Reception of random access response

Abstract

A wireless device transmits (3210) a first preamble via a cell. The wireless device receives (3220) a downlink grant for a random access response. The wireless device determines (3230) a failure to receive the random access response. The wireless device determines (3240) an uplink signal for transmission via the cell based on the failure and a time alignment timer of the cell. The uplink signal is one of a second preamble and a negative acknowledgement. The wireless device transmits (3250) the uplink signal.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 887,279, filed August 15, 2019, the entire contents of which are incorporated herein by reference. 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 example mobile communication network that can implement embodiments of this disclosure 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 way Figure 2A Example downlink data stream of the NR user plane protocol stack.

[0008] Figure 4B This shows an example format of the MAC subheader in a MAC PDU.

[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 example configuration is shown in which OFDM symbols are grouped into NR frames.

[0012] Figure 8 An example configuration of time slots in the time-frequency domain for NR carriers is shown.

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

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

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

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

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

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

[0019] Figure 13A , Figure 13B and Figure 13C The following are illustrated: a contention-based four-step random access procedure, a contention-free two-step random access procedure, and another two-step random access procedure.

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

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

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

[0023] Figure 16A , Figure 16B , Figure 16C and Figure 16D An example structure for uplink and downlink transmission is shown.

[0024] Figure 17A This is an example of the timing of a TDM PRACH using UL radio resources, according to one aspect of an exemplary embodiment of this disclosure.

[0025] Figure 17B This is an example of using UL radio resources for PRACH timing of FDM according to one aspect of an exemplary embodiment of this disclosure.

[0026] Figure 17C This is an example of using UL radio resources for PRACH timing of TDM and FDM according to one aspect of an exemplary embodiment of this disclosure.

[0027] Figure 18 An example of the ra-ssb-OccasionMaskIndex value according to one aspect of an exemplary embodiment of this disclosure is shown.

[0028] Figure 19A This is an example of a RAR according to one aspect of an exemplary embodiment of this disclosure.

[0029] Figure 19B This is an example of a RAR according to one aspect of an exemplary embodiment of this disclosure.

[0030] Figure 19C This is an example of a RAR according to one aspect of an exemplary embodiment of this disclosure.

[0031] Figure 20 This is an example of a MAC RAR format according to one aspect of an exemplary embodiment of this disclosure.

[0032] Figure 21 It is an example RAR format according to one aspect of an example embodiment of this disclosure.

[0033] Figure 22A It is an example RAR format according to one aspect of an example embodiment of this disclosure.

[0034] Figure 22B It is an example RAR format according to one aspect of an example embodiment of this disclosure.

[0035] Figure 23 This is an example diagram illustrating a two-step RA process according to an exemplary embodiment of the present disclosure.

[0036] Figure 24 This is an example diagram illustrating a two-step RA process according to an exemplary embodiment of the present disclosure.

[0037] Figure 25A This is an example diagram of a two-step RA process according to an exemplary embodiment of the present disclosure.

[0038] Figure 25B This is an example diagram of a two-step RA process according to an exemplary embodiment of the present disclosure.

[0039] Figure 26 This is an example diagram of an RA process according to one aspect of an exemplary embodiment of the present disclosure.

[0040] Figure 27A This is an example diagram of receiving one or more PDSCHs according to one aspect of an exemplary embodiment of this disclosure.

[0041] Figure 27B This is an example diagram of receiving one or more PDSCHs according to one aspect of an exemplary embodiment of this disclosure.

[0042] Figure 28A This is an example diagram illustrating the transmission of one or more PDSCHs according to one aspect of an exemplary embodiment of this disclosure.

[0043] Figure 28B This is an example diagram illustrating the transmission of one or more PDSCHs according to one aspect of an exemplary embodiment of this disclosure.

[0044] Figure 29 This is an example of a modified window according to one aspect of an exemplary embodiment of this disclosure.

[0045] Figure 30 An example of a modified window according to one aspect of an exemplary embodiment of this disclosure is shown.

[0046] Figure 31 This is an example diagram of PUCCH and / or Msg A transmission according to one aspect of an exemplary embodiment of this disclosure.

[0047] Figure 32 This is a flowchart of a wireless device according to an exemplary embodiment of the present disclosure.

[0048] Figure 33 This is a flowchart of a base station according to one aspect of an exemplary embodiment of the present disclosure. Detailed Implementation

[0049] In this disclosure, various embodiments are presented as examples of how the disclosed techniques can be implemented and / or how the disclosed techniques can be practiced in environments and scenarios. Those skilled in the art will understand that various changes in form and detail do not depart from the scope of this disclosure. In fact, after reading the specification, those skilled in the art will understand how to implement alternative embodiments. The embodiments of this disclosure should not be limited to any of the exemplary embodiments described. Embodiments of this disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed example embodiments can be combined to produce further embodiments within the scope of the disclosure. Any drawings highlighting features and advantages are presented for illustrative purposes only. The disclosed architecture is flexible and configurable enough that it can be used in ways other than those shown. For example, any actions listed in the flowcharts can be reordered or optionally used in some embodiments.

[0050] The embodiments can be configured to operate as needed. The disclosed mechanisms can be executed when certain criteria are met, for example, in wireless devices, base stations, radio environments, networks, and / or combinations thereof. Example 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, and / or combinations thereof. Various example embodiments can be applied when one or more criteria are met. Therefore, it is possible to implement example embodiments that selectively implement the disclosed protocols.

[0051] A base station can communicate with multiple wireless devices in a mixed manner. The wireless devices and / or base stations can support multiple technologies and / or multiple versions of the same technology. Wireless devices may have specific capabilities depending on their category and / or capabilities. When this disclosure refers to a base station communicating with multiple wireless devices, this disclosure may refer to a subset of all wireless devices within the coverage area. This disclosure may refer to, for example, multiple wireless devices having given capabilities and in a given sector of the base station using a given LTE or 5G version. Multiple wireless devices in this disclosure may refer to selected multiple wireless devices, and / or a subset of all wireless devices performing according to the disclosed method within the coverage area. Multiple base stations or multiple wireless devices may exist within the coverage area that may not conform to the disclosed method; for example, those wireless devices or base stations may be based on older versions of LTE or 5G technology.

[0052] In this disclosure, the terms “a”, “an”, and similar phrases should be understood as “at least one” and “one or more”. Similarly, any term not explicitly stated as singular may be interpreted as “at least one” and “one or more”. In this disclosure, the term “may” will be 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 variety of suitable possibilities that may or may not be employed by one or more of the various embodiments. The terms “comprising” and “consisting of” as used herein enumerate one or more components of the described element. The terms “comprising” and “including” are interchangeable, and unlisted components are not excluded from the described element. In contrast, “consisting of” provides a complete enumeration of one or more components of the described element. The term “based on” as used herein should be interpreted as “at least partially based on” rather than, for example, “based on only.” The term “and / or” as used herein refers to 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.

[0053] If A and B are sets and every element in A is an element in 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 of the various embodiments. 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 of the various embodiments. The phrase "depending on" (or equivalently "at least depending on") indicates that the phrase following the phrase "depending on" is an example of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments. The phrase "adopting / using" (or equivalently "adopting / using at least") indicates that the phrase following the phrase "adopting / using" is an example of one of a variety of suitable possibilities that may or may not be used in one or more of the various embodiments.

[0054] The term "configuration" can refer to the capabilities of a device regardless of whether it is in an operational or non-operational state. Configuration can 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, register and / or memory values, etc., can all be "configured" within the device to provide specific characteristics to the device regardless of whether it is in an operational or non-operational state. Terms such as "a control message causes..." can refer to a control message having parameters that can be used to configure specific characteristics or to implement certain actions within the device, regardless of whether the device is in an operational or non-operational state.

[0055] 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, 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 example embodiment, when one or more messages include multiple parameters, this means that one of the multiple parameters is present in at least one of the one or more messages, but not necessarily in every one of the one or more messages.

[0056] Many of the described features are described as optional by 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 the set of optional features. This disclosure should be understood as explicitly disclosing all such permutations. For example, a system described as having three optional features can be implemented in seven 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.

[0057] Many of the elements described in the disclosed embodiments can be implemented as modules. A module is defined herein as an element that performs a defined function and has a defined interface to other elements. Modules described in this disclosure can be implemented in hardware, a combination of software and hardware, firmware, wet software (e.g., hardware with biological elements), or a combination thereof, and may be behaviorally equivalent. For example, a module can be implemented as a software routine written in a computer language (such as C, C++, Fortran, Java, Basic, Matlab, etc.) or a modeling / simulation program (such as Simulink, StateFlow, GNU Octave, or LabVIEW MathScript) configured to be executed by a hardware machine. Modules can be implemented using physical hardware that includes 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, and C++. FPGAs, ASICs, and CPLDs are typically programmed using hardware description languages ​​(HDLs) such as VHSIC (VHDL) or Verilog. These HDLs configure connections between internal hardware modules with limited functionality on a programmable device. The techniques mentioned are often combined to achieve the desired functional modules.

[0058] Figure 1A An example of a mobile communication network 100 that can implement embodiments of the present disclosure is shown. The mobile communication network 100 may be, for example, 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 radio device 106.

[0059] 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 billing functions.

[0060] RAN 104 can connect CN102 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 called the downlink, and the communication direction from radio device 106 to RAN 104 via the air interface is called the uplink. Downlink transmissions and uplink transmissions can be separated using frequency division duplex (FDD), time division duplex (TDD), and / or some combination of these two duplexing technologies.

[0061] Throughout this disclosure, the term "wireless device" can be used to refer to and cover any mobile or fixed (non-mobile) device for which wireless communication is required or available. For example, a wireless device can be a telephone, smartphone, tablet, computer, laptop computer, 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, mobile phone, wireless transceiver unit (WTRU), and / or wireless communication device.

[0062] RAN 104 may include one or more base stations (not shown). Throughout this disclosure, the term base station may be used to refer to 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 ​​the host 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).

[0063] 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 the cells 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 in the cell. The cells of the base stations can provide radio coverage to wireless device 106 over a wide geographical area to support wireless device mobility.

[0064] Besides three-sector sites, other implementations of base stations are also possible. For example, one or more base stations in RAN104 can be implemented as sectorized sites with more or fewer than three sectors. One or more base stations in RAN104 can be implemented as access points, baseband processing units coupled to several remote radio heads (RRHs), and / or repeater nodes or relay nodes for extending the coverage area of ​​the host 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 relay radio signals received from the host node. Relay nodes can perform the same / similar functions as repeater nodes, but can decode radio signals received from the host node to remove noise before amplifying and relaying the radio signals.

[0065] RAN 104 can be deployed as a homogeneous network with similar antenna patterns and similar high-level transmit power to macrocell base stations. 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 with weak macrocell coverage. Examples of small cell base stations, in order of decreasing coverage area, include microcell base stations, picocell base stations, and femtocell base stations or home base stations.

[0066] The Third Generation Partnership Project (3GPP) was established in 1998 to provide [unclear - possibly related to technology or standards]. Figure 1AThe specifications for mobile communication networks similar to those in the 3GPP 100 mobile communication network are globally standardized. To date, 3GPP has produced 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). Embodiments of this disclosure are described with reference to the RAN (referred to as Next Generation RAN (NG-RAN)) of the 3GPP 5G network. The embodiments can be applied to the RANs of other mobile communication networks, such as... Figure 1A RAN 104, RAN for early 3G and 4G networks, and RAN for 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 provided to implement 4G radio access technology or other radio access technologies, including non-3GPP radio access technologies.

[0067] Figure 1B Another example mobile communication network 150 that can implement embodiments of this disclosure 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). These components can be used in conjunction with... Figure 1A The corresponding components described are implemented and operated in the same or similar way.

[0068] 5G-CN 152 provides UE 156 with interfaces to one or more DNs (such as public DNs (e.g., the Internet), private DNs, and / or carrier-internal DNs). As part of its interface functionality, 5G-CN 152 can establish end-to-end connections between UE 156 and one or more DNs, authenticate UE 156, and provide billing 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 that make up 5G-CN 152 can be defined as network functions that provide services to other network functions via interfaces. 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).

[0069] like Figure 1B As shown, 5G-CN 152 includes Access and Mobility Management Functions (AMF) 158A and User Plane Functions (UPF) 158B. For ease of illustration, they are shown in... Figure 1B The UPF 158B is shown as a component AMF / UPF158. It can serve as a gateway between the NG-RAN 154 and one or more DNs. The UPF 158B can perform functions such as packet routing and forwarding, packet inspection and user plane policy rule enforcement, traffic usage reporting, uplink classification supporting traffic flow routing to one or more DNs, user plane Quality of Service (QoS) processing (e.g., packet filtering, gating, uplink / downlink rate enforcement, and uplink traffic authentication), downlink packet buffering, and downlink data notification triggering. The UPF 158B can serve as an anchor point for intra / inter-Radio Access Technology (RAT) mobility, an external Protocol (or Packet) Data Unit (PDU) session point interconnected with one or more DNs, and / or a branch point supporting multihomed PDU sessions. The UE 156 can be configured to receive traffic through a PDU session that serves as a logical connection between the UE and the DN.

[0070] AMF 158A can perform a variety of functions, such as Non-Access Stratum (NAS) signaling termination, NAS signaling security, Access Stratum (AS) security control, inter-CN node signaling for mobility between 3GPP access networks, idle-mode UE reachability (e.g., paging retransmission control and execution), registration area management, intra-system and inter-system mobility support, access authentication, access authorization including roaming permission 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, while AS can refer to functions operating between the UE and the RAN.

[0071] 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 Open Function (NEF), Unified Data Management (UDM), Application Function (AF), and / or Authentication Server Function (AUSF).

[0072] NG-RAN 154 can connect 5G-CN 152 to UE 156 via radio communication through an air interface. NG-RAN 154 may include one or more gNBs shown as gNB 160A and gNB 160B (collectively referred to as gNB 160) and / or one or more ngeNBs shown as ng-eNB 162A and ng-eNB 162B (collectively referred to as ng-eNB 162). gNB 160 and ng-eNB 162 may be more specifically referred to as base stations. gNB 160 and ng-eNB 162 may include one or more sets of antennas for communicating with UE 156 via the air interface. For example, one or more of gNB 160 and / or one or more of ng-eNB 162 may include three sets of antennas to control three cells (or sectors) respectively. The cells of gNB 160 and ng-eNB 162 together can provide radio coverage to UE 156 over a wide geographic area to support UE mobility.

[0073] 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 direct physical connections and / or indirect connections on the 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, gNB 160a can connect to UE 156A 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 Network elements in a network are used to exchange data and signaling messages, and can include two planes: a user plane and a control plane. The user plane processes data that is of interest to the user. The control plane processes signaling messages that are of interest to the network elements.

[0074] The gNB 160 and / or ng-eNB 162 can connect to one or more AMF / UPF functions (e.g., AMF / UPF 158) of the 5G-CN 152 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., unguaranteed delivery) between the gNB 160A and the UPF 158B. The gNB 160A can connect to the AMF 158A 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 transmission, paging, PDU session management, and configuration delivery and / or warning message transmission.

[0075] 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.

[0076] 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 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 in Figure 1B Only one AMF / UPF 158 is shown, but a gNB or ng-eNB can connect to multiple AMF / UPF nodes to provide redundancy and / or load balancing across multiple AMF / UPF nodes.

[0077] 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: the user plane and the 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.

[0078] 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 stack of the Uu interface between UE 156A and gNB 160B shown in the figure is the same or similar.

[0079] 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 correspond to Layer 1 of the Open Systems Interconnection (OSI) model. The next four protocols above PHY 211 and 221 include the Media Access Control (MAC) layers 212 and 222, the Radio Link Control (RLC) layers 213 and 223, the Packet Data Convergence Protocol (PDCP) layers 214 and 224, and the Service Data Application Protocol (SDAP) layers 215 and 225. These four protocols together constitute Layer 2 of the OSI model, or the Data Link Layer.

[0080] Figure 3 This illustrates an example of the 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. A PDU session can have one or more QoS flows. The CN's UPF (e.g., UPF158B) can map IP packets to 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 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. The mapping between QoS flows and data radio bearers can be notified to SDAP 215 at UE 210 via reflected mapping or control signaling received from gNB 220. For reflection mapping, the SDAP 225 at gNB 220 can mark downlink packets with QoS Flow Indicators (QFIs), which can be observed by the SDAP 215 at UE 210 to determine the mapping / demapping between QoS flows and data radio bearers.

[0081] PDCP 214 and 224 can perform header compression / decompression to reduce the amount of data transmitted over the air interface, perform encryption / decryption to prevent unauthorized decoding of data transmitted over the air interface, and perform integrity protection (to ensure that control messages originate from their intended source). PDCP 214 and 224 can perform retransmission of undelivered packets, packet reordering and repackaging, and removal of duplicated packets 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 duplicated packets at the receiver. Packet duplication is useful for services requiring high reliability.

[0082] Although not in Figure 3 As shown, PDCP 214 and 224 can perform mapping / demapping between split radio bearers and RLC channels in dual connectivity scenarios. Dual connectivity is a technique that allows a UE to connect to two cells or more commonly two cell groups—the primary cell group (MCG) and the secondary cell group (SCG). Split bearers are bearers that are handled by a single radio bearer (such as one of the radio bearers provided as services to SDAP 215 and 225 by PDCP 214 and 224) in dual connectivity. PDCP 214 and 224 can map / demapping split radio bearers between RLC channels belonging to a cell group.

[0083] 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 the mentioned functions. RLC configuration can be performed on a per-logical-channel basis, independent of the underlying parameter set 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.

[0084] 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 elements belonging to one or more logical channels into transport blocks (TBs) transmitted to PHYs 211 and 221 and demultiplexing data elements belonging to one or more logical channels from transport blocks (TBs) transmitted from PHYs 211 and 221. MAC 222 can be configured to perform scheduling, scheduling information reporting, and priority processing among 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 among logical channels of UE 210 by means of logical channel prioritization, and / or padding. MACs 212 and 222 can support one or more basic parameter sets and / or transmission timing. In one example, mapping constraints in logical channel prioritization can control which set of underlying parameters and / or transmission timing the logical channel can use. For example... Figure 3 As shown, MAC 212 and 222 can provide logical channels as services to RLC 213 and 223.

[0085] PHYs 211 and 221 can perform transmission-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 to MACs 212 and 222 as services.

[0086] Figure 4A An example downlink data flow through the NR user plane protocol stack is shown. Figure 4A The downlink data flow is illustrated, generating three IP packets (n, n+1, and m) of two TB at gNB 220 via the NR user plane protocol stack. The uplink data flow via the NR user plane protocol stack can be similar. Figure 4A The downlink data flow described in the text.

[0087] When the SDAP 225 receives three IP packets from one or more QoS flows and maps these three packets to radio bearers, Figure 4A The downlink data stream begins. 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 4A Data 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.

[0088] Figure 4A The remaining protocol layers can perform their associated functions (e.g., regarding...). Figure 3 As described, it adds the corresponding header and forwards its 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 described). Figure 4A (As shown in the diagram for IP packets m) and forwards the output to MAC 222. MAC 222 can multiplex several RLC PDUs and can attach MAC subheaders to RLC PDUs to form transport blocks. In NR, MAC subheaders can be distributed across MAC PDUs, such as... Figure 4A As shown. In LTE, the MAC subheader can be located entirely at the beginning of the MAC PDU. Because the MAC PDU subheader can be calculated before assembling the complete MAC PDU, the NR MAC PDU structure can reduce processing time and associated latency.

[0089] Figure 4B The example format of the MAC subheader in a MAC PDU is shown. The MAC subheader includes: an SDU length field, which indicates the length of the MAC SDU corresponding to the MAC subheader (e.g., in bytes); a Logical Channel Identifier (LCID) field, which identifies the logical channel from which the MAC SDU originates to aid in demultiplexing processing; a flag (F) field, which indicates the size of the SDU length field; and a reserved bit (R) field for future use.

[0090] Figure 4B Also shown is a MAC control element (CE) inserted into the MAC PDU by a MAC (such as MAC 223 or MAC 222). For example, Figure 4B The diagram shows two MAC CEs inserted into the MAC PDU. MAC CEs can be placed at the beginning of the MAC PDU used for downlink transmission (e.g., ...). Figure 4B(As shown) and inserted at the end of the MAC PDU for uplink transmission. MAC CEs can be used for in-band control signaling. Example MAC CEs include: scheduling-related MAC CEs, such as buffer status reports and power headroom reports; activation / deactivation MAC CEs, such as MAC CEs for activating / deactivating PDCP repeated detection, Channel State Information (CSI) reports, Sounding Reference Signal (SRS) transmissions, and previously configured components; Discontinuous Reception (DRX)-related MAC CEs; Timing Advancement MAC CEs; and Random Access-related MAC CEs. The MAC CE may be preceded by a MAC subheader with a format similar to that described for the MAC SDU and may be identified by a reserved value in the LCID field, which indicates the type of control information included in the MAC CE.

[0091] 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 channels can be used to perform functions associated with the NR control plane protocol stack, which will be described later below.

[0092] 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 traffic channels carrying data in the NR user plane. Logical channels can be classified as dedicated logical channels for a specific UE or 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:

[0093] —Paging Control Channel (PCCH), used to carry paging messages for UEs whose location is unknown to the network at the cell level;

[0094] —The Broadcast Control Channel (BCCH) is used to carry system information messages in the form of a Master Information Block (MIB) and several System Information Blocks (SIBs). The UE can use the system information messages to obtain information about how to configure the cell and how to operate within the cell.

[0095] —Common Control Channel (CCCH), used to carry control messages and random access;

[0096] —A dedicated control channel (DCCH) used to carry control messages to / from a specific UE to configure that UE; and

[0097] —Dedicated Service Channel (DTCH) is used to carry user data sent to a specific UE / to carry user data from that specific UE.

[0098] 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:

[0099] —Paging Channel (PCH), used to carry paging messages originating from PCCH;

[0100] —Broadcast channel (BCH), used to carry MIBs from BCCH;

[0101] —Downlink Shared Channel (DL-SCH), used to carry downlink data and signaling messages including SIBs from BCCH;

[0102] —Uplink Shared Channel (UL-SCH), used to carry uplink data and signaling messages; and

[0103] —Random Access Channel (RACH) is used to allow the UE to contact the network without any prior scheduling.

[0104] A PHY can use physical channels to transfer information between processing levels within 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 its lower-level operations and can 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:

[0105] —Physical Broadcast Channel (PBCH), used to carry MIBs from the BCH;

[0106] —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;

[0107] —The Physical Downlink Control Channel (PDCCH) is used to carry downlink control information (DCI), which may include downlink scheduling commands, uplink scheduling grants, and uplink power control commands;

[0108] —The Physical Uplink Shared Channel (PUSCH) is used to carry uplink data and signaling messages from the UL-SCH, and in some instances carries uplink control information (UCI) as described below;

[0109] —The Physical Uplink Control Channel (PUCCH) used to carry the UCI, which may include HARQ acknowledgments, Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), and Scheduling Request (SR); and

[0110] —Physical Random Access Channel (PRACH) for random access.

[0111] 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 (PTRS). These physical layer signals will be described in more detail below.

[0112] Control plane protocol stack

[0113] Figure 2B An example 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 example NR user plane protocol stack. These four protocol layers include PHY 211 and 221, MAC 212 and 222, RLC 213 and 223, and PDCP 214 and 224. Instead of having SDAP 215 and 225 at the top of the stack as in the NR user plane protocol stack, the NR control plane 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.

[0114] NAS protocols 217 and 237 can provide control plane functions between UE 210 and AMF 230 (e.g., AMF 158A) or more commonly between UE 210 and CN. NAS protocols 217 and 237 can provide control plane functions between UE 210 and AMF 230 via signaling messages (referred to as NAS messages). There is no direct path for transmitting NAS messages between UE 210 and AMF 230. NAS messages can be transmitted using the AS interfaces 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.

[0115] RRC 216 and 226 can provide control plane functions between UE 210 and gNB 220, or more commonly between UE 210 and RAN. RRC 216 and 226 can provide control plane functions between UE 210 and gNB 220 via signaling messages (referred to 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). RRC216 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; control of UE measurement reports and reports; detection and recovery of radio link failures (RLFs); and / or NAS message transmission. 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.

[0116] 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 depicted in the text Figure 2A and Figure 2B The UE 210 depicted in this disclosure is the same as or similar to any other wireless device described herein. Figure 6 As shown, the UE can be in at least one of three RRC states: RRC connected state 602 (e.g., RRC_CONNECTED), RRC idle state 604 (e.g., RRC_IDLE), and RRC inactive state 606 (e.g., RRC_INACTIVE).

[0117] In RRC connection state 602, the UE has an established RRC context and can have at least one RRC connection with a base station. The base station can be similar to... Figure 1A One of the one or more base stations included in RAN 104 as depicted in the diagram. Figure 1B One of gNB 160 or ng-eNB 162 described in the text. Figure 2A and Figure 2BThe UE may be connected to the gNB 220 depicted herein or any other base station described in this disclosure. The base station to which the UE is connected 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., related to data radio bearers, signaling radio bearers, logical channels, QoS flows, and / or PDU sessions); security information; and / or PHY, MAC, RLC, PDCP, and / or SDAP layer configuration information. When in RRC connected state 602, the UE's mobility may be managed by the RAN (e.g., RAN 104 or NG-RAN154). 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 handover to one of the neighboring base stations based on the reported measurements. The RRC state can be transitioned from the RRC connected state 602 to the RRC idle state 604 through the connection release process 608, or to the RRC inactive state 606 through the connection deactivation process 610.

[0118] In RRC idle state 604, an RRC context may not be established for the UE. In RRC idle state 604, the UE may not have an RRC connection with the base station. When in RRC idle state 604, the UE may be in sleep mode for most of the time (e.g., to conserve battery power). The UE may periodically wake up (e.g., once in each discontinuous reception cycle) to monitor paging messages from the RAN. UE mobility may be managed by the UE through a process known as cell reselection. The RRC state can be transitioned from RRC idle state 604 to RRC connected state 602 through connection establishment procedure 612, which may involve a random access procedure discussed in more detail below.

