Configuration message 1320 may be similar to configuration message 1310 in some respects. Figure 13B The process shown involves the transmission of two messages: Msg 1 1321 and Msg 2 1322. Msg 1 1321 and Msg 2 1322 can be similar in some respects to... Figure 13A The Msg 1 1311 and Msg2 1312 are shown. (As from...) Figure 13A and Figure 13B It will be understood that a contention-free random access procedure may not include messages such as Msg 3 1313 and / or Msg 4 1314.

[0186] It can be initiated for beam failure recovery, other SI requests, SCell addition and / or handover. Figure 13B The diagram illustrates a contention-free random access procedure. For example, the base station may indicate or assign a preamble to the UE for Msg 1 1321. The UE may receive the preamble indication (e.g., ra-PreambleIndex) from the base station via PDCCH and / or RRC.

[0187] After transmitting the preamble, the UE can initiate a time window (e.g., ra-ResponseWindow) to monitor the PDCCH of the RAR. In the event of a beam failure recovery request, the base station can configure the UE with a separate time window and / or a separate PDCCH within the search space indicated by the RRC message (e.g., recoverySearchSpaceId). The UE can monitor the PDCCH transmission of the Cell RNTI (C-RNTI) addressed to the search space. Figure 13B In the contention-free random access procedure shown, the UE can determine that the random access procedure was successfully completed after or in response to the transmission of Msg 1 1321 and the reception of the corresponding Msg 2 1322. For example, if the PDCCH transmission addresses to the C-RNTI, the UE can determine that the random access procedure was successfully completed. For instance, if the UE receives a RAR including a preamble identifier corresponding to the preamble transmitted by the UE and / or the RAR includes a MAC sub-PDU with the preamble identifier, the UE can determine that the random access procedure was successfully completed. The UE can determine that this response is an indication of confirmation of the SI request.

[0188] Figure 13C Another two-step random access procedure is shown. (Compared to...) Figure 13A and Figure 13B Similar to the random access procedure shown, the base station can transmit configuration message 1330 to the UE before the procedure is initiated. Configuration message 1330 may be similar in some respects to configuration message 1310 and / or configuration message 1320. Figure 13C The process shown involves the transmission of two messages: Msg A1331 and Msg B1332.

[0189] Msg A 1331 can be transmitted by the UE in uplink transmission. Msg A 1331 may include one or more transmissions of preamble 1341 and / or one or more transmissions of transport block 1342. Transport block 1342 may include... Figure 13A The content shown in Msg 3 1313 is similar to and / or equivalent to that of Msg 3 1313. Transport block 1342 may include UCIs (e.g., SR, HARQ ACK / NACK, etc.). The UE may receive Msg B 1332 after or in response to the transmission of Msg A 1331. Msg B 1332 may include content similar to and / or equivalent to that shown in Msg 3 1313. Figure 13A and Figure 13B The Msg 2 1312 shown (e.g., RAR) and / or Figure 13A The content shown in Msg 4 1314 is similar to and / or equivalent to the content shown in Msg 4 1314.

[0190] UE can initiate [activities] on licensed spectrum and / or unlicensed spectrum. Figure 13C The two-step random access procedure is used in the UE. The UE may determine whether to initiate a two-step random access procedure based on one or more factors. These one or more factors may be: the radio access technology being used (e.g., LTE, NR, etc.); whether the UE has a valid TA; cell size; the UE's RRC status; the type of spectrum (e.g., licensed vs. unlicensed); and / or any other suitable factors.

[0191] The UE can determine the radio resources and / or uplink transmission power of the preamble 1341 and / or transport block 1342 included in Msg A 1331 based on the two-step RACH parameters included in configuration message 1330. The RACH parameters can indicate the modulation and coding scheme (MCS), time-frequency resources, and / or power control of the preamble 1341 and / or transport block 1342. The time-frequency resources (e.g., PRACH) for the transmission of the preamble 1341 and the time-frequency resources (e.g., PUSCH) for the transmission of the transport block 1342 can be multiplexed using FDM, TDM, and / or CDM. The RACH parameters enable the UE to determine the receive timing and downlink channel for monitoring and / or receiving Msg B 1332.

[0192] Transport block 1342 may include data (e.g., delay-sensitive data), a UE identifier, 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 include at least one of the following: a preamble identifier; a timing advanced 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., a C-RNTI or a TC-RNTI). The UE can determine that the two-step random access procedure was successfully completed if: 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., transport block 1342).

[0193] The UE and the base station can 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 include downlink control signaling transmitted from the base station to the UE and / or uplink control signaling transmitted from the UE to the base station.

[0194] Downlink control signaling may include: downlink scheduling assignment; uplink scheduling authorization indicating uplink radio resources and / or transmission format; time 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) shared by the UE group.

[0195] A base station can attach one or more Cyclic Redundancy Check (CRC) parity bits to a DCI to aid in the detection of transmission errors. When the DCI is intended for use with a UE (or a group of UEs), the base station can scramble the CRC parity bits with the UE's identifier (or the UE group's identifier). Scrambling the CRC parity bits with the identifier can include a Modulo-2 appending (or an exclusive OR operation) of the identifier value and the CRC parity bits. This identifier can include the 16-bit value of the Radio Network Temporary Identifier (RNTI).

[0196] DCIs can be used for various purposes. The purpose can be indicated by the type of RNTI used to scramble the CRC parity bits. For example, a DCI with CRC parity bits scrambled using a paging RNTI (P-RNTI) can indicate paging information and / or system information change notifications. A P-RNTI can be predefined as "FFFE" in hexadecimal. A DCI with CRC parity bits scrambled using a system information RNTI (SI-RNTI) can indicate broadcast transmission of system information. A SI-RNTI can be predefined as "FFFF" in hexadecimal. A DCI with CRC parity bits scrambled using a random access RNTI (RA-RNTI) can indicate a random access response (RAR). A DCI with CRC parity bits scrambled using a cell RNTI (C-RNTI) can indicate dynamically scheduled unicast transmissions and / or triggering of PDCCH ordered random access. A DCI with CRC parity bits scrambled using a temporary cell RNTI (TC-RNTI) can indicate contention resolution (e.g., similar to...). Figure 13AThe Msg 3 shown is Msg 3 of 1313. Other RNTIs configured by the base station for the UE may include: the configured scheduling RNTI (CS-RNTI), transmission power control PUCCH RNTI (TPC-PUCCH-RNTI), transmission power control PUSCH RNTI (TPC-PUSCH-RNTI), transmission power control SRS RNTI (TPC-SRS-RNTI), interrupt RNTI (INT-RNTI), slot format indication RNTI (SFI-RNTI), semi-persistent CSI RNTI (SP-CSI-RNTI), modulation and coding scheme cell RNTI (MCS-C-RNTI), etc.

[0197] 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 can be used for PUSCH scheduling in a cell. DCI format 0_0 can be a fallback DCI format (e.g., with a compact DCI payload). DCI format 0_1 ​​can be used for PUSCH scheduling in a cell (e.g., with a larger DCI payload than DCI format 0_0). DCI format 1_0 can be used for PDSCH scheduling in a cell. DCI format 1_0 can be a fallback DCI format (e.g., with a compact DCI payload). DCI format 1_1 can be used for PDSCH scheduling in a cell (e.g., with a larger DCI payload than DCI format 1_0). DCI format 2_0 can be used to provide slot format indication to a UE group. DCI format 2_1 can be used to notify a UE group of physical resource blocks and / or OFDM symbols, where the UE may assume that transmission to the UE is not expected. DCI format 2_2 can be used to transmit Transmission Power Control (TPC) commands for PUCCH or PUSCH. DCI format 2_3 can be used to transmit a set of TPC commands for SRS transmission by one or more UEs. New DCI formats for new features can be defined in future versions. DCI formats can have different DCI sizes, or they can share the same DCI size.

[0198] After scrambling the DCI with RNTI, the base station can process the DCI using channel coding (e.g., polarity coding), rate matching, scrambling, and / or QPSK modulation. The base station can map the coded and modulated DCI onto resource elements used for and / or configured for the PDCCH. Based on the DCI payload size and / or the base station's coverage area, the base station can transmit the DCI via a PDCCH occupying multiple consecutive control channel elements (CCEs). The number of consecutive CCEs (referred to as the aggregation level) can be 1, 2, 4, 8, 16, and / or any other suitable number. CCEs can include the number of resource element groups (REGs) (e.g., 6). REGs can include resource blocks in OFDM symbols. The mapping of the coded and modulated DCI onto resource elements can be based on the mapping between CCEs and REGs (e.g., CCE-to-REG mapping).

[0199] Figure 14A An example of a CORESET configuration for the bandwidth portion is shown. A base station can transmit DCI via PDCCH on one or more control resource sets (CORESETs). A CORESET can include time-frequency resources in which a UE attempts to decode the DCI using one or more search spaces. The base station can configure the CORESET in the time-frequency domain. Figure 14A In the example, the first CORESET 1401 and the second CORESET 1402 appear at the first symbol of the time slot. The first CORESET 1401 overlaps with the second CORESET 1402 in the frequency domain. The third CORESET 1403 appears at the third symbol of the time slot. The fourth CORESET 1404 appears at the seventh symbol of the time slot. CORESETs can have different numbers of resource blocks in the frequency domain.

[0200] Figure 14B An example of CCE-to-REG mapping for DCI transmission is shown in CORESET and PDCCH processing. CCE-to-REG mapping can be interleaved (e.g., for providing frequency diversity) or non-interleaved (e.g., for facilitating interference coordination and / or frequency-selective transmission in the control channel). The base station can perform different or the same CCE-to-REG mappings for different CORESETs. A CORESET can be associated with CCE-to-REG mapping via RRC configuration. A CORESET can be configured with antenna port quasi-co-location (QCL) parameters. Antenna port QCL parameters can indicate the QCL information for the demodulation reference signal (DMRS) used for PDCCH reception in the CORESET.

[0201] The base station can transmit an RRC message to the UE including configuration parameters for one or more CORESETs and one or more search space sets. The configuration parameters can indicate the association between the search space set and the CORESET. The search space set can include a set of PDCCH candidates formed by CCEs at a given aggregation level. The configuration parameters can indicate: the number of PDCCH candidates to be monitored at each aggregation level; the PDCCH monitoring period and PDCCH monitoring type; 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 can be predefined and known to the UE. The set of CCEs in the UE-specific search space set can be configured based on the UE's identifier (e.g., C-RNTI).

[0202] like Figure 14B As shown, the UE can determine the time-frequency resources of the CORESET based on RRC messages. The UE can determine the CCE-to-REG mapping of the CORESET (e.g., interleaved or non-interleaved and / or mapping parameters) based on the CORESET's configuration parameters. The UE can determine the number of search space sets configured on the CORESET (e.g., up to 10) based on RRC messages. The UE can monitor a set of PDCCH candidates based on the configuration parameters of the search space sets. The UE can monitor a set of PDCCH candidates in one or more CORESETs for detecting one or more DCIs. Monitoring may include decoding one or more PDCCH candidates in the set of PDCCH candidates according to the monitored DCI format. Monitoring may include decoding the DCI content of one or more PDCCH candidates, which have possible (or configured) PDCCH locations, 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. Decoding may be referred to as blind decoding. The UE can determine that the DCI is valid for the UE in response to a CRC check (e.g., scrambling bits of the CRC parity bit of the DCI that match the RNTI value). The UE can process the information contained in the DCI (e.g., scheduling assignment, uplink grant, power control, slot format indication, downlink preemption, etc.).

[0203] The UE can transmit uplink control signaling (e.g., uplink control information (UCI)) to the base station. Uplink control signaling transmission may include a Hybrid Automatic Repeat Request (HARQ) acknowledgment for a received DL-SCH transport block. The UE may transmit the HARQ acknowledgment after receiving the DL-SCH transport block. Uplink control signaling may include channel state information (CSI) indicating the channel quality of the physical downlink channel. The UE may transmit the CSI to the base station. Based on the received CSI, the base station can determine transmission format parameters (e.g., including multiple antennas and beamforming schemes) for downlink transmission. Uplink control signaling may include a scheduling request (SR). The UE may transmit an SR indicating that uplink data is available for transmission to the base station. The UE may transmit UCI (e.g., HARQ acknowledgment, CSI report, SR, etc.) via the Physical Uplink Control Channel (PUCCH) or the Physical Uplink Shared Channel (PUSCH). The UE may use one of several PUCCH formats to transmit uplink control signaling via the PUCCH.

[0204] Five PUCCH formats can exist, and the UE can determine the PUCCH format based on the size of the UCI (e.g., the number of uplink symbols transmitted in the UCI 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 more than one or two symbols are transmitted and the number of HARQ-ACK information bits (HARQ-ACK / SR bits) with positive or negative SR is one or two, the UE can use PUCCH format 0 to transmit the UCI in the PUCCH resource. PUCCH format 1 can occupy between four and fourteen OFDM symbols and can include two or fewer bits. If four or more symbols are transmitted 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 more than one or two symbols are transmitted and the number of UCI bits is two or more, the UE can use PUCCH format 2. PUCCH format 3 can occupy between four and fourteen OFDM symbols and can include more than two bits. If four or more symbols are transmitted, the number of UCI bits is two or more, and the PUCCH resource does not include an orthogonal overlay code, the UE can use PUCCH format 3. PUCCH format 4 can occupy between four and fourteen OFDM symbols and can include more than two bits. If four or more symbols are transmitted, the number of UCI bits is two or more, and the PUCCH resource includes an orthogonal overlay code, the UE can use PUCCH format 4.

[0205] The base station can transmit configuration parameters for multiple PUCCH resource sets to the UE using, for example, an RRC message. These multiple PUCCH resource sets (e.g., up to four sets) can be configured on the cell's uplink BWP. A PUCCH resource set can be configured with: a PUCCH resource set index; multiple PUCCH resources (e.g., pucch-Resourceid) identified by a PUCCH resource identifier; and / or multiple (e.g., a maximum number) UCI ​​information bits that the UE can transmit using one of the multiple PUCCH resources in the PUCCH resource set. When multiple PUCCH resource sets are configured, the UE can select one of the multiple PUCCH resource sets based on the total bit length of the UCI information bits (e.g., HARQ-ACK, SR, and / or CSI). If the total bit length of the UCI information bits is two or fewer, the UE can select a first PUCCH resource set with a PUCCH resource set index equal to "0". If the total length of the UCI information bits is greater than two and less than or equal to the first configuration value, the UE can select a second PUCCH resource set with a PUCCH resource set index equal to "1". If the total length of the UCI information bits is greater than the first configuration value and less than or equal to the second configuration value, the UE can select a third PUCCH resource set with a PUCCH resource set index equal to "2". If the total length of the UCI information bits is greater than the second configuration value and less than or equal to the third value (e.g., 1406), the UE can select a fourth PUCCH resource set with a PUCCH resource set index equal to "3".

[0206] After determining a PUCCH resource set from multiple PUCCH resource sets, the UE can determine the PUCCH resources used for UCI (HARQ-ACK, CSI, and / or SR) transmission from the PUCCH resource set. The UE can determine the PUCCH resources based on the PUCCH resource indicator in the DCI received on the PDCCH (e.g., a DCI with DCI format 1_0 or a DCI for 1_1). The three-bit PUCCH resource indicator in the DCI can indicate one of the eight PUCCH resources in the PUCCH resource set. Based on the PUCCH resource indicator, the UE can use the PUCCH resource indicated by the PUCCH resource indicator in the DCI to transmit UCI (HARQ-ACK, CSI, and / or SR).

[0207] Figure 15 An example of a wireless device 1502 communicating with a base station 1504 according to an embodiment of this 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 shown or any other communication network. Figure 15 The diagram shows only one wireless device 1502 and one base station 1504, but it should be understood that a mobile communication network may include more than one UE and / or more than one base station, which have the same characteristics as... Figure 15 The same or similar configurations shown.

[0208] Base station 1504 can connect wireless device 1502 to the core network (not shown) via radio communication through air interface (or radio interface) 1506. The communication direction from base station 1504 to wireless device 1502 via air interface 1506 is referred to as the downlink, while the communication direction from wireless device 1502 to base station 1504 via air interface 1506 is referred to as the uplink. Downlink transmissions can be separated from uplink transmissions using some combination of FDD, TDD, and / or two duplex technologies.

[0209] In the downlink, data to be transmitted from base station 1504 to wireless device 1502 can be provided to processing system 1508 of base station 1504. This data can be provided to processing system 1508 via, for example, the core network. In the uplink, data to be transmitted from wireless device 1502 to base station 1504 can be provided to processing system 1518 of wireless device 1502. Processing systems 1508 and 1518 can implement Layer 3 and Layer 2 OSI functions to process the data for transmission. Layer 2 may include, for example, information about... Figure 2A , Figure 2B , Figure 3 and Figure 4A The SDAP layer, PDCP layer, RLC layer, and MAC layer. Layer 3 may include, for example, the SDAP layer, PDCP layer, RLC layer, and MAC layer. Figure 2B The RRC layer.

[0210] After being processed by processing system 1508, data to be sent to wireless device 1502 can be provided to transmission processing system 1510 of base station 1504. Similarly, after being processed by processing system 1518, data to be sent to base station 1504 can be provided to transmission processing system 1520 of wireless device 1502. Transmission processing systems 1510 and 1520 can implement Layer 1 OSI functions. Layer 1 may include information about... Figure 2A , Figure 2B , Figure 3 and Figure 4A The PHY layer. For transmission processing, the PHY layer can perform operations such as 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 multiple-antenna processing, etc.