[0119] In RRC inactive state 606, the previously established RRC context is maintained in both the UE and the base station. This allows for a rapid transition to RRC connected state 602 with reduced signaling overhead compared to the transition from RRC idle state 604 to RRC connected state 602. While in RRC inactive state 606, the UE can be in sleep mode, and its mobility can be managed by the UE through cell reselection. The RRC state can be transitioned from RRC inactive state 606 to RRC connected state 602 via connection restoration procedure 614, or to RRC idle state 604 via connection release procedure 616, which can be the same as or similar to connection release procedure 608.

[0120] RRC states can be associated with mobility management mechanisms. In RRC idle state 604 and RRC inactive state 606, the UE manages mobility through cell reselection. The purpose of mobility management in RRC idle state 604 and RRC inactive state 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 state 604 and RRC inactive state 606 allow the network to track the UE at the cell group level, enabling paging messages to be broadcast on cells within the cell group where the UE is currently camped, rather than across the entire mobile network. The mobility management mechanisms in RRC idle state 604 and RRC inactive state 606 track the UE at the cell group level. They can do this using different grouping 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 a group of cells within a RAN area, referred to as the tracking area and identified by a Tracking Area Identifier (TAI).

[0121] Tracking areas can be used to track UEs at the CN level. A 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 via cell reselection to a cell associated with a TAI not included in the list of TAIs associated with the UE's registration area, the UE can perform a registration update using the CN, allowing the CN to update the UE's location and provide the UE with a new UE registration area.

[0122] RAN areas can be used to track UEs at the RAN level. For UEs in the RRC inactive 606 state, RAN notification areas can be assigned to them. A RAN notification area can include one or more cell identifiers, RAI lists, or TAI lists. 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 the RAN notification area assigned to it, the UE can perform a notification area update with the RAN to update its RAN notification area.

[0123] The base station storing the UE's RRC context or the UE's last serving base station can be referred to as the anchor base station. The anchor base station may maintain the UE's RRC context at least during the time period when the UE is in the anchor base station's RAN notification area and / or during the time period when the UE is in the RRC inactive state 606.

[0124] 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.

[0125] In NR, physical signals and physical channels (about Figure 5A and Figure 5B The data discussed can be mapped onto Orthogonal Frequency Division Multiplexing (OFDM) symbols. OFDM is a multicarrier communication scheme that transmits data over F orthogonal subcarriers (or tones). Before transmission, the data can be mapped onto a series of complex symbols called source symbols (e.g., M-QAM or M-Phase Shift Keying (MPSK) symbols) and can be divided into F parallel symbol streams. The F parallel symbol streams can be viewed as being in the frequency domain and used as inputs to an Inverse Fast Fourier Transform (IFFT) block that transforms them to the time domain. The IFFT block can receive F source symbols at a time, one source symbol from each of the F parallel symbol streams, and use each source symbol to modulate the amplitude and phase of one of the F 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. The F time-domain samples can form a single OFDM symbol. After some processing (e.g., adding a cyclic prefix) and up-conversion, the OFDM symbols provided by the IFFT block can be transmitted over the air interface at the carrier frequency. 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). Inverse processing of the OFDM symbols can be performed at the receiver using the FFT block to recover the data mapped to the source symbols.

[0126] Figure 7 This diagram illustrates an example configuration of NR frames in which OFDM symbols are grouped. NR frames are identified by their System Frame Number (SFN). SFNs can repeat at a period of 1024 frames. As shown, the duration of an NR frame can be 10 milliseconds (ms), and an NR frame can include 10 subframes with a duration of 1 ms. Subframes can be divided into multiple time slots, which include, for example, 14 OFDM symbols per time slot.

[0127] The duration of a time slot can depend on the fundamental parameter set of the OFDM symbols used for the time slot. In NR, a flexible fundamental parameter set is supported to accommodate different cell deployments (e.g., cells with carrier frequencies below 1 GHz to cells with carrier frequencies in the millimeter-wave range). The fundamental parameter set can be defined based on the subcarrier spacing and the cyclic prefix duration. For the fundamental parameter set in NR, the subcarrier spacing can be increased by powers of 2 from a baseline subcarrier spacing of 15 kHz, and the cyclic prefix duration can be decreased by powers of 2 from a baseline cyclic prefix duration of 4.7 μs. For example, NR defines fundamental 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; 240 kHz / 0.29 μs.

[0128] A time slot can have a fixed number of OFDM symbols (e.g., 14 OFDM symbols). A base parameter set with a higher subcarrier spacing has a shorter time slot duration, and correspondingly, more time slots per subframe. Figure 7 The time slot duration and per-subframe time slot transmission structure associated with this basic parameter set are shown (not shown in the diagram for ease of illustration). Figure 7 The diagram shows the basic parameter set with a subcarrier spacing of 240 kHz. Subframes in NR can be used as time references independent of the basic 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 decoupled from time slot duration and can begin at any OFDM symbol and continue for as many symbols as required for transmission. These partial time slot transmissions can be referred to as micro-time slots or sub-time slot transmissions.

[0129] Figure 8 An example configuration of time slots in the time-frequency domain for NR carriers is shown. A time slot comprises a resource element (RE) and a resource block (RB). An RE is the smallest physical resource in NR. (The text continues with further details about the configuration and resource blocks, which are not directly related to the previous sentence.) Figure 8 As shown, the RE occupies one OFDM symbol in the time domain and one subcarrier in the frequency domain. For example... Figure 8 As shown, the RB spans twelve consecutive REs in the frequency domain. The NR carrier can be limited to a width of 275 RBs or 275 × 12 = 3300 subcarriers. Using such a limitation, the NR carrier can be limited to 50MHz, 100MHz, 200MHz, and 400MHz for subcarrier spacings of 15kHz, 30kHz, 60kHz, and 120kHz, respectively, where the 400MHz bandwidth can be set based on a 400MHz bandwidth limit per carrier.

[0130] Figure 8This illustrates a single set of basic parameters used across the entire bandwidth of an NR carrier. In other example configurations, multiple sets of basic parameters can be supported on the same carrier.

[0131] NR can support wide carrier bandwidth (e.g., 400MHz for a subcarrier spacing of 120kHz). Not all UEs can receive the full carrier bandwidth (e.g., due to hardware limitations). Furthermore, from a UE power consumption perspective, receiving the full carrier bandwidth may be prohibited. In one example, to reduce power consumption and / or for other purposes, the UE can adapt its receive bandwidth based on the amount of traffic it is scheduled to receive. This is called bandwidth adaptation.

[0132] The NR defines a Bandwidth Partition (BWP) 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 adjacent RBs on a carrier. A UE can be configured (e.g., via the RRC layer) with one or more downlink BWPs and one or more uplink BWPs for each serving cell (e.g., up to four downlink BWPs and up to four uplink BWPs per serving cell). At any given time, one or more of the BWPs configured 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.

[0133] For unpaired spectrum, if the downlink BWP index of the downlink BWP and the uplink BWP index of the uplink BWP are the same, then a downlink BWP from a set of configured downlink BWPs can be associated with an uplink BWP from a 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.

[0134] For a set of configured downlink BWPs on the primary cell (PCell), the base station can configure one or more control resource sets (CORESETs) for the UE for at least one search space. A search space is a set of locations in the time and frequency domains where the UE can find control information. The search space can be a UE-specific search space or a common search space (potentially usable by multiple UEs). For example, the base station can configure a common search space for the UE on the PCell or the primary / secondary cell (PSCell) while activating the downlink BWP.

[0135] For an uplink BWP in a set of configured 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 receptions (e.g., PDCCH or PDSCH) in the downlink BWP based on the base parameter set configured for the downlink BWP (e.g., subcarrier spacing and cyclic prefix duration). The UE can transmit uplink transmissions (e.g., PUCCH or PUSCH) in the uplink BWP based on the configured base parameter set (e.g., subcarrier spacing and cyclic prefix length for the uplink BWP).

[0136] 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 a set of configured BWPs is the active downlink BWP for one or more downlink receptions. The value of one or more BWP indicator fields can indicate the active uplink BWP for one or more uplink transmissions.

[0137] The base station can semi-statically configure a set of default downlink BWPs associated with the PCell within the configured downlink BWPs for the UE. If the base station does not provide a default downlink BWP to the UE, the default downlink BWP can be the initially active downlink BWP. The UE can determine which BWP is the initially active downlink BWP based on the CORESET configuration obtained using the PBCH.

[0138] The base station can configure a 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 used for paired spectrum operations; 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 used for unpaired spectrum operations. If the UE does not detect a DCI during the time interval (e.g., 1 ms or 0.5 ms), the UE can run the BWP inactivity timer until it expires (e.g., incrementing from zero to the BWP inactivity timer value, or decrementing from the BWP inactivity timer value to zero). When the BWP inactivity timer expires, the UE can switch from the active downlink BWP to the default downlink BWP.

[0139] In one example, the base station can semi-statically configure one or more BWPs for the UE. In response to receiving a DCI indicating that the second BWP is the active BWP and / or in response to the expiration of a BWP inactivity timer (e.g., if the second BWP is the default BWP), the UE can switch the active BWP from the first BWP to the second BWP.

[0140] 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.

[0141] Figure 9 An example of bandwidth adaptation using three configured BWPs for an NR carrier is shown. A UE configured with three BWPs can switch from one BWP to another at the handover point. Figure 9 In the example shown, the BWPs include: BWP 902 with a bandwidth of 40MHz and a subcarrier spacing of 15kHz; BWP 904 with a bandwidth of 10MHz and a subcarrier spacing of 15kHz; and BWP 906 with a bandwidth of 20MHz and a subcarrier spacing of 60kHz. BWP 902 can be the initially active BWP, and BWP 904 can be the default BWP. The UE can switch between BWPs at the handover point. Figure 9 In the example, the UE can switch from BWP902 to BWP904 at handover point 908. The handover at handover point 908 can occur for any suitable reason, such as the expiration of a BWP inactivity timer (indicating a switch to the default BWP) and / or in response to receiving a DCI indicating BWP904 as the active BWP. In response to receiving a DCI indicating BWP906 as the active BWP, the UE can switch from active BWP904 to BWP906 at handover point 910. In response to the expiration of a BWP inactivity timer and / or in response to receiving a DCI indicating BWP904 as the active BWP, the UE can switch from active BWP906 to BWP904 at handover point 912. In response to receiving a DCI indicating BWP902 as the active BWP, the UE can switch from active BWP904 to BWP902 at handover point 914.

[0142] If, for the UE, a default downlink BWP and timer values ​​from a set of configured downlink BWPs are configured for the secondary cell, the UE procedure for switching BWPs on the secondary cell can be the same as / similar to those procedures on the primary cell. For example, the UE can use the timer values ​​and default downlink BWP for the secondary cell in the same / similar way as the UE uses these values ​​for the primary cell.

[0143] To provide higher data rates, two or more carriers can be aggregated, and carrier aggregation (CA) is used to transmit two or more carriers to / from the same UE simultaneously. The aggregated carriers in CA can be referred to as member carriers (CCs). When using CA, there are multiple serving cells for the UE, one serving cell per CC. CCs can have three configurations in the frequency domain.

[0144] 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 are directly adjacent to each other within that band. In the intra-band discontinuous configuration 1004, the two CCs are aggregated in the same frequency band (band A) and are separated by a certain gap within that band. In the inter-band configuration 1006, the two CCs are located in multiple frequency bands (band A and band B).

[0145] In one example, up to 32 CCs can be aggregated. Aggregated CCs can have the same or different bandwidths, subcarrier spacings, and / or duplex schemes (TDD or FDD). The serving cell of a UE using CA can have downlink CCs. For FDD, one or more uplink CCs can optionally be configured for the serving cell. The ability to aggregate more downlink carriers than uplink carriers can be useful, for example, when the UE has more data traffic in the downlink than in the uplink.

[0146] 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, reconstruction, 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). The UE's other aggregated cells 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 procedure. In the downlink, the carrier corresponding to the SCell can be referred to as the downlink secondary CC (DL SCC). In the uplink, the carrier corresponding to the SCell can be referred to as the uplink secondary CC (UL SCC).

[0147] The configured SCells of a UE can be activated and deactivated based on factors such as service and channel conditions. Deactivating a 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 of the UE (e.g., in 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).

[0148] Downlink control information for a cell (such as scheduling allocation and scheduling grant) can be transmitted on the cell corresponding to the allocation and grant; this is called self-scheduling. DCI for a cell can be transmitted on another cell; this is called cross-carrier scheduling. Uplink control information for aggregated 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 aggregated downlink CCs, the PCell's PUCCH may become overloaded. Cells can be divided into multiple PUCCH groups.

[0149] Figure 10B This illustrates an example of how to configure aggregated cells 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. In this example, PUCCH group 1050 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) associated with the downlink CCs of PUCCH group 1010 (shown as UCI 1031, UCI 1032, and UCI 1033) can be sent in the uplink of PCell 1021. Uplink control information (UCI) associated with the downlink CC of PUCCH group 1050 (shown as UCI 1071, UCI 1072, and UCI 1073) 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, the single uplink PCell used for transmitting UCI related to the downlink CC may become overloaded. Overload can be prevented by dividing the transmission of UCI between PCell 1021 and PSCell 1061.

[0150] A cell comprising a downlink carrier and an optional uplink carrier may be assigned a physical cell ID and a cell index. The physical cell ID or cell index may, for example, identify the downlink carrier and / or uplink carrier of the cell based on the context in which the physical cell ID is used. The physical cell ID may be determined using synchronization signals transmitted on the downlink component carriers. The cell index may be determined using RRC messages. In this disclosure, the physical cell ID may be referred to as a carrier ID, and the cell index may be referred to as a carrier index. For example, when this disclosure refers to a first physical cell ID for a first downlink carrier, this disclosure may mean that the first physical cell ID is for a cell comprising the first downlink carrier. The same / similar concepts may be applied, for example, to carrier activation. When this disclosure indicates that a first carrier is activated, the specification may mean that a cell comprising the first carrier is activated.

[0151] In CA, the multi-carrier nature of the PHY can be exposed to the MAC. In one example, the HARQ entity can operate on the serving cell. Transport blocks can be generated according to each allocation / grant for each serving cell. Transport blocks and potential HARQ retransmissions of transport blocks can be mapped to the serving cell.

[0152] In the downlink, the base station may transmit (e.g., unicast, multicast, and / or broadcast) one or more reference signals (RS) 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 (e.g., DMRS, PT-RS, and / or SRS, such as...) to the base station. Figure 5B (As shown in the diagram). PSS and SSS can be transmitted by the base station and used by the UE to synchronize the UE to 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.

[0153] 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 every 20ms). Bursts can be limited to half-frames (e.g., the first half-frame lasting 5ms). It will be understood that... Figure 11A This is one example, and these parameters (the number of SS / PBCH blocks per burst, the periodicity of the bursts, and the location of the bursts within a frame) can be configured based on, for example, the carrier frequency of the cell transmitting the SS / PBCH blocks; the cell's basic parameter set or subcarrier spacing; the network configuration (e.g., using RRC signaling); or any other suitable factor. In one example, the UE can assume the subcarrier spacing used for the SS / PBCH blocks based on the monitored carrier frequency, unless the radio network configures the UE to assume a different subcarrier spacing.

[0154] An SS / PBCH block can occupy 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 occupy 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 occupy, for example, 1 OFDM symbol and 127 subcarriers. SSS can be transmitted after PSS (e.g., after two symbols) and can occupy 1 OFDM symbol and 127 subcarriers. PBCH can be transmitted after PSS (e.g., spanning the next 3 OFDM symbols) and can occupy 240 subcarriers.

[0155] The UE may not know the location of the SS / PBCH block in the time and frequency domains (e.g., if the UE is searching for a cell). To find and select a cell, the UE can monitor the carrier to search for 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 grid. If the PSS is found at the location in both the time and frequency domains, the UE can determine the location of the SSS and PBCH separately based on the known structure of the SS / PBCH block. The SS / PBCH block can be a cell-defined SS block (CD-SSB). In one example, the primary cell may be associated with a CD-SSB. The CD-SSB may be located on a synchronization grid. In one example, cell selection / search and / or reselection may be based on the CD-SSB.

[0156] The UE can use the SS / PBCH block 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 sequences 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 pattern, wherein the SS / PBCH block in the transmission pattern is at a known distance from the frame boundary.

[0157] The PBCH can use QPSK modulation and forward error correction (FEC). FEC can use polar coding. One or more symbols occupied by the PBCH can carry one or more DMRSs for demodulating the PBCH. The PBCH can include an indication of the cell's current system frame number (SFN) and / or SS / PBCH block timing index. These parameters facilitate time synchronization between the UE and the base station. The PBCH can include a Master Information Block (MIB) to provide one or more parameters to the UE. The UE can use the MIB 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 for the UE to access the cell. The UE can use one or more parameters of the MIB to monitor the PDCCH, which can be used to schedule the PDSCH. The PDSCH can include SIB1. SIB1 can be decoded using 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.

[0158] The UE may assume that one or more SS / PBCH blocks transmitted with 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). For SS / PBCH block transmissions with different SS / PBCH block indices, the UE may not assume QCL.

[0159] SS / PBCH blocks (e.g., those within a half-frame) can be transmitted in multiple 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.

[0160] In one example, a base station can transmit multiple SS / PBCH blocks within the frequency span of a carrier. In another example, the first PCI of a first SS / PBCH block among the multiple SS / PBCH blocks may differ from the second PCI of a second SS / PBCH block among the multiple SS / PBCH blocks. The PCIs of SS / PBCH blocks transmitted at different frequency locations may be different or the same.

[0161] CSI-RS can be transmitted by the base station and used by the UE to acquire Channel State Information (CSI). The base station can configure one or more CSI-RS for the UE for channel estimation or any other suitable purpose. The base station can configure one or more identical / similar CSI-RS for the UE. The UE can measure one or more CSI-RS. The UE can estimate the downlink channel state and / or generate a CSI report based on measurements of one or more downlink CSI-RS. The UE can provide the CSI report to the base station. The base station can use feedback provided by the UE (e.g., the estimated downlink channel state) to perform link adaptation.

[0162] The base station can semi-statically configure one or more CSI-RS resource sets for the UE. 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.

[0163] The base station can configure the UE to report CSI measurements. The base station can configure the UE to provide CSI reports periodically, non-periodically, or semi-persistently. For periodic CSI reporting, the UE can be configured with multiple CSI reports at specific times and / or periodically. For non-periodic 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 measurement-related CSI reports. For semi-persistent CSI reporting, the base station can configure the UE to transmit periodically and selectively activate or deactivate periodic reporting. The base station can use RRC signaling to configure the CSI-RS resource set and CSI reports for the UE.

[0164] 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 CORESET when the downlink CSI-RS and the control resource set (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 the 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.

[0165] 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 coherent demodulation of one or more downlink physical channels (e.g., PDSCH). The NR network can support one or more variable and / or configurable DMRS modes for data demodulation. At least one downlink DMRS configuration can support a preceding DMRS mode. The preceding 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 multiple preceding DMRS symbols (e.g., a maximum number) for the PDSCH for the UE. The DMRS configuration can support one or more DMRS ports. For example, for single-user MIMO, the DMRS configuration can support up to eight orthogonal downlink DMRS ports per UE. For multi-user MIMO, the DMRS configuration can support up to four orthogonal downlink DMRS ports per UE. The radio network can (e.g., at least for CP-OFDM) support a common DMRS structure for downlink and uplink, wherein the DMRS location, DMRS mode, and / or scrambling sequence can be the same or different. The base station can use the same precoding matrix to transmit downlink DMRS and the corresponding PDSCH. The UE can use one or more downlink DMRS to perform coherent demodulation / channel estimation of PDSCH.

[0166] 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 be different based on the difference between the first and second bandwidths. The UE may assume that the same precoder matrix is ​​used across a set of PRBs. The set of PRBs may be represented as a Precoder Resource Block Group (PRG).

[0167] A PDSCH may include one or more layers. The UE may assume that at least one symbol with DMRS exists on one of the layers of the PDSCH. Higher layers can configure up to three DMRS for the PDSCH.

[0168] 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 mode of downlink PT-RS can be configured on a UE-specific basis using RRC signaling and / or a combination of one or more parameters (e.g., modulation and coding scheme (MCS)) that can be indicated by DCI for other purposes. The dynamic presence of downlink PT-RS can be associated with one or more DCI parameters, including at least an MCS, when configured. NR networks can support multiple PT-RS densities defined in the time and / or frequency domains. Frequency domain density, when present, can be associated with at least one configuration of scheduling bandwidth. The UE can assume the same precoding for DMRS ports and PT-RS ports. The number of PT-RS ports can be less than the number of DMRS ports in the scheduling resources. Downlink PT-RS can be restricted to the scheduling time / frequency duration used by the UE. Downlink PT-RS can be transmitted symbol-by-symbol to facilitate phase tracking at the receiver.

[0169] The UE can transmit uplink DMRS to the base station for channel estimation. For example, the base station can use uplink DMRS for coherent demodulation of one or more uplink physical channels. For example, the UE can transmit uplink DMRS along with PUSCH and / or PUCCH. The frequency range that uplink DMRS can span is similar to the frequency range associated with the corresponding physical channel. The base station can configure one or more uplink DMRS configurations for the UE. At least one DMRS configuration can support a frontload DMRS mode. The frontload DMRS can be mapped onto 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 multiple frontload DMRS symbols (e.g., a maximum number) for PUSCH and / or PUCCH for the UE, which the UE can use to schedule single-symbol DMRS and / or dual-symbol DMRS. NR networks can (e.g., for Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM)) support a common DMRS structure for downlink and uplink, where the DMRS location, DMRS mode and / or scrambling sequence used for DMRS can be the same or different.

[0170] A PUSCH can include one or more layers, and a UE can transmit at least one symbol, wherein a DMRS exists on one or more layers of the PUSCH. In one example, a higher layer can configure up to three DMRSs for the PUSCH.

[0171] 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 depending on the UE's RRC configuration. The presence and / or mode of uplink PT-RS can be configured on a UE-specific basis via RRC signaling and / or by a combination of one or more parameters (e.g., modulation and coding scheme (MCS)) indicated by the DCI for other purposes. The dynamic presence of uplink PT-RS can be associated with one or more DCI parameters, including at least an MCS, when configured. The radio network can support multiple uplink PT-RS densities defined in the time / frequency domain. The frequency domain density, when present, can be associated with at least one configuration of the scheduling bandwidth. The UE can assume the same precoding for DMRS ports and PT-RS ports. The number of PT-RS ports can be less than the number of DMRS ports in the scheduling resources. For example, uplink PT-RS can be restricted to the scheduling time / frequency duration used by the UE.

[0172] SRS can be transmitted by the UE to the base station for channel state estimation, thereby supporting 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 allocate one or more resource blocks for uplink PUSCH transmissions from the UE. The base station can semi-statically configure one or more SRS resource sets for the UE. For each SRS resource set, the base station can configure one or more SRS resources for the UE. SRS resource set applicability can be configured through higher-layer (e.g., RRC) parameters. For example, when higher-layer parameters indicate beam management, SRS resources from one or more SRS resource sets (e.g., those with the same / similar temporal behavior, periodicity, and / or aperiodicity, etc.) can be transmitted instantaneously (e.g., simultaneously). The UE can transmit one or more SRS resources from the SRS resource set. NR networks 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 one or more trigger types may include higher-layer signaling (e.g., RRC) and / or one or more DCI formats. In one example, the UE can employ at least one DCI format to select at least one 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 can be configured to transmit SRS after transmitting PUSCH and the corresponding uplink DMRS.

[0173] The base station can semi-statically configure one or more SRS configuration parameters for the UE, which indicate at least one of the following parameters: 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 periodicity; offset of periodic and / or aperiodic SRS resources; number of OFDM symbols in SRS resources; starting OFDM symbol of SRS resources; SRS bandwidth; frequency hopping bandwidth; cyclic shift; and / or SRS sequence ID.

[0174] An antenna port is defined such that the channel on which a symbol is transmitted at the antenna port can be inferred from the channel on which another symbol is transmitted at the same antenna port. If a first symbol and a second symbol are transmitted at the same antenna port, the receiver can infer from the channel used to transmit the first symbol at the antenna port the channel used to transmit the second symbol at that antenna port (e.g., fading gain and / or multipath delay, etc.). If one or more large-scale properties of the channel on which the first symbol at the first antenna port is transmitted can be inferred from the channel on which the second symbol at the second antenna port is transmitted, then the first antenna port and the second antenna port can be referred to as quasi-co-located (QCL). One or more large-scale properties may include at least one of the following parameters: delay spread; Doppler spread; Doppler shift; average gain; average delay; and / or spatial reception (Rx) parameters.

[0175] 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 using one or more beamforming reference signals. The UE can perform downlink beam measurements based on downlink reference signals (e.g., Channel State Information Reference Signal (CSI-RS)) and generate a beam measurement report. The UE can perform the downlink beam measurement procedure after establishing an RRC connection with the base station.

[0176] 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 can span a resource block (RB) within the cell bandwidth. The base station can 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 by higher-layer signaling (e.g., RRC and / or MAC signaling) for CSI-RS resource configuration: 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, transmission 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.

[0177] Figure 11B The three beams shown can be configured for the UE in a UE-specific configuration. Figure 11B The diagram shows three beams (beam #1, beam #2, and beam #3), but more or fewer beams can be configured. Beam #1 can be assigned CSI-RS 1101, which can be transmitted in one or more subcarriers in the RB of the first symbol. Beam #2 can be assigned CSI-RS 1102, which can be transmitted in one or more subcarriers in the RB of the second symbol. Beam #3 can be assigned CSI-RS 1103, which can be transmitted in 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 subcarriers not used to transmit CSI-RS 1101) to transmit another CSI-RS associated with the beam for another UE. By using time domain multiplexing (TDM), the beam for the UE can be configured such that the beam for the UE uses symbols from beams of other UEs.

[0178] Such as Figure 11BThe CSI-RS 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 the configured CSI-RS resources. The base station can configure a reporting configuration for the UE, and the UE can report the RSRP measurement to the network based on the reporting configuration (e.g., via one or more base stations). 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 use the receive (Rx) beam determined based on one or more TCI states to receive downlink transmissions. 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 filter of the transmit (Tx) beam based on the spatial filter of the corresponding Rx beam. If the UE lacks beam correspondence capability, it can perform an uplink beam selection procedure to determine the spatial 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 it by the base station. The base station can select and indicate the uplink beam for the UE based on measurements of one or more SRS resources transmitted by the UE.

[0179] During beam management, the UE can evaluate (e.g., measure) the channel quality of one or more beampair links, which include transmit beams transmitted by the base station and receive beams received by the UE. Based on this evaluation, the UE can transmit a beam measurement report indicating the quality parameters of one or more beampairs, including, for example, one or more beam identifiers (e.g., beam index or reference signal index), RSRP, precoding matrix indicator (PMI), channel quality indicator (CQI), and / or rank indicator (RI).

[0180] Figure 12AExamples of three downlink beam management procedures, P1, P2, and P3, are shown. Procedure P1 enables UE measurements of the transmit (Tx) beams of the 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 may include a Tx beam scan for a set of beams (shown as an ellipse rotating counterclockwise in the top rows of P1 and P2, indicated by dashed arrows). Beamforming at the UE may include an Rx beam scan for a set of beams (shown as an ellipse rotating clockwise in the bottom rows of P1 and P3, indicated by dashed arrows). Procedure P2 can be used to enable UE measurements of the Tx beams of the TRP (shown as an ellipse rotating counterclockwise in the top row of P2, indicated by 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 set 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 scanning the Rx beam at the UE.

[0181] Figure 12B Examples of three uplink beam management procedures U1, U2, and U3 are shown. Procedure U1 can be used to enable the base station to perform measurements on the Tx beam of the UE, for example, to support the selection of one or more UE Tx beams and / or base station Rx beams (shown as ellipses in the top and bottom rows of U1, respectively). Beamforming at the UE may include, for example, a Tx beam scan from a beam set (shown as an ellipse rotating clockwise in the bottom rows of U1 and U3, indicated by a dashed arrow). Beamforming at the base station may include, for example, an Rx beam scan from a beam set (shown as an ellipse rotating counterclockwise in the top rows of U1 and U2, indicated by a dashed arrow). Procedure U2 can be used to enable the base station to adjust its Rx beam when the UE uses a fixed Tx beam. The UE and / or base station can perform procedure U2 using a smaller beam set than the beam set used in procedure P1 or using a narrower beam than the beam used in procedure P1. This can be referred to as beam refinement. The UE can perform procedure U3 to adjust its Tx beam when the base station is using a fixed Rx beam.

[0182] The UE can initiate a beam fault recovery (BFR) procedure based on the detection of a beam fault. The UE can transmit a BFR request (e.g., preamble, UCI, SR, and / or MAC CE) based on the initiation of the BFR procedure. The UE can detect a beam fault based on determining that the quality of the beam pair link of the associated control channel is unsatisfactory (e.g., an error rate higher than an error rate threshold, received signal power lower than a received signal power threshold, and / or timer expiration).

[0183] The UE can use one or more reference signals (RS) comprising one or more SS / PBCH blocks, one or more CSI-RS resources, and / or one or more demodulation reference signals (DMRS) to measure the quality of the beamp-link. 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 can indicate one or more DM-RS quasi-co-location (QCL) of RS resources and channels (e.g., control channels and / or shared data channels). QCL can be applied to one or more DMRS of RS resources and channels when the channel characteristics from transmissions to the UE via RS resources (e.g., Doppler shift, Doppler spread, average delay, delay spread, spatial Rx parameter, and / or fading, etc.) are similar to or the same as the channel characteristics from transmissions to the UE via channels.

[0184] The network (e.g., the network's gNB and / or ng-eNB) and / or the UE can initiate a random access procedure. A UE in an RRC idle state and / or an 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 an RRC connected state. A UE can initiate a random access procedure to request uplink resources (e.g., requesting uplink transmission for SR when no PUCCH resources are available) and / or acquire uplink timing (e.g., when the uplink synchronization state is asynchronous). 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 and / or SIB3). A UE can initiate a random access procedure for beam fault recovery requests. The network can initiate random access procedures for handover and / or for adding establishment time alignment for SCells.

[0185] 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 illustrated includes the transmission of four messages: Msg 1 1311, Msg 2 1312, Msg 3 1313, and Msg 4 1314. Msg 1 1311 may include and / or be referred to as a preamble (or random access preamble). Msg 2 1312 may include and / or be referred to as a random access response (RAR).

[0186] Configuration message 1310 can be transmitted, for example, using one or more RRC messages. One or more RRC messages can indicate one or more Random Access Channel (RACH) parameters to the UE. The one or more RACH parameters can 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 can broadcast or multicast one or more RRC messages to one or more UEs. The one or more RRC messages can be UE-specific (e.g., dedicated RRC messages transmitted to UEs in an RRC connected state and / or an RRC inactive state). The UE can determine the time-frequency resources and / or uplink transmit power for the transmission of Msg 1 1311 and / or Msg 3 1313 based on one or more RACH parameters. Based on one or more RACH parameters, the UE can determine the receive timing and downlink channel for receiving Msg 2 1312 and Msg 4 1314.

[0187] One or more RACH parameters provided in configuration message 1310 may indicate one or more physical RACH (PRACH) timings available for transmitting Msg 1 1311. The one or more PRACH timings may be predefined. The one or more RACH parameters may indicate one or more available sets of one or more PRACH timings (e.g., prach-ConfigIndex). The one or more RACH parameters may indicate the association between (a) one or more PRACH timings and (b) one or more reference signals. The one or more RACH parameters may indicate the association between (a) one or more preambles and (b) one or more reference signals. The one or more reference signals may be SS / PBCH blocks and / or CSI-RS. For example, the one or more RACH parameters may indicate the number of SS / PBCH blocks mapped to PRACH timings and / or the number of preambles mapped to SS / PBCH blocks.

[0188] One or more RACH parameters provided in configuration message 1310 can be used to determine the uplink transmit power of Msg 1 1311 and / or Msg 3 1313. For example, one or more RACH parameters can indicate a reference power for preamble transmission (e.g., the receive target power and / or initial power for preamble transmission). One or more power offsets indicated by one or more RACH parameters may exist. For example, 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. 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).

[0189] 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 may determine at least one reference signal whose RSRP is higher than an RSRP threshold (e.g., rsrp-ThresholdSSB and / or rsrp-ThresholdCSI-RS). For example, if the association between one or more preambles and at least one reference signal is configured by an RRC message, the UE can select at least one preamble associated with one or more reference signals and / or the selected preamble group.

[0190] 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 magnitude of Msg 3 1313. As another example, one or more RACH parameters can indicate: the preamble format; the maximum number of preambles transmitted; and / or one or more thresholds used to determine one or more preamble groups (e.g., group A and group B). The base station can use 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 an association is configured, the UE can determine the preamble to be 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) to select the preamble and determine the PRACH timing. One or more RACH parameters (e.g., ra-ssb-OccasionMskIndex / or ra-OccasionList) can indicate the association between the PRACH timing and one or more reference signals.

[0191] If no response is received after a preamble transmission, the UE may perform a preamble retransmission. The UE may increase the uplink transmit power used for preamble retransmission. The UE may select the initial preamble transmit power based on path loss measurements and / or the target receive preamble power configured by the network. The UE may determine the preamble to be retransmitted and may ramp up the uplink transmit power. The UE may receive one or more RACH parameters (e.g., PREAMBLE_POWER_RAMPING_STEP) indicating the ramp step size used for preamble retransmission. The ramp step size may be an increment of the uplink transmit power used for retransmission. 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 transmit 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.

[0192] 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 can use to adjust the UE's transmission timing, a scheduling grant for the transmission of Msg 3 1313, and / or a Temporary Cell RNTI (TC-RNTI). After the preamble is transmitted, the UE may start a time window (e.g., ra-ResponseWindow) to monitor the PDCCH for Msg 2 1312. The UE can determine when to start the time window based on the PRACH timing used by the UE to transmit the preamble. For example, the UE can start the time window at one or more symbols after the last symbol of the preamble (e.g., at the first PDCCH timing from the end of the preamble transmission). One or more symbols can be determined based on a set of underlying parameters. The PDCCH can be in a common search space configured by the RRC message (e.g., the Type 1-PDCCH common search space). The UE can identify the RAR based on the Radio Network Temporary Identifier (RNTI). The RNTI can be used based on one or more events that initiate the random access procedure. The UE can use the Random Access RNTI (RA-RNTI). The RA-RNTI can be associated with the PRACH timing of the UE's preamble transmission. For example, the UE can 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. An example of the RA-RNTI is as follows:

[0193] RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id, 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).

[0194] The UE can transmit Msg 3 1313 in response to successful receipt 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 the base station, and the base station may provide a RAR corresponding to each UE. A conflict may occur if multiple UEs interpret the RAR as corresponding to themselves. Contention resolution (e.g., using Msg 3 1313 and Msg 4 1314) can be used to increase the likelihood that a UE is not incorrectly using another UE's identifier. To perform contention resolution, the UE may include a device identifier (e.g., a C-RNTI (if assigned), a TC-RNTI included in Msg 2 1312, and / or any other suitable identifier) ​​in Msg 3 1313.

[0195] Msg 4 1314 may be received after or in response to the transmission of Msg 3 1313. If the C-RNTI is included in Msg 3 1313, 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 the TC-RNTI is included in Msg 3 1313 (e.g., if the UE is in an RRC idle state or is not otherwise connected to the base station), Msg 4 1314 will be received using the DL-SCH associated with the TC-RNTI. If the MAC PDU is successfully decoded and the MAC PDU 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.

[0196] 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 the UE with two separate RACH configurations: one for the SUL carrier and the other for the NUL carrier. For 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 random access procedures (e.g., Msg 1 1311 and / or Msg 3 1313) can be maintained on the selected carrier. In one or more cases, the UE can switch uplink carriers during random access procedures (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 accessibility assessment (e.g., listen before speaking).

[0197] Figure 13B This illustrates a two-step contention-free random access process. Similar to... Figure 13A The contention-based four-step random access procedure shown in the figure allows the base station to 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 Msg2 1322. Msg 1 1321 and Msg 2 1322 can be similar in some respects to... Figure 13A Msg 1 1311 and Msg 2 1312 are shown in the image. (The last part, "from...", appears to be a fragment and doesn't translate directly. It's unclear what it refers to.) Figure 13A and 13B Understood, a contention-free random access procedure may not include messages such as Msg 31313 and / or Msg 4 1314.

[0198] Can initiate Figure 13B The contention-free random access procedure shown is used for beam failure recovery, additional SI requests, SCell addition, and / or handover. 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.

[0199] After transmitting the preamble, the UE can begin a time window (e.g., ra-ResponseWindow) to monitor the PDCCH for RAR. In the event of a beam failure recovery request, the base station can configure a separate time window and / or a separate PDCCH for the UE within the search space indicated by the RRC message (e.g., RecoverySearchSpaceId). The UE can monitor PDCCH transmissions addressed to the cell RNTI (C-RNTI) in the search space. Figure 13B In the contention-free random access procedure illustrated, the UE can determine that the random access procedure has been successfully completed either after transmitting Msg 1 1321 and receiving the corresponding Msg 2 1322, or in response to transmitting Msg 1 1321 and receiving the corresponding Msg 2 1322. For example, if the PDCCH transmission is addressed to CRNTI, the UE can determine that the random access procedure has been successfully completed. For example, 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 subPDU with a preamble identifier, the UE can determine that the random access procedure has been successfully completed. The UE can determine the response as an indication of acknowledgment of the SI request.

[0200] Figure 13C This illustrates another two-step random access procedure. Similar to... Figure 13A and 13B The random access procedure shown in the figure may involve the base station transmitting configuration message 1330 to the UE prior to the initiation of the procedure. Configuration message 1330 may be similar in some respects to configuration message 1310 and / or configuration message 1320. Figure 13C The process shown includes the transmission of two messages, Msg A 1331 and Msg B 1332.

[0201] 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 of Msg 3 1313 shown is similar to and / or equivalent to that of Msg 3 1313. Transport block 1342 may include UCIs (e.g., SR and / or HARQACK / 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... Figure 13A and Figure 13B Msg 2 1312 (e.g., RAR) and / or shown in the document Figure 13A The content shown is similar to and / or equivalent to Msg 4 1314.

[0202] UE can initiate Figure 13C The two-step random access procedure applies to licensed and / or unlicensed spectrum. The UE may determine whether to initiate a two-step random access procedure based on one or more factors. These factors may include: the radio access technology used (e.g., LTE and / or NR, etc.); whether the UE has a valid TA; cell size; the UE's RRC status; the type of spectrum (e.g., licensed spectrum, unlicensed spectrum); and / or any other suitable factors.

[0203] The UE can determine the radio resources and / or uplink transmit power for 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 for the preamble 1341 and / or transport block 1342. FDM, TDM, and / or CDM can be used to multiplex the time-frequency resources for transmitting the preamble 1341 (e.g., PRACH) and the time-frequency resources for transmitting the transport block 1342 (e.g., PUSCH). The RACH parameters enable the UE to determine the receive timing and downlink channel for monitoring and / or receiving Msg B 1332.

[0204] 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 advance command; a power control command; an uplink grant (e.g., radio resource allocation 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).

[0205] 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.

[0206] Downlink control signaling may include: downlink scheduling allocation; uplink scheduling grants indicating uplink radio resources and / or transmission formats; time slot format information; preemption indication; power control commands; 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-shared PDCCH (GC-PDCCH) shared by a group of UEs.

[0207] A base station can append one or more Cyclic Redundancy Check (CRC) parity bits to a Digital Cipher Interface (DCI) to facilitate the detection of transmission errors. When the DCI is for a UE (or a group of UEs), the base station can use the UE's identifier (or the identifiers of the group of UEs) to scramble the CRC parity bits. Scrambling the CRC parity bits with the identifier can include a modulo-2 addition (or XOR operation) of the identifier value and the CRC parity bits. The identifier can include the 16-bit value of the Radio Network Temporary Identifier (RNTI).

[0208] DCI can be used for various purposes. This 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 with 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 with 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 with a random access RNTI (RA-RNTI) can indicate a random access response (RAR). A DCI with CRC parity bits scrambled with a cell RNTI (C-RNTI) can indicate dynamically scheduled unicast transmissions and / or random access triggering of PDCCH commands. A DCI with CRC parity bits scrambled with a temporary cell RNTI (TC-RNTI) can indicate contention resolution (e.g., similar to...). Figure 13AThe Msg 3 shown is Msg 31313. Other RNTIs configured by the base station for the UE may include the configured scheduling RNTI (CS-RNTI), transmit power control - PUCCH RNTI (TPC-PUCCH-RNTI), transmit power control - PUSCH RNTI (TPC-PUSCH-RNTI), transmit power control - SRS RNTI (TPC-SRS-RNTI), interrupt RNTI (INT-RNTI), slot format indication RNTI (SFI-RNTI), semi-persistent CSI RNTI (SP-CSI-RNTI), and / or modulation and coding scheme cell RNTI (MCS-C-RNTI), etc.

[0209] 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 scheduling PUSCH in a cell (e.g., with more DCI payload than DCI format 0_0). DCI format 1_0 can be used for scheduling PDSCH 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 scheduling PDSCH in a cell (e.g., with more DCI payload than DCI format 1_0). DCI format 2_0 can be used to provide slot format indication to a group of UEs. DCI format 2_1 can be used to notify a group of UEs of physical resource blocks and / or OFDM symbols that UEs may assume are not intended to be transmitted to UEs. DCI format 2_2 can be used for the transmission of transmit power control (TPC) commands for PUCCH or PUSCH. DCI format 2_3 can be used by one or more UEs to transmit a set of TPC commands for SRS transmission. 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.

[0210] After scrambling the DCI using RNTI, the base station can process the DCI using channel coding (e.g., polar coding), rate matching, scrambling, and / or QPSK modulation. The base station can map the coded and modulated DCI onto resource elements used and / or configured for the PDCCH. Based on the DCI payload size and / or the base station's coverage, the base station can transmit the DCI via a PDCCH occupying several 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. A CCE can include multiple (e.g., 6) resource element groups (REGs). 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).

[0211] Figure 14A An example of a CORESET configuration for the bandwidth portion is shown. The base station can transmit DCI via PDCCH over one or more control resource sets (CORESETs). A CORESET can include time-frequency resources that the UE attempts to use 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 occurs at the seventh symbol of the time slot. CORESETs can have different numbers of resource blocks in the frequency domain.

[0212] Figure 14B An example of CCE-to-REG mapping for DCI transmission and PDCCH processing on a CORESET is shown. 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 of the control channel). Base stations can perform different or the same CCE-to-REG mappings on 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.

[0213] The base station can transmit an RRC message to the UE containing 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. A 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 periodicity and PDCCH monitoring mode; 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. A set of CCEs in a UE-specific search space set can be configured based on the UE's identifier (e.g., C-RNTI).

[0214] like Figure 14B As shown, the UE can determine the time-frequency resources for the CORESET based on RRC messages. The UE can determine the CCE-to-REG mapping (e.g., interleaved or non-interleaved and / or mapping parameters) for the CORESET based on the CORESET 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 one or more sets of PDCCH candidates in one or more CORESETs to detect one or more DCIs. Monitoring may include decoding one or more PDCCH candidates from this set of PDCCH candidates according to the monitored DCI format. Monitoring may include decoding the DCI content of one or more PDCCH candidates having 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., scrambled bits of the CRC parity check bits of the DCI that match the RNTI value). The UE can process the information contained in the DCI (e.g., scheduling allocation, uplink grant, power control, slot format indication and / or downlink preemption and / or other information).

[0215] The UE can transmit uplink control signaling (e.g., uplink control information (UCI)) to the base station. Uplink control signaling may include a Hybrid Automatic Repeat Request (HARQ) acknowledgment for a received DL-SCH transport block. The UE may transmit a 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 to the base station indicating that uplink data is available for transmission. 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.

[0216] 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 and the number of UCI bits transmitted). PUCCH format 0 can have a length of one or two OFDM symbols and can include two or fewer bits. If transmitted on one or two symbols 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 UCI in the PUCCH resource. PUCCH format 1 can occupy between four and fourteen OFDM symbols and can include two or fewer bits. If the transmission is four or more symbols and the number of HARQ-ACK / SR bits is one or two, the UE can use PUCCH format 1. PUCCH format 2 can occupy one or two OFDM symbols and can include more than two bits. If transmitted on one or two symbols and the number of UCI bits is two or more, the UE can use PUCCH format 2. PUCCH format 3 can occupy between four and fourteen OFDM symbols and can include more than two bits. If the transmission consists of four or more symbols, 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 the transmission consists of four or more symbols, 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.

[0217] The base station can transmit configuration parameters for multiple PUCCH resource sets to the UE using, for example, RRC messages. 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 having PUCCH resources identified by a PUCCH resource identifier (e.g., pucch-Resourceid), and / or the number of UCI information bits (e.g., a maximum number) 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 less, the UE can select a first PUCCH resource set with a PUCCH resource set index equal to "0". If the total bit length of the UCI information bits is greater than two and less than or equal to a first configuration value, the UE can select a second PUCCH resource set with a PUCCH resource set index equal to "1". If the total bit 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 the third PUCCH resource set with a PUCCH resource set index of "2". If the total bit 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 the fourth PUCCH resource set with a PUCCH resource set index of "3".

[0218] After determining a PUCCH resource set from multiple PUCCH resource sets, the UE can identify 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 DCI for 1_1). The three-bit PUCCH resource indicator in the DCI can indicate one of 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).

[0219] 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 a mobile communication network (such as...). Figure 1A The mobile communication network 100 shown in the figure Figure 1BIt is part of the mobile communication network 150 or any other communication network shown in the diagram. Figure 15 Only one wireless device 1502 and one base station 1504 are shown, but it should be understood that mobile communication networks can be integrated with... Figure 15 The configurations shown are the same or similar to those of UEs and / or more than one base station.

[0220] Base station 1504 can connect wireless device 1502 to the core network (not shown) via wireless communication on air interface (or wireless interface) 1506. The communication direction from base station 1504 to wireless device 1502 via air interface 1506 is called the downlink, and the communication direction from wireless device 1502 to base station 1504 via air interface 1506 is called the uplink. Downlink transmissions can be separated from uplink transmissions using FDD, TDD, and / or some combination of these two duplex technologies.

[0221] 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. The data can be provided to processing system 1508, for example, by 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 description includes the SDAP layer, PDCP layer, RLC layer, and MAC layer. Layer 3 may include, as per [reference to...] Figure 2B The RRC layer is described.

[0222] Data destined for wireless device 1502, after being processed by processing system 1508, can be provided to transmission processing system 1510 of base station 1504. Similarly, data destined for base station 1504, after being processed by processing system 1518, 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 is described. For transmission processing, the PHY layer can perform operations such as forward error correction coding of the transmission channel, interleaving, rate matching, mapping of the transmission channel to the physical channel, modulation of the physical channel, multiple-input multiple-output (MIMO) or multiple-antenna processing, etc.

[0223] 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 is described. For receive processing, the PHY layer can perform tasks such as error detection, forward error correction decoding, deinterleaving, demapping from the transport channel to the physical channel, demodulation of the physical channel, MIMO or multi-antenna processing, etc.

[0224] like Figure 15 As shown, wireless device 1502 and base station 1504 may include multiple antennas. 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.

[0225] 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 executable by processing systems 1508 and / or 1518 to implement one or more functions discussed in this application. Although in 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.

[0226] Processing system 1508 and / or processing system 1518 may include one or more controllers and / or one or more processors. 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 functions: 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.

[0227] 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 one or more peripheral devices 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, and / or cameras, etc.). Processing system 1508 and / or processing system 1518 may receive user input data from one or more peripheral devices 1516 and / or one or more peripheral devices 1526 and / or provide user output data to one or more peripheral devices 1516 and / or one or more peripheral devices 1526. 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 of the following: a battery, a solar cell, a 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.

[0228] Figure 16AAn example architecture 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 modulated symbols onto one or more transport layers; transform precoding to generate complex-valued symbols; precoding of 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 / or similar functions. In one example, when transform precoding is enabled, an SC-FDMA signal for uplink transmission can be generated. In another example, when transform precoding is not enabled, Figure 16A CP-OFDM signals for uplink transmission can be generated. These functions are shown as examples, and other mechanisms are expected to be implemented in various embodiments.

[0229] Figure 16B An example structure for modulating and up-converting a baseband signal to a carrier frequency is shown. The baseband signal can be a complex-valued SC-FDMA or CP-OFDM baseband signal for the antenna port and / or a complex-valued Physical Random Access Channel (PRACH) baseband signal. Filtering can be applied before transmission.

[0230] Figure 16C An example architecture 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 on the layers 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 / or similar processing. These functions are shown as examples, and other mechanisms are contemplated for implementation in various embodiments.

[0231] Figure 16D Another example architecture for modulating and up-converting a baseband signal to a carrier frequency is shown. The baseband signal can be a complex-valued OFDM baseband signal for the antenna port. Filtering can be applied before transmission.

[0232] 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 multiple cells. One or more messages (e.g., as part of the configuration parameters) may include parameters for configuring the physical layer, MAC layer, RLC layer, PCDP layer, SDAP layer, and RRC layer of the wireless device. For example, configuration parameters may include parameters for configuring physical and MAC layer channels, bearers, etc. For example, configuration parameters may 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.

[0233] 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 value, or it can start from zero and expire once that value is reached). The duration of a timer may not be updated until the timer stops or expires (e.g., due to a BWP switch). A timer can be used to measure a time period / window of a process. When the specification refers to implementations and processes associated with one or more timers, it should be understood that there are multiple ways to implement one or more timers. For example, it should be understood that one or more of the various ways of implementing a timer can be used to measure a time period / window of the 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 the start and expiration of the random access response window timer, the time difference between two timestamps can be used. When the timer is restarted, the process for measuring the time window can be restarted. Other example implementations can be provided to restart the measurement of the time window.

[0234] For a two-step RA procedure, the wireless device can receive one or more RRC messages from the base station, including two-step RACH configuration parameters 1330. The one or more RRC messages can be broadcast to the wireless device (e.g., via system information broadcast messages), multicast (e.g., via system information broadcast messages), and / or unicast (e.g., via dedicated RRC messages and / or lower-layer control signals such as PDCCH). The one or more RRC messages can be wireless device-specific messages, such as dedicated RRC messages transmitted to a wireless device having an RRC inactive state 604 or an RRC connected state 602. The one or more RRC messages can include parameters required for transmitting MsgA 1331. For example, this parameter may indicate at least one of the following: PRACH resource allocation, preamble format, SSB information (e.g., total number of SSBs, downlink resource allocation for SSB transmission, transmission power for SSB transmission), uplink radio resources (time-frequency radio resources, DMRS, MCS, etc.) for transmission of one or more transport blocks, and / or the association between PRACH resource allocation and uplink radio resources (or the association between uplink radio resources and downlink reference signals).

[0235] In a two-step RA process UL transmission (e.g., Msg A1331), the radio device may transmit at least one random access preamble (RAP) (e.g., preamble 1341) and / or one or more transport blocks (e.g., transport block 1342) to the base station via the cell. For example, one or more transport blocks may include one of data, security information, device information such as IMSI / TMSI, and / or other information. For example, one or more transport blocks may include a radio device identifier (ID) that can be used for contention resolution. In a two-step RA process DL transmission, the base station may transmit Msg B1332 (e.g., a random access response corresponding to Msg A 1331) that may include at least one of the following parameters: a timing advance command indicating a TA value, a power control command, UL authorization (e.g., radio resource allocation and / or MCS), an identifier for contention resolution, an RNTI (e.g., C-RNTI or TC-RNTI), and / or other information. Msg B 1332 may include a preamble identifier corresponding to preamble 1341, a positive or negative acknowledgment of reception of one or more transport blocks 1342, an implicit and / or explicit indication of successful decoding of one or more transport blocks 1342, or a return to a non-two-step RA procedure (e.g., Figure 13A Competition-based RA process or Figure 13B Instructions for non-competitive RA processes and / or combinations thereof.