[0211] At base station 1504, receiving processing system 1512 can receive uplink transmissions from wireless device 1502. At wireless device 1502, receiving processing system 1522 can receive downlink transmissions from base station 1504. Receiving processing systems 1512 and 1522 can implement Layer 1 OSI functions. Layer 1 may include information about... Figure 2A , Figure 2B , Figure 3 and Figure 4A The PHY layer. For receive processing, the PHY layer can perform tasks such as error detection, forward error correction decoding, deinterleaving, demapping of the transport channel to the physical channel, demodulation of the physical channel, MIMO or multi-antenna processing, etc.

[0212] like Figure 15 As shown, wireless device 1502 and base station 1504 may include multiple antennas. These multiple antennas can 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.

[0213] Processing systems 1508 and 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 can be executed by processing systems 1508 and / or 1518 to perform one or more of the functions discussed in this application. Although Figure 15 Although not shown, the transmission processing system 1510, transmission processing system 1520, receiving processing system 1512 and / or receiving 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 can be executed to perform one or more of their respective functions.

[0214] 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, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) and / or other programmable logic devices, discrete gate and / or transistor logic, discrete hardware components, onboard 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.

[0215] Processing system 1508 and / or processing system 1518 may be connected to one or more peripheral devices 1516 and one or more peripheral devices 1526, respectively. The one or more peripheral devices 1516 and 1526 may include software and / or hardware providing features and / or functions, such as speakers, microphones, keyboards, displays, touchpads, power supplies, satellite transceivers, universal serial bus (USB) ports, hands-free headsets, 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 1526 and / or provide user output data to the aforementioned one or more peripheral devices. The processing system 1518 in wireless device 1502 can receive power from a power source and / or can be configured to distribute power to other components in wireless device 1502. The power source may include one or more power sources, such as a battery, solar cell, fuel cell, or any combination thereof. Processing system 1508 and / or processing system 1518 may be connected to GPS chipset 1517 and GPS chipset 1527, respectively. GPS chipset 1517 and GPS chipset 1527 may be configured to provide geographic location information for wireless device 1502 and base station 1504, respectively.

[0216] Figure 16AAn exemplary structure for uplink transmission is shown. The baseband signal representing the physical uplink shared channel can perform one or more functions. These functions may include at least one of the following: scrambling; modulating scrambling bits to generate complex-valued symbols; mapping complex-valued modulation symbols onto one or more transport layers; transform precoding to generate complex-valued symbols; precoding the complex-valued symbols; mapping precoded complex-valued symbols to resource elements; generating complex-valued time-domain single-carrier frequency division multiple access (SC-FDMA) or CP-OFDM signals for antenna ports; and so on. In one example, when transform precoding is enabled, an SC-FDMA signal for uplink transmission can be generated. In one example, when transform precoding is not enabled, it can be achieved through... Figure 16A Generate CP-OFDM signals for uplink transmission. These functions are shown as examples, and other mechanisms are expected to be implemented in various implementation schemes.

[0217] Figure 16B An exemplary structure for modulation and upconversion of a baseband signal to a carrier frequency is shown. The baseband signal can be a complex-value SC-FDMA or CP-OFDM baseband signal from the antenna port and / or a complex-value Physical Random Access Channel (PRACH) baseband signal. Filtering can be applied before transmission.

[0218] Figure 16C An exemplary structure for downlink transmission is shown. The baseband signal representing the physical downlink channel can perform one or more functions. These functions may include: scrambling coded bits in a codeword to be transmitted over the physical channel; modulating the scrambled bits to generate complex-valued modulation symbols; mapping the complex-valued modulation symbols onto one or more transport layers; precoding the complex-valued modulation symbols for transmission at the antenna port; mapping the complex-valued modulation symbols for the antenna port to resource elements; generating a complex-valued time-domain OFDM signal for the antenna port; and so on. These functions are shown as examples, and other mechanisms are contemplated for implementation in various embodiments.

[0219] Figure 16D Another exemplary structure for modulation and upconversion of a baseband signal to a carrier frequency is shown. The baseband signal can be a complex-value OFDM baseband signal at the antenna port. Filtering can be applied before transmission.

[0220] A wireless device can receive one or more messages (e.g., RRC messages) from a base station, including configuration parameters for multiple cells (e.g., primary cell, secondary cell). The wireless device can communicate with at least one base station (e.g., two or more base stations in dual connectivity) via these cells. These messages (e.g., as part of the configuration parameters) can include parameters for configuring the wireless device at the physical layer, MAC layer, RLC layer, PCDP layer, SDAP layer, and RRC layer. For example, configuration parameters can include parameters for configuring physical and MAC layer channels, bearers, etc. For example, configuration parameters can include parameters indicating the values ​​of timers used for the physical layer, MAC layer, RLC layer, PCDP layer, SDAP layer, RRC layer, and / or communication channels.

[0221] A timer can begin running once started and continues running until it stops or expires. If a timer is not running, it can be started, or if it is running, it can be restarted. A timer can be associated with a value (e.g., a timer can start or restart from a certain value, or it can start from zero and expire once it reaches that value). The duration of a timer may not be updated until the timer stops or expires (e.g., due to a BWP switch). Timers can be used to measure time periods / windows of a process. When the specification refers to implementations and processes 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 these multiple ways of implementing a timer can be used to measure time periods / windows of a process. For example, a random access response window timer can be used to measure a time window for receiving a random access response. In one example, instead of starting and expiring the random access response window timer, the time difference between two timestamps can be used. When the timer restarts, the measurement process for the time window can be restarted. Other exemplary implementations for restarting the measurement of a time window can be provided.

[0222] When an RRC connection is established, the UE is in an RRC connected state. When no RRC connection is established, the UE is in an RRC idle state. When an RRC connection is suspended, the UE can be in an RRC inactive state. When the UE is in an 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 an RRC idle state with a suspended RRC connection.

[0223] RRC connection establishment may include the establishment of SRB1. The base station may complete RRC connection establishment before completing S1 connection establishment (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 is not activated. During the initial phase of the RRC connection, the base station may configure the UE to perform measurement reporting. After successful AS security activation, the UE may send the corresponding measurement report. When AS security is activated, the UE may receive or accept handover messages (e.g., handover commands).

[0224] After initiating the initial (AS) security activation procedure, the base station can initiate the establishment of SRB2 and DRB. For example, the base station can initiate the establishment of SRB2 and DRB before receiving confirmation of initial security activation from the UE. The base station can apply encryption and integrity protection to RRC (connection) reconfiguration messages, which are used to establish SRB2 and DRB. The base station can release the RRC connection based on initial security activation and / or radio bearer establishment failure. For example, security activation and DRB establishment can be triggered by a joint S1 procedure, which may not support partial success. For SRB2 and DRB, security can be activated from the outset. For example, the base station may not establish these bearers before activating security.

[0225] The base station can initiate a suspension of an RRC connection. When an RRC connection is suspended, the UE can store the UE AS context and recovery identifier (or I-RNTI) and transition to the RRC_IDLE state. The RRC message for suspending the RRC connection is integrity protected and encrypted. Suspension can be performed when at least one DRB is successfully established. When the UE has a stored UE AS context, the UE (e.g., UE-NAS layer) initiates the recovery of the suspended RRC connection, the base station allows the RRC connection to resume, and the UE needs to transition from the RRC idle state to the RRC connected state. When the RRC connection is restored, the UE (UE-RRC layer) can configure the UE according to the RRC connection recovery procedure based on the stored UE AS context and the RRC configuration received from the base station. The RRC connection recovery procedure can reactivate (AS) security and rebuild the SRB and DRB. The request to restore the RRC connection (e.g., RRC recovery request message) may include a recovery identifier. This request may not be encrypted and protected with a message authentication code.

[0226] In response to a request to restore an RRC connection, the base station (or core network entity) may restore a suspended RRC connection, refuse the restoration request, and instruct the UE to retain or discard the stored context, or establish a new RRC connection.

[0227] Based on CP EDT or CP transmissions using PUR (e.g., CP small data transmission), data can be appended to RRC Early Data Request and RRC Early Data Completion messages and sent via SRB0. Based on UP EDT or UP transmissions using PUR (e.g., UP small data transmission), security can be reactivated (AS) before transmitting RRC messages during a previous suspension process using the next-hop link count provided in the RRC (connection) release message with a suspension indication (e.g., suspension configuration parameters), and the radio bearer can be rebuilt. Uplink data can be transmitted encrypted on a DTCH multiplexed with an RRC (connection) recovery request message on the CCCH. In the downlink, data can be transmitted on a DTCH multiplexed with an RRC (connection) release message on the DCCH. In response to an EDT request or a transmission using PUR (e.g., small data transmission), the base station can also choose to establish or restore an RRC connection.

[0228] When the base station indicates that the RRC connection is suspended in the RRC release message, a UE in the RRC connected state can transition to the RRC inactive state. Upon transitioning to the RRC inactive state, the UE can store the UE inactive AS context and RRC configuration received from the base station. Resuming the RRC connection from the RRC inactive state can be initiated by the UE (e.g., the UE-NAS layer) when the UE needs to transition from the RRC inactive state to the RRC connected state, or by the UE (e.g., the UE-RRC layer) for RNAU or receiving RAN paging. When the RRC connection is restored, the base station can configure the UE according to the RRC connection restoration procedure based on the stored UE inactive AS context and the RRC configuration received from the base station. The RRC connection restoration procedure can reactivate (AS) security and rebuild the SRB and DRB. In response to a request to restore the RRC connection from the RRC inactive state, the base station can restore the suspended RRC connection, and the UE can transition to the RRC connected state. In response to a request to resume RRC connection from an RRC inactive state, the base station may, without security protection, refuse the request to resume using RRC messages and send the UE to an RRC inactive state with a waiting time, or directly re-suspend the RRC connection and put the UE into an RRC inactive state, or directly release the RRC connection and put the UE into an RRC idle state, or instruct the UE to initiate a NAS-level recovery. Based on the NAS-level recovery, the UE may send a NAS message (e.g., a registration update message) to the AMF.

[0229] When a UE context is received from a core network entity (e.g., AMF), the base station can activate (AS) security (encryption and integrity protection) using an initial security activation procedure. The RRC message for activating security (command and success response) can be integrity protected. Encryption can only begin after the initial security activation procedure is complete. For example, the response to the RRC message used to activate security may not be encrypted. Subsequent messages (e.g., those used to establish SRB2 and DRB) can be integrity protected and encrypted.

[0230] The UE-RRC layer can initiate the RRC connection establishment process, the RRC connection recovery process, or the RRC connection reconstruction process. Based on initiating an RRC connection establishment or RRC connection recovery procedure, the UE may execute one or more procedures, wherein the one or more procedures include at least one of the following: performing a unified access control procedure (e.g., access prohibition check) for access attempts during the RRC establishment / recovery procedure on the serving cell; applying default configuration parameters and configuration / parameters provided by SIB1 (e.g., applying the default configuration and configuration / parameters provided by SIB1 based on an allowed access attempt); for example, sending a random access preamble to the serving cell based on an allowed access attempt; sending an RRC request message to the serving cell (e.g., sending an RRC request message to serving cell 0 based on successful reception of a random access response; starting a timer based on sending the RRC request message; receiving an RRC response message or an RRC rejection message from the serving cell (e.g., in response to the RRC request message); or sending an RRC completion message (e.g., sending an RRC completion message in response to receiving an RRC response message). For the RRC connection reconstruction procedure, the UE may not perform a unified access procedure (e.g., access prohibition check) for access attempts during the RRC reconstruction procedure.

[0231] Base stations (e.g., NG-RAN) can support overload and access control functions such as RACH backoff, RRC connection rejection, RRC connection release, and UE-based access denial mechanisms. A unified access control framework applies to all UE states (e.g., RRC idle, inactive, and connected states). Base stations can broadcast denial control information associated with access category and access identifier (in the case of network sharing, denial control information can be set individually for each PLMN). The UE can determine whether an access attempt is authorized based on the denial information broadcast by the selected PLMN, the selected access category, and the access identifier of the access attempt. For NAS-triggered requests, the UE-NAS layer can determine the access category and access identifier. For AS-triggered requests, the UE-RRC layer determines the access category, while the NAS layer determines the access identifier. Base stations can handle access attempts with high-priority establishment reasons such as "emergency," "MPS priority access," and "MCS priority access" (i.e., emergency calls, MPS, MCS users), and respond to these access attempts with RRC rejection only under extreme network load conditions that may threaten base station stability.

[0232] Based on initiating an RRC connection establishment or recovery procedure, a UE in an RRC inactive or idle state can perform or initiate an access denial check (or unified access control procedure) for an access attempt during the RRC connection establishment or recovery procedure. Based on performing or initiating the access denial check, the UE can determine the access category and access identifier of the access attempt. The UE can determine that the access attempt is denied based on at least one of the following: timer T309 is running for the access category of the access attempt; and timer T302 is running, and the access category is neither '2' nor '0'. The UE can determine that an access attempt is allowed based on at least one of the following: the access category is '0'; and the system information block (system information block type 25) including the unified access control (UAC) denial parameter is not broadcast by the serving cell. The UE may determine that an access attempt is denied based on at least one of the following: the establishment reason (e.g., for the access attempt) is not an emergency; the access denial for each RSRP parameter of the system information block includes (or is set to) threshold 0, and the radio device is in enhanced coverage; the access denial for each RSRP parameter of the system information block includes (or is set to) threshold 1, and the measured RSRP is less than the first entry in the RSRP threshold PRACH information list; the access denial parameter for each RSRP of the system information block includes (or is set to) threshold 2, and the measured RSRP is less than the second entry in the RSRP threshold PRACH information list; and the access denial for each RSRP parameter of the system information block includes (or is set to) threshold 3, and the measured RSRP is less than the third entry in the RSRP threshold PRACH information list. The UE may determine that an access attempt is allowed based on the system information block not including UAC denial parameters for the access attempt. For example, the UE may determine that an access attempt is allowed based on the system information block not including UAC denial parameters for the PLMN selected by the UE and common UAC denial parameters. The UE may determine that an access attempt is allowed based on the common UAC denial parameters not including the access category of the access attempt. The UAC prohibition parameter may include at least one of the following: a UAC prohibition parameter per PLMN; and a 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 the access attempt is allowed based on at least one access identifier in the access identifier of the UAC prohibition parameter having a corresponding bit that is zero. The UE may draw a first random number uniformly distributed within a range, where the range is greater than or equal to 0 and less than 1. The UE may determine that the access attempt is allowed based on the first random number being lower than the UAC prohibition factor in the UAC prohibition parameter. The UE may determine that the access attempt is prohibited based on the first random number being greater than the UAC prohibition factor in the UAC prohibition parameter.In response to determining that an access attempt is prohibited, the UE may draw 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 class based on the second random number. While the prohibition timer T309 is running, access attempts associated with the access class are prohibited (e.g., transmission is not allowed). Upon the expiration of the prohibition timer T309, the UE may consider the prohibition for the access class to be mitigated. Based on the mitigation of the prohibition for the access class, if the UE has an access attempt for that access class, the UE may perform an access prohibition check for that access class.

[0233] Based on the initiation of the RRC connection reconstruction procedure, if one or more prohibition timers T309 are running, the UE can stop one or more prohibition timers T309 for all access categories. Based on stopping one or more prohibition timers T309, the UE can determine that the prohibition for all access categories is being alleviated. The UE can perform the RRC connection reconstruction procedure based on the fact that the prohibition for all access categories is being alleviated. For example, based on the fact that the prohibition for all access categories has been alleviated, the UE can send an RRC reconstruction request even without any prohibition.

[0234] To initiate RRC connection establishment / restoration / reconstruction procedures, the UE-RRC layer can use parameters from the received SIB1. The UE-RRC layer can use L1 parameter values ​​and time alignment timers from SIB1. The UE-RRC layer can use UAC prohibition information from SIB1 to perform unified access control procedures. Based on the unified access control procedures, the UE-RRC layer can determine whether access attempts for these RRC procedures are prohibited or permitted. Based on determining that the access attempt is permitted, 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 restoration request message, or an RRC reconstruction message. The UE-NAS layer may or may not provide the S-TMSI as a UE identifier. The UE-RRC layer can set the UE identifier in the RRC request message.

[0235] For RRC establishment request messages, a UE in RRC idle state can initiate an RRC connection establishment procedure. Based on initiating the RRC connection establishment procedure, if the UE-NAS layer provides an S-TMSI, the UE-RRC layer in RRC idle state can set the UE identifier to the S-TMSI. Otherwise, the UE-RRC layer in RRC idle state can extract a 39-bit random value and set the UE identifier to that random value. For RRC recovery request messages, the UE-RRC layer in RRC inactive or idle state can set the UE identifier to the restored stored identifier. For RRC reconstruction request messages, the UE-RRC layer in RRC connected state can set the UE identifier to the C-RNTI used in the source PCell. The UE-NAS layer can provide a establishment reason (e.g., the UE-NAS layer itself). The UE-RRC layer can set the establishment reason for RRC request messages.