[0236] A wireless device initiating a two-step RA procedure can transmit a Msg A including at least one preamble and at least one transport block. At least one transport block can include an identifier used by the wireless device for contention resolution. For example, the identifier is a C-RNTI (e.g., for a wireless device with an RRC connection). The wireless device can indicate the C-RNTI to the base station based on a specific message format that can be predefined. For example, at least one transport block includes a C-RNTI MAC CE with an LCID in a subheader corresponding to the C-RNTI MAC CE (e.g., a 16-bit field indicating the C-RNTI). For example, the LCID can be used by the base station to identify (detect, parse, and / or decode) the C-RNTI MACCE from received signals or messages (e.g., MAC PDUs) transmitted from the wireless device. The identifier can be one or more sequences and / or one or more numbers generated by the wireless device (e.g., in cases where the base station has not yet assigned a C-RNTI to the wireless device). The wireless device can randomly generate the identifier and / or generate the identifier based on subscriber, wireless device device information (e.g., IMSI / TMSI), and / or a recovery identifier assigned to the wireless device by the base station. For example, the identifier can be extended and / or truncated subscriber and / or device information (e.g., IMSI / TMSI) of the wireless device. The wireless device can, for example, begin monitoring the downlink control channel for Msg B corresponding to Msg A after transmitting Msg A or in response to transmitting Msg A. The control resource set and / or search space used for monitoring the downlink control channel can be indicated and / or configured by messages transmitted by the base station (e.g., broadcast RRC messages and / or wireless device-specific RRC messages). Msg B can be scrambled by a specific RNTI. The wireless device can use an RNTI already assigned by the base station (e.g., C-RNTI) as that specific RNTI. The wireless device may determine the specific RNTI based on at least one of the following: the time resource index of the PRACH timing for transmitting at least one preamble (e.g., the index of the first OFDM symbol and / or the index of the first time slot), the frequency resource index of the PRACH timing for transmitting at least one preamble, the time resource index of the PUSCH timing for transmitting at least one transport block (e.g., the index of the first OFDM symbol and / or the index of the first time slot), the frequency resource index of the PUSCH timing for transmitting at least one transport block, and an indicator (e.g., 0 or 1) of the uplink carrier for transmitting Msg A. The wireless device may consider (or determine) the successful completion of the two-step RA process based on one or more conditions. At least one of the one or more conditions may be that Msg B includes a preamble index (or identifier) ​​that matches at least one preamble transmitted by the wireless device to the base station.At least one of the conditions may be that Msg B includes and / or indicates a contention resolution identifier that matches the identifier transmitted by the wireless device to the base station for contention resolution. In one example, the wireless device may receive a Msg B indicating a retransmission of at least one transport block. For example, the Msg B indicating a retransmission of at least one transport block includes a UL authorization indicating uplink resources for the retransmission of at least one transport block.

[0237] In the UL transmission of a two-step RA process, the radio device can transmit at least one RAP and one or more TBs to the base station via a cell. The radio device can, for example, receive a message of one or more configuration parameters for the UL transmission of the two-step RA process at step 1330 in Figure 13. For example, the one or more configuration parameters may indicate at least one of the following: PRACH timing, preamble format, number of transmitted SSBs, downlink resources for SSB transmission, transmission power for SSB transmission, association between each PRACH timing and each SSB, PUSCH resources for one or more TB transmissions (in terms of time, frequency, code / sequence / signature), association between each PRACH timing and each PUSCH resource, and / or power control parameters for one or more TB transmissions. The power control parameters for one or more TB transmissions may include at least one of the following: a power parameter value for determining the cell-specific power adjustment for receiving the target power, a scaling factor for path loss measurement (e.g., inter-cell interference control parameters), a reference signal power for determining path loss measurement, a power offset relative to the power of the preamble transmission, and / or one or more power offsets. For example, a wireless device measures the received signal power (e.g., RSRP) and / or quality (e.g., RSRQ) of one or more SSBs transmitted by a base station. The wireless device may select at least one SSB based on the measurement results and determine at least one PRACH timing associated with the at least one SSB and / or at least one PUSCH resource associated with the at least one PRACH timing and / or the at least one SSB (this association may be explicitly configured by a message and / or implicitly configured through a first association between the at least one SSB and the at least one PRACH timing and a second association between the at least one PRACH timing and the at least one PUSCH resource). The wireless device may transmit at least one RAP via the at least one PRACH timing and / or at least one TB via the at least one PUSCH resource. The wireless device may determine the transmit power of at least one RAP and / or at least one TB based on configuration parameters indicated by (multiple) messages. For example, the configuration parameters indicate uplink transmit power control parameters including at least one of the following: target received power for the base station, one or more power offsets, power ramp step size, power ramp counter, retransmission counter, (one or more) path loss reference signal index, and path loss reference signal reference power. At least one of the uplink transmit power control parameters may be shared between the uplink transmit power used for at least one RAP and the uplink transmit power used for at least one TB. For example, sharing at least one uplink transmit power control parameter can reduce the message size (e.g., compared to a case where at least one uplink transmit power control parameter is repeated for at least one RAP and at least one TB in the message).None of the uplink transmit power control parameters may be shared between the uplink transmit power used for at least one RAP and the uplink transmit power used for at least one TB. The message structure can be flexible, allowing the base station to indicate to the radio device whether at least one (or which one or more) of the uplink transmit power control parameters can be shared between the uplink transmit power used for at least one RAP and the uplink transmit power used for at least one TB. For example, the radio device determines whether at least one (or which one or more) of the uplink transmit power control parameters can be shared between the uplink transmit power used for at least one RAP and the uplink transmit power used for at least one TB based on the message structure of message(s).

[0238] A wireless device may generate one or more candidate preambles for use in a two-step RA process in one or more ways. For example, a two-step RACH configuration includes RAP generation parameters (e.g., root sequence), based on which the wireless device generates one or more candidate preambles. The wireless device may (e.g., randomly) select one of the one or more candidate preambles as the RAP to be used for transmitting preamble 1341. The RAP generation parameters may be DL reference signal (e.g., SSB or CSI-RS) specific, cell specific, and / or wireless device specific. For example, the RAP generation parameters for a first DL reference signal may differ from those for a second DL reference signal. For example, the RAP generation parameters may be common to one or more DL reference signals of the cell in which the wireless device initiates the two-step RA process. For example, the wireless device receives control messages (e.g., SIB messages, RRC messages dedicated to the wireless device, and / or PDCCH commands for secondary cell addition) from a base station that indicate the index of one or more preambles for one or more RAPs to be used in the two-step RA process of the wireless device. One or more candidate preambles may be grouped into one or more groups. For example, each group is associated with a specific amount of data to be transmitted. For instance, the data amount indicates the size of one or more transport blocks that the wireless device intends to transmit and / or the size of the remaining uplink data in the buffer. Each of the one or more groups may be associated with a range of data sizes. For example, a first group of one or more groups may include a RAP indicating small data transmissions of a transport block during a two-step RA process, a second group may include a RAP indicating larger data transmissions of a transport block during a two-step RA process, and so on. The base station may transmit an RRC message including one or more thresholds, based on which the wireless device can determine which RAP group the wireless device selects. For example, one or more thresholds indicate one or more data sizes for determining one or more groups. Based on the size of the uplink data that the wireless device may potentially transmit, the wireless device may compare the size of the uplink data with one or more data sizes and determine a specific group from one or more groups. By transmitting the RAP selected from the specific group, the wireless device may indicate to the base station the (e.g., estimated) size of the uplink data that the wireless device will transmit to the base station. The indication of the uplink data size allows the base station to determine the appropriate size of the uplink radio resources for (re)transmission of the uplink data.

[0239] During a two-step RA process, a wireless device may transmit a RAP via a PRACH timing indicated by a two-step RACH configuration. The wireless device may transmit one or more TBs via UL radio resources (e.g., PUSCH) indicated by a two-step RACH configuration. The first transmission of the RAP and the second transmission of one or more TBs may be scheduled in TDM (Time Division Multiplexing), FDM (Frequency Division Multiplexing), CDM (Code Division Multiplexing), and / or any combination thereof. The first transmission of the RAP may overlap (partially or completely) with the second transmission of one or more TBs in time. The two-step RACH configuration may indicate the portion of radio resources (e.g., in the frequency and / or time domain) that overlap between the RAP and one or more TB transmissions. The first transmission of the RAP may be time-division multiplexed without overlapping with the second transmissions of one or more TBs at different frequencies (e.g., PRB) or the same frequencies (e.g., PRB). The two-step RACH configuration may indicate one or more UL radio resources associated with one or more RAPs (or RAP groups) and / or PRACH timings. For example, each of one or more downlink reference signals (SSB or CSI-RS) is associated with one or more PRACH timings and / or one or more RAPs. The wireless device can determine at least one PRACH timing and / or at least one RAP among the one or more PRACH timings. For example, the wireless device measures the RSRP and / or RSRQ of one or more downlink reference signals and selects a first downlink reference signal from the one or more downlink reference signals. For example, the RSRP of the first downlink reference signal is greater than a threshold (e.g., indicated by a base station via a control message or signal). The wireless device can select at least one RAP and / or at least one PRACH timing associated with the first downlink reference signal as a radio resource for preamble 1341. Based on the selection of at least one RAP and / or at least one PRACH timing, the wireless device can determine at least one UL radio resource (e.g., a PUSCH timing) for which the wireless device transmits one or more TBs as part of a two-step RACH process. For example, if a control message and / or control signal received by a wireless device from a base station indicates an association between one or more UL radio resources (e.g., PUSCH timing) and one or more downlink reference signals, the wireless device can determine at least one UL radio resource (e.g., PUSCH timing) based on a first downlink reference signal.

[0240] Based on Figure 7 Frame structure and / or Figure 8The OFDM radio architecture is used to indicate one or more UL radio resources. For example, the time-domain resources of one or more UL radio resources can be indicated relative to a specific SFN (SFN=0), slot number, OFDM symbol number, and / or combinations thereof. For example, the time-domain resources of one or more UL radio resources can be indicated relative to a subcarrier number, the number of resource elements, the number of resource blocks, RBG number, the frequency index of the frequency-domain radio resource, and / or combinations thereof. For example, one or more UL radio resources can be indicated based on the time offset and / or frequency offset of one or more PRACH timings with respect to a selected RAP. UL transmissions can occur, for example, in the same slot (or subframe) and / or in different slots (e.g., in consecutive slots (or subframes)). For example, one or more UL radio resources (e.g., PUSCH timings) can be configured periodically, for example, configured as periodic resources of license type 1 or type 2.

[0241] The PUSCH timing for a two-step RA procedure can be uplink radio resources used for the transmission of transport block 1342 (e.g., payload) associated with the PRACH preamble in the MsgA1331 of the two-step RA procedure. One or more examples of resource allocation for PUSCH timing can be (but are not limited to) configuring PUSCH timing separately from PRACH timing. For example, PUSCH timing can be determined based on periodic resources indicated by configured grants (e.g., configured grant type 1 / type 2 and / or SPS). The radio device can further determine PUSCH timing based on the association between PRACH and PUSCH used for MsgA transmission. For example, a wireless device may receive configuration parameter indications from a base station for at least one of the following: modulation and coding scheme, transport block size, number of frequency division multiplexing PUSCH opportunities (frequency division multiplexing PUSCH opportunities may include guard bands and / or guard intervals (e.g., if present), and frequency division multiplexing PUSCH opportunities under the same Msg A PUSCH configuration may be consecutive in the frequency domain), number of PRBs per PUSCH opportunity, number of DMRS symbols / ports / sequences per PUSCH opportunity, number of repetitions for Msg APUSCH (transport block 1342) transmission, bandwidth of PRB-level guard bands, duration of guard intervals, PUSCH mapping type of transport block 1342, periodicity (e.g., Msg A PUSCH configuration period), (one or more) offsets (e.g., in any combination of at least one of symbols, time slots, subframes, and / or SFNs), time-domain resource allocation (e.g., in time slots used for Msg A PUSCH: start symbol, number of symbols per PUSCH opportunity, number of time-domain PUSCH opportunities), and frequency start point.

[0242] One or more examples of resource allocation for PUSCH timing can be (but are not limited to) the base station configuring the relative position of PUSCH timing with respect to PRACH timing (e.g., in time and / or frequency). For example, the time and / or frequency relationship between a PRACH timing and a PRACH preamble in a PUSCH timing can be a single, fixed-value specification. For example, the time and / or frequency relationship between each PRACH preamble in a PRACH timing and the PUSCH timing is a single, fixed-value specification. For example, different preambles in different PRACH timings have different values. For example, the time and / or frequency relationship between a PRACH timing and a PRACH preamble in a PUSCH timing is a single, semi-statically configured value. For example, the time and / or frequency relationship between each PRACH preamble in a PRACH timing and the PUSCH timing is a semi-statically configured value. For example, different preambles in different PRACH timings have different values. For example, any combination of the above examples can be implemented / configured, and the time and frequency relationships do not need to be identical alternatives. For example, a wireless device may receive configuration parameter indications from a base station for at least one of the following: modulation and coding scheme, transport block size, number of frequency-division multiplexed PUSCH times (frequency-division multiplexed PUSCH times may include guard bands and / or guard intervals (e.g., if present), and frequency-division multiplexed PUSCH times under the same Msg A PUSCH configuration may be consecutive in the frequency domain), number of PRBs per PUSCH time, number of DMRS symbols / ports / sequences per PUSCH time, number of repetitions for Msg A PUSCH (transport block 1342) transmission, bandwidth of the PRB-level guard band, duration of the guard time, PUSCH mapping type of transport block 1342, time offset relative to a reference point (e.g., a specific SFN, the start or end of the associated PRACH time and / or associated PRACH slot) (e.g., a combination of slot-level and symbol-level indications), number of symbols per PUSCH time, and number of time-division multiplexed PUSCH times.

[0243] For a two-step RA procedure, resource allocation for payload transmission during the PUSCH timing can be predefined and / or configured. For example, the size of resources during the PUSCH timing can be predefined and / or configured. Resources can be contiguous or non-contiguous (e.g., the base station can flexibly configure the resources). Resources can be divided into multiple resource groups. For example, the size of each resource group within a PUSCH timing can be the same or different (e.g., depending on the configuration of the two-step RA procedure). Each resource group index can be mapped to one or more preamble indices.

[0244] For example, a base station can configure one or more parameters for a wireless device that indicate the start time and / or frequency of a PUSCH timing, the number of resource groups, and the size of each resource group. The index of each resource group can be mapped to a preamble index (e.g., a specific preamble) and / or a specific PPRCH timing. The wireless device can determine the location of each resource group based at least on the preamble index (e.g., where RO and PUSCH timing are mapped one-to-one) and / or based on the RO index and preamble index (e.g., where multiple ROs are associated with a single PUSCH timing).

[0245] The wireless device can receive configuration parameters from the base station indicating the start point of the time / frequency for PUSCH timing and / or a set of consecutive basic units of PUSCH resources. The resource units can be of uniform size, and the total number of available basic units can be pre-configured. Depending on the payload size, the wireless device can use one or more resource units for Msg A1331 transmissions. The starting resource unit index can be mapped to a preamble index, and the length of the occupied PUSCH resources (as the number of resource units) can be mapped to the preamble index or explicitly indicated (e.g., in UCI).

[0246] The number of resource groups and / or the detailed mapping between (multiple) preambles, (multiple) resource groups and (multiple) DMRS ports can be predefined and / or semi-statically configured (and / or dynamically indicated by DCI), for example, to avoid blind detection from the base station when multiple preambles are mapped to the same resource group.

[0247] For payload transmission via PUSCHC timing during a two-step RA process, the wireless device can receive configuration parameters from the base station indicating one or more MCSs and one or more resource sizes for payload transmission. The MCS and resource sizes can be related to the payload size. For example, the configuration parameters received by the wireless device can indicate one or more combinations (and / or associations) of payload size, MCS, and resource sizes. For example, one or more specific modulation types (e.g., pi / 2-BPSK, BPSK, QPSK) can be associated with a small-sized payload. For example, one or more specific modulation types (e.g., QPSK) can be used for a wireless device with a specific RRC state (e.g., RRC idle and / or RRC inactive). For example, the configuration parameters received by the wireless device can indicate the number of PRBs used for payload transmission across the entire UL BWP and / or a portion of the UL BWP (e.g., this can be predefined and / or semi-statically configured by RRC). The configuration parameters received by the wireless device can indicate one or more repetitions of transport block 1342 (e.g., the payload). For example, the number of repetitions can be predefined, semi-statically configured, and / or triggered based on one or more conditions for coverage enhancement for payload transmission (e.g., RSRP of the downlink reference signal, and / or a specific RRC state, and / or the type of wireless device (e.g., fixed, IoT, etc.)).

[0248] The wireless device can receive one or more two-step RA configurations from the base station for transmitting block 1342 (e.g., payload). The one or more two-step RA configurations may indicate one or more combinations of payload size, MCS, and / or resource size. The number of one or more two-step RA configurations and the one or more parameter values ​​(e.g., payload size, MCS, and / or resource size) for each of the one or more two-step RA configurations may depend on the content of MsgA and / or the RRC state of the wireless device.

[0249] Based on the configured two-step RA configuration parameters, the wireless device can transmit MsgA to the base station, including, for example, at least one preamble transmitted via PRACH timing and / or transport block 1342 (e.g., payload) transmitted via PUSCH timing. MsgA may include identifiers for contention resolution. For example, the wireless device may construct a MAC header as a MsgA payload with multiple bits (e.g., 56 and / or 72 bits). For example, MsgA may include BSR, PHR, RRC messages, connection requests, etc. For example, MsgA may include UCI. For example, if MsgA includes UCI, the UCI in MsgA may include at least one of the following: MCS indication, HARQ-ACK / NACT, and / or CSI report. HARQ for MsgA may be combined between the initial transmission of MsgA and one or more retransmissions of MsgA PUSCH. For example, MsgA may indicate the transmission time of MsgA in the MsgA PUSCH. The size of MsgA may depend on the use case.

[0250] There may be situations where a radio device receives configuration parameters from a base station indicating different (or independent) PRACH timings between two-step RA and four-step RA. Different (or independent) PRACH timings can reduce receiver uncertainty and / or access latency. The base station can configure different (or independent) PRACH resources for the radio device, allowing the base station to identify whether a received preamble was transmitted by the radio device for a two-step RA or a four-step RA based on the PRACH timing of the received preamble. The base station can flexibly determine whether to configure shared PRACH timings or separate PRACH timings between the two-step and four-step RA processes. The radio device can receive RRC messages and / or DCI from the base station, which indicate, explicitly or implicitly, whether shared PRACH timings or separate PRACH timings are configured between the two-step and four-step RA processes. There may be situations where the base station configures one or more PRACH timings shared between the two-step and four-step RA, as well as preambles allocated for the two-step and four-step RA.

[0251] Figure 17A , Figure 17B and Figure 17CThese are examples of radio resource allocation of PRACH resources and one or more associated UL radio resources based on time offset, frequency offset, and a combination of time offset and frequency offset, according to one aspect of exemplary embodiments of this disclosure. For example, the PRACH timing for Msg A 1331 and one or more associated UL radio resources (e.g., PUSCH timing) may be allocated with time offset and / or frequency offset, for example, provided by RRC messages (as part of RACH configuration) and / or predefined (e.g., as a mapping table). Figure 17A This is an example of a PRACH timing that is time-division multiplexed with UL radio resources (e.g., PUSCH timing) according to an exemplary embodiment of the present disclosure. Figure 17B This is an example of a PRACH timing that is frequency-division multiplexed with UL radio resources (e.g., PUSCH timing) according to an exemplary embodiment of the present disclosure. Figure 17C This is an example of a PRACH timing that is time-division multiplexed and frequency-division multiplexed with UL radio resources (e.g., PUSCH timing) according to an exemplary embodiment of the present disclosure.

[0252] The wireless device may receive one or more downlink reference signals (e.g., SSB or CSI-RS) from a base station, and each of the one or more downlink reference signals may be associated with one or more RACH resources (e.g., PRACH timing) and / or one or more UL radio resources (e.g., PUSCH timing) provided by a two-step RACH configuration. The wireless device may measure the one or more downlink reference signals and, based on the measured received signal strength and / or quality (or based on other selection rules), may select at least one downlink reference signal from the one or more downlink reference signals. The wireless device may transmit RAP (e.g., preamble 1341) and one or more TBs (e.g., transport block 1342) via the PRACH timing associated with at least one downlink reference signal and via the UL radio resources (e.g., PUSCH timing) associated with the PRACH timing and / or associated with at least one downlink reference signal.

[0253] In one example, a base station can use RAP received from a radio device to adjust the UL transmission timing of one or more TBs of radio devices in the cell and / or assist in UL channel estimation for one or more TBs. A portion of the UL transmission for one or more TBs during a two-step RACH process may include, for example, radio device ID, C-RNTI, service requests (such as buffer status reports (BSRs)), one or more user data packets, and / or other information. For example, a radio device in the RRC Connected 602 state may use the C-RNTI as its identifier (e.g., radio device ID). For example, a radio device in the RRC Inactive 604 state may use the C-RNTI (if available), recovery ID, or short MAC-ID as its identifier. For example, a radio device in the RRC Idle 606 state may use the C-RNTI (if available), recovery ID, short MAC-ID, IMSI (International Mobile Subscriber Identifier), T-IMSI (Temporary IMSI), and / or a random number (e.g., generated by the radio device) as its identifier.

[0254] During the two-step RA process, the radio device can receive two separate responses corresponding to Msg A: a first response for a RAP (e.g., preamble 1342) transmission; and a second response for one or more TBs of transmission (e.g., transport block 1342). The radio device can monitor the PDCCH (e.g., the common search space and / or the radio device-specific search space) to detect the first response with a random access RNTI generated based on the time and / or frequency index of the PRACH resources for the radio device's RAP transmission. The radio device can monitor the common search space and / or the radio device-specific search space to detect the second response. The radio device can employ a second RNTI to detect the second response. For example, the second RNTI is a C-RNTI (if configured), a random access RNTI generated based on the time and / or frequency index of the PRACH timing for the radio device's RAP transmission, or an RNTI generated based on the time and / or frequency index (and / or DM-RS ID) of one or more TBs of PUSCH resources transmitted by the radio device. The radio device-specific search space can be predefined and / or configured by RRC messages received from the base station.

[0255] One or more events can trigger a two-step random access procedure. For example, one or more events can be at least one of the following: initial access from RRC_IDLE, RRC connection reconstruction procedure, handover, arrival of DL or UL data during RRC connection 602 when UL synchronization states are out of sync, transition from RRC inactivity 604, beam fault recovery procedure, and / or request for other system information. For example, a PDCCH command, a radio device's MAC entity, and / or a beam fault indication can initiate a random access procedure.

[0256] A wireless device can initiate a two-step RA procedure under specific conditions, such as depending on the traffic of the data to be transmitted (e.g., latency-sensitive data such as URLLC) and / or radio conditions. For example, if the cell is small (e.g., TA is not required) and / or for fixed wireless devices (e.g., TA updates are not required), the base station can configure a two-step RA procedure for one or more wireless devices. The wireless device can obtain the configuration via one or more RRC messages (e.g., MIB, System Information Block, multicast and / or unicast RRC signaling) and / or via L1 control signaling (e.g., PDCCH command) used to initiate the two-step RA procedure.

[0257] For example, in a macro coverage area, wireless devices may have stored and / or persistent TA values, such as stationary or near-stationary wireless devices, like sensor-type wireless devices. In this case, a two-step RA procedure can be initiated. A base station with macro coverage can use broadcast and / or dedicated signaling to configure a two-step RA procedure with one or more wireless devices that have stored and / or maintained TA values ​​under the coverage.

[0258] A wireless device in the RRC Connected 602 state can perform a two-step RA procedure. For example, this can be initiated when the wireless device performs a handover (e.g., a network-initiated handover), and / or when the wireless device needs or requests a UL authorization for transmitting delay-sensitive data and there are no physical layer uplink control channel resources available for transmitting a scheduling request. A wireless device in the RRC Inactive 604 state can perform a two-step RA procedure, for example, for small data transmission or for reconnection while remaining in the RRC Inactive 604 state. A wireless device can initiate a two-step RA procedure, for example, for initial access, such as establishing a wireless link, re-establishing a wireless link, handover, establishing UL synchronization, and / or for scheduling requests in the absence of UL authorization.

[0259] The following description provides one or more examples of RA processes. The processes and / or parameters described below may not be limited to a specific type of RA process. The processes and / or parameters described below can be applied to four-step RA processes and / or two-step RA processes. For example, an RA process may refer to the four-step RA process and / or two-step RA process described below.

[0260] A wireless device can perform a cell search. For example, during a cell search process, the wireless device can acquire time and frequency synchronization with the cell and detect the cell's first physical layer cell ID. For example, the wireless device can perform a cell search when it has received one or more synchronization signals (SS) (e.g., primary synchronization signal (PSS) and secondary synchronization signal (SSS)). The wireless device can assume that the reception timing of one or more physical broadcast channels (PBCH), PSS, and SSS is in consecutive symbols and, for example, forms an SS / PBCH block (SSB). For example, the wireless device can assume that the SSS, PBCH demodulation reference signal (DM-RS), and PBCH data have the same energy per resource element (EPRE). For example, the wireless device can assume that the ratio of PSS EPRE to SSS EPRE in the SS / PBCH block is a specific value (e.g., 0 dB or 3 dB). For example, when the wireless device has not been provided with dedicated higher-layer parameters, such as those semi-statically configured by RRC messages, the wireless device can determine that the ratio of PDCCH DM-RS EPRE to SSS EPRE is within a specific range (e.g., from -8 dB to 8 dB).

[0261] A wireless device can determine a first symbol index for one or more candidate SS / PBCH blocks. For example, for a half-frame with SS / PBCH blocks, the first symbol index for one or more candidate SS / PBCH blocks can be determined based on the subcarrier spacing of the SS / PBCH blocks. For example, index 0 corresponds to the first symbol of the first slot in the half-frame. As an example, for a 15 kHz subcarrier spacing, the first symbol of one or more candidate SS / PBCH blocks can have an index {2,8}+14·n, where, for example, for carrier frequencies less than or equal to 3 GHz, n = 0,1, and for example, for carrier frequencies greater than 3 GHz and less than or equal to 6 GHz, n = 0,1,2,3. One or more candidate SS / PBCH blocks in a half-frame can be indexed in ascending time order (e.g., from 0 to L-1). The wireless device can determine some bits of the SS / PBCH block index for each half-frame based on, for example, a one-to-one mapping to one or more indices of the DM-RS sequence transmitted in the PBCH (e.g., 2 least significant bits (LSBs) for L = 4, or 3 LSB bits for L > 4).

[0262] Before initiating a random access procedure, the base station may transmit one or more RRC messages to configure the radio device using one or more parameters configured in the RACH, such as for a four-step RA procedure, a two-step RA procedure, and / or both a four-step RA procedure and a two-step RA procedure. The one or more RRC messages may be broadcast or multicast to one or more radio devices. The one or more RRC messages may be radio device-specific messages, such as dedicated RRC messages transmitted to radio devices with RRC inactivity 1520 or RRC connection 1530. The one or more RRC messages may include one or more parameters required for transmitting at least one preamble via one or more random access resources. For example, the one or more parameters may indicate at least one of the following: PRACH resource allocation (e.g., resource allocation for one or more PRACH timings), preamble format, SSB information (e.g., total number of SSBs, downlink resource allocation for SSB transmission, transmit power for SSB transmission, SSB index corresponding to the beam transmitting one or more RRC messages and / or other information), and / or uplink radio resources for one or more transport blocks.

[0263] The base station may also transmit one or more downlink reference signals. For example, the one or more downlink reference signals may include one or more discovery reference signals. The wireless device may select a first downlink reference signal from the one or more downlink reference signals. For example, the first downlink reference signal may include one or more synchronization signals and a physical broadcast channel (SS / PBCH). For example, the wireless device may adjust downlink synchronization based on one or more synchronization signals. For example, the one or more downlink reference signals may include one or more channel state information-reference signals (CSI-RS).

[0264] One or more RRC messages may also include one or more parameters indicating one or more downlink control channels (e.g., PDDCH). Each of the one or more downlink control channels may be associated with at least one of one or more downlink reference signals. For example, a first downlink reference signal may include one or more system information (e.g., Master Information Block (MIB) and / or System Information Block (SIB)). The base station may transmit messages(s) including one or more system information, for example, on the Physical Broadcast Channel (PBCH), Physical Downlink Control Channel (PDCCH), and / or Physical Downlink Shared Channel (PDSCH).

[0265] One or more system information may include at least one information element (e.g., PDCCH-Config, PDCCH-ConfigSIB1, PDCCH-ConfigCommon, and / or any combination thereof). At least one information element may be transmitted from the base station, for example, to indicate one or more control parameters to the radio device. One or more control parameters may indicate one or more control resource sets (CORESETs). For example, one or more control parameters may include parameters indicating a first common CORESET#0 (e.g., controlResourceSetZero) and / or a second common CORESET (e.g., commonControlResourceSet). One or more control parameters may also include one or more search space sets. For example, one or more control parameters may include parameters for a first search space (e.g., SearchSpaceSIB1), and / or a first common search space #0 (e.g., SearchSpaceZero), and / or a first random access search space (e.g., RA-SearchSpace), and / or a first paging search space (e.g., PagingSearchSpace) for system information blocks. The radio device may use one or more control parameters to acquire, configure, and / or monitor one or more downlink control channels.

[0266] A wireless device can monitor one or more candidate sets of one or more downlink control channels in one or more control resource sets. One or more control resource sets can be defined in a first active downlink frequency band (e.g., active bandwidth portion (BWP)) on a first active serving cell. For example, the first active serving cell is configured by the network for a wireless device having one or more search space sets. For example, the wireless device decodes each of the one or more downlink control channels in the candidate set of one or more downlink control channels according to a first format of the first downlink control information (DCI). One or more candidate sets of downlink control channels can be defined based on one or more search space sets. For example, one or more search space sets are one or more common search space sets (e.g., Type 0-PDCCH, Type 0A-PDCCH, Type 1-PDCCH, Type 2-PDCCH, and / or Type 3-PDCCH), one or more wireless device-specific search space sets, and / or any combination thereof.

[0267] For example, a wireless device can monitor a candidate set of one or more downlink control channels in a Type0-PDCCH common search space set. For example, the Type0-PDCCH common search space set can be configured by at least one information element (e.g., PDCCH-ConfigSIB1 in the MIB). For example, the Type0-PDCCH common search space set can be configured by one or more search space sets (e.g., searchSpaceSIB1 in PDCCH-ConfigCommon or searchSpaceZero in PDCCH-ConfigCommon). For example, the Type0-PDCCH common search space set can be configured for a first format of first downlink control information scrambled with a specific radio network temporary identifier (e.g., System Information-Radio Network Temporary Identifier (SI-RNTI)).

[0268] For example, a wireless device can monitor a candidate set of one or more downlink control channels in a Type 1-PDCCH common search space set. For example, the Type 1-PDCCH common search space set can be configured by one or more search space sets (e.g., ra-SearchSpace in PDCCH-ConfigCommon). For example, the Type 1-PDCCH common search space set can be configured for a second format of second downlink control information scrambled by a second radio network temporary identifier (e.g., Random Access Radio Network Temporary Identifier (RA-RNTI), Temporary Cell Radio Network Temporary Identifier (TC-RNTI), C-RNTI, and / or an RNTI generated by the wireless device based on a two-step RA process, such as msgB-RNTI).

[0269] A wireless device may, for example, determine the existence of a first control resource set for a first common search space (e.g., Type 0-PDCCH) during cell search. The first control resource set may include one or more resource blocks and one or more symbols. One or more RRC messages may include one or more parameters indicating one or more monitoring opportunities for one or more downlink control channels. For example, the wireless device determines the number of consecutive resource blocks and the number of consecutive symbols in the first control resource set for the first common search space. For example, one or more bits (e.g., four most significant bits) of at least one information element (e.g., PDCCH-ConfigSIB1) indicate the number of consecutive resource blocks and the number of consecutive symbols. The wireless device may determine one or more monitoring opportunities for one or more downlink control channels based on one or more bits (e.g., four least significant bits) of at least one information element (e.g., PDCCH-ConfigSIB1). For example, one or more monitoring opportunities for one or more downlink control channels associated with a first downlink reference signal (e.g., SSB or CSI-RS) are determined based on one or more system frame numbers and one or more time slot indices of the first control resource set. For example, a first downlink reference signal with a first index overlaps temporally with a first frame number and a first time slot index.

[0270] A wireless device can select (or determine) a specific downlink channel from one or more downlink control channels based on a first downlink reference signal (e.g., SSB or CSI-RS). For example, the wireless device receives messages(s) indicating the association between one or more downlink control channels and one or more downlink reference signals. The wireless device can select a first downlink reference signal (e.g., SSB or CSI-RS) from one or more downlink reference signals, for example, based on the RSRP of the first downlink reference signal being greater than a first value. Based on this association, the wireless device determines the specific downlink channel associated with the first downlink reference signal. The wireless device can determine that the demodulation reference signal antenna port associated with the reception of the first downlink channel is quasi-co-located (QCL) with the first downlink reference signal. For example, the demodulation reference signal antenna port associated with the reception of the first downlink channel and the first downlink reference signal (e.g., the corresponding SS / PBCH block) can be quasi-co-located with respect to at least one of the following: average gain, QCL-Type A, and / or QCL-Type D.

[0271] A wireless device can receive one or more RRC messages from a base station that include one or more random access parameters. For example, one or more RRC messages may include a common (or generic) random access configuration message (e.g., RACH-ConfigCommon and / or RACH-ConfigGeneric) indicating at least one of the following: the total number of random access preambles (e.g., totalNumberOfRA-Preambles), one or more PRACH configuration indices (e.g., prach-ConfigurationIndex), the number of PRACH moments that can be multiplexed in the frequency domain (FDM) within a time instance (e.g., msg1-FDM), and the offset of the lowest PRACH moment in the frequency domain relative to the first resource block (e.g., msg1-FrequencyStart). This includes the power ramping step size for PRACH (e.g., powerRampingStep), the target power level on the network receiver side (preambleReceivedTargetPower), the maximum number of random access preamble transmissions that can be performed (e.g., preambleTransMax), the window length for the random access response (i.e., RAR, e.g., Msg2) (e.g., ra-ResponseWindow), the number of SSBs per random access channel (RACH) timing, and the number of contention-based preambles per SSB (e.g., ssb-perRACH-OccasionAndCB-PreamblesPerSSB). For example, the total number of random access preambles can be a multiple of the number of SSBs per RACH timing. For example, the window length for RAR can be the number of time slots. For example, a dedicated random access configuration message (e.g., RACH-ConfigDedicated) can include one or more RACH timings (e.g., timings) for contention-free random access, and one or more PRACH mask indices (e.g., ra-ssb-OccasionMaskIndex) for random access resource selection.

[0272] One or more random access parameters (e.g., ssb-perRACH-OccasionAndCB-PreamblesPerSSB) may indicate a first number (e.g., N) of one or more downlink reference signals (e.g., SS / PBCH blocks) that can be associated with the first PRACH timing. One or more random access parameters (e.g., ssb-perRACH-OccasionAndCB-PreamblesPerSSB) may indicate a second number (e.g., R) of one or more random access preambles for the first downlink reference signal and for the first PRACH timing. The one or more random access preambles may be contention-based preambles. The first downlink reference signal may be the first SS / PBCH block. For example, the first number (e.g., if N<1) indicates that the first SS / PBCH block can be mapped to at least one (e.g., 1 / N) consecutive valid PRACH timings. For example, the second number (e.g., R) indicates that at least one preamble with a consecutive index associated with the first SS / PBCH block may start from the first preamble index for the first valid PRACH timing.

[0273] For example, one or more PRACH configuration indices (e.g., prach-ConfigurationIndex) may indicate the preamble format, the periodicity for one or more PRACH time resources, one or more PRACH subframe numbers, the number of PRACH slots within one or more PRACH subframes, the PRACH start symbol number, and / or the number of time-domain PRACH opportunities within a PRACH slot.

[0274] The one or more random access parameters may also include associated time periods for mapping one or more SS / PBCH blocks to one or more PRACH times. For example, one or more SS / PBCH block indices are mapped to one or more PRACH times based on order. Examples of order may be as follows: ascending order of indices of at least one preamble in a first PRACH time; ascending order of indices of one or more frequency resources (e.g., PRACH times for frequency reuse); ascending order of indices of indices of one or more time resources in a first PRACH time slot (e.g., PRACH times for time reuse); and / or ascending order of indices for PRACH time slots.

[0275] Control commands that initiate a RA procedure (e.g., for SCell addition and / or TA update) may include at least one PRACH mask index. At least the PRACH mask index may indicate one or more PRACH timings associated with one or more downlink reference signals (e.g., SSB and / or CSI-RS). Figure 18An example of a PRACH mask index value that can be indicated by a control command, according to an exemplary embodiment of this disclosure, is shown. A wireless device can identify one or more PRACH timings for a specific downlink reference signal (e.g., SSB and / or CSI-RS) based on the PRACH mask index value indicated by a control command (e.g., a PDCCH command). The control command (e.g., PDCCH) may include a field indicating a specific SSB (or CSI-RS). For example, the index can be mapped (e.g., sequentially) for a specific SSB. Figure 18 The allowed PRACH timings in the first associated period. The wireless device can select a first PRACH timing indicated by a first PRACH mask index value for a specific SSB in the first associated period. The first associated period can be a first mapping period. The wireless device can reset one or more indices for one or more PRACH timings used in the first mapping period.

[0276] Wireless devices can receive instructions from base stations Figure 13A and / or Figure 13B The random access procedure and / or Figure 13C The random access procedure in a two-step random access process includes one or more messages containing random access parameters. For example, one or more messages may be broadcast RRC messages, device-specific RRC messages, and / or combinations thereof. For example, one or more messages may include at least one of a common random access configuration (e.g., RACH-ConfigCommon), a general random access configuration (e.g., RACH-ConfigGeneric), and / or a device-specific random access configuration (e.g., RACH-ConfigDedicated). For example, for a contention-based (four-step and / or two-step) random access procedure, the device receives at least RACH-ConfigCommon and RACH-ConfigGeneric from the base station. For example, for a contention-free (four-step and / or two-step) random access procedure, the device receives at least RACH-ConfigDedicated, RACH-ConfigCommon, and / or RACH-ConfigGeneric from the base station. The random access procedure on the SCell may be initiated by a PDCCH command having a ra-PreambleIndex that is different from a first index (which may be predefined or configured, e.g., 0b000000).

[0277] A wireless device may initiate a random access procedure based on at least one of the parameters configured in RACH-ConfigCommon, RACH-ConfigGeneric, and RACH-ConfigDedicated. For example, the wireless device may initiate a random access procedure by its MAC entity and / or its RRC, such as after receiving a PDCCH command from a base station or in response to receiving a PDCCH command from a base station. The wireless device may be under one or more conditions depending on which one or more random access procedures need to be initiated. For example, there may be an ongoing random access procedure at any point in time within the MAC entity. For example, if the wireless device's MAC entity receives a request for a random access procedure while another random access procedure is already in progress within the MAC entity, the wireless device may continue the ongoing procedure or begin a new procedure (e.g., for an SI request).

[0278] An example of randomly accessing a common configuration (e.g., RACH-ConfigCommon) could be as follows:

[0279]

[0280]

[0281]

[0282] For example, `messagePowerOffsetGroupB` indicates the threshold used for preamble selection. The value of `MessagePowerOffsetGroupB` can be in dB. For example, `minusInfinity` in `RACH-ConfigCommon` corresponds to infinity. A value of dB0 can correspond to 0 dB, dB5 can correspond to 5 dB, and so on. `msg1-SubcarrierSpacing` in `RACH-ConfigCommon` can indicate the subcarrier spacing of the PRACH. One or more values ​​can be applicable, for example, 15 or 30 kHz (<6 GHz), 60 or 120 kHz (>6 GHz). A Layer 1 parameter corresponding to `msg1-SubcarrierSpacing` (e.g., `prach-Msg1SubcarrierSpacing`) can exist. For example, if this parameter does not exist, the wireless device can apply the SCS derived from `prach-ConfigurationIndex` in `RACH-ConfigGeneric`. The base station can use `msg3-TransformPrecoding` to indicate to the radio device whether transform precoding is enabled for data transmission (e.g., Msg3 in a four-step RA process and / or one or more TB transmissions in a two-step RA process). The absence of `msg3-transformPrecoding` indicates that it is disabled. `numberOfRA-PreamblesGroupA` can indicate the number of contention-based (CB) preambles per SSB in group A. This implicitly determines the number of CB preambles available per SSB in group B. This setting can be consistent with the setting of `ssb-perRACH-OccasionAndCB-PreamblesPerSSB`. `prach-RootSequenceIndex` can indicate the PRACH root sequence index. A Layer 1 parameter corresponding to `ssb-perRACH-OccasionAndCB-PreamblePerSSB` (e.g., 'PRACHRootSequenceIndex') can exist. The value range can depend on the size of the preamble, e.g., whether the preamble length (L) is L = 839 or L = 139. `ra-ContentionResolutionTimer` can indicate the initial value of the timer used for contention resolution. For example, a value of `ms8` in `RACH-ConfigCommon` can indicate 8ms, a value of `ms16` can indicate 16ms, and so on. `ra-Msg3SizeGroupA` can indicate a transport block size threshold in bits. For example, when the transport block size is less than `ra-Msg3SizeGroupA`, the wireless device can use a contention-based RA preamble for group A.`rach-ConfigGeneric` can indicate one or more generic RACH parameters. `restrictedSetConfig` can indicate the configuration of an unrestricted set or one of two types of restricted sets. `rsrp-ThresholdSSB` can indicate a threshold for SS block selection. For example, a radio device can select SS blocks and corresponding PRACH resources for path loss estimation and (re)transmission based on SS blocks that meet the threshold. `rsrp-ThresholdSSB-SUL` can indicate a threshold for uplink carrier selection. For example, a radio device can select supplementary uplink (SUL) carriers to perform random access based on this threshold. `ssb-perRACH-OccasionAndCB-PreamblesPerSSB` can indicate the number of SSBs per RACH occasion and the number of contention-based preambles per SSB. One or more Layer 1 parameters (e.g., 'SSB-per-rach-occasion' and / or 'CB-preambles-per-SSB') can exist corresponding to `ssb-perRACH-OccasionAndCB-PreamblesPerSSB`. For example, the total number of CB preambles in the RACH timing can be given by CB-preambles-per-SSB*max(1,SSB-per-rach-occasion). totalNumberOfRA-Preambles can indicate the total number of preambles used for contention-based and contention-free random access. For example, totalNumberOfRA-Preambles may not include one or more preambles used for other purposes (e.g., for SI requests). For example, if this field is not present, the wireless device can use one or more of 64 preambles for RA.

[0283] A sample random access common configuration for RACH-ConfigGeneric can be as follows:

[0284]

[0285]

[0286] For example, `msg1-FDM` can indicate the number of frequency-division multiplexed PRACH transmission opportunities in a time instance. A Layer 1 parameter corresponding to `msg1-FDM` (e.g., `prach-FDM`) may exist. `msg1-FrequencyStart` can indicate the offset of a PRACH transmission opportunity (e.g., the lowest PRACH transmission opportunity) in the frequency domain relative to a specific PRB (e.g., PRB 0). The base station can configure the value of `msg1-FrequencyStart` such that the corresponding RACH resource is within the bandwidth of the UL BWP. A Layer 1 parameter corresponding to `msg1-FrequencyStart` (e.g., `prach-frequency-start`) may exist. `powerRampingStep` can indicate the power ramp step size for PRACH. `prach-ConfigurationIndex` can indicate the PRACH configuration index. For example, radio access technologies (e.g., LTE and / or NR) can predefine one or more PRACH configurations, and `prach-ConfigurationIndex` can indicate one of the one or more PRACH configurations. A Layer 1 parameter (e.g., 'PRACHConfigurationIndex') can exist corresponding to prach-ConfigurationIndex. `preambleReceivedTargetPower` can indicate the target power level on the network receiver side. For example, a multiple of a specific value (e.g., in dBm) can be selected. The RACH-ConfigGeneric above shows an example when a multiple of 2dBm is selected (e.g., -202, -200, -198…). `preambleTransMax` can indicate the number of RA preamble transmissions to be performed before a failure declaration. For example, `preambleTransMax` can indicate the maximum number of RA preamble transmissions to be performed before a failure declaration. `ra-ResponseWindow` can indicate the RAR window length in units of the number of slots (or subframes, microslots, and / or symbols). The base station can configure a value less than or equal to a specific value (e.g., 10ms). This value can be greater than a specific value (e.g., 10ms). `zeroCorrelationZoneConfig` can indicate the index of the preamble sequence generation configuration (e.g., N-CS configuration). Radio access technologies (e.g., LTE and / or NR) can predefine one or more preamble sequence generation configurations, and zeroCorrelationZoneConfig can indicate one of the one or more preamble sequence generation configurations.For example, a wireless device can determine the cyclic shift of a preamble sequence based on zeroCorrelationZoneConfig. zeroCorrelationZoneConfig can determine the properties of the random access preamble (e.g., zero-correlation zone).

[0287] Example random access-specific configurations (e.g., RACH-ConfigDedicated) could be as follows:

[0288]

[0289]

[0290] For example, the CSI-RS is indicated to the radio device by an identifier (e.g., ID) of the CSI-RS resource defined in the measurement object associated with the serving cell. `ra-OcessionList` can indicate one or more RA opportunities. For example, when the radio device performs a contention-free random access (CFRA) procedure while selecting a candidate beam identified by the CSI-RS, the radio device can employ one or more RA opportunities. `ra-PreambleIndex` can indicate the RA preamble index used in the RA opportunity associated with that CSI-RS. `ra-ssb-OccasionMaskIndex` can indicate the PRACH mask index used for RA resource selection. The mask can be valid for one or more SSB resources signaled in `ssb-ResourceList`. `rach-ConfigGeneric` can indicate the configuration of the contention-free random access opportunity used for the CFRA procedure. `ssbs-perRACH-Ocasion` can indicate the number of SSBs for each RACH opportunity. `ra-PreambleIndex` can indicate the preamble index that the radio device can employ when performing CFRA while selecting a candidate beam identified by that SSB. The `ssb` field in `RACH-ConfigDedicated` can indicate the identifier (e.g., ID) of the SSB transmitted by the serving cell. The `cfra` field in `RACH-ConfigDedicated` can indicate one or more parameters for contention-free random access to a given target cell. For example, if the field (e.g., `cfra`) is not present, the radio device can perform contention-based random access. `ra-prioritization` can indicate one or more parameters applied to the priority random access procedure for a given target cell. For example, if the `resource` field in `CFRA` is set to `ssb`, the `SSB-CFRA` field in `RACH-ConfigDedicated` can exist; otherwise, it may not exist.

[0291] The wireless device can receive from the base station one or more RRC messages indicating at least one of the following: a set of available PRACH timings for the transmission of the random access preamble (e.g., prach-ConfigIndex); initial random access preamble power (e.g., preambleReceivedTargetPower); and RSRP thresholds (e.g., rsrp-ThresholdSSB) for the selection of the SSB and the corresponding random access preamble and / or PRACH timing. The rsrp-ThresholdSSB can be configured in beam failure recovery configuration (e.g., BeamFailureRecoveryConfig). Configured in the IE (e.g., if the random access procedure is initiated for beam fault recovery); RSRP thresholds for selecting CSI-RS and the corresponding random access preamble and / or PRACH timing (e.g., rsrp-ThresholdCSI-RS, rsrp-ThresholdCSI-RS can be set to values ​​calculated based on rsrp-ThresholdSSB and the offset value, e.g., by multiplying rsrp-ThresholdSSB by powerControlOffset); RSRP thresholds for selecting between NUL and SUL carriers (e.g., rsrp-ThresholdSSB-SUL); when the random access procedure is initiated for beam fault recovery; The power offset between rsrp-ThresholdSSB and rsrp-ThresholdCSI-RS to be used during beam fault recovery (e.g., PowerControlOffset); power ramp factor (e.g., powerRampingStep); power ramp factor in the case of differential random access procedures (e.g., powerRampingStepHighPriority); index of the random access preamble (e.g., ra-PreambleIndex); index of the PRACH timing associated with the SSB indicating that the MAC entity can transmit the random access preamble (e.g., ra-ssb-OccasionMaskIndex), for example, Figure 18An example of the ra-ssb-OccasionMaskIndex value is shown; the PRACH timing associated with CSI-RS for which the MAC entity can transmit random access preambles (e.g., ra-OccasionList); the maximum number of random access preambles transmitted (e.g., preambleTransMax); the number of SSBs mapped to each PRACH timing; and the number of random access preambles mapped to each SSB (e.g., ssb-perRACH-OccasionAndCB-PreamblesPerSSB), the time window (duration and / or interval) for monitoring RA responses (e.g., ra-ResponseWindow), and / or the contention resolution timer (e.g., ra-ContentionResolutionTimer).

[0292] In one example, the wireless device initiates a RA procedure for beam fault detection and recovery. For instance, the wireless device receives multiple RRC messages from the base station for the beam fault recovery procedure. The wireless device can then indicate to the serving base station, based on the beam fault recovery procedure, one or more serving SSBs / CSI-RSs on which the wireless device has detected a beam fault. Beam faults can be detected by counting one or more beam fault instance indications from the lower layer to the wireless device's MAC entity. For example, a wireless device receives an RRC message (e.g., including beam fault recovery configuration, such as BeamFailureRecoveryConfig) from a base station, which indicates at least one of the following: beamFailureInstanceMaxCount for beam fault detection, beamFailureDetectionTimer for beam fault detection, beamFailureRecoveryTimer for beam fault recovery process, rsrp-ThresholdSSB for beam fault recovery RSRP threshold, powerRampingStep for beam fault recovery, preambleReceivedTargetPower for beam fault recovery, PreambleReceivedTargetPower for beam fault recovery, PreambleTransMax for beam fault recovery, a time window (e.g., ra-ResponseWindow) for monitoring the response for beam fault recovery using a contention-free random access preamble, prach-ConfigIndex for beam fault recovery, ra-ssb-OcessionMaskIndex for beam fault recovery, and ra-OccasionList for beam fault recovery.

[0293] Wireless devices may adopt (or use or maintain) one or more parameters (or variables) for the random access procedure. For example, one or more parameters (or variables) include at least one of the following: PREAMBLE_INDEX;

[0294] PREAMBLE_TRANSMISSION_COUNTER;

[0295] PREAMBLE_POWER_RAMPING_COUNTER;

[0296] PREAMBLE_POWER_RAMPING_STEP;

[0297] PREAMBLE_RECEIVED_TARGET_POWER; PREAMBLE_BACKOFF; PCMAX; SCALING_FACTOR_BI; and TEMPORARY_C-RNTI.

[0298] The wireless device can perform random access resource selection to select one or more preambles and one or more PRACH timings (or resources including time, frequency, and / or code). For example, one or more of the following conditions may exist: a random access procedure can be initiated for beam failure recovery; and / or the beamFailureRecoveryTimer is running or not configured; and / or contention-free random access resources for beam failure recovery requests associated with any SSB and / or CSI-RS have been explicitly provided by the RRC; and / or at least one of the SSBs in the candidateBeamRSList with an SS-RSRP higher than rsrp-ThresholdSSB, or the CSI-RSs in the candidateBeamRSList with a CSI-RSRP higher than rsrp-ThresholdCSI-RS, is available. In this scenario, the wireless device can select one or more SSBs from the candidateBeamRSList whose corresponding SS-RSRP values ​​are higher than rsrp-ThresholdSSBs, or it can select one or more CSI-RSs from the candidateBeamRSList whose corresponding CSI-RSRP values ​​are higher than rsrp-ThresholdCSI-RSs. For example, if there is no ra-PreambleIndex associated with at least one CSI-RS, the wireless device can select at least one CSI-RS and set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the SSB in the candidateBeamRSList, which is quasi-co-located with the at least one CSI-RS selected by the wireless device. Otherwise, the wireless device can set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the SSB or CSI-RS selected from the random access preamble set to perform a beam fault recovery request.