[0236] For RRC recovery request messages, a UE in an RRC inactive state can initiate an RRC connection recovery procedure. A UE in an RRC idle state with a suspended RRC connection can initiate an RRC connection recovery procedure. A UE in an RRC inactive or idle state can initiate an RRC connection procedure based on at least one of the following: restoring (suspending) the RRC connection; and performing / initiating UP small data transfer. Based on initiating an RRC connection recovery procedure, the UE-RRC layer can restore stored configuration parameters and stored security keys from the stored UE inactive AS context. Based on the security key, the UE-RRC layer in an RRC inactive or idle state can set the recovery MAC-I value to the 16 least significant bits of the MAC-I calculated based on the variable recovery 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 recovery MAC input may include at least one of the following: the physical cell identifier of the source cell; the C-RNTI of the source cell; and the cell identifier of the target cell (e.g., the selected cell), wherein the cell identifier is the cell identifier 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 an RRC inactive or idle state derives new security keys for integrity protection and encryption, and configures lower layers (e.g., the UE-PDCP layer) to apply them. The UE may have stored NCC values ​​and recovery identifiers. The UE may receive an RRC release message with a suspension indication (or suspension configuration parameters), wherein the RRC release message includes at least one of the following: the recovery identifier; and the NCC value. The UE-RRC layer in an RRC inactive or idle state may rebuild PDCP entities for one or more bearers. The UE-RRC layer may recover one or more bearers. For example, based on recovering the RRC connection, the UE-RRC layer may recover SRB1. Based on the execution of UP small data transmission, the UE-RRC layer can restore one or more SRBs and DRBs. A UE-RRC layer in an RRC inactive or idle state can send an RRC recovery request message to the base station, wherein the RRC recovery request message may include at least one of the following: recovery identifier; recovery MAC-I; and recovery reason.

[0237] For an RRC re-establishment request message, a UE in RRC connected state can initiate an RRC connection re-establishment process. Based on initiating the RRC connection re-establishment process, the UE-RRC layer in RRC connected state can include the physical cell identifier of the source PCell and a short MAC-I in the RRC re-establishment message. The UE-RRC layer in RRC connected state can set the short MAC-I to the 16 least significant bits of the MAC-I calculated based on the variable short MAC input, the security key and integrity protection algorithm for the integrity protection of the RRC layer (which is used in the source PCell or the PCell in which the re-establishment is triggered), and other security parameters (e.g., count, bearer, and direction). The variable short MAC input can include at least one of the following: the physical cell identifier of the source cell; the c-RNTI of the source cell; and the cell identifier of the target cell (e.g., the selected cell), wherein the cell identifier is the cell identifier in the system information block (e.g., SIB1) of the target cell (e.g., the selected cell). The UE-RRC layer in RRC connected state can reconstruct the PDCP entity and RLC entity for SRB1 and apply the default SRB1 configuration parameters for SRB1. A UE in RRC connection state can configure a lower layer (e.g., PDCP layer) to suspend SRB1 integrity protection and encryption and resume SRB1.

[0238] The UE-RRC layer can send RRC request messages to lower layers (e.g., PDCP layer, RLC layer, MAC layer and / or PHY layer) for transmission. The RRC request message can be an RRC establishment request message, an RRC recovery request message or an RRC reconstruction message.

[0239] The UE-RRC layer can receive an RRC establishment message in response to an RRC recovery request message or an RRC reconstruction request message. Based on the RRC establishment message, the UE-RRC layer can discard any stored AS context, suspended configuration parameters, and current AS security context. The UE-RRC layer can release radio resources of all established RBs except SRB0, including releasing associated PDCP entities and SDAP RLC entities. The UE-RRC layer can release RRC configurations except for default L1 parameter values, default MAC cell group configuration, and CCCH configuration. The UE-RRC layer can indicate the fallback of RRC connections to higher layers (e.g., the NAS layer). If timer T380 is operating as a periodic RNA update timer, the UE-RRC layer can stop timer T380.

[0240] The UE-RRC layer can receive an RRC establishment message in response to an RRC establishment request message, an RRC recovery request message, or an RRC reconstruction request message. The RRC establishment message may include cell group configuration parameters and radio bearer configuration parameters. Radio bearer configuration parameters may include at least one of signaling bearer configuration parameters, data radio bearer configuration parameters, and / or security configuration parameters. Security configuration parameters may include security algorithm configuration parameters and a key usage indication indicating whether the radio bearer configuration parameters use a master key or a secondary key. 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 PDCP reconstruction indication, and / or a PDCP discard indication. 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 PDCP reconstruction indication, and / or a PDCP recovery indication. The radio bearer configuration in the RRC establishment message may include radio configuration parameters signaling SIB1. Based on the RRC establishment message, the UE-RRC layer can establish SRB1. Based on the RRC establishment message, the UE-RRC layer can perform cell group configuration or radio bearer configuration. The UE-RRC layer can stop the disable timer and wait timer to allow the cell to send the RRC establishment message. Upon receiving the RRC establishment message, the UE-RRC layer can perform one or more of the following: transition to RRC connected state; stop the cell reselection process; treat the current cell that sent the RRC establishment message as a PCell; or / and send an RRC establishment completion message by setting the content of the RRC establishment completion message.

[0241] The UE-RRC layer can receive an RRC recovery message in response to an RRC recovery request message. Based on the RRC recovery message, the UE-RRC layer can discard the UE inactive AS context and release suspended configuration parameters except for the RAN notification area information. Based on the configuration parameters in the RRC recovery message, the UE-RRC layer can perform cell group configuration, radio bearer configuration, security key update procedures, and measurement configuration procedures. Upon receiving the RRC recovery 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 restored; restore SRB2, all DRBs, and measurements; enter the RRC connection state; stop the cell reselection process; treat the current cell that sent the RRC recovery message as a PCell, or / and send an RRC recovery completion message by setting the content of the RRC recovery completion message.

[0242] Cell group configuration parameters may include at least one of the following: RLC bearer configuration parameters of the first cell group, MAC cell group configuration parameters, physical cell group configuration parameters, SpCell configuration parameters, or SCell configuration parameters of other cells of the second base station. SpCell configuration parameters may include at least one of the following: radio link failure timer and constraints, radio link monitoring in synchronization / dissynchronization thresholds, and / or serving cell configuration parameters of the first cell. Serving cell configuration parameters may include at least one of the following: downlink BWP configuration parameters; uplink configuration parameters; supplementary uplink carrier uplink configuration parameters (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) identifier (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 for the access procedure of shared spectrum channel access operation.

[0243] CSI measurement configuration parameters can include configuring the CSI-RS (reference signal) belonging to the serving cell, configuring 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 the DCI received on the serving cell.

[0244] In one example, downlink BWP configuration parameters can be used to configure dedicated (UE-specific) parameters for one or more downlink BWPs. The one or more downlink BWPs may include at least one of an initial downlink BWP, a default downlink BWP, and a first active downlink BWP. Downlink BWP configuration parameters may include at least one of the following: configuration parameters for the one or more downlink BWPs; one or more downlink BWP IDs for the one or more downlink BWPs; and a BWP inactivity timer. Downlink BWP configuration parameters may 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 failures of the downlink BWP. One or more downlink BWP IDs may include at least one of an initial downlink BWP ID, a default downlink BWP identifier (ID), and a first active downlink BWP ID.

[0245] In one example, uplink configuration parameters can be uplink configuration parameters for a normal uplink carrier (not a supplementary uplink carrier). 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. 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 UE's BWPs in the serving cell; SRS carrier handover information; and power control configuration parameters. Configuration parameters for the uplink BWP may include at least one of the following: one or more PUCCH configuration parameters for the uplink BWP; PUSCH configuration parameters for the uplink BWP; authorization configuration parameters for one or more configurations of 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.

[0246] 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 the PUSCH is not configured, as well as PUSCH-independent SRS power control. Power control configuration parameters may include at least one of PUSCH power control configuration parameters, PUCCH power configuration control parameters, and SRS power control parameters.

[0247] A UE-RRC layer in an RRC inactive or idle state can receive an RRC rejection message in response to an RRC establishment request message or an RRC recovery request message. The RRC rejection message may include a wait timer. Based on the wait timer, the UE-RRC layer can start timer T302, where the timer value is set to the wait timer. Based on the RRC rejection message, the UE-RRC layer can notify the upper layer (e.g., the UE-NAS layer) about the failure to establish or recover an RRC connection. The UE-RRC layer can reset the MAC and release the default MAC cell group configuration. Based on an RRC rejection received in response to a request from an upper layer, the UE-RRC layer can notify the upper layer (e.g., the NAS layer) that access prohibition applies to all access categories except categories '0' and '2'.

[0248] A UE-RRC layer in an RRC inactive or idle state can receive an RRC rejection message in response to an RRC recovery request message. Based on the RRC rejection message, the UE-RRC layer can discard the current security key. The UE-RRC layer can then re-suspend the RRC connection. If recovery is triggered due to an RNA update, the UE-RRC layer can set the pending RNA update value to true.

[0249] A UE-RRC layer in an RRC inactive or idle state can perform a cell (re)selection procedure while simultaneously performing an RRC procedure to establish an RRC connection. Based on cell selection or cell reselection, the UE-RRC layer can change the cell on which the UE is camped and stop the RRC procedure. The UE-RRC layer can notify upper layers (e.g., the NAS layer) of the failure of the RRC procedure.

[0250] A UE in an RRC idle or RRC inactive state can perform one of two procedures (such as initial cell selection and cell selection) by utilizing stored information. When the UE has not yet stored cell information for the selected PLMN, it can perform initial cell selection. Otherwise, the UE can perform cell selection by utilizing stored information. For initial cell selection, the UE can scan all RF channels in the NR band based on its ability to find suitable cells. Based on the scan results, the UE can search for the strongest cell on each frequency. The UE can then select a cell as a suitable cell. For cell selection using stored information, the UE may need stored frequency information, and optionally, 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, it can search for and select that cell. If the UE does not find a suitable cell, it can perform initial cell selection.

[0251] The base station can configure cell selection criteria for cell selection. The UE can seek to identify a suitable cell 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 PLMN, or an equivalent PLMN, (3) the cell is not banned or reserved, and (4) the cell is not part of a tracking area in the "Roaming Prohibited Tracking Areas" list. The RRC layer in the UE can notify the NAS layer in the UE of the cell selection and reselection results based on changes in received system information related to NAS. For example, the cell selection and reselection results can be the cell identifier, tracking area code, and PLMN identifier.

[0252] A UE in RRC connection state can detect a connection failure with the base station. A UE in RRC connection state can activate AS security with the base station before detecting a failure. Failures include at least one of the following: radio link failure (RLF); synchronization failure reconfiguration; mobility failure from a new radio (NR); integrity check failure indication from a lower layer (e.g., PDCP layer) regarding Signaling Radio Bearer 1 (SRB1) or Signaling Radio Bearer 2 (SRB2); or RRC connection reconfiguration failure.

[0253] Radio link failure can be a failure of the primary cell's radio link. The base station can send a synchronized reconfiguration to the UE in an RRC-connected state in an RRC message. The synchronized reconfiguration can include a reconfiguration timer (e.g., T304). Based on receiving the synchronized reconfiguration, the UE can start the reconfiguration timer and perform synchronized reconfiguration (e.g., handover). Based on the expiration of the reconfiguration timer, the UE determines that the synchronized reconfiguration has failed. The base station can send mobility information from an NR command message to the UE in an RRC-connected state. Based on receiving the mobility information from the NR command message, the UE can perform handover from the NR to the cell using another RAT (e.g., E-UTRA). The UE can determine from the NR that mobility has failed based on meeting at least one condition: whether the UE has failed to establish a connection to the target radio access technology; or whether the UE fails to comply with any part of the configuration included in the mobility command message from the NR; or whether there is a protocol error in the inter-RAT information included in the mobility message from the NR.

[0254] Based on the detected failure, a UE in RRC connection state can initiate an RRC connection re-establishment process. Upon initiating the RRC connection re-establishment process, the UE can start timer T311, suspend all radio bearers except SRB0, and reset the MAC (layer). Based on initiating the RRC connection re-establishment process, a UE in RRC connection state can release the MCG SCell, release the special cell (SpCell) configuration parameters, and release the Multi-Radio Dual Connectivity (MR-DC) related configuration parameters. For example, based on initiating the RRC connection re-establishment process, the UE can release the primary cell group configuration parameters.

[0255] Cell group configuration parameters can be used to configure either a primary cell group (MCG) or a secondary cell group (SCG). If the cell group configuration parameters are used to configure an MCG, then the cell group configuration parameters are primary cell group configuration parameters. If the cell group configuration parameters are used to configure an SCG, then the cell group configuration parameters are secondary cell group configuration parameters. A cell group comprises a MAC entity, logical channels with associated RLC entities, a primary cell (SpCell), and a set of one or more secondary cells (SCells). Cell group configuration parameters (e.g., primary cell group configuration parameters or secondary cell group configuration parameters) may include at least one of the following: RLC bearer configuration parameters of the cell group, MAC cell group configuration parameters of the cell group, physical cell group configuration parameters of the cell group, SpCell configuration parameters of the cell group, or SCell configuration parameters of the cell group. MAC cell group configuration parameters may include MAC parameters of the cell group, wherein the MAC parameters may include at least DRX parameters. Physical cell group configuration parameters may include cell group-specific L1 (Layer 1) parameters.

[0256] A special cell (SpCell) can include the primary cell (PCell) of an MCG or the primary SCG cell (PSCell) of an SCG. SpCell configuration parameters can include serving cell-specific MAC and PHY parameters for the SpCell. MR-DC configuration parameters can include at least one of the following: SRB3 configuration parameters, SCG measurement configuration parameters, and SCG configuration parameters.

[0257] Based on the initiated RRC connection re-establishment process, a UE in RRC connected state can perform a cell selection process. Based on the cell selection process, the UE can select a cell based on whether the cell's signal quality exceeds a threshold. The UE can determine whether the selected cell exceeds the threshold based on the cell selection process. 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.

[0258] Based on the selection of a suitable cell, a UE in RRC connection state can stop timer 311 and start timer T301. Based on the selection of a suitable cell, a UE in RRC connection state can stop the prohibition timer T390 for all access categories. Based on stopping the prohibition timer T390, a UE in RRC connection state can consider the cell-based mitigation of the prohibition for all access categories. Based on the selection of a cell, a UE in RRC connection state can apply the 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 reconstruction request message.

[0259] A UE in RRC connected state can stop timer T301 upon receiving an RRC response message in response to an RRC rebuild request message. The RRC response message may include at least one of an RRC rebuild message, an RRC establishment message, or an RRC rebuild rejection message. A UE in RRC connected state can also stop timer T301 when the selected cell becomes unsuitable.

[0260] Based on the cell selection process triggered by the RRC connection re-establishment procedure, a UE in RRC connected state can select an inter-RAT cell. Based on the selection of an inter-RAT cell, a UE in RRC connected state (UE-AS layer) can transition to RRC IDLE state and can provide the release reason 'RRC connection failed' to the upper layer (UE-NAS layer).

[0261] Based on the transmission of the RRC Reconstruction Request message, a UE in RRC connected state can send an RRC Reconstruction Request message. The RRC Reconstruction Request message may include at least one of the following: the C-RNTI used in the source PCell, the Physical Cell Identifier (PCI) of the source PCell, a short MAC-I, or a reconstruction reason. The reconstruction reason may include at least one of reconfiguration failure, handover failure, or other failures.

[0262] Based on the transmission of the RRC Reconstruction Request Message, a UE in RRC connected state (RRC layer) can reconstruct the PDCP of SRB1, reconstruct 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, restore SRB1, and submit the RRC Reconstruction Request Message to the lower layer (PDCP layer) for transmission. Based on submitting the RRC Reconstruction Request Message to the lower layer, the UE in RRC connected state can send the RRC Reconstruction 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.

[0263] Based on the expiration of timer T311 or T301, the UE (UE-AS layer) can transition to the RRC idle state and provide the release reason 'RRC connection failure' to the upper layer (UE-NAS layer) of the UE.

[0264] Based on the received release reason 'RRC connection failed', when a UE in RRC idle state (UE-NAS layer) has no pending signaling or user data, it can perform a NAS signaling connection restoration procedure. Based on this NAS signaling connection restoration procedure, a UE in RRC idle state can initiate a registration procedure by sending a registration request message to the AMF.

[0265] Based on the received release reason 'RRC connection failed', when a UE (UE-NAS layer) in the RRC idle state has pending signaling or pending user data, the UE can perform a service request procedure by sending a service request message to the AMF.

[0266] Upon receiving an RRC reconstruction request message, the target base station can check whether the UE context is locally available. If the UE context is not locally available, the target base station can perform the UE context retrieval process by sending a UE context retrieval request message to the UE's source base station (the last serving base station).

[0267] For the RRC connection re-establishment procedure, the UE context request message may include at least one of the following: UE context ID, integrity protection parameters, or new cell identifier. The UE context ID may include at least one of the following: a C-RNTI containing the RRC re-establishment request message; and the PCI of the source PCell (the last serving PCell). The integrity protection parameter for the RRC re-establishment procedure may be a short MAC-I. The new cell identifier may be an identifier of the target cell, where the target cell is the cell that has already requested to re-establish the RRC connection. 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).

[0268] During the RRC connection re-establishment process, based on the received Retrieve UE Context Request message, the source base station can examine the message. If the source base station can identify the UE context using the UE context ID and successfully authenticate the UE using 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 can respond to the target base station with a Retrieve UE Context Response message. If the source base station cannot identify the UE context using the UE context ID, or if the integrity protection included in the Retrieve UE Context Request message is not valid, the source base station can respond to the target base station with a Retrieve UE Context Failure message.

[0269] For the RRC connection re-establishment process, retrieving the UE context response message may include at least one of the target base station's Xn Application Protocol (XnAP) ID, the source base station's XnAP ID, a globally unique AMF identifier (GUAMI), or UE context information (e.g., UE context information retrieval of the UE context response). UE context information may include at least one of the following: NG-C UE-associated signaling reference, UE security capabilities, AS security information, UE aggregated maximum bit rate, a list of PDU sessions to be established, RRC context, a mobility restriction list, or an index to RAT / frequency selection priority. The NG-C UE-associated signaling reference may be the NG Application Protocol ID assigned at the UE's AMF on the NG-C connection with the source base station. AS security information may include the base station's security key (K). gNB The list of PDU sessions to be established may include PDU session resource information used in the UE context at the source base station. PDU session resource information may include the PDU session ID, maximum bit rate of PDU session resource aggregation, security indication, PDU session type, or the QoS flow list to be established. Security indication may include user plane integrity protection indication and confidentiality protection indication, which respectively indicate the requirements for user plane (UP) integrity protection and encryption for the corresponding PDU session. Security indication may also include at least one of the following: indication of whether UP integrity protection is applied to the PDU session, indication of whether UP encryption is applied to the PDU session, and the maximum integrity protection data rate value (uplink and downlink) per UE for the 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 established may include at least one of the following: QoS flow identifier, QoS flow level QoS parameter (QoS parameter to be applied to the QoS flow), or bearer identifier.

[0270] For the RRC connection reconstruction process, retrieving the UE context failure message can include at least the target base station's XnAP ID and the cause value.

[0271] For the RRC connection reconstruction process, based on the received UE context retrieval response message, the target base station can send an RRC reconstruction message to the UE. The RRC reconstruction message may include at least the Network Hop Link Count (NCC) value.

[0272] Based on the received RRC reconstruction message, the UE can use the current K value associated with the NCC value. gNB The new security key (K) for the base station is derived from at least one of the next-hop (NH) parameters. gNBBased on the base station's new security key and the previously configured integrity protection algorithm, the UE can derive the security key (K) for RRC signaling integrity protection. RRCint Security keys (K) for the integrity protection of user plane (UP) data. UPint Based on the base station's new security key and the previously configured encryption algorithm, the UE can derive a security key (K) used to encrypt RRC signaling. RRCenc ) and the security key (K) used to encrypt user plane (UP) data. UPenc Based on K RRCint Based on the previously configured integrity protection algorithm, the UE can verify the integrity protection of the RRC reconstruction message. If verification fails, the UE (UE-AS layer) can enter the RRC IDLE state and provide the release reason 'RRC connection failed' to the UE's upper layer (UE-NAS layer). If verification succeeds, the UE can be configured to use the previously configured integrity protection algorithm and K... RRCint To restore the integrity protection of SRB1, and configured to use the previously configured encryption algorithm and K. RRCenc To restore the encryption of SRB1, the UE can send an RRC reconstruction complete message to the target base station.

[0273] Based on the received UE context retrieval failure message, the target base station can send an RRC release message to the UE. For example, if the UE context retrieval failure message includes an RRC release message, the target base station can send an RRC release message to the UE. Based on the received UE context retrieval failure message, the target base station can send an RRC establishment message or an RRC rejection message. Based on the received UE context retrieval failure message, the target base station may choose not to send any response message to the UE.

[0274] Figure 17An example of an RRC connection re-establishment process is illustrated. A UE in an RRC connected state can send and receive data to / from a first base station (e.g., a source base station) via cell 1, where cell 1 is the primary cell (PCell) of the first base station. The UE can detect a connection failure with the first base station. Based on this failure, the UE can initiate an RRC re-establishment process. Based on initiating the RRC connection re-establishment process, the UE can start timer T311, suspend all radio bearers except SRB0, and / or reset the MAC (layer). Based on initiating the RRC connection re-establishment process, the UE can release the MCG SCell, release the special cell (SpCell) configuration parameters, and the multiple radio dual connectivity (MR-DC) related configuration parameters. Based on initiating the RRC connection re-establishment process, the UE can perform a cell selection process. Based on the cell selection process, 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 a suitable cell, the UE can stop timer T311 and start timer T301. Based on selecting a suitable cell, if one or more disable timers T309 are running, the UE can stop one or more disable timers T309 for all access categories. Based on stopping one or more prohibition timers T309, the UE can consider the prohibition on all access categories to be mitigated for this cell. Based on cell selection, the UE can apply default L1 parameter values ​​other than those provided in SIB1, apply default MAC cell group configuration, apply CCCH configuration, apply timer alignment timers in SIB1, and initiate the transmission of an RRC reconstruction request message. The RRC reconstruction message may include at least one of the following: C-RNTI used in the source PCell (e.g., cell 1), physical cell identifier (PCI) of the source PCell, short MAC-I, or reconstruction reason. Based on the transmission of the initiated RRC reconstruction request message, the UE (RRC layer) can reconstruct the PDCP of SRB1, reconstruct 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, restore SRB1, and submit the RRC reconstruction request message to the lower layer (PDCP layer) for transmission. Based on the transmission of the initiated RRC reconstruction request message, the UE can send the RRC reconstruction request message to the second base station via cell 2. Upon receiving an RRC reconstruction request message, the second base station can check whether the UE's UE context is locally available. If the UE context is not 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 source base station. The UE context retrieval request message may include at least one of the following: UE context ID; integrity protection parameters; or new cell identifier.The UE context ID may include at least one of the following: a C-RNTI containing the RRC Reconstruction Request message; and the PCI of the source PCell (the last serving PCell). The integrity protection parameter for the RRC reconstruction process may be a short MAC-I. The new cell identifier may be an identifier of the target cell, where the target cell is the cell that has requested to reconstruct the RRC connection. 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). Based on receiving the Retrieve UE Context Request message, the source base station may examine the Retrieve UE Context Request message. If the source base station can identify the UE context using the C-RNTI and successfully authenticate the UE using 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 Retrieve UE Context Response message. The Retrieve UE Context Response message may include at least the GUAMI or UE context information. Based on receiving the Retrieve UE Context Response message, the second base station may send an RRC Reconstruction message to the UE. The RRC Reconstruction message may include a Network Hop Link Count (NCC) value. Based on receiving the RRC Reconstruction message, the UE may, based on the current K associated with the NCC value... gNB The new security key (K) for the base station is derived from at least one of the next-hop (NH) parameters. gNB A new security key based on the base station (K) gNB Based on the previously configured security algorithms, the UE can derive the security keys for integrity protection and encryption of RRC signaling (e.g., K, respectively). RRCint and K RRCenc ) and the security keys for integrity protection and encryption of user plane (UP) data (e.g., K respectively) UPint and K UPenc Security Key for Integrity Protection Based on RRC Signaling (K) RRCint The UE can verify the integrity protection of the RRC reconstruction message. Based on successful verification, the UE can be configured to use the previously configured integrity protection algorithm and K. RRCint To restore integrity protection for one or more bearers (e.g., signaling radio bearers or RRC messages), and configured to be based on a previously configured encryption algorithm and K. RRCencTo restore encryption for one or more bearers, the second base station can send a first RRC reconfiguration message. The first RRC reconfiguration message may include SpCell configuration parameters. Based on the received SpCell configuration parameters, the UE can initiate data transmission and reception to / from the second base station. The UE can send an RRC reconstruction completion message to the second base station. The RRC reconstruction completion message may include a measurement report. Based on the received measurement report, the second base station can determine the configuration of the SCell and / or secondary cell group (e.g., SCG or PSCell). Based on this determination, the second base station can 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 can transmit and receive data via the SCell and / or SCG.

[0275] The RRC reconfiguration message may include at least one of the cell group configuration parameters of the MCG and / or SCG, radio bearer configuration parameters, or AS security key parameters.

[0276] The UE can remain CM-CONNECTED and move within the area configured by the base station without notifying the base station when the UE is in an RRC inactive state in that area (RNA). In the RRC inactive state, the last serving base station can maintain the UE context and the NG connection associated with the UE in the serving AMF and UPF. Based on downlink data received from the UPF or downlink UE-associated signaling received from the AMF when the UE is in an RRC inactive state, the last serving base station can perform paging in the cell corresponding to the RNA, and can send RAN paging to neighboring base stations via the Xn interface if the RNA includes cells of neighboring base stations.

[0277] The AMF (Application Management Function) can provide core network auxiliary information to the base station to assist in determining whether the UE can be sent to an RRC inactive state. Core network auxiliary information may include the registration area configured for the UE, periodic registration update timers, UE identifier index values, UE-specific DRX, an indication of whether the UE is configured with a Mobile-Initiated Connection (MICO) mode via the AMF, or expected UE behavior. The base station can use the UE-specific DRX and UE identifier index value to determine the timing of paging for RAN paging. The base station can use periodic registration update timers to configure periodic RNA update timers (e.g., timer T380). The base station can use expected UE behavior to assist in UE RRC state transition decisions.

[0278] The base station can initiate an RRC connection release procedure to transition the UE's RRC state from an RRC connected state to an RRC idle state, from an RRC connected state to an RRC inactive state, from an RRC inactive state to an RRC inactive state when the UE attempts to recover, or from an RRC inactive state to an RRC idle state when the UE attempts to recover. The RRC connection procedure can also be used to release the UE's RRC connection and redirect the UE to another frequency. When the UE's RRC state transitions to an RRC inactive state, the base station can send an RRC release message including suspend configuration parameters. Suspension configuration parameters can include at least one of the following: a recovery identifier, RNA configuration, RAN paging loop, or Network Hop Link Count (NCC) value, where RNA configuration can include RNA notification area information or a periodic RNA update timer value (e.g., a T380 value). When the UE is in an RRC inactive state, the base station can use a recovery identifier (e.g., an inactive RNTI (I-RNTI)) to identify the UE context.

[0279] If the base station has a new and unused {NCC, next hop (NH)} pair, the base station can include the NCC in the pending configuration parameters. Otherwise, the base station can include the pair with the current K in the pending configuration parameters. gNB The associated NCC. NCC is used for AS security. After sending an RRC release message to the UE including suspend configuration parameters, the base station can delete the current AS key (e.g., K). RRCenc K UPenc ) and K UPint However, the current AS key K can be retained. RRCint If the transmitted NCC value is new and belongs to an unused {NCC, NH} pair, the base station can save the {NCC, NH} pair in the current UE AS security context and can delete the current AS key K. gNB If the sent NCC value is equal to the current K... gNB With the associated NCC value, the base station can maintain the current AS key K. gNB And NCC. The base station can store the transmitted recovery identifier along with the current UE context, which includes the remainder of the AS security context.

[0280] After receiving an RRC release message including suspend configuration parameters from the base station, the UE can verify the integrity of the received RRC release message by checking the PDCP MAC-I. If the verification is successful, the UE can obtain the received NCC value and save it as a stored NCC with the current UE context. The UE can delete the current AS key K. RRCenc K UPenc and KUPint However, keep the current AS key K RRCint Key. If the stored NCC value differs from the current key. gNB If the associated NCC value is obtained, the UE can delete the current AS key K. gNB If the stored NCC is equal to the current K gNB If the associated NCC value is obtained, the UE will retain the current AS key KgNB. The UE can store the received recovery identifier along with the current UE context, including the rest of the AS security context, for use in the next state transition.

[0281] Based on receiving an RRC release message including suspended configuration parameters, the UE can reset the MAC, release the default MAC cell group configuration, and rebuild the RLC entity for one or more bearers. Based on receiving an RRC release message including suspended configuration parameters, the UE can store the current configuration parameters and the current security key in the UE's inactive AS context. For example, the UE can store some configuration parameters from the current configuration parameters. The stored current configuration parameters may include the Robust Header Compression (ROHC) state, Quality of Service (QoS) flow-to-DRB mapping rules, the C-RNTI used in the source PCell, the global cell identifier and physical cell identifier of the source PCell, and all other configuration parameters except for the serving cell configuration common parameters in synchronous reconfiguration and SIB. The stored security key may include K... gNB and K RRCint At least one of the following. Common parameters for serving cell configuration in the SIB can be used to configure cell-specific parameters of the UE's serving cell in SIB1. Based on receiving an RRC release message including suspend configuration parameters, the UE can suspend all SRBs and DRBs except SRB0. Based on receiving an RRC release message including suspend configuration parameters, the UE can start timer T380, enter the RRC inactive state, and perform the cell selection process.

[0282] A UE in an RRC inactive state can initiate an RRC connection recovery procedure. For example, a UE in an RRC inactive state can initiate an RRC connection recovery procedure if it has data or signaling to transmit or receive RAN paging messages. Based on initiating the RRC connection recovery procedure, the UE can select the access class based on the triggering conditions of the RRC connection recovery procedure and execute a unified access control procedure based on the access class. Based on the unified access control procedure, the UE can treat the access attempt in the RRC connection recovery procedure as allowed. Based on treating the access attempt as allowed, the UE can apply the default L1 parameter values ​​as specified in the corresponding physical layer specification, in addition to the parameters for which values ​​are provided in SIB1, apply the default SRB1 configuration, apply the CCCH configuration, apply the common time alignment timer included in SIB1, apply the default MAC cell group configuration, start timer T319, and initiate the transmission of an RRC recovery request message.

[0283] Based on the transmission of the RRC recovery request message, the UE can configure the content of the RRC recovery request message. The RRC recovery request message may include at least one of the following: recovery identifier, recovery MAC-I, or recovery reason. The recovery reason may include at least one of the following: emergency, high priority access, MT access, MO signaling, MO data, MO voice call, MO SMS, RAN update, MPS priority access, and MCS priority access.

[0284] Based on the transmission of the RRC recovery request message, in addition to the primary cell group configuration parameters, MR-DC related configuration parameters (e.g., secondary cell group configuration parameters), and PDCP configuration parameters, the UE can restore stored configuration parameters and stored security keys from the (stored) UE inactive AS context. Configuration parameters may include at least one of the following: the C-RNTI used in the source PCell, the global cell identifier and physical cell identifier of the source PCell, and all other parameters configured except those within the reconfiguration in the SIB that have synchronization and serving cell configuration common parameters. Based on the current (restored) K associated with the stored NCC value... gNB Or the next hop (NH) parameter, the UE can derive the base station's new key (K). gNB Based on the base station's new key, the UE can derive security keys for integrity protection and encryption of RRC signaling (e.g., K, respectively). RRCenc and K RRCint ) and the security keys for integrity protection and encryption of user plane data (e.g., K, respectively) UPint and K UPenc Configuration-based algorithms and K RRCint and K UPintThe UE can configure lower layers (e.g., PDCP layer) to apply integrity protection to all radio bearers except SRB0. This is based on the configured algorithm and K. RRCenc and K UPenc The UE can configure lower layers (e.g., PDCP layer) to apply encryption to all radio bearers except SRB0.

[0285] Based on the transmission of the RRC recovery request message, the UE can rebuild the PDCP entity for one or more bearers, restore one or more bearers, and submit the RRC recovery request message to a lower layer, wherein the lower layer may include at least one of the PDCP layer, RLC layer, MAC layer, or physical (PHY) layer.

[0286] The target base station can receive RRC recovery request messages. Based on the received RRC recovery request message, the target base station can check whether the UE context is locally available. If the UE context is not locally available, the target base station can perform the UE context retrieval process by sending a UE context retrieval request message to the UE's source base station (the last serving base station). The UE context retrieval request message may include at least one of the following: UE context ID, integrity protection parameters, new cell identifier, or recovery reason, wherein the recovery reason is included in the RRC recovery request message.

[0287] For the RRC connection recovery process, based on the received Retrieve UE Context Request message, the source base station can examine the message. If the source base station can identify the UE context using the UE context ID and successfully authenticate the UE using 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 can respond to the target base station with a Retrieve UE Context Response message. If the source base station cannot identify the UE context using 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 can respond to the target base station with a Retrieve UE Context Failure message.

[0288] For the RRC connection recovery process, the UE context failure message can include at least the target base station's XnAPID, RRC release message, or cause value.

[0289] For the RRC connection restoration process, based on the received UE context response message, the target base station can send an RRC restoration message to the UE. The RRC restoration message may include at least one of the following: radio bearer configuration parameters, cell group configuration parameters of the MCG and / or SCG, measurement configuration parameters, or an sk counter, wherein the sk counter is used to determine the connection restoration process based on K. gNB Export the security key of the secondary base station.

[0290] Based on the received UE context retrieval failure message, the target base station can send an RRC release message to the UE. For example, if the UE context retrieval failure message includes an RRC release message, the target base station can send an RRC release message to the UE. Based on the received UE context retrieval failure message, the target base station can send an RRC establishment message or an RRC rejection message. Based on the received UE context retrieval failure message, the target base station may choose not to send any response message to the UE.

[0291] Upon receiving the RRC recovery message, the UE can stop timers T319 and T380. Based on the received RRC recovery message, the UE can restore the primary cell group configuration parameters, secondary cell group configuration parameters, and PDCP configuration parameters in the UE inactive AS context. Based on restoring the primary cell group configuration parameters and / or secondary cell group configuration parameters, the UE can configure the SCells of the MCG and / or SCG by configuring lower layers, treating the restored MCG and / or SCG SCells as disabled, discarding the UE inactive AS context, and releasing the suspended configuration parameters.

[0292] Based on the cell group configuration parameters received in the RRC recovery message, the UE can perform cell group configuration for the MCG and / or SCG. Based on the radio bearer configuration parameters received in the RRC recovery message, the UE can perform radio bearer configuration. Based on the sk counter in the RRC recovery message, the UE can update the security key of the secondary base station.