[0299] The wireless device can receive the ra-PreambleIndex via PDCCH or RRC, which is not a specific preamble index (it can be predefined or configured, for example, 0b000000). In this case, the wireless device can set PREAMBLE_INDEX to the ra-PreambleIndex that is signaled.

[0300] One or more of the following scenarios may exist: Contention-free random access resources associated with an SSB have been explicitly provided to the radio device via RRC, and at least one of the associated SSBs with an SS-RSRP higher than the rsrp-Threshold SSB is available. In this case, the radio device can select the SSB with an SS-RSRP higher than the rsrp-Threshold SSB from the associated SSBs. For example, the radio device sets PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the selected SSB.

[0301] One or more of the following situations may exist: Contention-free random access resources associated with a CSI-RS have been explicitly provided to the radio device via RRC, and at least one of the associated CSI-RSs with a CSI-RS RSRP higher than rsrp-ThresholdCSI-RS is available. In this case, the radio device can select the associated CSI-RS with a CSI-RS RSRP higher than rsrp-ThresholdCSI-RS. For example, the radio device sets PREAMBLE_INDEX to ra-PreambleIndex corresponding to the selected CSI-RS.

[0302] One or more conditions may exist where at least one of the SSBs with an SS-RSRP higher than rsrp-ThresholdSSB is available. In this case, for example, the wireless device may select an SSB with an SS-RSRP higher than rsrp-ThresholdSSB. For example, if no SSB with an SS-RSRP higher than rsrp-ThresholdSSB is available, the wireless device may select any SSB. For example, random access resource selection is performed during retransmissions of Msg1 1311, Msg3 1313, Msg A 1331, and / or transport block 1342. The wireless device may select the same random access preamble group used in the random access preamble transmission attempt corresponding to the first transmission of Msg1 1311, Msg3 1313, Msg A 1331, and / or transport block 1342. For example, if an association between a random access preamble and an SSB is configured, the radio device randomly selects ra-PreambleIndex from the random access preamble associated with the selected SSB and the selected random access preamble group with equal probability. Conversely, if no association between a random access preamble and an SSB is configured, the radio device randomly selects ra-PreambleIndex from the random access preambles within the selected random access preamble group with equal probability. The radio device can set PREAMBLE_INDEX to the selected ra-PreambleIndex.

[0303] In one example, if an SSB is selected as described above and the association between the PRACH timing and the SSB is configured, the wireless device determines the next available PRACH timing from the PRACH timing corresponding to the selected SSB, which is allowed by the constraints given by ra-ssb-OccasionMaskIndex (if configured). (For example, the MAC entity of the wireless device may select a PRACH timing from PRACH timings that occur simultaneously but on different subcarriers (e.g., randomly with equal probability); when determining the next available PRACH timing corresponding to the selected SSB, the MAC entity may consider the possible occurrence of measurement intervals).

[0304] In one example, if a CSI-RS is selected as described above and the association between the PRACH timing and the CSI-RS is configured, the wireless device determines the next available PRACH timing from the PRACH timings in the ra-OccasionList corresponding to the selected CSI-RS (e.g., the MAC entity of the wireless device can randomly select a PRACH timing with equal probability from among the PRACH timings that occur simultaneously but on different subcarriers corresponding to the selected CSI-RS; when determining the next available PRACH timing corresponding to the selected CSI-RS, the MAC entity can consider the possibility of measurement intervals).

[0305] If a CSI-RS is selected as described above, and there is no contention-free random access resource associated with the selected CSI-RS, the radio device can determine the next available PRACH opportunity from the PRACH opportunities, for example, indicated by ra-ssb-OccasionMaskIndex (if configured) (e.g., ra-ssb-OccasionMaskIndex can indicate restrictions on which PRACH opportunities are allowed to be available), which corresponds to an SSB in the candidateBeamRSList quasi-co-located with the selected CSI-RS (e.g., the radio device's MAC entity can consider the possibility of measurement intervals when determining the next available PRACH opportunity corresponding to an SSB quasi-co-located with the selected CSI-RS).

[0306] The wireless device can determine the next available PRACH opportunity. For example, the MAC entity of the wireless device selects a PRACH opportunity from those that occur simultaneously but on different subcarriers (e.g., randomly with equal probability). The MAC entity can determine the next available PRACH opportunity based on (e.g., by taking into account) the possible occurrence of measurement intervals.

[0307] The wireless device can perform random access preamble transmission based on the selected PREABLE INDEX and PRACH timing. For example, if a notification of a pause power ramp counter has not yet been received from a lower layer (e.g., the physical layer); and / or if the selected SSB and / or CSI-RS have not changed (e.g., are the same as the previous random access preamble transmission), the wireless device can increment PREMBLE_POWER_RAMPING_COUNTER, for example, by 1 or increment it to the next value (e.g., the counter step size can be predefined and / or semi-statically configured). For example, the wireless device selects a value of DELTA_PREAMBLE that can be predefined and / or semi-statically configured by the base station and sets PREMBLE_RECEIVED_TARGET_POWER to preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREMBLE_POWER_RAMPING_STEP.

[0308] The MAC entity of a wireless device can instruct the physical layer to use the selected PRACH, the corresponding RA-RNTI (e.g., if available), PREAMBLE_INDEX, and PREAMBLE_RECEIVED_TARGET_POWER to transmit the random access preamble. For example, the wireless device determines the RA-RNTI associated with the timing of the PRACH for transmitting the random access preamble. In one example, the RA-RNTI can be determined based on the index of the first OFDM symbol of the specified PRACH, the index of the first slot of the specified PRACH in the system frame, the index of the specified PRACH in the frequency domain, and / or the uplink carrier indicator. For example, the specified PRACH is the PRACH for which the wireless device transmits the random access preamble. An example RA-RNTI is determined as:

[0309] RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id, where s_id can be the index of the first OFDM symbol specifying the PRACH (0 ≤ s_id < 14), t_id can be the index of the first slot specifying the PRACH in the system frame (0 ≤ t_id < 80), f_id can be the index of the PRACH in the frequency domain (0 ≤ f_id < 8), and ul_carrier_id (0 for NULL carriers, 1 for SUL carriers, and vice versa) can be the UL carrier used for Msg1 1311 transmission or preamble 1341. In unlicensed bands, RA-RNTI can be further determined based on SFN and / or RAR window size. For example, the RA-RNTI can be further determined based on the remainder after dividing the SFN by the RAR window size (e.g., the modulo of the RAR window size). An example RA-RNTI determination in the unlicensed band could be:

[0310] RA-RNTI=1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id×14×80×8×2×(SFN modulo RAR window size),

[0311] Here, SFN is the system frame number of the first time slot, and the RAR window size is configured by higher-level parameters (e.g., ra-ResponseWindow in RACH-ConfigGeneric). For example, according to an implementation, (SFN modulo RARwindow size) can precede any component (s_id, 14×t_id, 14×80×f_id, and / or 14×80×8×ul_carrier_id) in the RA-RNTI calculation formula.

[0312] A radio device that has transmitted a random access preamble can begin monitoring the downlink control channel in response to the random access response corresponding to the random access preamble. For a two-step RA procedure, the radio device can begin monitoring the downlink control channel, for example, after or in response to the transmission of a RAP via PRACH, or after or in response to the transmission of one or more TBs via PUSCH. The possibility of measurement intervals may prevent determination of when the radio device begins monitoring the downlink control channel.

[0313] For example, if a wireless device performs a contention-free random access procedure for a beam failure recovery request, the wireless device may open a random access window (e.g., ra-ResponseWindow) configured in beam management configuration parameters (e.g., BeamFailureRecoveryConfig) at the timing of the first downlink control channel (e.g., PDCCH) after either the end of a random access preamble transmission (e.g., Msg1 1311 or Msg1 1321 in the case of a four-step RA procedure) or the end of one or more TB transmissions (e.g., transport block 1342 in the case of a two-step RA procedure). The wireless device may monitor the first downlink control channel of the SpCell while the random access window is running to look for a response to a beam failure recovery request identified by a specific RNTI (e.g., RA-RNTI or C-RNTI).

[0314] For example, if the wireless device does not perform a contention-free random access procedure for beam fault recovery requests, the wireless device may open a random access window (e.g., ra-ResponseWindow) configured in the random access configuration parameters (e.g., RACH-ConfigCommon) at the first downlink control channel timing after the end of a random access preamble transmission (e.g., Msg1 1311 or Msg11321 in the case of a four-step RA procedure) or after the end of a transmission of one or more TBSs (e.g., transport block 1342 in the case of a two-step RA procedure). While the random access response window (e.g., ra-ResponseWindow) is running, the wireless device may monitor the first downlink control channel timing of the SpCell for random access responses identified by a specific RNTI (e.g., RA-RNTI or C-RNTI).

[0315] A wireless device can receive a PDCCH based on RA-RNTI. The PDCCH can indicate a downlink allocation, upon which the wireless device can receive one or more TBs including a MAC PDU. For example, the MAC PDU includes at least one MAC sub-PDU with a corresponding subheader that includes a random access preamble identifier (e.g., RAPID) that matches the preamble transmitted by the wireless device to the base station. In this case, the wireless device can determine that the random access response reception was successful. For example, at least one MAC sub-PDU includes only a random access preamble identifier (e.g., RAPID), for example, for a random access procedure initiated by the wireless device in response to a system information request.

[0316] During the RA process, the wireless device can receive at least one RAR (e.g., Msg2 1312, Msg2 1322, or MsgB 1332) from the base station as a response to Msg1 1313, Msg1 1321, or MsgA 1331. The wireless device can monitor a search space set (e.g., Type 1-PDCCH common search space) for first downlink control information (e.g., DCI format 1_0). The first downlink control information can be scrambled by a specific radio network temporary identifier (e.g., RA-RNTI, C-RNTI, or msgB-RNTI). The first downlink control information may include a downlink allocation indicating the scheduling of a PDSCH including at least one RAR. The wireless device can use the downlink allocation to identify parameters required for decoding / detecting the PDSCH. For example, the downlink allocation indicates at least one of the following: time and frequency resource allocation for the PDSCH, the size of the PDSCH, MCS, etc. The wireless device can receive the PDSCH including at least one RAR based on these parameters.

[0317] The wireless device can monitor first downlink control information (e.g., DCI format 1_0) during a time window. The time window can be indicated by one or more RRC messages. For example, the time window may begin at a specific symbol (e.g., the first or last symbol) of the first control resource set. The wireless device can receive one or more RRC messages from the network or base station, which include one or more parameters required to receive the first downlink control information on the first control resource set. The wireless device can determine the length of the time window based on one or more parameters (e.g., ra-ResponseWindow). The length of the time window can be defined based on the number of time slots, OFDM symbols, and / or any combination thereof. In this case, the length may depend on the duration of the time slots and / or OFDM symbols, which can be determined based on a set of underlying parameters. The length of the time window can be defined based on an absolute duration (e.g., in milliseconds).

[0318] A wireless device may stop a time window, for example, after determining that one or more random access responses have been successfully received, or in response to determining that one or more random access responses have been successfully received. For example, the reception of one or more random access responses may be determined to be successful when they include a preamble index (e.g., random access preamble identifier: RAPID) corresponding to a preamble transmitted by the wireless device to the base station. For example, RAPID may be associated with a PRACH transmission. One or more random access responses may include uplink grants indicating one or more uplink resources granted to the wireless device. The wireless device may transmit one or more transport blocks (e.g., Msg 3 1313) via one or more uplink resources.

[0319] RARs can be in the form of MAC PDUs that include one or more MAC sub-PDUs and / or optional padding. Figure 19A This is an example of a RAR according to an exemplary embodiment of this disclosure. The MAC subheader may be octet aligned. Each MAC subPDU may include at least one of the following: a MAC subheader with only a backoff indicator; a MAC subheader with only a RAPID (i.e., acknowledgment of an SI request); or a MAC subheader with both a RAPID and a MAC RAR. Figure 19B This is an example of a MAC subheader with a backoff indicator according to an exemplary embodiment of the present disclosure. For example, a MAC subheader with a backoff indicator includes one or more header fields, such as... Figure 19B The E / T / R / R / BI described in [reference needed]. For example, if a MAC sub-PDU includes a fallback indicator, then the MAC sub-PDU with the fallback indicator can be placed at the beginning of the MAC PDU. MAC sub-PDUs with only RAPID and MAC sub-PDUs with both RAPID and MAC RAR can be placed anywhere after the MAC sub-PDU with the fallback indicator, and if present, before padding, as [reference needed]. Figure 19A According to one aspect of an exemplary embodiment of this disclosure, a MAC subheading with RAPID may include one or more header fields, for example, Figure 19C The E / T / RAPID is described in [reference needed]. If padding is present, it can be placed at the end of the MAC PDU. The presence and length of padding can be implicit, depending on the TB size and the size of the MAC sub-PDU.

[0320] In one example, one or more header fields in the MAC subheader may indicate the following: The E field may indicate an extension field, which may be a flag indicating whether the MAC subPDU containing the MAC subheader is the last MAC subPDU in the MAC PDU. The E field may be set to "1" to indicate that at least one other MAC subPDU follows. The E field may be set to "0" to indicate that the MAC subPDU containing the MAC subheader is the last MAC subPDU in the MAC PDU; The T field may be a flag indicating whether the MAC subheader contains a random access preamble ID or a backoff indicator (one or more backoff values ​​may be predefined, and the BI may indicate one of the backoff values). The T field may be set to "0" to indicate that a backoff indicator field exists in the subheader (BI). The T field may be set to "1" to indicate that a random access preamble ID field exists in the subheader (RAPID); The R field may indicate a reserved bit that can be set to "0"; The BI field may be a backoff indicator field that identifies overload conditions in the cell. The BI field can be 4 bits in size; the RAPID field can be a random access preamble identifier field, which can identify the transmitted random access preamble. For example, if the RAPID in the MAC subheader of the MAC subPDU corresponds to one of the random access preambles configured for the SI request, then the MAC subPDU may not include the MAC RAR.

[0321] One or more MAC RAR formats may exist. At least one of the following MAC RAR formats can be used in a four-step RA process or a two-step RA process. For example, Figure 20 This is an example of one of the MAC RAR formats according to an exemplary embodiment of this disclosure. MAC RAR can be as follows: Figure 20 The RAR is a fixed size and may include at least one of the following fields: an R field, which may indicate reserved bits set to "0" or "1"; a timing advance command field, which may indicate an index value TA used to control the timing adjustment amount; a UL authorization field, which indicates the resources to be used on the uplink; and an RNTI field (e.g., temporary C-RNTI and / or C-RNTI), which may indicate the identity used during random access. For example, for a two-step RA procedure, the RAR may include at least one of the following: a UE contention resolution identifier, an RV ID for retransmission of one or more TBs, a decoding success or failure indicator for one or more TB transmissions, and Figure 20 One or more fields as shown.

[0322] It is possible for a base station to multiplex RARs in the MAC PDU for both two-step and four-step RA procedures. The wireless device may not require a RAR length indicator field, and / or the wireless device may determine the boundaries of each RAR in the MAC PDU based on predetermined RAR size information (e.g., if the RARs used for two-step and four-step RA procedures have the same size). Figure 21 This is an example RAR format that can be used in a MAC PDU according to an example embodiment of the present disclosure, which multiplexes RAR for two-step RA processes and four-step RAR RA processes. Figure 21 The RAR shown can be a fixed-size file using the same format for both two-step and four-step RA procedures. Depending on the type of RA procedure, the wireless device may use different methods (parse, interpret, or determine). Figure 21 The bit string (e.g., 6 octets) used for the UE contention resolution identifier. For example, a radio device initiating a two-step RA procedure identifies whether contention resolution was successful (e.g., resolved or made) based on the bit string, for example, by comparing the contention resolution identifier with the bit string (e.g., 6 octets) used for the UE contention resolution identifier. For example, a radio device initiating a four-step RA procedure uses (parses, interprets, or determines) the bit string (e.g., 6 octets) differently, for example, for purposes different from contention resolution. For example, in this case, the bit string could indicate another UL authorization for one or more additional Msg3 1313 transmission opportunities, padding bits, etc.

[0323] In one example, a RAR used for a two-step RA procedure can have a different format, size, and / or fields than a RAR used for a four-step RA procedure. For example, Figure 22A and Figure 22B This is an example RAR format that can be used in a two-step RA process, according to an example embodiment of this disclosure. For example, if one or more RARs (e.g., RARs for two-step and four-step RA processes) are multiplexed into a MAC PDU, and the RARs have different formats between the multiplexed RARs (e.g., between two-step RA processes and / or between two-step and four-step RA processes), then the RAR may include a field indicating the RAR type or RAR length (e.g., such as...). Figure 21 , Figure 22A and Figure 22B The reserved "R" field is shown. Fields indicating the RAR type (or length) can be in a subheader (such as a MAC subheader), in the MAC RAR, or in a separate MAC subPDU within the RAR (e.g., like...). Figure 19AThe MAC sub-PDU 1 and / or MAC sub-PDU 2 may contain another MAC sub-PDU indicating the RAR type (or length). The RAR may include fields of different types corresponding to implicit and / or explicit indicators in the sub-header or RAR. The wireless device may determine the boundaries of one or more RARs in the MAC PDU based on one or more indicators.

[0324] A random access response window may exist, whereby a wireless device can monitor the downlink control channel in response to a random access response transmitted from a base station, which serves as a response to a preamble received from the wireless device. For example, the base station may transmit a message including the value of the RAR window. For example, cell-common or wireless device-specific random access configuration parameters in the message (e.g., RACH-ConfigGeneric, RACH-ConfigCommon, RACH-ConfigDedicated, or ServingCellConfig) indicate the value of the RAR window (e.g., ra-ResponseWindow). For example, the value of the RAR window may be fixed, for example, fixed at 10 ms or other time values. For example, the value of the RAR window may be defined according to the number of time slots shown in RACH-ConfigGeneric. The wireless device may identify (or determine) the size of the RAR window (e.g., absolute duration and / or length) based on a set of underlying parameters configured for the random access procedure. For example, a basic parameter set defines one or more system parameters, such as subcarrier spacing, slot duration, cyclic prefix size, number of OFDM symbols per slot, number of slots per frame, number of slots per subframe, minimum number of physical resource blocks, and / or maximum number of physical resource blocks. For example, one or more system parameters associated with the basic parameter set can be predefined using different subcarrier spacings, slot durations, and / or cyclic prefix sizes. For example, for a basic parameter set μ = 0, a wireless device can identify a subcarrier spacing of 15 kHz, a normal cyclic prefix, 14 symbols per slot, 10 slots per frame, and / or 1 slot per subframe. For example, for a basic parameter set μ = 1, a wireless device can identify a subcarrier spacing of 30 kHz, a normal cyclic prefix, 14 symbols per slot, 20 slots per frame, and / or 2 slots per subframe. For example, for a basic parameter set μ = 2 with a normal cyclic prefix, a wireless device can identify a subcarrier spacing of 60 kHz, 14 symbols per slot, 40 slots per frame, and / or 4 slots per subframe. For example, for a base parameter set μ=2 with an extended cyclic prefix, a wireless device can identify a subcarrier spacing of 60 kHz, 12 symbols per time slot, 40 time slots per frame, and / or 4 time slots per subframe. For example, for a base parameter set μ=3, a wireless device can identify a subcarrier spacing of 120 kHz, a normal cyclic prefix, 14 symbols per time slot, 80 time slots per frame, and / or 8 time slots per subframe. For example, for a base parameter set μ=4, a wireless device can identify a subcarrier spacing of 240 kHz, a normal cyclic prefix, 14 symbols per time slot, 160 time slots per frame, and / or 16 time slots per subframe.

[0325] A wireless device can determine (or identify) the size (e.g., duration or length) of a RAR window based on a configured RAR window value and a base parameter set. For example, if the configured RAR window value is sl20 (e.g., 20 time slots) and the base parameter set is μ = 0 (e.g., for μ = 0, the time slot duration is 1 ms), then the RAR window has a duration of 20 ms. In one example, a specific RAR window value (e.g., ra-ResponseWindow) configured by an RRC message (e.g., broadcast and / or radio-specific unicast) can be associated with a specific base parameter set. For example, in RACH-ConfigGeneric, sl10, sl20, sl40, and sl80 can be the values ​​of ra-ResponseWindow for base parameter sets μ = 0, μ = 1, μ = 2, and μ = 3, respectively. In one example, the base station configures a wireless device-specific RAR window value independently of the base parameter set. In licensed frequency bands, the size (e.g., duration or length) of the RAR window can be no longer than 10 ms (and / or the periodicity of the PRACH timing). In unlicensed frequency bands, the duration (e.g., size or length) of the RAR window can be longer than 10 ms (and / or the periodicity of the PRACH timing).

[0326] A radio device may perform one or more retransmissions of one or more preambles during a random access procedure (e.g., a two-step RA procedure and / or a four-step RA procedure). One or more conditions may exist upon which the radio device determines one or more retransmissions of one or more preambles, based at least on these conditions. For example, the radio device may determine one or more retransmissions of one or more preambles when it determines that a random access response reception was unsuccessful. For example, if at least one random access response including one or more random access preamble identifiers matching the transmitted PREAMBLE_INDEX is not received until the expiration of the RAR window (e.g., ra-ResponseWindow configured by RRC such as RACH-ConfigCommonIE), the radio device may determine that the random access response reception was unsuccessful. For example, if a PDCCH addressed to C-RNTI has not been received on the serving cell transmitting the preamble until the expiration of the RAR window used for beam failure recovery procedures (e.g., ra-ResponseWindow configured in BeamFailureRecoveryConfig), the radio device may determine that the random access response reception was unsuccessful.

[0327] For example, when a wireless device determines that contention resolution is unsuccessful, it can determine one or more retransmissions of one or more preambles. For instance, the wireless device can determine whether contention resolution was successful based on Msg 3 1313 for a four-step RA process and / or MsgB 1332 for a two-step RA process.

[0328] For example, once the wireless device transmits Msg3 1313 to the base station, the wireless device's MAC entity can start a contention resolution timer (e.g., ra-ContentionResolutionTimer) and can restart the contention resolution timer (e.g., ra-ContentionResolutionTimer) during each HARQ retransmission in the first symbol after the Msg3 transmission ends. For example, if the wireless device does not receive an indication of contention resolution while the contention resolution timer (e.g., ra-ContentionResolutionTimer) is running, the wireless device can determine that contention resolution was unsuccessful. For example, if no indication of contention resolution is received before the contention resolution timer (e.g., ra-ContentionResolutionTimer) expires, the wireless device can determine that contention resolution was unsuccessful. The wireless device can discard the TEMPRARY_C-RNTI indicated by Msg2 1312 (or Msg B 1332) after the contention resolution timer expires or in response to the expiration of the contention resolution timer (and / or in response to determining that contention resolution was unsuccessful).

[0329] For a two-step RA procedure, the wireless device may, for example, start a timer (e.g., a RAR window, a MsgB window, or a contention-resolving timer) after or in response to the transmission of a transport block 1342 including the wireless device's contention-resolving identifier. For example, if at least one MsgB including the contention-resolving identifier transmitted by the wireless device has not been received by the timer expires, the wireless device may determine one or more retransmissions of MsgA 1331 (e.g., preamble 1341 and / or transport block 1342). For example, for a two-step RA procedure, the wireless device may backtrack to a four-step RA procedure based on explicit and / or implicit indications of the MsgB. For example, if the MsgB received by the wireless device includes such an explicit indication and / or the RNTI of the PDCCH used to detect the scheduling of the MsgB is a specific RNTI (e.g., RA-RNTI or msgB RNTI), the wireless device may determine to backtrack to a four-step RA procedure. The wireless device may transmit Msg3, for example, after determining that it has fallen back to the four-step RA procedure via the resources indicated by the UL authorization in Msg B, or in response to determining that it has fallen back to the four-step RA procedure via the resources indicated by the UL authorization in Msg B. In this case, the wireless device may follow the four-step RA procedure, for example, starting a contention resolution timer, and / or determining whether contention resolution was successful. The wireless device may monitor the PDCCH while the contention resolution timer (e.g., ra-ContentionResolutionTimer) is running. The wireless device may restart the contention resolution timer (e.g., ra-ContentionResolutionTimer) at each HARQ retransmission in the first symbol after the end of Msg3 transmission. For example, if no indication of contention resolution is received before the contention resolution timer (e.g., ra-ContentionResolutionTimer) expires, the wireless device may determine that contention resolution was unsuccessful. A wireless device may discard the TEMPRARY_C-RNTI indicated by Msg2 1312 (or Msg B 1332) after the contention resolution timer expires or in response to the expiration of the contention resolution timer (and / or in response to determining that contention resolution was unsuccessful). A wireless device that determines a retransmission during a four-step RA process that has fallen back from a two-step RA process may perform a retransmission of MsgA 1331. A wireless device that determines a retransmission during a four-step RA process that has fallen back from a two-step RA process may perform a retransmission of Msg11311. For example, if a notification of a received PDCCH transmission from a cell (e.g., SpCell) is received from a lower layer, and the wireless device recognizes that the PDCCH transmission is an indication of contention resolution corresponding to a Msg3 transmission (or Msg B transmission) performed by the wireless device, the wireless device may stop the contention resolution timer and determine that contention resolution was successful.

[0330] For example, after unsuccessful random access response reception or in response to unsuccessful random access response reception, and / or after unsuccessful contention resolution or in response to unsuccessful contention resolution, a wireless device may maintain (e.g., increment) the value of a counter step (e.g., 1) of a counter (e.g., PREAMBLE_TRANSMISSION_COUNTER) that counts the number of preamble transmissions. For example, if the number of preamble transmissions can reach a predefined or semi-statically configured value (e.g., if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1, where preambleTransMax is a predefined or semi-statically configured value), then the wireless device may determine that the random access procedure has not been successfully completed and / or the MAC entity of the wireless device may indicate a random access problem to the upper layer. For example, if the number of preamble transmissions does not reach a predefined or semi-statically configured value (e.g., if PREAMBLE_TRANSMISSION_COUNTER < preambleTransMax + 1), then the wireless device may determine that the random access procedure has not been completed and / or may perform one or more retransmissions of one or more of Msg1 1311, Msg1 1321, or MsgA 1331.