[0293] Figure 18 An example of the RRC connection recovery process is shown. A UE in an RRC connected state can transmit and receive data to / from a 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 an RRC inactive state. Based on this determination, the base station can send an RRC release message including suspend configuration parameters. Based on receiving the RRC release message including suspend configuration parameters, the UE can store the current security key (e.g., K) in the UE inactive AS context. gNB and K RRCintThe UE can store some configuration parameters from the current configuration parameters. The stored (current) configuration parameters can be at least one of the following: Robust Header Compression (ROHC) state; QoS flow-to-DRB mapping rules; C-RNTI used in the source PCell; global cell identifier and physical cell identifier of the source PCell; and all other configuration parameters except for common parameters for serving cell configuration in synchronization reconfiguration and SIB. The Robust Header Compression (ROHC) state can include the ROHC state of all PDCP entities (or all bearers), where each PDCP entity (or each bearer) of each bearer can have one ROHC state. The QoS flow-to-DRB mapping rules can be QoS flow-to-DRB mapping rules for all data radio bearers (DRBs), where each DRB can have a QoS that follows the DRB mapping rules. Based on receiving an RRC release message that includes the suspension configuration parameters, the UE can suspend all SRBs and DRBs except SRB0. Upon receiving an RRC release message including suspend configuration parameters, the UE can start timer T380, enter the RRC inactive state, and perform a cell selection procedure. Based on the cell selection procedure, the UE can select cell 2 of the second base station (target base station). A UE in the RRC inactive state can initiate an RRC connection recovery procedure. The UE can execute a unified access control procedure. Based on the unified access control procedure, the UE can treat the access attempt during the RRC connection recovery procedure as permitted. The UE can apply the default L1 parameter values ​​specified in the corresponding physical layer specification, in addition to the parameters for which values ​​are provided in SIB1, apply the default SRB1 configuration, apply the CCCH configuration, apply the common time alignment timer included in SIB1, apply the default MAC cell group configuration, start timer T319, and initiate the transmission of an RRC recovery request message. Based on initiating the transmission of the RRC recovery request message, the UE can restore the stored configuration parameters and stored security keys from the (stored) UE inactive AS context. For example, in addition to primary cell group configuration parameters, MR-DC related configuration parameters (e.g., secondary cell group configuration parameters), and PDCP configuration parameters, the UE can restore stored configuration parameters and stored security keys (e.g., K) from the stored UE inactive AS context. gNB and K RRCint Based on the current (restored) K value associated with the stored NCC value. gNB Or the next hop (NH) parameter, the UE can derive the base station's new key (K). gNB Based on the base station's new key, the UE can derive security keys for integrity protection and encryption of RRC signaling (e.g., K, respectively). RRCenc and K RRCint) and the security keys for integrity protection and encryption of user plane data (e.g., K, respectively) UPint and K UPenc Configuration-based algorithms and K RRCint and K UPint The UE (RRC layer) can configure lower layers (e.g., PDCP layer) to apply integrity protection to all radio bearers except SRB0. This is based on the configured algorithm and K. RRCenc and K UPenc The UE can configure lower layers (e.g., the 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 the second base station. The UE can use restored configuration parameters to transmit and receive data to / from the second base station. Based on the transmission of an RRC recovery request message, the UE can rebuild the PDCP entity for one or more bearers, recover one or more bearers, and submit an RRC recovery request message to the lower layers. Based on receiving the RRC recovery request message, the second base station can check whether the UE's UE context is locally available. If the UE context is not locally available, the second base station can perform a UE context retrieval procedure 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 may include at least one of the following: a recovery identifier; a recovery MAC-I; or a recovery reason. Based on receiving the UE context retrieval request message, the first base station can examine the UE context retrieval request message. If the first base station can identify the UE context using the UE context ID and successfully authenticate the UE using the recovered MAC-I, and decides to provide the UE context to the second base station, the first base station can 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 can send an RRC recovery message to the UE. Based on receiving the RRC recovery message, the UE can restore the primary cell group configuration parameters, secondary cell group configuration parameters, and PDCP configuration parameters in the UE inactive AS context. Based on restoring the primary cell group configuration parameters and / or secondary cell group configuration parameters, the UE can configure the SCell of the MCG and / or SCG by configuring lower layers to treat the restored MCG and / or SCG SCell as disabled, discard the UE inactive AS context, and release the suspended configuration parameters. The UE can transmit and receive data via the SCell and / or SCG.

[0294] The RRC recovery message may include at least one of the cell group configuration parameters of the MCG and / or SCG, radio bearer configuration parameters, or AS security key parameters (e.g., sk counter).

[0295] The base station can send an RRC release message to the UE to release the UE's RRC connection. Based on the RRC release message, the UE can release established radio bearers and all radio resources.

[0296] The base station can send an RRC release message to the UE to suspend the RRC connection. Based on the RRC release message, the UE can suspend all radio bearers except for Signaling Radio Bearer 0 (SRB0). The RRC release message may include suspension configuration parameters. Suspension configuration parameters may include the next-hop link count (NCC) and a recovery identifier (e.g., ID or identifier).

[0297] The base station can send an RRC release message to transition a UE in an RRC connected state to an RRC idle state; or to transition a UE in an RRC connected state to an RRC inactive state; or to transition a UE in an RRC inactive state back to an RRC inactive state when the UE attempts to recover; or to transition a UE in an RRC inactive state to an RRC idle state when the UE attempts to recover.

[0298] The base station can send an RRC release message to redirect the UE to another frequency.

[0299] 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 in response to the RRC release message from the base station. The UE can delay its actions for a period of time (e.g., 60ms) from the moment the RRC release message is received or upon successful confirmation of receipt. 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) including the RRC release message and the RLC PDU including polling bits, the UE can send an RLC message (e.g., a status report) to the base station to confirm the RRC release message.

[0300] UE actions in response to an RRC release message from a base station may include at least one of the following: suspending the RRC connection; releasing the RRC connection; cell (re)selection procedure; and / or idle / inactive measurement.

[0301] The RRC release message from the base station may include suspend configuration parameters. Based on the suspend configuration parameters, the UE may suspend the RRC connection. Suspending the RRC connection may include at least one of the following: Media Access Control (MAC) reset (or MAC reset); releasing the default MAC cell group configuration; rebuilding the RLC entity for one or more radio bearers; storing the current configuration parameters and the current security key; suspending one or more bearers, wherein the bearers include signaling radio bearers and data radio bearers; and / or changing the RRC idle state or RRC inactive state.

[0302] For example, the suspend configuration parameters may also include RNA configuration parameters. Based on the RNA configuration parameters, the UE can transition to an RRC inactive state. For example, if the suspend configuration parameters do not include RNA configuration parameters, the UE can transition to an RRC idle state. For example, an RRC release message that includes suspend configuration parameters may include an indication to transition to an RRC inactive state. Based on this indication, the UE can transition to an RRC inactive state. For example, if the RRC release message does not include this indication, the UE can transition to an RRC idle state.

[0303] Based on a MAC reset, the UE may perform at least one of the following: stop all timers running in the UE-MAC layer; treat all time-aligned timers as expired; set the New Data Indicator (NDI) for all uplink HARQ procedures to a value of 0; stop the ongoing RACH procedure; discard contention-free random access resources that are explicitly signaled (if any); flush the Msg 3 buffer; cancel triggered scheduling request procedures; cancel triggered buffer status report procedures; cancel triggered power headroom report procedures; flush the soft buffers for all DL HARQ procedures; treat the next received transmission of the TB as the first transmission for each DL HARQ procedure; and / or release the temporary C-RNTI.

[0304] Based on the assumption that the time alignment timers have expired, the UE may perform at least one of the following: refresh all HARQ buffers of all serving cells; notify the RRC to release the PUCCH of all serving cells (if configured); notify the RRC to release the SRS of all serving cells (if configured); clear any configured downlink assignments and configured uplink grants; clear any PUSCH resources used for semi-persistent CSI reporting; and / or assume that all running time alignment timers have expired.

[0305] Default MAC cell group configuration parameters may include the base station's cell group buffer state report (BSR) configuration parameters (e.g., BSR timer) and the base station's cell group power headroom report (PHR) configuration parameters (e.g., PHR timer or PHR transmission power factor change parameters).

[0306] Reconstructing an RLC entity may include at least one of the following: discarding all RLC SDUs, RLC SDU segments, and RLCPDUs (if any); stopping and resetting all timers of all RLC entities; and resetting all state variables of the RLC entity to their initial values.

[0307] The RRC release message from the base station may not include suspended configuration parameters. Based on the absence of suspended configuration parameters in the RRC message, the UE can release the RRC connection. Releasing the RRC connection may include at least one of the following: MAC reset (or resetting the MAC); discarding stored configuration parameters and stored security keys (or discarding stored UE inactive AS context); releasing suspended configuration parameters; releasing all radio resources, including releasing all established radio bearer RLC entities, MAC configurations, and associated PDCP entities and SDAPs; and / or transitioning to an RRC idle state.

[0308] An RRC release message can be an RRC early data completion message.

[0309] Based on performing small data transmission, the UE can send or receive small amounts of data without transitioning from an RRC idle state or an RRC inactive state to an RRC connected state. When in an RRC idle state or an RRC inactive state (e.g., without transitioning to an RRC connected state), performing small data transmission can include at least one of the following: initiating small data transmission; sending small data; and / or receiving a response message.

[0310] For example, based on small data transmission, a UE in an RRC idle state or an RRC inactive state can initiate small data transmission. In response to initiating small data transmission, a UE in an RRC idle state or an RRC inactive state can transmit small data. In response to transmitting small data, the UE can receive a response message. For example, the response message may include downlink data (or downlink signaling). For example, based on small data transmission, a UE in an RRC idle state or an RRC inactive state can transmit small data. In response to transmitting small data, a UE in an RRC idle state or an RRC inactive state can receive a response message. Transmitting small data may include at least one of sending an RRC request message, uplink data (or uplink signaling), or a buffer status report (BSR). For example, transmitting small data may include sending an RRC request message. For example, transmitting small data may include sending an RRC request message and uplink data. For example, transmitting small data may include sending an RRC request message, first uplink data, and a BSR requesting uplink resources for second uplink data. An RRC request message may include at least one of the following: an RRC recovery request message; or an RRC early data request message. The response message may include at least one of the following: an RRC response message in response to the RRC request message; downlink data; or acknowledgment of uplink data (e.g., first uplink data); or uplink resources for uplink data (e.g., second uplink data). An RRC response message to an RRC request message may include at least one of the following: an RRC release message; an RRC early data completion message; an RRC establishment message; an RRC recovery message; or an RRC rejection message.

[0311] Upon receiving an RRC release message, a UE in an RRC idle or inactive state can transition to or remain in an RRC idle or inactive state. Upon receiving an RRC early data completion message, a UE in an RRC idle or inactive state can transition to an RRC idle state (or remain in an RRC idle state). Upon receiving an RRC release message or an RRC early data completion message, the UE can consider sending small data successfully. Upon receiving an RRC establishment message or an RRC recovery message, a UE in an RRC idle or inactive state can transition to an RRC connected state. Upon receiving an RRC establishment message or an RRC recovery message, the UE can consider sending small data successfully. Upon receiving an RRC rejection message, a UE in an RRC idle or inactive state can transition to an RRC idle state. Upon receiving an RRC rejection message, the UE can consider sending small data unsuccessful.

[0312] Figure 19An example of small data transmission is illustrated. Based on receiving a first RRC release message, the UE can transition to an RRC inactive or idle state. A UE in an RRC inactive or idle state can perform small data transmission. A UE in an RRC inactive or idle state can initiate / trigger small data transmission based on having small data to send or based on receiving a paging message. The paging message can indicate small data transmission. Based on performing small data transmission, a UE in an RRC idle or RRC inactive state can send uplink data via Msg 3. Msg 3 can be a message transmitted on the UL-SCH, containing a C-RNTI MAC CE or CCCH SDU optionally multiplexed with the DTCH. For example, as part of the random access procedure, the CCCHSDU can be associated with the UE contention resolution identifier. For example, a UE in an RRC idle or RRC inactive state can use pre-configured uplink resources (PUR) to send a CCCH SDU. The CCCH SDU can include at least one of an RRC request message and uplink data (e.g., first uplink data). DTCH may include uplink data (e.g., first uplink data). Based on performing small data transmission, in response to sending small data, a UE in an RRC idle state or an RRC inactive state can receive downlink data without transitioning to an RRC connected state. For example, based on performing small data transmission, a UE in an RRC idle state or an RRC inactive state can send an RRC request message and, in response to the RRC request message, receive at least one of an RRC response message and / or downlink data. The RRC release message may include a second RRC release message, wherein the RRC release message may include downlink data. Based on the RRC release message, the UE can transition to an RRC idle state.

[0313] Small data transmission can include user plane (UP) small data transmission and control plane (CP) small data transmission. Based on UP small data transmission, a UE in RRC idle or RRC inactive state can transmit uplink data via the user plane (e.g., DTCH). Based on CP small data transmission, a UE in RRC idle or RRC inactive state can transmit uplink data via the control plane (e.g., CCCH). Based on UP small data transmission, the UE's base station can receive downlink data from the UE's UPF via the user plane. Based on CP small data transmission, the UE's base station can receive downlink data from the UE's AMF via the control plane. In response to CCCH SDU and / or DTCH SDU, the base station can send a response message to a UE in RRC idle or RRC inactive state.

[0314] Small data transmission may include at least one of initiating small data transmission, sending small data, and receiving a response message. UP small data transmission may include at least one of initiating UP small data transmission, sending UP small data, and receiving a response message. CP small data transmission may include at least one of sending CP small data via the control plane and receiving a response message.

[0315] Initiating a small data transfer may include initiating a UP small data transfer. Sending small data may include sending at least one of UP small data and / or CP small data via the control plane. The response message may be a response message in response to at least one of an RRC request message and / or (first) uplink data.

[0316] For UP small data transmission, the DTCH SDU may include uplink data. For example, for UP small data transmission, the UE may send a DTCH SDU multiplexed with the CCCH SDU. For example, for UP small data transmission, the CCCH SDU may include at least one of uplink data and an RRC request message. For example, for UP small data transmission, the RRC request message may be an RRC recovery request message. For CP small data transmission, the UE may send a CCCH SDU that includes uplink data. For example, for CP small data transmission, the RRC request message includes uplink data. For example, for CP small data transmission, the RRC request message may be an RRC early data request message.

[0317] Small data transmission may include at least one of Early Data Transmission (EDT) and Preconfigured Uplink Resource (PUR) transmission (transmission using PUR). EDT may include a random access procedure, while PUR may not. For small data transmission, a UE in an RRC idle or RRC inactive state may require uplink resources (grants) to transmit uplink data. Uplink resources may include dynamic uplink resources from the base station or preconfigured uplink resources. For EDT, in response to a random access preamble configured for EDT and a request for uplink resources, the UE may receive uplink resources (e.g., dynamic uplink resources).

[0318] UP small data transfers can include UP EDT and UP PUR. CP small data transfers can include CP EDT and CPPUR.

[0319] A typical EDT condition may include at least one of the following: for a mobile-originating call, the size of the resulting MAC PDU, including total uplink data, is expected to be less than or equal to the maximum transport block size (TBS) of Msg 3 for the UE performing the EDT; and / or the establishment or recovery request is for a mobile-originating call, and the establishment reason is mo data or mo abnormal data or delay-tolerant access.

[0320] The UE may determine to initiate small data transmission for UP EDT based on the satisfaction of UP EDT conditions. UP EDT conditions may include normal EDT conditions and at least one of the following: the UE supports UP EDT; the system information of the serving cell indicates support for UPEDT; and / or the UE has a stored NCC value provided in an RRC release message, which includes the suspension configuration parameters during the previous suspension procedure.

[0321] The UE can determine whether to transmit CP small data via the control plane of CP EDT based on the satisfaction of CP EDT conditions. CP EDT conditions may include ordinary EDT conditions and at least one of the following: the UE supports CP EDT; or the system information of the serving cell indicates that CP EDT is supported.

[0322] Figure 20An example of EDT is shown. Based on receiving a first RRC release message from the base station, the UE can transition to an RRC inactive or idle state. A UE in an RRC idle or RRC inactive state can determine to perform small data transmission based on satisfying the UP EDT condition or the CPEDT condition. The UE may have first uplink data in the uplink buffer. In response to performing small data transmission, the UE can perform an EDT RACH procedure. Based on the EDT RACH procedure, the UE can select a random access preamble configured for the EDT and send the random access preamble to the base station. In response to the random access preamble configured for the EDT, the UE can receive uplink resources / grants for the EDT. Based on the uplink resources / grants for the EDT, the UE can transmit small data. For example, a UE in an RRC inactive or idle state can use uplink resources for the EDT to transmit at least one of an RRC request message and / or first uplink data. A UE in an RRC idle or RRC inactive state can receive a response message in response to at least one of the RRC request message and / or first uplink data. The response message may include an RRC release message. The RRC release message may include downlink data. Based on receiving the response message, a UE in an RRC idle state or RRC inactive state may consider the small data transmission successful. Based on this consideration, a UE in an RRC idle state or RRC inactive state may clear at least one uplink buffer used for the first uplink data. For example, in response to Msg 3, which includes at least one of an RRC request message and / or the first uplink data, a UE in an RRC idle state or RRC inactive state may receive Msg 4. Msg 4 may include an RRC release message. Based on receiving Msg 4, a UE in an RRC idle state or RRC inactive state may consider the small data transmission successful. Based on this consideration, a UE in an RRC idle state or RRC inactive state may clear at least one of the uplink buffer used for the first uplink data and / or the uplink buffer used for the RRC request message. For example, based on this consideration, a UE in an RRC idle state or RRC inactive state may refresh at least one of the HARQ buffer used for the first uplink data and / or the HARQ buffer used for the RRC request message. Based on the RRC release message not including suspend configuration parameters, a UE in an RRC idle state or RRC inactive state can release the RRC connection. For example, based on releasing the RRC connection, a UE in an RRC idle state or RRC inactive state can transition to an RRC idle state. Based on the RRC release message including suspend configuration parameters, a UE in an RRC idle state or RRC inactive state can use the suspend configuration parameters to suspend the RRC connection.For example, by suspending the RRC connection using the suspend configuration parameter, the UE can change the UE's RRC state from RRC inactive state back to RRC inactive state, or from RRC idle state back to RRC idle state.

[0323] Figure 21 Example diagrams of UP EDT and CP EDT are shown. A UE in RRC connected state can communicate with a first base station based on a first configuration parameter and a first security key. The first base station can send an RRC release message to the UE. Based on receiving the RRC release message including the first suspend configuration parameter, the UE can suspend the RRC connection based on the first suspend configuration parameter. The UE can transition to an RRC idle state or an RRC inactive state. Based on the RRC release message, the UE can perform a cell (re)selection procedure. Based on the cell (re)selection procedure, a UE in an RRC idle state or an RRC inactive state can select cell 2 of a second base station (target base station). A UE in an RRC idle state or an RRC inactive state can determine to initiate UP small data transmission based on satisfying UP EDT conditions. Based on determining to initiate UP small data transmission, a UE in an RRC idle state or an RRC inactive state can use the first suspend configuration parameter to initiate UP small data transmission. In response to initiating UP small data transmission, a UE in an RRC idle state or an RRC inactive state can perform an EDT RACH procedure. Based on the EDT RACH procedure, the UE can select a random access preamble configured for the EDT and send it to the second base station via cell 2. In response to the random access preamble configured for the EDT, a UE in RRC idle state or RRC inactive can receive (dynamic) uplink resources for the EDT. Based on the uplink resources of the EDT, a UE in RRC idle state or RRC inactive can use the first suspend configuration parameter to perform uplink data transmission. For example, a UE in RRC idle state or RRC inactive can use the uplink resources of the EDT to transmit uplink data.

[0324] For PUR transmission, the UE may send a PUR configuration request message to the base station, wherein the PUR configuration request message may include at least one of the following: the number of requested PUR opportunities, wherein the number may be one or infinite; the requested period of the PUR; the requested transport block size (TBS) of the PUR; and / or the requested time offset of the first PUR opportunity.

[0325] The base station can send PUR configuration parameters, including pre-configured uplink resources, to the UE. For example, in response to a PUR configuration request message, the base station can send PUR configuration parameters, including pre-configured uplink resources, to the UE. Alternatively, the base station can send an RRC release message, including PUR configuration parameters.

[0326] PUR configuration parameters may include at least one of the following: an indication to establish or release PUR configuration parameters; the number of PUR opportunities; the PUR resource identifier (RNTI PUR); the time offset value of the first PUR opportunity (PUR start time); the periodicity of the PUR resource (PUR periodicity); the duration of the PUR response window (PUR response window time); a threshold for the change in serving cell RSRP in dB for TA verification (PUR change threshold), wherein the threshold includes an RSRP increase threshold and an RSRP decrease threshold; the value of the time alignment timer for the PUR; and / or the physical configuration parameters of the PUR. The physical configuration parameters of the PUR may include at least one of the following: the PUSCH configuration parameters of the PUR; the PDCCH configuration parameters of the PUR; the PUCCH configuration parameters of the PUR; the downlink carrier configuration parameters for the PUR; and / or the uplink carrier frequency for the PUR.

[0327] The UE can determine whether to initiate UP small data transmission for PUR based on the satisfaction of PUR conditions. PUR conditions may include at least one of the following: the UE has valid PUR configuration parameters; the UE has valid timing alignment (TA) values; and / or the establishment or recovery request is for a mobile-originating call, and the establishment reason is mo data or mo abnormal data or delay-tolerant access.

[0328] The UE can determine to perform UP small data transmission that initiates UP PUR based on the satisfaction of UP PUR conditions. UP PUR conditions may include PUR conditions and at least one of the following: the UE supports UP PUR; the system information of the serving cell indicates support for UPPUR; and / or the UE has a stored NCC value provided in an RRC release message, which includes the suspension configuration parameters during the previous suspension procedure.

[0329] The UE can determine whether to transmit CP small data via the control plane through the CP PUR based on the satisfaction of the CP PUR conditions. The CP PUR conditions may include PUR conditions and at least one of the following: the UE supports the CP PUR; the system information of the serving cell indicates that the CP PUR is supported; and / or the size of the resulting MAC PDU, which includes total uplink data, is expected to be less than or equal to the TBS configured for the PUR.

[0330] The UE can determine the timing alignment value of small data transmission in the PUR as valid based on the TA verification conditions of the PUR. The TA verification conditions of the PUR may include at least one of the following: the timing alignment timer for the PUR is running; or the serving cell RSRP has not increased by more than the RSRP increase threshold and has not decreased by more than the RSRP increase threshold.

[0331] In response to receiving PUR configuration parameters, the UE can store or replace the PUR configuration parameters provided by the PUR configuration parameters based on the indication to request the establishment of PUR configuration parameters. In response to receiving PUR configuration parameters, the UE can start a time alignment timer for the PUR using the value of the time alignment timer used for the PUR, and configure the PUR configuration parameters. For example, based on the indication to request the establishment of PUR configuration parameters, the UE can start a time alignment timer for the PUR using the value of the time alignment timer used for the PUR, and configure the PUR configuration parameters. In response to receiving PUR configuration parameters, the UE can discard the PUR configuration parameters based on the indication to request the release of PUR configuration parameters. In response to configuring PUR configuration parameters, the UE can generate pre-configured uplink resources / grants for the PUR based on the PUR configuration parameters. For example, based on the PUR configuration parameters, the UE can determine when to generate pre-configured uplink resources / grants. For example, based on the PUR start time and PUR period, the UE can determine when to generate pre-configured uplink resources / grants (transport blocks). For example, based on the PUSCH configuration parameters, the UE can determine the transport blocks of the pre-configured uplink resources / grants. For example, based on PUSCH configuration parameters, the UE can determine the pre-configured uplink resources / grants (transport blocks).

[0332] Figure 22An example of a PUR is shown. Based on receiving a first RRC release message, the UE can transition to an RRC idle state or an RRC inactive state. The UE can receive PUR configuration parameters via a previous RRC release message. The previous RRC release message can be the first RRC release message. In response to receiving the PUR configuration parameters, the UE in the RRC idle state or RRC inactive state can start a time alignment timer for the PUR using the value of the time alignment timer for the PUR and configure the PUR configuration parameters. In response to configuring the PUR configuration parameters, the UE in the RRC idle state or RRC inactive state can generate a pre-configured uplink resource / grant for the PUR based on the PUR configuration parameters. Based on the first RRC release message, the UE can perform a cell (re)selection procedure. Based on the cell (re)selection procedure, the UE in the RRC idle state or RRC inactive state can select cell 2 of the second base station (target base station). The UE in the RRC idle state or RRC inactive state can have first uplink data in the uplink buffer or receive a paging message. A UE in an RRC idle or RRC inactive state can determine to perform small data transmission based on satisfying the UP PUR condition or the CP PUR condition. For example, in response to having first uplink data or receiving a paging message, a UE in an RRC idle or RRC inactive state can determine to perform small data transmission based on satisfying the UPPUR condition or the CP PUR condition. Based on this determination, the UE can perform small data transmission. Based on the uplink resources / grants used for the PUR, the UE can perform small data transmission. For example, a UE in an RRC idle or RRC inactive state can use the uplink resources used for the PUR to transmit at least one of an RRC request message and / or first uplink data. For example, based on small data transmission, a UE in an RRC idle or RRC inactive state can transmit Msg 3 including at least one of a CCCH SDU and / or a DTCH SDU, where the CCCH SDU includes an RRC request message and the DTCH SDU includes first uplink data. In response to transmitting small data using the PUR, the UE (UE-MAC entity) can start a PUR response window timer with the PUR response window time. Based on this startup, the UE can monitor the PDCCH identified by the PUR RNTI until the PUR response window timer expires. The UE (UE-MAC entity) can receive downlink messages (e.g., DCI) identified by the PUR RNTI on the PDCCH. Based on receiving a downlink message indicating uplink grant for retransmission, the UE can restart the PUR response window timer at the last subframe of the PUSCH transmission indicating the uplink grant pulse time interval (e.g., 4 subframes).Based on this restart, a UE in RRC idle or RRC inactive state can monitor the PDCCH identified by the PUR RNTI until the PUR response window timer expires. Based on receiving a downlink message indicating an L1 (Layer 1) ack for PUR, a UE in RRC idle or RRC inactive state can stop the PUR response window timer and consider small data transmission using PUR to be successful. Based on receiving a downlink message indicating a fallback for PUR, a UE in RRC idle or RRC inactive state can stop the PUR response window timer and consider small data transmission using PUR to be failed. Based on receiving a downlink message indicating a PUR RNTI and / or MAC PDU addressing a PDCCH transmission (downlink grant or downlink assignment) including successfully decoded uplink data, a UE in RRC idle or RRC inactive state can stop the PUR response window timer and consider small data transmission using PUR to be successful. Based on PDCCH transmission, a UE in RRC idle or RRC inactive state can receive at least one of an RRC response message and downlink data, wherein the RRC response message is at least one of an RRC release message or an RRC early data completion message. If no downlink message is received until the PUR response window timer expires, a UE in RRC idle or RRC inactive state can consider small data transmission using PUR to have failed. Based on this assumption of PUR small data transmission failure, the UE can execute a random access procedure. For example, the random access procedure may include an EDT RACH procedure.

[0333] Figure 23Examples of UP PUR and CP PUR are shown. A UE in RRC connected state can communicate with a first base station based on a first configuration parameter and a first security key. The first base station can send an RRC release message to the UE. Based on receiving the RRC release message including the first suspend configuration parameter, the UE can suspend the RRC connection based on the first suspend configuration parameter. The UE can transition to an RRC idle state or an RRC inactive state. The UE can receive PUR configuration parameters via a previous RRC release message. The previous RRC release message can be an RRC release message. In response to receiving the PUR configuration parameters, a UE in RRC idle or RRC inactive state can start a time alignment timer for the PUR using the value of the time alignment timer for the PUR and configure the PUR configuration parameters. In response to configuring the PUR configuration parameters, a UE in RRC idle or RRC inactive state can generate a pre-configured uplink resource / grant for the PUR based on the PUR configuration parameters. Based on the RRC release message, a UE in RRC idle or RRC inactive state can perform a cell (re)selection procedure. Based on the cell (re)selection process, a UE in an RRC idle or inactive state can select cell 2 of the second base station (target base station). A UE in an RRC idle or inactive state can determine whether to initiate UP small data transmission based on satisfying the UP PUR condition. Based on this determination, a UE in an RRC idle or inactive state can use the first suspend configuration parameter to initiate UP small data transmission. Based on the (pre-configured) uplink resources used for the PUR, a UE in an RRC idle or inactive state can use the first suspend configuration parameter to transmit UP small data. For example, a UE in an RRC idle or inactive state can use the uplink resources of the PUR to transmit uplink data.

[0334] exist Figure 23In the example, a UE in RRC connected state can communicate with a first base station based on a first configuration parameter and a first security key. The first base station can send an RRC release message to the UE. Based on receiving an RRC release message that does not include the first pending configuration parameter, the UE can release the RRC connection based on the RRC release message. The UE can transition to an RRC idle state. The UE can receive PUR configuration parameters via a previous RRC release message. The previous RRC release message can be an RRC release message. In response to receiving the PUR configuration parameters, the UE in RRC idle state can start a time alignment timer for the PUR using the value of the time alignment timer for the PUR and configure the PUR configuration parameters. In response to configuring the PUR configuration parameters, the UE in RRC idle state can generate a pre-configured uplink resource / grant for the PUR based on the PUR configuration parameters. Based on the RRC release message, the UE in RRC idle state can perform a cell (re)selection procedure. Based on the cell (re)selection procedure, the UE in RRC idle state can select cell 2 of the second base station (target base station). A UE in RRC idle state can determine whether to transmit CP small data via the control plane based on satisfying the CP PUR condition. Based on this determination, the UE in RRC idle state can transmit CP small data via the control plane. For example, based on the (pre-configured) uplink resources used for the PUR, the UE in RRC idle state can transmit CP small data via the control plane. For example, the UE in RRC idle state can use the uplink resources used for the PUR to transmit at least one of an RRC request message and / or uplink data. For example, the RRC request message can be an RRC Early Data Request message and / or include uplink data.

[0335] A UE in RRC idle or RRC inactive state can have first uplink data and second uplink data. A UE in RRC idle or RRC inactive state can transmit the first and second uplink data without using uplink resources for small data transmission, wherein the uplink resources include at least one of uplink resources for EDT or (pre-configured) uplink resources for PUR. For example, a UE in RRC idle or RRC inactive state can use uplink resources for small data transmission to transmit the first uplink data, but not use uplink resources for small data transmission to transmit both the first and second uplink data. For example, the size of the resulting MAC PDU including the first uplink data can be expected to be less than or equal to the TBS configured for the PUR. The size of the resulting MAC PDU including the first uplink data can be expected to be less than or equal to the maximum transport block size (TBS) of Msg 3 applicable to the UE performing EDT. A UE in RRC idle or RRC inactive state can send a BSR requesting uplink resources for the second uplink data. For example, a UE in an RRC idle state or RRC inactive state can use uplink resources for small data transmission to send a BSR along with a first uplink and / or RRC request message. For example, a UE can use uplink resources for small data transmission to send a BSR along with a first uplink and / or RRC request message via Msg 3. Based on sending at least one of the BSR, the first uplink, and / or RRC request message, a UE in an RRC idle state or RRC inactive state can receive a response message in response to the first uplink and / or RRC request message. This response message may include an RRC response message requesting the establishment / restore of an RRC connection and at least one of uplink resources for second uplink data. Based on the response message, a UE in an RRC idle state or RRC inactive state can consider the small data transmission successful. Based on receiving the RRC response message, a UE in an RRC idle state or RRC inactive state can transition from an RRC idle state or RRC inactive state to an RRC connected state. Based on this transition, a UE in an RRC connected state can use uplink resources for second uplink data to transmit second uplink data. Transitioning to an RRC connected state can introduce overhead and complexity. For example, the RRC response message may include configuration parameters. Based on the received configuration parameters, a UE in an RRC connected state can configure the configuration parameters. Based on this configuration, a UE in an RRC connected state can perform actions related to the configuration parameters. For example, actions may include at least one of monitoring, measuring, and reporting. UEs in an RRC idle state or RRC inactive state may avoid transitioning if the second uplink data is small-sized.The base station can allow a UE in an RRC idle or RRC inactive state to perform subsequent transmissions without transitioning to an RRC connected state after deeming the small data transmission successful. Based on the subsequent transmission permission information, the UE can send second uplink data without transitioning to an RRC connected state.

[0336] A UE in an RRC inactive or idle state can send an RRC request message. Based on sending the RRC request message, the UE (UE-RRC layer) can start an RRC timer (e.g., T300 or T319). A UE in an RRC inactive or idle state can receive an RRC response message in response to the RRC request message. Based on receiving the RRC response message, a UE in an RRC inactive or idle state can stop the RRC timer.

[0337] When the RRC timer is running, a UE in an RRC inactive or idle state can detect a failure. This failure may include at least one of the following: RRC timer expiration; cell (re)selection; receiving an RRC rejection message; and integrity check failure of SRB1 or SRB2.

[0338] The RRC timer may expire. For example, the RRC timer may expire based on the absence of an RRC response message. Based on the RRC timer expiring and the RRC request message being an RRC recovery request message, a UE in the RRC idle state may perform at least one of the following: reset the MAC; rebuild the RLC for one or more established radio bearers; delete (or discard) the security key; (re)suspend the RRC connection; and be configured to suspend integrity protection and encryption. Based on the RRC timer expiring and the RRC request message not being an RRC recovery request message, a UE in the RRC idle state may perform at least one of the following: reset the MAC; release the MAC configuration (parameters); and rebuild the RLC for one or more established bearers. Based on the RRC timer expiring, a UE in the RRC inactive state may perform at least one of the following: reset the MAC; discard the UE inactive AS context; release the suspended configuration parameters; delete (or discard) the security key; release all radio resources and transition to the RRC idle state, where releasing all radio resources may include releasing the MAC configuration (parameters), RLC entity, PDCP entity, and SDAP for one or more established bearers; and transition to the RRC idle state.

[0339] Based on re-suspending the RRC connection, a UE in an RRC inactive or idle state may perform at least one of the following: rebuild the RLC entity for one or more SRBs and DRBs; delete the security key; suspend one or more SRBs and DRBs other than Signaling Radio Bearer 0 (SRB0); and / or remain in the current RRC state, where the current RRC state includes an RRC idle state or an RRC inactive state.