[0331] The wireless device may delay a specific period of time (e.g., backoff time) for performing retransmissions of one or more of Msg1 1311, Msg1 1321, or MsgA 1331. For example, when initiating a random access procedure, the wireless device may set the backoff time to 0 ms. The wireless device may set (or update) the backoff time based on PREAMBLE_BACKOFF determined by the value in the BI field of the MAC sub-PDU (e.g., Figure 19B the BI field in Figure 19BThe example format shows the allocation of four bits for the BI field. In this case, 16 values ​​can exist in a predefined or semi-statically configured table (e.g., each of the 16 values ​​is identified by a specific row index). For example, if a wireless device receives one or more RRC messages from a base station indicating a scaling factor, the wireless device can set PREAMBLE_BACKOFF to the value indicated by multiplying the BI field of the MAC sub-PDU by the scaling factor (e.g., SCALING_FACTOR_BI). For example, if a downlink allocation for RA-RNTI has been received on the PDCCH and the received TB has been successfully decoded, and / or if the random access response includes a backoff indicator ( Figure 19B If the MAC subPDU contains a BI field, the wireless device can set (or update) PREMABLE_BACKOFF based on the BI field. For example, if a downlink allocation for RA-RNTI has not yet been received on the PDCCH and / or the received TB has not been successfully decoded, and / or if the random access response does not include a backoff indicator (...). Figure 20 If the MAC subPDU of BI in B is used, then the wireless device can set PREAMBLE_BACKOFF to 0ms.

[0332] For example, if the wireless device determines that the random access response was unsuccessful and / or contention resolution was unsuccessful, the wireless device can determine a backoff time. The wireless device can employ a specific selection mechanism to determine the backoff time. For example, the wireless device can determine the backoff time based on a uniform distribution between 0 and PREAMBLE_BACKOFF. The wireless device can use any type of distribution to select a backoff time based on PREAMBLE_BACKOFF. The wireless device can ignore PREAMBLE_BACKOFF (e.g., Figure 20 The value in the BI field of B) and / or may not have a backoff time. For example, the wireless device may determine whether to apply backoff time to the retransmission of at least one preamble based on the type of event that initiated the random access procedure (e.g., beam failure recovery request, handover, etc.) and / or the type of random access procedure (e.g., four-step RA or two-step RA and / or CBRA or CFRA). For example, if the random access procedure is CBRA (e.g., where the preamble is selected by the MAC entity of the wireless device) and / or if the wireless device determines that the random access procedure is not complete based on the unsuccessful reception of the random access response, the wireless device may apply backoff time to the retransmission. For example, if the wireless device determines that the random access procedure is not complete based on the unsuccessful contention resolution, the wireless device may apply backoff time to the retransmission.

[0333] For example, if the random access procedure is not completed, the radio device may perform a random access resource selection procedure (e.g., selecting at least one SSB or CSI-RS and / or selecting a PRACH corresponding to at least one SSB or CSI-RS selected by the radio device). The radio device may delay subsequent random access preamble transmissions (e.g., or delay to perform the random access resource selection procedure) by a rollback time.

[0334] Radio access technologies can allow wireless devices to change (switch) channels (uplink carrier, BWP, and / or subbands) to transmit at least one preamble for retransmission. This can increase the number of preamble transmission opportunities in unlicensed frequency bands. For example, a base station can transmit one or more messages (broadcast messages and / or RRC messages) to a wireless device indicating the configuration of one or more channels (e.g., uplink carrier, BWP, and / or subbands) configured with one or more PRACHs. The wireless device can select one of the one or more channels (e.g., BWP and / or subbands) as the channel (e.g., uplink carrier, BWP, and / or subband) for transmitting at least one first preamble. The wireless device can select a channel (e.g., uplink carrier, BWP, and / or subband) based on LBT results. For example, the wireless device performs one or more LBTs on one or more channels and selects a channel from those sensed as idle. The wireless device can select one of the sensed idle channels based on, for example, random selection. There may be situations where switching the channel used for retransmission is not allowed (e.g., the indication may be predefined or semi-statically notified).

[0335] The wireless device can determine the transmission power for retransmission of at least one preamble (or Msg A) based on PREAMBLE_POWER_RAMPING_COUNTER. For example, as initialization of a random access procedure, the wireless device can set PREAMBLE_POWER_RAMPING_COUNTER to an initial value (e.g., 1). For example, for each random access preamble and / or for each transmission of at least one preamble transmitted, for example, after determining that random access reception was unsuccessful and / or contention resolution was unsuccessful, or in response to determining that random access reception was unsuccessful and / or contention resolution was unsuccessful, the MAC entity of the wireless device can increment PREAMBLE_POWER_RAMPING_COUNTER by a counter step size predefined or semi-statically configured by the base station. For example, if PREAMBLE_TRANSMISSION_COUNTER is greater than one; if a notification of a pause power ramp counter has not yet been received from a lower layer (e.g., in response to a dropped preamble transmission due to LBT failure and / or in response to a spatial filter change); and / or the selected SSB or CSI-RS has not changed from the selection in the last random access preamble transmission, the MAC entity of the wireless device may increment PREAMBLE_POWER_RAMPING_COUNTER by 1. The wireless device may determine the value of DELTA_PREAMBLE based on the preamble format and / or base parameter set selected for the random access procedure (e.g., one or more values ​​of DELTA_PREAMBLE are predefined in association with one or more preamble formats and / or base parameter sets. For a given preamble format and base parameter set, the wireless device can select a specific value of DELTA_PREAMBLE from one or more values). The wireless device can determine PREAMBLE_RECEIVED_TARGET_POWER as preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER – 1) × PREAMBLE_POWER_RAMPING_STEP. The MAC layer of the wireless device can instruct the physical layer to transmit the random access preamble based on the selected PRACH timing, the corresponding RA-RNTI (e.g., if available), PREAMBLE_INDEX, and / or PREAMBLE_RECEIVED_TARGET_POWER.

[0336] For a two-step RA procedure, MsgA 1331 (or transport block 1342) may include a Common Control Channel (CCCH) SDU. For example, the transmission of transport block 1342 is directed to the CCCH logical channel. For instance, the radio device may transmit an RRC (re)establishment request, an RRC establishment request, and / or an RRC recovery request to the base station via the CCCH. The radio device may begin monitoring a downlink control channel (e.g., a PDCCH) with a first RNTI (e.g., msgB RNTI). The PDCCH received via the downlink control channel indicates a downlink allocation including a PDSCH (e.g., a MAC PDU) containing MsgB 1332. In this case, the MsgB 1332 (or the PDSCH including MsgB 1332, e.g., a MAC PDU) received by the radio device based on the downlink assignment may include a Signaling Radio Bearer (SRB) RRC message. SRB RRC messages may include RRC (re)establishment, RRC establishment, and / or RRC recovery, respectively, as responses to RRC (re)establishment requests, RRC establishment requests, and / or RRC recovery requests transmitted by the wireless device via Msg A1331 (or transport block 1342).

[0337] When Msg A1331 (or transport block 1342) includes a Common Control Channel (CCCH) SDU, a MAC PDU (or PDSCH) may multiplex one or more MsgBs for one or more radio devices. A MAC PDU may multiplex one or more MsgBs indicating only the success of Msg A. A MAC PDU may multiplex one or more MsgBs indicating only the failure of Msg A (e.g., a fallback response). A MAC PDU may multiplex multiple MsgBs including one or more responses indicating the success of Msg A and / or one or more responses indicating the failure of Msg A (e.g., a fallback RAR). A MAC PDU may include at least one backoff indication. For a MsgB indicating the success of Msg A, the MsgB may include at least one of the following: a contention resolution identifier (which matches the identifier transmitted by the radio device via Msg A), a C-RNTI, and / or a TA command. For a MsgB indicating MsgA failure (e.g., a fallback RAR), the MsgB may include at least one of the following: RAPID, UL authorization (e.g., for retransmitting the MsgA payload), TC-RNTI, and / or TA command. For example, upon receiving a MsgB indicating MsgA failure (e.g., a fallback RAR), the wireless device may proceed with a four-step RACH process for Msg3 1313 transmission (e.g., in...). Figure 13A(In the context of a fallback procedure). For example, Msg3 1313 transmitted by a wireless device as part of a fallback procedure includes a CCCH SDU transmitted via MsgA. A MAC PDU including MsgB indicating the success of MsgA may not be multiplexed with a four-step RACH RAR (e.g., Msg 2 1312).

[0338] Figure 23 This is an example diagram illustrating a two-step RA process performed between a wireless device and a base station according to an exemplary embodiment of the present disclosure. Figure 23 As shown, the wireless device can transmit a MsgA including a first transmission of a preamble and a second transmission of a transport block. The transport block may include a CCCH SDU. The CCCH SDU may include an RRC (re)establishment request, an RRC establishment request, and / or an RRC recovery request. The wireless device can begin monitoring the downlink control channel addressed to a specific RNTI. The wireless device can begin a MsgB RAR window after transmitting the MsgA or transport block, or in response to transmitting the MsgA or transport block. This specific RNTI may be referred to as the msgB-RNTI or RA-RNTI. The wireless device can determine the specific RNTI based on the timing (e.g., OFDM symbols, time slots, subframes, and / or SFN numbers) and / or frequency index of the radio resources used for the first transmission of the preamble and / or the second transmission of the transport block. The wireless device can further determine the specific RNTI based on the preamble index of the preamble and / or the DMRS port index.

[0339] The wireless device can detect and / or receive a PDCCH addressed to a specific RNTI during the Msgb RAR window. The DCI received via the PDCCH may include a downlink allocation indicating PDSCH reception. The DCI may be a specific DCI whose format is predefined. For example, the DCI may be DCI format 1_0 or DCI format 1_1. The wireless device can receive and / or decode the PDSCH based on the downlink allocation. The physical layer can decode the PDSCH and transmit the decoded data to the MAC entity in the form of a MAC PDU. The wireless device can identify a response (e.g., MsgB) to the MsgA in the MAC PDU. The response to MsgA may include a preamble identifier that matches the preamble identifier transmitted by the wireless device to the base station via MsgA. The response to MsgA may include explicit or implicit indicators indicating a successful RAR or a backtracking RAR. For example, the response to MsgA may include a field indicating the type of RAR (success or backtracking). The wireless device can identify the type of RAR based on the format of the received RAR. For example, successful RARs and returned RARs may include one or more different field types and / or sizes, which wireless devices can use to identify the type of RAR.

[0340] For a two-step RA process, it is similar to Figure 23In the two-step RA process, the wireless device can determine whether contention resolution was successful and / or whether MsgB was successfully received, based at least on the C-RNTI. If the wireless device already has an assigned C-RNTI, it can transmit MsgA, including the C-RNTI, to the base station. For example, the wireless device may have received a message including the C-RNTI from the base station before the transmission of MsgA. MsgA (or a transport block of MsgA) may include a C-RNTI MAC CE indicating the C-RNTI to the base station. The wireless device may begin monitoring the downlink control channel for MsgB with one or more RNTIs, for example, after transmitting MsgA (or a transport block of MsgA) or in response to the transmission of MsgA (or a transport block of MsgA). For example, after or in response to a MsgA transmission indicating a C-RNTI (e.g., C-RNTI MAC CE), the wireless device can monitor a downlink control channel (e.g., PDCCH) with one or more RNTIs. The one or more RNTIs may include a first RNTI (e.g., MsgB-RNTI) determined (or calculated) based on uplink radio resources used for MsgA transmission. For example, the first RNTI may be an RA-RNTI. For example, the first RNTI may be determined based on uplink radio resources used for the preamble and / or transport block of MsgA. Uplink radio resources may include the timing (e.g., represented from any combination of OFDM symbols, slot numbers, subframe numbers, and / or SFNs) and / or frequency indexes for the PRACH timing of the MsgA preamble transmission, the preamble identifier for the MsgA preamble, the timing (e.g., represented from any combination of OFDM symbols, slot numbers, subframe numbers, SFNs, and / or time offsets with respect to the associated PRACH timing) and / or frequency indexes, and / or DMRS indexes (e.g., DMRS port identifiers for the PUSCH timing of the MsgA transport block transmission). For example, a radio device may monitor the PDCCH addressed to the C-RNTI for a successful response to MsgA and monitor the PDCCH addressed to the first RNTI (e.g., MsgB-RNTI) for a failed (or backoff) response to MsgA. The radio device may start a timer (e.g., a contention-resolved timer) and / or monitor the downlink control channel while the timer is running. For example, a timer can determine how long a wireless device monitors the downlink control channel (e.g., within a specific time interval or period) to receive a response to MsgA from the base station (e.g., a success response and / or a backoff response).

[0341] If the wireless device receives at least one response (e.g., a PDCCH addressed to a C-RNTI and / or a PDCCH addressed to a first RNTI), the wireless device may stop monitoring the downlink channel. The wireless device may determine that contention resolution was successful based on one or more conditions. For example, if the PDCCH addressed to a C-RNTI is detected to be included in the MsgA, and the PDSCH indicated by the PDCCH (e.g., downlink allocation via DCI) includes a TA command, the wireless device may determine that contention resolution was successful. For example, if the PDCCH addressed to a C-RNTI is detected to be included in the MsgA, and the PDSCH indicated by the PDCCH (e.g., downlink allocation via DCI) includes a UL grant (e.g., if the wireless device has been synchronized), the wireless device may determine that contention resolution was successful. The PDCCH addressed to a C-RNTI may be an indication of a successful response. For example, if the wireless device receives a fallback response (e.g., RAR), the wireless device stops monitoring the PDCCH addressed to a C-RNTI. In this scenario, contention resolution is unsuccessful, and the wireless device can fall back to Msg3 transmission (e.g., as discussed above in Figure 13) based on a fallback operation. The wireless device can identify the fallback response based on a PDCCH addressed to a first RNTI (e.g., MsgBRNTI). For example, when the wireless device monitors a PDCCH, it detects a PDCCH addressed to a first RNTI (e.g., msgB RNTI). The PDCCH (e.g., a DCI with downlink allocation) may include a downlink allocation, based on which the wireless device receives a PDSCH including the fallback response. The PDSCH may include one or more responses. The wireless device identifies a response from the one or more responses based on one or more identifiers. For example, if the identifier of a response matches the preamble index of the MsgA preamble, the wireless device identifies the response from the one or more responses. The response may include a UL grant indicating that the wireless device transmits uplink radio resources(s) of Msg3 based on a fallback operation. Figure 19A (For example, with) Figure 19B and Figure 19C Together, an example format of a PDU based on the PDSCH received by the first RNTI is shown. For example, Figure 19C In this context, RAPID is an example identifier, based on which the wireless device identifies its corresponding response to the fallback response (e.g., ...). Figure 19AThe MAC RAR in the timer. If no backoff response or PDCCH addressed to C-RNTI is detected within a timer (e.g., a contention-resolved timer), the wireless device can determine that MsgB reception (or contention-resolved or MsgA transmission attempt) has failed. In this case, if a backoff indicator is received in MsgB, the wireless device can determine the failure based on the backoff indicator (e.g., MAC RAR in the timer). Figure 19B Use this to perform the rollback operation.

[0342] Figure 24 This is an example diagram illustrating a two-step RA process performed between a wireless device and a base station according to an exemplary embodiment of the present disclosure. Although not shown in... Figure 24 As shown, however, the wireless device can receive a message including the C-RNTI from the base station before performing the two-step RA procedure. The wireless device can transmit the C-RNTI (e.g., a C-RNTI MAC CE indicating the C-RNTI) to the base station via the MsgA during the two-step RA procedure. For example, during the two-step RA procedure, the wireless device can transmit the MsgA including a first transmission of the preamble and a second transmission of the transport block. The transport block may include the C-RNTI (e.g., a C-RNTI MAC CE indicating the C-RNTI). The wireless device can begin monitoring the downlink control channel with multiple RNTIs. The multiple RNTIs may include the C-RNTI. The multiple RNTIs may include the msgB-RNTI. The multiple RNTIs may include the RA-RNTI. The wireless device can determine the MsgB-RNTI and / or RA-RNTI based on the timing (e.g., OFDM symbols, time slots, subframes, and / or SFN numbers) and / or frequency index of the radio resources used for the first transmission of the preamble and / or the second transmission of the transport block. The wireless device can further determine a specific RNTI based on the preamble index and / or DMRS port index. The wireless device can initiate an MsgB RAR window after or in response to the transmission of MsgA (or a transport block). The wireless device can monitor the downlink control channel during the MsgB RAR window. If the wireless device receives at least one PDCCH addressed to C-RNTI and / or MsgB-RNTI (or RA-RNTI) via the downlink control channel during the MsgB RAR window, the wireless device can stop monitoring the downlink control channel.

[0343] Figure 25A and Figure 25B This is an example diagram illustrating a two-step RA process performed between a wireless device and a base station according to an exemplary embodiment of the present disclosure. Although not shown in... Figure 25A or Figure 25BAs shown, however, the wireless device may receive a message including the C-RNTI from the base station before performing the two-step RA procedure. The wireless device may transmit the C-RNTI to the base station via MsgA during the two-step RA procedure (e.g., a C-RNTI MAC CE indicating the C-RNTI). The wireless device may begin the MsgB RAR window after transmitting MsgA (or a transport block) or in response to transmitting MsgA (or a transport block). The wireless device may monitor the downlink control channel during the MsgB RAR window. The wireless device may utilize the C-RNTI and / or MsgB-RNTI (or RA-RNTI) to monitor the downlink control channel. If the wireless device receives at least one PDCCH addressed to the C-RNTI and / or MsgB-RNTI (or RA-RNTI) via the downlink control channel during the MsgB RAR window, the wireless device may stop monitoring the downlink control channel.

[0344] Figure 25A This diagram illustrates an example of a wireless device receiving a PDCCH addressed to its C-RNTI via a downlink control channel. A wireless device transmitting a C-RNTI via Msg A (e.g., a C-RNTI MAC CE indicating the C-RNTI) can monitor a downlink control channel with the C-RNTI and / or MsgB-RNTI (or RA-RNTI). Upon receiving a PDCCH addressed to the C-RNTI, or in response to receiving such a PDCCH, the wireless device can cease monitoring the downlink control channel via the C-RNTI and / or MsgB-RNTI (or RA-RNTI). The detected PDCCH may include a DCI, which includes a downlink assignment, upon which the wireless device can receive a PDSCH (e.g., a MAC PDU). The received PDSCH (or MAC PDU) may include TA commands (e.g., a TA command MAC CE). Upon receiving a PDCCH addressed to C-RNTI and / or a corresponding PDSCH (or MAC CE) including a TA command, or in response to receiving a PDCCH addressed to C-RNTI and / or a corresponding PDSCH (or MAC CE) including a TA command, the radio device may cease monitoring the downlink control channel via C-RNTI and / or msgB-RNTI (or RA-RNTI). In this case, the radio device can determine that the two-step RA procedure was successfully completed, the reception of MsgB was successful, and / or contention resolution was successfully completed.

[0345] Figure 25BThis diagram illustrates an example of a wireless device receiving a PDCCH addressed to Msg B-RNTI (or RA-RNTI) via a downlink control channel. A wireless device transmitting a C-RNTI (e.g., a C-RNTI MAC CE indicating the C-RNTI) via MsgA can monitor the downlink control channel via C-RNTI and / or MsgB-RNTI (or RA-RNTI). Upon receiving a PDCCH addressed to msgB-RNTI (or RA-RNTI) or in response to receiving a PDCCH addressed to msgB-RNTI (or RA-RNTI), the wireless device can cease monitoring the downlink control channel via C-RNTI and / or MsgB-RNTI (or RA-RNTI). The detected PDCCH may include a DCI indicating a downlink allocation, upon which the wireless device can receive a PDSCH (e.g., a MAC PDU). The received PDSCH (or MAC PDU) may include one or more RARs (e.g., one or more MsgBs). Upon receiving a PDCCH addressed to the C-RNTI and / or a corresponding PDSCH (or MAC PDU) including one or more RARs (e.g., one or more MsgBs), or in response to receiving a PDCCH addressed to the C-RNTI and / or a corresponding PDSCH (or MAC PDU) including one or more RARs (e.g., one or more MsgBs), the wireless device may cease monitoring the downlink control channel via the C-RNTI and / or MsgB-RNTI (or RA-RNTI). The wireless device may identify the RAR (e.g., MsgB) corresponding to MsgA based on a preamble identifier that matches the preamble identifier transmitted by the wireless device in MsgA. For example, the RAR (e.g., MsgB) may include at least one preamble identifier. If the preamble identifier of the RAR (e.g., MsgB) matches the preamble identifier of the preamble transmitted by the wireless device to the base station via MsgA, the wireless device can determine that the RAR (e.g., MsgB) in the PDSCH (or MAC PDU) corresponds to MsgA. After identifying the RAR (e.g., MsgB) from the PDSCH (or MAC PDU) based on the preamble identifier, or in response to identifying the RAR (e.g., MsgB) from the PDSCH (or MAC PDU) based on the preamble identifier, the wireless device can stop monitoring the downlink control channel via C-RNTI and / or msgB-RNTI (or RA-RNTI). The RAR can indicate a fallback to the four-step RA procedure for Msg3 transmission. For example, the RAR may include UL authorization and TA commands. The wireless device can transmit Msg3 via radio resources indicated by the UL authorization, where the UL transmission timing is adjusted based on the TA commands. Msg3 may include at least a portion of a transport block.For example, Msg3 and the transport block can be the same. For example, Msg3 can include C-RNTI.

[0346] In a two-step RA process, the wireless device may transmit a C-RNTI (e.g., a C-RNTI MAC CE indicating the C-RNTI) to the base station via a MsgA transmission including a first transmission of a preamble and a second transmission of a transport block. For example, the transport block may include a C-RNTI (e.g., a C-RNTI MAC CE indicating the C-RNTI). The wireless device may begin monitoring the downlink control channel after transmitting the MsgA or in response to transmitting the MsgA. For example, the wireless device may begin a window (e.g., a MsgB RAR window) after transmitting the MsgA (e.g., a transport block) or in response to transmitting the MsgA (e.g., a transport block) and monitor the downlink control channel during the window (e.g., the MsgB RAR window) to obtain a response to the MsgA. The wireless device may receive and / or detect a PDCCH addressed to the C-RNTI via the downlink control channel during the window. The PDCCH may include a DCI indicating the downlink allocation of the PDSCH. The wireless device may attempt to receive and / or decode the PDSCH based on the downlink allocation. Downlink allocation can indicate multiple parameters based on which the wireless device receives the PDSCH. For example, downlink allocation can indicate at least one of the following: frequency domain resource allocation indicator (e.g., reflected in one or more frequency offsets), time domain resource allocation indicator (e.g., reflected in OFDM symbols and / or slot offsets with PDCCH reception timing and / or the duration of PDSCH transmission), modulation and coding scheme, redundancy version indicator, downlink allocation index, PUCCH resource indicator for ACK / NACK transmission for PDSCH reception, transmit power control command for scheduled PUCCH for ACK / NACK transmission, and PDSCH-toHARQ feedback (e.g., ACK / NACK transmission) timing indicator.

[0347] One possible scenario is that the wireless device successfully receives (and / or detects) the PDCCH addressed to the C-RNTI transmitted by the wireless device to the base station, but fails to decode the PDSCH received based on downlink allocation. The problem in this case is that if the PDSCH (or MAC PDU) includes a TA command and / or a valid TA value is unavailable to the wireless device, the wireless device may not transmit a negative acknowledgment (NACK) to the base station (e.g., using a NACK indication with UCI). For example, if the wireless device's TA timer expires, the wireless device may not transmit a NACK indication for PDSCH reception to the base station (e.g., using UCI). The wireless device's TA timer may be started (or restarted) before transmitting MsgA, after receiving a TA command, or in response to receiving a TA command. If no TA value is received, or the TA timer is not running or has expired, the wireless device may not transmit a NACK indication for PDSCH reception to the base station (e.g., using UCI). This could be a situation where a wireless device determines (or identifies) that contention resolution has been successfully resolved (or the base station has successfully received Msg A) based on the detection of a PDCCH addressed to C-RNTI, or in response to determining (or identifying) that contention resolution has been successfully resolved (or the base station has successfully received Msg A), and is therefore unable to transmit a transport block (or packet, PUSCH) or control signal (e.g., UCI and / or PUCCH) to the base station.

[0348] Figure 26This is an example diagram of an RA process according to an exemplary embodiment of the present disclosure. A wireless device may perform (or initiate) an RA process (e.g., a four-step RA process). The wireless device may transmit a preamble (e.g., Msg 1 1311). The wireless device may monitor the control channel for a DCI scrambled by RA-RNTI. The wireless device may receive a random access response (e.g., PDSCH and / or Msg 2 1312) corresponding to the preamble (e.g., Msg 1 1311). In one example, the wireless device may fail to decode the response. A wireless device that fails to decode the response (e.g., PDSCH and / or Msg 2 1312) may retransmit the preamble. In one example, the wireless device may successfully decode the random access response (e.g., PDSCH and / or Msg 2 1312). The response may include one or more fields indicating a TA value. The wireless device may adjust (or determine) the UL transmission timing based on the TA value. For example, the base station can determine the TA value based on the reception timing of the received preamble (Msg1 1311) (e.g., by comparing the reception timing of the received preamble at the base station with the scheduled transmission timing of the received preamble at the radio device). If a C-RNTI (e.g., C-RNTI MAC CE) is received from the base station, the radio device can transmit the C-RNTI via Msg3 1313. The radio device can receive a PDCCH addressed to the C-RNTI via the downlink control channel. The radio device can determine that contention resolution was successful after receiving the PDCCH addressed to the C-RNTI or in response to receiving the PDCCH addressed to the C-RNTI. For example, after detecting the PDCCH addressed to the C-RNTI or in response to detecting the PDCCH addressed to the C-RNTI, the radio device can determine that the initiated RA procedure was successfully completed and / or contention resolution was successful. The PDCCH may include a DCI. The radio device can receive a PDSCH (e.g., Msg4 1314) based on the downlink allocation indicated by the DCI in the PDCCH. The wireless device may fail to decode the PDSCH (e.g., MSG4 1314). The wireless device may transmit a NACK for Msg4 reception (e.g., an indication of PDSCH decoding failure (Msg4)). The wireless device may determine the UL transmission timing of the NACK based on the TA value indicated by Msg2 1312. For example, if the wireless device performs Msg4, a four-step RA procedure may provide the wireless device with a valid TA value. After transmitting MsgA (or a transport block) or in response to transmitting MsgA (or a transport block), the wireless device may determine (e.g., anticipate) that during the initial window period (e.g., when the timer is running, when the timer starts), there is a PDCCH transmission addressed to C-RNTI from the base station (and / or a PDSCH transmission scheduled by a PDCCH).