[0340] Cell (re)selection may occur when the RRC timer is running and the UE is in an RRC inactive or idle state. For example, while the RRC timer is running, the UE can change its serving cell based on cell (re)selection. Based on the cell (re)selection and RRC request message being an RRC recovery request message, a UE in an RRC idle state can perform at least one of the following: reset MAC; rebuild RLC for one or more established radio bearers; delete (or discard) security keys; (re)suspend the RRC connection; configure to suspend integrity protection and encryption. Based on the cell (re)selection and RRC request message not being an RRC recovery request message, a UE in an RRC idle state can perform at least one of the following: reset MAC; release MAC configuration (parameters); and rebuild RLC for one or more established bearers. Based on cell (re)selection, a UE in an RRC inactive state may perform at least one of the following: reset MAC; discard UE inactive AS context; release suspended configuration parameters; delete (or discard) security key; release all radio resources and transition to RRC idle state, wherein releasing all radio resources may include releasing MAC configuration (parameters), RLC entity and PDCP entity and SDAP for one or more established bearers; and transition to RRC idle state.

[0341] When the RRC timer is running, a UE in an RRC inactive or idle state can receive an RRC rejection message. Based on receiving the RRC rejection message, a UE in an RRC inactive or idle state can stop the RRC timer. Based on the RRC rejection message not including an RRC suspension indication and an RRC request message but an RRC recovery request message, a UE in an RRC idle state performs at least one of the following: resets the MAC; discards the UE inactive AS context; and releases all radio resources and transitions to an RRC idle state, where releasing all radio resources may include releasing the MAC configuration (parameters), RLC entity, PDCP entity, and SDAP for one or more established bearers. Based on the RRC rejection message including an RRC suspension indication and an RRC request message but an RRC recovery request message, a UE in an RRC idle state can perform at least one of the following: resets the MAC; re-establishes the RLC for one or more established radio bearers; deletes (or discards) the security key; (re)suspends the RRC connection; and configures to suspend integrity protection and encryption. Based on the fact that the RRC Reject message and the RRC Request message are not RRC Resumption Request messages, a UE in the RRC Idle state may perform at least one of the following: reset the MAC; and release the default MAC configuration parameters. Based on the RRC Reject message, a UE in the RRC Inactive state may perform at least one of the following: reset the MAC; release the default MAC configuration (parameters); delete (or discard) the security key; (re)suspend the RRC connection; and remain in the RRC Inactive state.

[0342] Integrity check failure occurs when the RRC timer is running and the UE is in an RRC inactive or idle state. For example, when the RRC timer is running, a UE in an RRC inactive or idle state can detect an integrity check failure on SRB1 or SRB2. Based on the integrity check failure and the fact that the RRC request message is an RRC recovery request message, the UE in an RRC idle state performs at least one of the following: resets the MAC; discards the UE inactive AS context; and releases all radio resources and transitions to an RRC idle state, wherein releasing all radio resources may include releasing the MAC configuration (parameters), RLC entity and PDCP entity, and SDAP used for one or more established bearers.

[0343] Based on the integrity check failure and the RRC request message being an RRC recovery request message, a UE in an RRC inactive state may perform at least one of the following: reset MAC; discard the UE inactive AS context; release suspended configuration parameters; delete (or discard) the security key; release all radio resources and transition to an RRC idle state, wherein releasing all radio resources may include releasing the MAC configuration (parameters), RLC entity and PDCP entity, and SDAP used for one or more established bearers; and transition to an RRC idle state.

[0344] When a UE in an RRC inactive or idle state restores its RRC connection, the RRC request message is an RRC restore request message.

[0345] When the RRC timer is running, a UE in an RRC inactive or idle state can detect a failure. A UE in an RRC inactive or idle state can (re)suspend the RRC connection based on this failure. Based on the suspended RRC connection, the UE in an RRC inactive or idle state can send an RRC recovery request message to the base station. For example, based on the suspended RRC connection, when a UE in an RRC inactive or idle state has data or signaling to send or receive paging messages from the base station, the UE can send an RRC recovery request message to the base station. A UE in an RRC inactive or idle state may not suspend the RRC connection based on this failure (e.g., releasing all radio resources). Based on not suspending the RRC connection (e.g., releasing all radio resources), a UE in an RRC inactive state can transition to an RRC idle state. Based on not suspending the RRC connection, a UE in an RRC idle state can send an RRC establishment request message. For example, based on the non-suspended RRC connection, when a UE in the RRC idle state has data or signaling to send or receive paging messages from the base station, the UE can send an RRC establishment request message to the base station.

[0346] A UE in RRC connection state can detect a connection failure with the base station. Based on this failure, the UE in RRC connection state can initiate an RRC connection reconstruction procedure. Based on initiating the RRC connection reconstruction procedure, the UE can send an RRC reconstruction request message to the base station. A connection failure with the base station includes at least one of the following: radio link failure; reconfiguration due to synchronization failure; mobility failure from a new radio (NR); integrity check failure; or RRC (connection) reconfiguration failure.

[0347] Figure 24AAn example of the RRC procedure is shown when a failure is detected in an RRC inactive or idle state. A UE in an RRC inactive or idle state may send a first RRC request message. A UE in an RRC inactive or idle state may send uplink data along with the first RRC request message. A UE in an RRC inactive or idle state may wait for / monitor an RRC response message in response to the first RRC request message. A UE in an RRC inactive or idle state may detect a failure, where the failure includes at least one of the following: RRC timer expiration; cell (re)selection; receiving an RRC rejection message; and integrity check failure of SRB1 or SRB2.

[0348] Based on this failure, a UE in an RRC inactive or idle state can initiate an RRC connection establishment or recovery procedure. Based on this initiation, the UE in an RRC inactive or idle state can perform an access denial check on access attempts during the RRC connection establishment or recovery procedure (e.g., access attempts via RRC request messages). Based on an allowed access attempt, the UE can send an RRC request message to the base station.

[0349] Figure 24B An example of the RRC procedure is shown when a failure is detected in the RRC connection state. A UE in the RRC connection state can communicate with a base station via its serving cell, where communication includes sending uplink data or signaling to the base station and receiving downlink data or signaling from the base station. A UE in the RRC connection state can activate AS security with the base station and communicate with the base station based on AS security. A UE in the RRC connection state can detect a failure, which can include at least one of the following: radio link failure; reconfiguration due to synchronization failure; mobility failure from a new radio (NR); an integrity check failure indication from a lower layer (e.g., the PDCP layer) regarding Signaling Radio Bearer 1 (SRB1) or Signaling Radio Bearer 2 (SRB2); or RRC connection reconfiguration failure. A UE in the RRC connection state can initiate an RRC connection reconstruction procedure. Based on this initiation, the UE in the RRC connection state can send an RRC reconstruction request message to the base station.

[0350] In the prior art, a wireless device in an RRC inactive or idle state can communicate via a base station cell (e.g., using small data transmission), where the communication includes at least one of sending data or signaling and receiving data or signaling via the cell. A wireless device in an RRC inactive or idle state can detect a communication failure via the cell. Based on this failure, the wireless device in an RRC inactive or idle state can initiate an RRC connection establishment / recovery procedure to recover from the failure or restore communication. To establish / recover, the wireless device can transmit an RRC request message. Based on receiving the RRC request message, the base station can determine to establish / recover a new connection with the wireless device. To establish / recover a new connection, the base station must determine the cell and / or configuration parameters for the new connection, which introduces latency. The base station can signal the configuration parameters to the wireless device via the cell, which introduces signaling overhead and further latency. During the latency period, communication may be blocked, potentially leading to packet loss, which is detrimental to the user.

[0351] In existing technologies, a wireless device initiating an RRC connection establishment / recovery process based on the detection of communication failure in an RRC inactive or idle state can release radio resources and configuration parameters received from the base station. Based on this release, the wireless device may need to receive new configuration parameters from the base station to recover from the failure or resume communication with the base station. For example, a wireless device that has detected a failure may need to receive new security parameters to recover from the failure or resume communication. The wireless device that has detected a failure can communicate with the base station using a new security key derived from the new security parameters. When a wireless device in an RRC inactive or idle state detects a communication failure, the RRC process of receiving new configuration parameters may result in signal overhead and delays in recovering from the failure or resuming communication. When a wireless device detects a failure, it may have a small amount of residual data. To transmit this small amount of data, the wireless device may consume significant power and radio resources to perform the RRC connection establishment / recovery process.

[0352] In embodiments of this disclosure, when a wireless device detects a communication failure via a first cell during an RRC inactive or idle state, it can send an RRC request message to the base station to request recovery from the failure or resumption of communication. The RRC request message may include a Cell Radio Network Temporary Identifier (C-RNTI). The C-RNTI may be assigned by the first cell (e.g., the cell associated with the communication failure). Based on the received C-RNTI from the RRC request message, the base station can identify the first cell and the wireless device. The base station can recover from the failure or resume communication with less signal overhead and lower latency by maintaining / reusing configuration parameters used for communication. For example, based on the C-RNTI included in the RRC request message, the base station can determine to maintain / reuse the configuration parameters used in the communication. Based on this determination, the base station can send an RRC response message. The RRC response message may include new security parameters (e.g., NCC values). Based on the received new security parameters, the wireless device can derive a new security key for communication after recovering from the failure, while maintaining / reusing existing security parameters (e.g., security algorithm parameters). In the prior art, RRC request messages may include various indicators, but these indicators may be detrimental to the maintenance / reuse of configuration parameters. For example, an RRC request may include a radio device identifier, but the base station receiving the RRC request may not be able to link the radio device identifier to reusable configuration parameters. For example, an RRC request may include a recovery identifier (recovery ID), but the recovery ID could be bound to an anchor base station that does not use the first cell and is unaware of the reusable configuration parameters of the first cell. In contrast, as will be discussed in more detail below, C-RNTI can facilitate the efficient preservation / reuse of configuration parameters.

[0353] In existing technology, a wireless device initiating an RRC connection establishment / recovery procedure to recover from communication failures in an RRC inactive or idle state may not complete the RRC connection establishment / recovery procedure based on: determining that the access attempt for the RRC connection establishment / recovery procedure is prohibited by an access prohibition check; or receiving an RRC rejection message. The wireless device may initiate an access attempt prohibition timer based on the determination that the access attempt is prohibited. The wireless device may initiate a waiting timer based on receiving an RRC rejection message. While the prohibition timer or waiting timer is running, the wireless device may not initiate the RRC connection establishment / recovery procedure. The wireless device may postpone the initiation / access attempt of the RRC connection establishment / recovery procedure until the prohibition timer or waiting timer expires. Access attempt prohibition and RRC rejection messages may lead to recovery failure or delays in restoring communication.

[0354] The exemplary implementation enables a wireless device to skip access prohibition checks on access attempts during an RRC connection establishment / recovery process when the wireless device initiates the process based on a detected communication failure in an RRC inactive or idle state. By skipping the access prohibition check, the wireless device can initiate the RRC connection establishment / recovery process without delay from the moment the access attempt is prohibited.

[0355] An exemplary implementation enables a wireless device to indicate to the base station a communication failure in an RRC inactive or idle state when the wireless device sends an RRC request message to recover from a failure or resume communication. Based on the RRC request message indicating failure, the base station can determine whether to accept the RRC request message (e.g., the base station can determine not to reject the request). Based on this determination, the base station can send an RRC response message. Based on the receipt of the RRC response message, the wireless device can successfully complete the RRC connection establishment / recovery process with less signal overhead and lower latency by avoiding rejection of the RRC request message.

[0356] In the prior art, a wireless device in an RRC inactive or idle state can communicate (e.g., perform small data transmission) via a first cell of a base station. This communication may include at least one of the following: sending a first message including first uplink data and an RRC request message; and receiving a first downlink message including first downlink data and an RRC response message. The wireless device sending the first message may determine communication failure based on the absence of an RRC response message within a specific time (e.g., failure to send first uplink data). For example, the wireless device may start an RRC timer in response to sending an RRC request message and stop the RRC timer in response to receiving an RRC response message before the RRC timer expires. Based on the RRC timer expiration, the wireless device may determine that communication has failed in the RRC inactive or idle state. In the prior art, communication in an RRC inactive or idle state may include more than one uplink transmission and / or more than one downlink transmission (e.g., subsequent transmissions). For communication, the base station may send an RRC response message to the wireless device when communication ends / completes. In response to the transmission of an RRC request message, a wireless device that transmits the first uplink data along with the RRC request message in an RRC inactive or idle state may not receive an RRC response message. For communications involving more than one transmission and / or one reception, the RRC timer used for the RRC request message may expire. Based on the expiration of the RRC timer, the wireless device can determine the communication failure that caused signal overhead and delay, and recover from the communication failure and interruption.

[0357] In embodiments of this disclosure, a wireless device communicating via a cell in an RRC inactive or idle state can start or restart a failure (detection) timer in response to the communication. For example, a wireless device in an RRC inactive or idle state can start or restart a failure timer in response to at least one of transmitting an uplink packet or receiving a downlink packet. The uplink / downlink packet may include at least one of: data; signaling (e.g., an RRC message, MAC CE, or physical signal). Exemplary embodiments can avoid erroneous decisions that lead to communication failures in an RRC inactive or idle state due to RRC timer expiration. The wireless device can reduce signal overhead and delays in the process of recovering from failures triggered by RRC timer expiration.

[0358] In one example, a UE in an RRC inactive or idle state can communicate via a first cell of a first base station, wherein such communication may include at least one of the following: sending one or more uplink data / signaling to the first base station; and receiving one or more downlink data / signaling from the first base station. A UE in an RRC inactive or idle state can detect a communication failure via the first cell. Based on this detection, the UE in an RRC inactive or idle state can send a first RRC request message including the Cell Radio Network Temporary Identifier (C-RNTI) of the first cell.

[0359] In one example, a UE in an RRC inactive or idle state may further determine to send a first RRC request message based on at least one of the following: to transmit data / signaling to or from a first base station; the UE supports failure recovery of communication in an RRC inactive or idle state; the UE identifier of the first cell is assigned; and / or the RRC connection is not suspended based on the failure.

[0360] In one example, based on this detection, a UE in an RRC inactive or idle state may have data / signaling to transmit to or receive from the first base station. For instance, if there is no data / signaling to transmit to or receive from the first base station, a UE in an RRC inactive or idle state may transition to an RRC idle state and send a NAS message to the AMF via the base station, where the NAS message may include a registration request message and / or a service request message.

[0361] In one example, a UE in an RRC inactive or idle state can receive a failure recovery (capability) indication from the base station. Based on the failure recovery (capability) indication, the UE can determine whether failure recovery of communication in the RRC inactive or idle state is supported. For example, based on this determination, a UE in an RRC inactive or idle state can send a first RRC request message based on communication failure.

[0362] In one example, a UE in an RRC inactive or idle state may not suspend the RRC connection based on the failure. For example, a UE in an RRC connected state may receive suspension configuration parameters from the base station. Based on the suspension configuration parameters, a UE in an RRC connected state may suspend the RRC connection and transition to an RRC inactive or idle state. A UE in an RRC inactive or idle state may resume communication with one or more bearers of the first base station. Based on the resumption of one or more bearers, a UE in an RRC inactive or idle state may communicate with the first base station, wherein the communication includes at least one of the following: sending one or more uplink signaling messages (e.g., RRC recovery request messages) and / or uplink data (e.g., small data); and receiving one or more downlink signaling messages and / or downlink data. A UE in an RRC inactive or idle state may detect a communication failure. Based on the type of failure, a UE in an RRC inactive or idle state may not suspend the RRC connection.

[0363] In one example, a UE in an RRC inactive or idle state can determine that the UE identifier of the first cell has been assigned based on receiving at least one of the following from the first base station via the first cell: a UE Contention Resolution Identifier Media Access Control Element (MAC CE); an RRC message including the UE identifier value; and a downlink message identified by a pre-configured Uplink Resource Radio Network Temporary Identifier (PUR RNTI) value from the radio device. The UE identifier value may include at least one of the following: a Cell Radio Network Temporary Identifier (C-RNTI) value; a PUR RNTI value; and a recovery identifier value. Based on determining that the UE identifier of the first cell has been assigned, the UE can set the C-RNTI of the first cell based on at least one of the following: a C-RNTI value of a random access response from the first cell, wherein the random access response is a response to a random access preamble sent by the radio device; the UE identifier value of the RRC message; the PUR RNTI value of the radio device; or the recovery identifier.

[0364] In one example, a UE in an RRC inactive or idle state can send a random access preamble to a first cell. The UE in an RRC inactive or idle state can receive a random access response including a temporary C-RNTI (TC-RNTI) value. Based on the random access response, the UE in an RRC inactive or idle state can send a Common Control Channel (CCCH) Service Data Unit (SDU) including an RRC request message to a first base station via the first cell, where the RRC request message is either an RRC establishment request message or an RRC recovery request message. In response to the RRC request message, the UE in an RRC inactive or idle state can receive a PDCCH transmission addressed to the TC-RNTI and a UE Contention Resolution Identifier (MAC CE). Based on the PDCCH transmission and the MAC CE, the UE in an RRC inactive or idle state can determine that the C-RNTI of the first cell has been assigned. For example, based on the MAC CE, the UE in an RRC inactive or idle state can set the C-RNTI of the first cell to the TC-RNTI value. The UE contention resolution identifier media access control unit (MAC CE) can match a predetermined first bit (e.g., 48 first bits) of a common control channel (CCCH) service data unit (SDU), wherein the CCCH SDU includes a first RRC request message.

[0365] In one example, a UE in an RRC inactive or idle state may have valid PUR configuration parameters. Based on these valid PUR configuration parameters, the UE in an RRC inactive or idle state can transmit small data using uplink resources / grants allocated for the PUR. Based on the transmitted small data, the UE in an RRC inactive or idle state can monitor downlink messages (e.g., PDCCH) identified by the PURRNTI value. Based on this monitoring, the UE in an RRC inactive or idle state can receive downlink messages identified by the PURRNTI value. The downlink messages may indicate PDCCH transmission (downlink grant or downlink assignment). Based on receiving PDCCH transmissions, the UE in an RRC inactive or idle state can receive RRC messages. The RRC messages may include C-RNTI values. Based on receiving downlink messages and / or RRC messages, the UE in an RRC inactive or idle state can determine that the C-RNTI of the first cell has been assigned. Based on this determination, a UE in an RRC inactive or idle state can set the C-RNTI of the first cell based on the C-RNTI value or PUR-RNTI of the RRC message. For example, based on receiving an RRC message including a C-RNTI value, a UE in an RRC inactive or idle state can set the C-RNTI of the first cell based on the C-RNTI value. Based on receiving an RRC message not including a C-RNTI value, a UE in an RRC inactive or idle state can set the C-RNTI of the first cell based on the PUR-RNTI value.

[0366] In one example, a UE in an RRC inactive or idle state can receive an RRC message including its UE identifier during communication. Based on receiving the RRC message including the UE identifier, the inactive or idle UE can determine that the UE identifier has been assigned. For example, the RRC message could be an RRC release message.

[0367] In one example, a UE in an RRC inactive or idle state can receive a mobility command (e.g., a handover command) from a base station. For example, a UE in an RRC inactive or idle state can receive a mobility command from a base station based on communication with the base station. The mobility command may include a C-RNTI value. Based on receiving the mobility command, the UE in an RRC inactive or idle state can determine that a C-RNTI for a first cell has been assigned. Based on this determination, the UE in an RRC inactive or idle state can set the C-RNTI for the first cell based on the C-RNTI value. Based on receiving the mobility command, the UE in an RRC inactive or idle state can start a mobility timer (e.g., T304) and perform synchronization with the first cell. Based on the synchronization, the UE in an RRC inactive or idle state can perform a random access procedure. Based on receiving a PDCCH transmission addressed by a C-RNTI value from the first cell, the UE in an RRC inactive or idle state can determine that a C-RNTI for the first cell has been assigned. Based on this determination, a UE in an RRC inactive or idle state can set the C-RNTI of a first cell based on the C-RNTI value. For example, a UE in an RRC inactive or idle state can communicate with a base station. Based on this communication, the UE in an RRC inactive or idle state performs cell (re)selection. Based on the cell (re)selection, the UE in an RRC inactive or idle state can determine to change its serving cell to the first cell. Based on this determination, the UE in an RRC inactive or idle state can send signaling (e.g., an RRC message or MAC CE) to the base station, wherein the signaling can include at least one of the following: a cell (re)selection indication for an RRC inactive or idle state; a first cell identifier; and / or a measurement report, wherein the measurement report may include at least a measurement report of the first cell. Based on this signaling, the base station can send a mobility command including the C-RNTI of the first cell. For example, based on this signaling, the base station can send a mobility command request to a first base station, wherein the mobility request message includes a mobility command. Based on the mobility request message, the first base station can send a mobility request ack message, wherein the mobility request ack may include configuration parameters of the first cell (or the first base station). Based on the mobility request message, the base station can send a mobility command to the UE. The mobility command may include at least one of the following: the mobility request ack message; an RRC reconfiguration message with a reconfiguration synchronization information element (IE); and / or mobility control information. The first cell identifier may include at least one of the following: the physical cell identifier (PCI) of the first cell; and / or the global cell identifier of the first cell.

[0368] In one example, a UE in an RRC inactive or idle state can communicate with a first base station using (or via) the user plane (UP). For example, a UE in an RRC connected state can receive suspend configuration parameters from the base station. Based on the suspend configuration parameters, the UE in an RRC connected state can suspend the RRC connection and transition to an RRC inactive or idle state. A UE in an RRC inactive or idle state can resume communication with one or more bearers of the first base station, where the one or more bearers include one or more user plane bearers. Based on resuming one or more bearers, the UE in an RRC inactive or idle state can communicate with the first base station using (or via) the user plane bearers. Communication using the user plane can include activating AS security. For example, a UE in an RRC connected state can receive suspend configuration parameters from the base station. Based on the suspend configuration parameters including an NCC value, the UE in an RRC connected state can suspend the RRC connection and transition to an RRC inactive or idle state. A UE in an RRC inactive or idle state can update the security key for the NCC value. Based on the updated security key, the UE in an RRC inactive or idle state activates AS security. A UE in an RRC inactive or idle state can resume communication with one or more bearers of the first base station, wherein the one or more bearers include one or more user plane bearers. Based on the resumption of one or more bearers, a UE in an RRC inactive or idle state can communicate with the first base station using (or via) user plane bearers.

[0369] In one example, a UE in an RRC inactive or idle state may store at least one of the following: the C-RNTI of the first cell; the physical cell identifier (PCI) of the first cell; and the global cell identifier of the first cell.

[0370] In one example, a UE in an RRC inactive or idle state may skip the access prohibition check for an access attempt to the first RRC request message on a second cell based on at least one of the following: detecting a failure; and / or determining to send the first RRC request message. For example, if a prohibition timer T309 is running based on determining to send the first RRC request message, the UE in an RRC inactive or idle state may stop one or more prohibition timers T309 for one or more access categories, wherein one or more access categories are associated with the access attempt for the first RRC request message. Based on stopping one or more prohibition timers T309, the UE in an RRC inactive or idle state considers / determines to have mitigated the prohibition for one or more access categories for the second cell. Based on mitigating the prohibition for the second cell, the UE in an RRC inactive or idle state may determine to skip the access prohibition check for the second cell.

[0371] In one example, communication failure may include at least one of the following: failure timer expiration; cell (re)selection by the radio device; and / or receiving a backoff indication or rejection message; mobility failure in RRC inactive or idle state; and / or inability to comply with RRC messages (e.g., reconfiguration failure).

[0372] In one example, a UE in an RRC inactive or idle state can start and / or restart a failure timer based on sending one or more uplink data or signaling messages in a communication with a first base station. If the failure timer is running, the UE in an RRC inactive or idle state can stop the failure timer based on receiving one or more downlink data or signaling messages. For example, this communication may include communication after determining that a C-RNTI has been assigned. A UE in an RRC inactive or idle state can (re)start the failure timer by sending one or more uplink data or signaling messages in a communication after determining that a C-RNTI has been assigned. If the failure timer is running, the UE in an RRC inactive or idle state can stop the failure timer based on receiving one or more downlink data or signaling messages in a communication after determining that a C-RNTI has been assigned. The base station may include a first base station.

[0373] In one example, a UE in an RRC inactive or idle state can receive a failure timer value from a base station. Restarting the failure timer may include restarting the failure timer if the timer value is set to the failure timer value. An RRC message may include the failure timer value. The RRC message may be a first RRC response message in response to a first RRC request message, wherein the first RRC request message may be an RRC message first sent by the UE in an RRC inactive or idle state to a first base station via a first cell. Based on the received failure timer, the UE in an RRC inactive or idle state may restart the failure timer. The base station may include the first base station.

[0374] In one example, a UE in an RRC inactive or idle state can monitor data / signaling activity from / to a first base station (or first cell) for the duration of a failure timer (e.g., a time interval). A UE in an RRC inactive or idle state can (re)start monitoring data / signaling activity from / to the first base station (or first cell) for the duration of the failure timer based on the detection of data / signaling activity. For example, after determining that a C-RNTI has been assigned, a UE in an RRC inactive or idle state can (re)start monitoring data / signaling activity. The duration can be set to a failure time value based on the detection of data / signaling activity or the (re)start of monitoring data / signaling activity. Data / signaling activity can include at least one of the following: sending data or signaling to a base station (or via a cell); and / or receiving data or signaling from a base station (or via a cell). In response to (re)starting monitoring data / signaling activity, a UE in an RRC inactive or idle state may not detect data / signaling activity during that duration. Based on the absence of detected data / signaling activity during this duration, the UE can determine that the failure timer has expired. The base station may include a first base station. The cell may include a first cell.

[0375] In one example, a UE in an RRC inactive or idle state can (re)start a failure timer based on sending one or more uplink data or signaling messages in a communication with a base station. If the failure timer is running, the UE in an RRC inactive or idle state can stop the failure timer based on receiving a response message for one or more uplink data or signaling messages in a communication with a base station. For example, this communication may include communication after determining that a C-RNTI has been assigned. The UE in an RRC inactive or idle state can (re)start a failure timer based on sending one or more uplink data or signaling messages in a communication after determining that a C-RNTI has been assigned. After determining that a C-RNTI has been assigned, the UE in an RRC inactive or idle state can stop the failure timer based on receiving a response message for one or more uplink data or signaling messages in a communication. The base station may be a first base station. For example, this communication may include one or more transmission timings. The UE in an RRC inactive or idle state may send one or more uplink data or signaling messages in each transmission timing, where the signaling may include RRC messages. The UE can determine a transport block (TB) (e.g., the size of uplink data or signaling to be transmitted) based on uplink resources or grants, wherein the uplink resources or grants may include at least one of the following: dynamic grants provided from a first base station; or a PUR in a valid PUR configuration parameter. A UE in an RRC inactive or idle state can (re)start a failure timer based on a timeout for each transmission. If a failure timer is running, a UE in an RRC inactive or idle state can stop the failure timer based on receiving a response message for each transmission, wherein the response message may include an acknowledgment for each transmission. The base station may include the first base station.

[0376] In one example, a UE in an RRC inactive or idle state can monitor data / signaling activity from / to a first base station (or first cell) for the duration of a failure timer. A UE in an RRC inactive or idle state can (re)start monitoring data / signaling activity from / to the first base station (or first cell) for the duration of the failure timer based on the detection of data / signaling activity. The duration can be set to a failure time value based on the detection of data / signaling activity or (re)starting monitoring of data / signaling activity. Data / signaling activity can include at least one of the following: sending data or signaling to a base station (or via a cell); and / or receiving response messages for one or more uplink data or signaling from a base station (or via a cell). A UE in an RRC inactive or idle state can (re)start monitoring data / signaling activity for the duration of the failure timer based on each transmission timing. After determining that a C-RNTI has been assigned, a UE in an RRC inactive or idle state can (re)start monitoring data / signaling activity. If a UE in an RRC inactive or idle state is monitoring data / signaling activity, it may stop monitoring data / signaling activity for the duration of a failure timer based on receiving a response message for each transmission, where the response message may include an acknowledgment for each transmission. In response to (re)starting monitoring data / signaling activity, the UE in an RRC inactive or idle state may not detect data / signaling activity for that duration. Based on the lack of detected data / signaling activity during that duration, the UE in an RRC inactive or idle state may determine that the failure timer has expired. The base station may include a first base station. The cell may include a first cell.

[0377] In one example, a UE in an RRC inactive or idle state can perform cell (re)selection during communication with a base station. Cell (re)selection can include cell (re)selection after determining that a C-RNTI has been assigned. For example, a UE in an RRC inactive or idle state can communicate via a first cell. A UE in an RRC inactive or idle state can perform cell (re)selection during communication. For example, based on cell (re)selection, a UE in an RRC inactive or idle state can change its serving cell from a first cell to a second cell.

[0378] In one example, a UE in an RRC inactive or idle state can receive a fallback indication or rejection message from a first base station during communication. Receiving a fallback indication or rejection message may include receiving it after determining that a C-RNTI has been assigned. A UE in an RRC inactive or idle state can receive the fallback indication or rejection message via an RRC message or a MAC CE. The first base station may send a fallback indication or rejection message based on at least one of the following: failure to successfully decode uplink data / signaling from the UE; congestion at the base station or the first cell. For example, the base station may be unable to successfully decode uplink data / signaling from the UE due to a failure in integrity protection of uplink data / signaling.

[0379] In one example, a UE in an RRC inactive or idle state can receive a mobility command (e.g., a handover command) from a base station. For instance, a UE in an RRC inactive or idle state can receive a mobility command from a base station based on communication with the base station. The mobility command may include a C-RNTI value. Based on receiving the mobility command, the UE in an RRC inactive or idle state can determine that a C-RNTI for a first cell has been assigned. In response to receiving the mobility command, the UE in an RRC inactive or idle state can start a mobility timer (e.g., T304) and perform synchronization with the first cell. The UE in an RRC inactive or idle state may fail to synchronize with the first cell until the mobility timer expires. Based on the expiration of the mobility timer, the UE in an RRC inactive or idle state can determine that mobility in the RRC inactive or idle state has failed.

[0380] In one example, a UE in an RRC inactive or idle state can receive RRC messages from a base station. For instance, a UE in an RRC inactive or idle state can receive RRC messages from a base station based on communication with the base station. The base station may include a first base station. A UE in an RRC inactive or idle state can determine that it cannot comply with (partial) configuration parameters in the RRC message, or detect that (partial) content in the RRC message is invalid. Based on this determination, a UE in an RRC inactive or idle state can determine that it cannot comply with the RRC message. A UE in an RRC inactive or idle state can determine that (partial) content in the RRC message is invalid based on the UE-NAS layer indicating that the NAS message (in the RRC message) is invalid.

[0381] In one example, the first RRC request message also includes at least one of the following: the physical cell identifier (PCI) of the first cell; the short message authentication code-integrity (MAC-I); and the reason for failure.

[0382] In one example, a UE in an RRC-inactive state can perform cell selection based on a detected failure. A UE in an RRC-inactive or idle state can select a second cell from a second base station based on cell (re)selection. For example, a UE in an RRC-inactive or idle state can select a second cell from a second base station based on the signal quality of the second cell exceeding a threshold.

[0383] In one example, a UE in an RRC inactive or idle state may receive a first RRC response message from a first base station or a second base station, wherein the first RRC response message may include at least one of the following: a next link hop count (NCC) value; radio resource configuration parameters; and / or the requested RRC status of the radio device.

[0384] In one example, a UE in an RRC inactive or idle state can derive a new security key based on the NCC value and the current security key. For instance, a UE in an RRC inactive or idle state can activate AS security. Based on activating AS security, the UE in an RRC inactive or idle state derives the current security key. Based on the current security key, the UE in an RRC inactive or idle state can communicate with the first base station. Based on receiving the NCC value in the first RRC response message, the UE in an RRC inactive or idle state can derive a new security key based on the NCC value and the current security key.

[0385] In one example, radio resource configuration parameters may include at least one of radio bearer configuration parameters and / or cell group configuration parameters. The cell group may include at least a first cell of the second base station, where the first cell is the UE's PCell and serving cell. For example, radio bearer configuration parameters may include signaling radio bearer configuration parameters. For example, radio bearer configuration parameters may be signaled based on UP small data transmission or AS security activation. Based on the radio bearer configuration parameters, a UE in an RRC idle or inactive state can reconfigure or (re)establish the signaling radio bearer.

[0386] In one example, a UE in an RRC inactive or idle state may determine communication based on at least one of the following: receiving an indication for communication in an RRC inactive or idle state; meeting small data transmission conditions; and / or receiving a paging message indicating small data transmission.

[0387] In one example, a UE in an RRC inactive or idle state may determine whether to use the user plane (UP) for communication in an RRC inactive or idle state based on performing / initiating ...

Claims

1. A method of communication, the method comprising: communicating, by a wireless device (106) in a radio resource control (RRC) inactive state, via a first cell of a first base station (104); and transmitting, by the wireless device, an RRC request message to a second base station based on a communication failure of the first cell while in the RRC inactive state, the RRC request message including a cell radio network temporary identifier (C-RNTI) of the first cell.

2. The method of claim 1, wherein the communicating includes communicating a packet for a small data transmission.

3. The method of claim 2, wherein the communicating the packet includes: transmitting the packet via the first cell; and receiving the packet via the first cell.

4. The method of any one of claims 2-3, further comprising transmitting, by the wireless device in the RRC inactive state, a first RRC request message for the small data transmission via the first cell of the first base station.

5. The method of claim 4, wherein the transmitting the first RRC request message includes transmitting the first RRC request message based on a determination that a C-RNTI of the first cell is set.

6. The method of any one of claims 4-5, further comprising receiving a second RRC message including the C-RNTI via the first cell.

7. The method of claim 6, wherein the second RRC message is received after the transmitting the first RRC request message.

8. The method of any one of claims 1-7, further comprising: receiving, via the first cell, a downlink message identified by a preconfigured uplink resource radio network temporary identifier (PUR-RNTI) value of the wireless device; and setting the C-RNTI to a value of the PUR-RNTI.

9. The method of any one of claims 4-7, further comprising: receiving, via the first cell, a random access response including a temporary C-RNTI; and setting the C-RNTI to a value of the temporary C-RNTI.

10. The method of claim 9, further comprising: transmitting, in response to the random access response, a common control channel (CCCH) service data unit (SDU) including the first RRC request message; and receiving, via the first cell, a contention resolution identification medium access control (MAC) control element (CE) matching the CCCH SDU; wherein the setting the C-RNTI to the value of the temporary C-RNTI is based on the receiving the MAC CE matching the CCCH SDU.

11. The method of any one of claims 1-10, further comprising receiving, from the first base station, a grant indicating resources for a small data transmission packet.

12. The method of claim 11, wherein the communicating includes transmitting or receiving the small data transmission packet via the resources. ​ ​ ​ ​ 13. A wireless device (106), comprising one or more processors and memory storing instructions that, when executed by the one or more processors, cause the wireless device to perform the method of any of claims 1-12.

14. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform the method of any of claims 1-12.

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