[0349] During a two-step RA process, the wireless device may transmit a MsgA including a transport block that indicates the wireless device's C-RNTI. In this case, the wireless device can determine the random access response (e.g., PDSCH) to the MsgA based at least on whether the PDCCH scheduling the random access response (e.g., PDSCH) addresses to the C-RNTI. For example, if the wireless device receives a PDCCH addressed to the C-RNTI and / or if the wireless device receives (e.g., successfully decodes) a random access response (e.g., scheduled by the PDCCH), the wireless device can determine that the two-step RA process has been successfully completed.

[0350] In existing technologies, if a wireless device fails to decode a random access response (e.g., PDSCH) during a two-step RA process, the wireless device may determine a retransmission of MsgA or Msg1 for the two-step RA process. Determining a retransmission can be inefficient. A retransmission of MsgA or Msg1 determined based on the failure to decode the PDSCH may increase the latency of the two-step RA process. For example, a retransmission may require the wireless device to wait for the next available PRACH and / or PUSCH for retransmission. Retransmissions of MsgA or Msg1 may increase the congestion level of PRACH and / or PUSCH in the network, which in turn may increase the likelihood of collisions with other wireless devices during retransmission. For example, when a wireless device fails to decode a random access response (e.g., PDSCH) scheduled by the PDCCH addressed to the wireless device's C-RNTI during a two-step RA process, mechanisms for enhancing the procedures for both the wireless device and the base station are needed.

[0351] For example, when a random access response is not successfully decoded, an example embodiment implements an enhanced two-step RA procedure to reduce latency and congestion levels. In one example embodiment, the wireless device may selectively determine when and / or whether to retransmit MsgA, for example, based on whether a valid TA is available. For example, the wireless device may have a valid TA (e.g., the TA timer is running), may be adjacent to a base station where TA is not required (e.g., TA=0), or may be in a small cell where uplink transmission does not require TA (e.g., TA=0). In this case, the wireless device transmits a NACK via a PUCCH indicated by the PDCCH, which is an indication of failure to decode a PDSCH scheduled by the PDCCH. The PUCCH may be a channel dedicated to the wireless device. Due to contention occurring in a shared channel, transmission via a dedicated channel (e.g., PUCCH) (e.g., NACK) provides better performance (e.g., a higher uplink transmission success rate) compared to transmission (e.g., MsgA) via a shared channel (e.g., PRACH and / or PUSCH for MsgA). For example, a radio device with an invalid TA (e.g., an expired TA timer) may be located in a cell edge area requiring uplink transmission timing adjustment, or in a large (or macro) cell requiring TA for uplink transmission timing adjustment. In this case, the radio device can determine MsgA retransmission after or in response to a failure to decode a PDSCH scheduled by the PDCCH addressed to the radio device's C-RNTI. A radio device requiring uplink transmission timing adjustment may have one or more additional opportunities to receive one or more PDSCHs (e.g., MsgB) based on an adjusted (or extended) timer or window (e.g., based on the example embodiments disclosed in this specification) to monitor the downlink control channel and / or for one or more PDSCHs (e.g., MsgB). Determining whether a valid TA is available can provide the radio device with the correct choice to correct for the reception of PDSCHs that the radio device failed to decode. The example embodiments improve uplink transmission efficiency in a two-step RA process. Unlike the four-step RA procedure, the first step of the RACH procedure (e.g., MsgA transmission) transmits an uplink transport block including a radio device identifier (e.g., C-RNTI) and a preamble. For example, if the radio device transmits ACK / NACK regardless of the TA value, the radio device and the base station need to implement a more complex uplink control channel format and uplink transmission procedure to enable ACK / NACK transmission in the uplink. In one example embodiment, the base station receiving the MagA can determine the radio device identifier. The base station can determine the C-RNTI based on the radio device identifier and can use the C-RNTI dedicated to the radio device to transmit the random access response.Appropriate choices in the example embodiments can reduce latency, signaling overhead, and / or avoid unnecessary battery power consumption of wireless devices.

[0352] In one example, the wireless device can initiate a two-step RA procedure. The wireless device can transmit MsgA, which includes a preamble and a transport block. For example, the transport block may include a C-RNTI MAC CE indicating the wireless device's C-RNTI. A wireless device transmitting C-RNTI (e.g., C-RNTI MAC CE) via MsgA (or a transport block of MsgA) may fail to decode a PDSCH that includes a response to MsgA (MsgB). In this case, the wireless device can selectively choose to retransmit MsgA (and / or Msg1) or transmit a PUCCH (NACK) indicating a decoding failure in response to MsgA (PDSCH or MsgB). For example, if the wireless device determines that a TA is not needed (e.g., no uplink transport timing adjustment) to transmit a PUCCH or that the current TA is valid (e.g., the TA timer is running) for PUCCH transmission, the wireless device determines to transmit a PUCCH scheduled (indicated) by the PDCCH that schedules the PDSCH. For example, if the radio device determines that a new or updated TA (e.g., uplink transmission timing adjustment) is needed to transmit the PUCCH, the radio device determines to retransmit MsgA. The radio device can determine whether to transmit the PUCCH based on one or more methods. The radio device determines whether to transmit the PUCCH based on a TA timer. For example, if the TA timer expires, the radio device determines that a new or updated TA (e.g., uplink transmission timing adjustment) is needed. In this case, the radio device can determine to retransmit MsgA. For example, if the TA timer is running, the radio device determines to transmit the PUCCH. In this case, the radio device can determine to transmit the PUCCH with an uplink transmission timing adjusted to the current TA value. For example, if no TA is needed to transmit the PUCCH (e.g., no uplink transmission timing adjustment), the radio device determines to transmit the PUCCH. For example, SIB or RRC messages received by the radio device from the base station can indicate that no TA is needed through explicit or implicit indicators. For example, the explicit or implicit indicator is a small cell indicator. In this scenario, the wireless device can determine whether to transmit the PUCCH (e.g., with a TA value set to zero or a value semi-statically configured by the SIB or RRC). In one example embodiment, determining whether to retransmit MsgA (or Msg1) or transmit the PUCCH can reduce signaling overhead, battery consumption, and / or the likelihood of collisions with other wireless devices during retransmission.

[0353] In one example embodiment, the wireless device determines whether to transmit a PUCCH based on a measured received signal strength of a downlink reference signal (e.g., a path loss reference signal). For example, the measured received signal strength indicates the distance between the wireless device and the base station. For example, an SIB or RRC message received by the wireless device from the base station may indicate a power value, which the wireless device uses to determine whether it is near the base station. For example, if the measured received signal strength exceeds the power value, the wireless device determines to transmit the PUCCH. For example, if the measured received signal strength is less than or equal to the power value, the wireless device determines to retransmit MsgA.

[0354] Figure 31 This is an example diagram of PUCCH and / or MsgA transmission according to an exemplary embodiment of the present disclosure. The wireless device initiating the two-step RA procedure can transmit MsgA 1331, including a preamble 1341 and a transport block 1342. MsgA 1331 (or transport block 1342) can indicate the wireless device's C-RNTI (or include a C-RNTI MACCE indicating the wireless device's C-RNTI). The wireless device can, for example, begin monitoring the downlink control channel during a time interval in response to the transmission of MsgA 1331 (or transport block 1342) to look for a response (MsgB) to MsgA. For example, this time interval can be implemented by a timer started in response to the transmission of MsgA 1331 (or transport block 1342). For example, this time interval can be implemented by a window (e.g., as shown in the image) started in response to the transmission of MsgA 1331 (or transport block 1342). Figure 31 The PDCCH (as shown in the MsgB RAR window) is implemented. The wireless device can detect the PDCCH addressed to the C-RNTI. The PDCCH may include a DCI (a response to MsgA, e.g., MsgB) indicating the downlink allocation of the PDSCH. The DCI may also indicate the time / frequency radio resources of the PUCCH, where the wireless device transmits ACK or NACK as an indication of successful or failed PDSCH decoding. The PDSCH (a response to MsgA, e.g., MsgB) may include a new or updated TA. The wireless device may fail to decode the PDSCH. For example, if a TA is not required (e.g., TA=0) to transmit the PUCCH and / or the current TA is valid (e.g., the TA timer is running) for uplink transmission timing adjustment of the PUCCH, the wireless device may determine to transmit the PUCCH. For example, if a new or updated TA is required to transmit the PUCCH (e.g., the TA timer has expired) for uplink transmission timing adjustment of the PUCCH, the wireless device may fail to transmit the PUCCH. The wireless device may have an example embodiment based on the examples in this specification (e.g., Figure 27A , Figure 27B , Figure 28A , Figure 28B , Figure 29 and / or Figure 30 The public timer or window adjustment (or extension) provides one or more additional opportunities to receive one or more PDSCHs. For example, if the TA timer expires (e.g., no valid TA value is available), the wireless device can determine to retransmit MsgA.

[0355] For example, a wireless device may transmit a first message including a first preamble and a first transport block including a wireless device identifier. The wireless device may receive first downlink control information addressed to the wireless device identifier via a downlink control channel. The wireless device may determine a decoding failure of the received first response based on the first downlink control information. The wireless device may transmit, based on the determination of decoding failure and / or whether a valid timing advance value is available for transmitting uplink control signals: a second message including a second preamble and a second transport block; or uplink control signals.

[0356] For example, a wireless device may transmit a first message including a first preamble and a first transport block including a wireless device identifier. The wireless device may receive first downlink control information addressed to the wireless device identifier via a downlink control channel. The wireless device may determine, based on the first downlink control information, that decoding of the received first response has failed. The wireless device may determine whether a valid timing advance value is available for transmitting uplink control signals. Based on determining whether a valid timing advance value is available, the wireless device may select one of the following: a second message including a second preamble and a second transport block; or uplink control signals. The wireless device may transmit the selected one.

[0357] Figure 32 This is an example flowchart of a wireless device according to an exemplary embodiment of the present disclosure. The wireless device may transmit a first preamble via a cell. The wireless device may receive a downlink grant for a random access response. The wireless device may determine a failure to receive the random access response. The wireless device may determine an uplink signal for transmission via the cell based on the failure and the cell's time alignment timer, wherein the uplink signal is one of a second preamble and a negative acknowledgment.

[0358] Figure 33 This is an example flowchart of a base station according to an exemplary embodiment of the present disclosure. The base station may receive a first preamble via a cell. The base station may transmit a downlink grant for a random access response. The base station may receive uplink signals. For example, based on a failure to transmit a random access response and a cell time alignment timer, the uplink signals include one of a second preamble and a negative acknowledgment.

[0359] The exemplary embodiments of this disclosure can improve the determination of MsgA retransmission. In one example, for instance, if the base station does not receive and / or decode MsgA (e.g., a transport block) including C-RNTI (e.g., C-RNTI MAC CE), the base station may not transmit a PDCCH addressed to C-RNTI to the radio device. For instance, if the base station successfully receives and / or decodes MsgA (e.g., a transport block) including C-RNTI (e.g., C-RNTI MAC CE), the base station may transmit a PDCCH addressed to C-RNTI to the radio device. A radio device that detects a PDCCH addressed to C-RNTI and fails to decode the PDSCH based on the downlink allocation indicated by the DCI of the PDCCH can determine that the base station has successfully received MsgA. In this case, the radio device can determine that the PDSCH was transmitted from the base station to the radio device (e.g., not to any other radio device), for example, determining that contention resolution was successful. In this case, retransmitting the PDSCH from the base station can improve the increased latency and congestion levels compared to the prior art. For example, after determining that a PDSCH could not be decoded based on the downlink allocation indicated by the DCI of the PDCCH detected by C-RNTI, or in response to such determination, the radio device may maintain (or continue) monitoring another PDSCH. For example, if the base station does not receive a PUCCH (e.g., ACK or NACK) scheduled by the downlink allocation in the PDCCH, the base station may determine that the radio device may be unable to decode the transmitted PDSCH. The base station may, for example, transmit the PDSCH after determining that the radio device could not decode the transmitted PDSCH, or in response to such determination. For example, after determining that the radio device could not decode the transmitted PDSCH, or in response to such determination, the base station transmits a second PDCCH to the radio device, including a second downlink allocation, to indicate the transmission of the second PDSCH to the radio device. For example, after transmitting the second PDCCH, or in response to such transmission, the base station may transmit the second PDSCH to the radio device based on a second downlink allocation. Example embodiments may provide a radio device with a way to monitor another PDSCH using enhanced timer or window management. Example embodiments may enhance the determination of MsgA retransmissions based on enhanced timer or window management. Example embodiments may provide the base station with improved determination of whether another PDSCH needs to be transmitted to the radio device.

[0360] In the example embodiments described in this specification, for example, before transmitting MsgA and / or before receiving MsgB, the wireless device may not have received a TA value from the base station and / or may not have a valid TA (e.g., the TA timer has expired). For example, the wireless device may set the TA value to zero for uplink transmission of MsgA (e.g., preamble 1341 and / or transport block 1342). The wireless device in the example embodiments described in this specification may initiate a two-step RA procedure without a valid TA or without a TA. Figure 25A As shown, the wireless device can transmit a C-RNTI via MsgA and receive a PDCCH addressed to the C-RNTI. The wireless device can successfully detect the PDCCH addressed to the C-RNTI, but may be unable to decode a PDSCH received based on the downlink allocation indicated by the DCI in the PDCCH. In this case, for example, because the wireless device does not have a valid TA, the wireless device may not send a NACK to the base station for the received PDSCH (e.g., MsgB). For example, as... Figure 25A As described, a new or updated TA value can be included in a PDSCH that the wireless device failed to decode (e.g., failed to acquire a new or updated TA value due to PDSCH decoding failure). In this case, the wireless device can determine the retransmission of MsgA (e.g., Figure 25A (e.g., the MsgB RAR window expires), where contention resolution is based on (or by) detecting a PDCCH addressed to the C-RNTI. After detecting a PDCCH addressed to the C-RNTI, or in response to detecting a PDCCH addressed to the C-RNTI, the wireless device may be unable to determine that the initiated two-step RA procedure was successfully completed.

[0361] In one example, a radio device that detects a PDCCH addressed to a C-RNTI and fails to decode a PDSCH received based on the downlink allocation indicated by the PDCCH can continue to monitor (or maintain monitoring) the downlink control channel. For example, the radio device determines whether the PDSCH has been successfully decoded based on the cyclic redundancy check (CRC) result of the PDSCH (decoding success or failure). For example, if a timer started after or in response to a MsgA (or transport block) transmission is running (or during an initiated window (e.g., a MsgB RAR window) after or in response to a MsgA (or transport block) transmission), the radio device continues to monitor (or maintains monitoring) the downlink control channel. After or in response to the transmission of MsgA (or a transport block), the wireless device can determine (e.g., anticipate) that during the initial window period (e.g., when a timer is running, when the timer starts), there are one or more PDCCHs (and / or one or more PDSCHs scheduled by one or more PDCCHs) addressed to the C-RNTI from the base station. The wireless device can receive a second PDCCH including a second DCI indicating a second downlink allocation. The wireless device can use the second downlink allocation to receive the second PDSCH (e.g., MsgB). The wireless device can successfully decode the second PDSCH. The second PDSCH can include a response to MsgA (e.g., MsgB). This response can indicate a TA value (e.g., indicated by a TA command). For example, the TA value is indicated by the TA command MAC CE. For example, after or in response to the successful decoding of the second PDSCH (e.g., MsgB), the wireless device can transmit an ACK (e.g., using UCI) received for MsgB to the base station. Uplink transmissions of ACKs can be indicated (and / or scheduled) by a second PDCCH. For example, a second downlink allocation may include a resource indicator for a PUCCH for ACK / NACK transmissions of PDSCH reception, a transmit power control command for a PUCCH for ACK / NACK transmissions, and a PDSCH-to-HARQ feedback (e.g., ACK / NACK transmission) timing indicator. The radio device may attempt to decode one or more PDSCHs scheduled (and / or indicated) by one or more PDCCHs addressed to the C-RNTI during the window period (or while the timer is running). The radio device may fail to decode one or more PDSCHs, for example, until the end of the window or the timer expires. In this case, for example, after failing to decode one or more PDSCHs and / or after the timer expires (or the window ends), or in response to failing to decode one or more PDSCHs and / or after the timer expires (or the window ends), the radio device may determine a retransmission of MsgA.

[0362] At the base station, the base station can determine the transmission of the second PDSCH based on whether the base station receives a PUCCH (e.g., ACK or NACK). The base station can start a base station timer (or base station window), for example, after receiving MsgA (and / or transport block 1342) from the radio device or in response to receiving MsgA (and / or transport block 1342) from the radio device. For example, the base station transmits a DCI including downlink allocation to the radio device via the PDCCH. The downlink allocation may include one or more fields indicating the time and / or frequency resource allocation of the PDSCH. The radio device can receive the PDSCH based on the downlink allocation. The downlink allocation may also include: a resource indicator for the PUCCH for ACK / NACK transmission of PDSCH reception; a transmit power control command for the PUCCH for ACK / NACK transmission; and a PDSCH to HARQ feedback (e.g., ACK / NACK transmission) timing indicator. For example, if the radio device successfully decodes the PDSCH, the base station can determine that the base station can receive an ACK (e.g., a UCI indicating ACK) from the radio device via the PUCCH indicated by the resource indicator. For example, if the radio device fails to decode the PDSCH, the base station can determine that the base station did not receive (and / or the radio device did not transmit) an ACK (e.g., a UCI indicating ACK) from the radio device via the PUCCH indicated by the resource indicator. For example, after determining that the base station did not receive (and / or the radio device did not transmit) an ACK (e.g., a UCI indicating ACK) from the radio device via the PUCCH indicated by the resource indicator, or in response to determining that the base station did not receive (and / or the radio device did not transmit) an ACK (e.g., a UCI indicating ACK) from the radio device via the PUCCH indicated by the resource indicator, the base station can determine the transmission of a second PDSCH (and / or a second PDCCH scheduling the second PDSCH). For example, if the base station timer is running (or during the base station window), the base station can transmit the second PDSCH (and / or a second PDCCH scheduling the second PDSCH). For example, if the base station timer expires (or after the base station window ends), the base station can determine not to transmit the second PDSCH (and / or a second PDCCH scheduling the second PDSCH).

[0363] Figure 27A and Figure 27B This is an example diagram illustrating the receipt of one or more PDSCHs according to an exemplary embodiment of this disclosure. Figure 27AIn this process, the wireless device initiates a two-step RA procedure. The wireless device may transmit preamble 1341 and transport block 1342 as a transmission of MsgA 1331. Transport block 1342 may include the wireless device's C-RNTI (e.g., a C-RNTI MAC CE indicating the C-RNTI). The wireless device may start a window (e.g., a MsgB RAR window) or a timer in response to transmitting MsgA 1331 (e.g., transmitting transport block 1342). The wireless device may monitor the downlink control channel during the window period (or while the timer is running). The wireless device may receive a first PDCCH addressed to the C-RNTI via the downlink control channel. The wireless device may not be able to decode the first PDSCH scheduled by the first downlink allocation indicated by the first DCI in the first PDCCH. For example, if the (current) time does reach the end of the window or if the timer is running, the wireless device may continue monitoring the downlink control channel. The wireless device may receive a second PDCCH addressed to the C-RNTI via the downlink control channel. The wireless device may fail to decode the second PDSCH scheduled by the second downlink allocation indicated by the second DCI in the second PDCCH. The wireless device may repeat this process N+1 times during the window period or while the timer is running (e.g., if previous N attempts to receive (and / or decode) N PDSCHs have failed), where N ≥ 1, to receive N+1 PDSCHs. The wireless device may successfully decode the N+1th PDSCH (e.g., responses to MsgB and MsgA). The wireless device may transmit an ACK (e.g., UCI) via PUCCH based on the downlink allocation indicated by the DCI of the PDCCH scheduling the N+1th PDSCH. There may be instances where the wireless device fails to decode one or more PDSCHs during the window period (or until the timer expires). Figure 27B This illustrates an example of a wireless device failing to decode N PDSCHs. For...

Claims

1. A method of random access comprising: transmitting, by a wireless device via a cell, a first message comprising a first preamble and a first transport block, wherein the first transport block comprises an identifier of the wireless device; receiving, based on the identifier, downlink control information indicating a downlink assignment for a random access response to the first message; and determining a failure to receive the random access response; determining, based on the failure and a time alignment timer of the cell, an uplink signal for transmission via the cell, wherein: in response to the time alignment timer not running, the uplink signal comprises a second preamble; and in response to the time alignment timer running, the uplink signal comprises a negative acknowledgement; and transmitting the uplink signal.

2. The method of claim 1, further comprising: receiving configuration parameters of a two-step random access procedure, wherein the configuration parameters indicate: one or more preambles comprising the first preamble; a random access channel occasion for transmitting the first preamble; and an uplink channel occasion for transmitting the first transport block.

3. The method of any one of claims 1-2, wherein, the first transport block comprises a cell radio network temporary identifier (C-RNTI) medium access channel (MAC) control element (CE) indicating the identifier of the wireless device.

4. The method of any one of claims 1 to 2, wherein, the identifier of the wireless device is a C-RNTI of the wireless device.

5. The method of any of claims 1-2, further comprising: receiving the random access response based on the downlink assignment.

6. The method of any one of claims 1 to 2, wherein, determining the failure is based on failing to decode the random access response.

7. The method of any one of claims 1 to 2, wherein, the random access response comprises a timing advance command MAC CE indicating a timing advance value.

8. The method of any of claims 1-2, further comprising: in response to the time alignment timer not running, determining that the timing advance value is invalid.

9. The method of any of claims 1-2, further comprising: in response to the time alignment timer running, determining that the timing advance value is valid.

10. The method of claim 9, wherein, the timing advance value is used for transmitting the uplink signal comprising the negative acknowledgement.

11. The method of any one of claims 1 to 2, wherein, the downlink control information indicates a wireless resource of an uplink channel for transmitting the uplink signal comprising the negative acknowledgement.

12. The method of any one of claims 1 to 2, wherein, the negative acknowledgement indicates a failure to receive the random access response.

13. The method of any one of claims 1 to 2, wherein, the uplink signal comprising the second preamble is for retransmission of the first message.

14. The method of any one of claims 1 to 2, wherein, the uplink signal comprising the second preamble is based on a two-step random access procedure.

15. The method of any one of claims 1 to 2, wherein, the uplink signal comprising the second preamble further comprises a second transport block.

16. The method of any one of claims 1 to 2, further comprising: in response to transmitting the uplink signal comprising the negative acknowledgement, starting a time window for receiving a second random access response that is a retransmission of the random access response.

17. The method of any one of claims 1-2, further comprising, in response to transmitting the uplink signal comprising the negative acknowledgement, receiving a second random access response.

18. The method of claim 17, wherein, the second random access response is a retransmission of the random access response.

19. The method of claim 17, further comprising: determining to decode the second random access response based on combining the random access response and the second random access response.

20. The method of claim 17, wherein, the second random access response comprises a timing advance command MAC CE indicating a timing advance value.

21. A method of random access comprising: transmitting, by a wireless device via a cell, a first preamble; receiving a downlink grant for a random access response; determining a failure to receive the random access response; determining, based on the failure and a time alignment timer of the cell, an uplink signal for transmission via the cell, wherein the uplink signal is one of a second preamble and a negative acknowledgement; and transmitting the uplink signal; wherein the uplink signal comprises the negative acknowledgement in response to the time alignment timer being running.

22. The method of claim 21, wherein, the uplink signal comprises the second preamble in response to the time alignment timer not being running in association with the cell.

23. The method of any one of claims 21-22, wherein, the first preamble is transmitted as a first message with a first transport block.

24. The method of claim 23, wherein, the first transport block comprises an identifier of the wireless device.

25. The method of claim 24, wherein, the first transport block comprises a cell radio network temporary identifier (C-RNTI) medium access channel (MAC) control element (CE) indicating the identifier of the wireless device.

26. The method of claim 24, wherein, receiving the downlink grant comprises receiving, based on the identifier, a downlink control information comprising the downlink grant.

27. The method of claim 24, wherein, the identifier of the wireless device is a C-RNTI of the wireless device.

28. The method of any of claims 21-22, further comprising: receiving the random access response based on the downlink grant.

29. The method of any one of claims 21-22, wherein, determining the failure is based on failing to decode the random access response.

30. The method of any one of claims 21-22, wherein, the random access response comprises a timing advance command MAC CE indicating a timing advance value.

31. The method of any one of claims 21-22, further comprising: determining a timing advance value is invalid in response to the time alignment timer not being running.

32. The method of any one of claims 21-22, further comprising: determining a timing advance value is valid in response to the time alignment timer being running.

33. The method of any one of claims 21-22, wherein, the downlink grant indicates a radio resource of an uplink channel for transmission of the uplink signal comprising the negative acknowledgement.

34. The method of any one of claims 21-22, wherein, the uplink signal comprising the second preamble is for retransmission of the first preamble.

35. The method of any one of claims 21-22, wherein, the uplink signal comprising the second preamble is based on a two-step random access procedure.

36. The method of any one of claims 21-22, wherein, the uplink signal comprising the second preamble further comprises a second transport block.

37. The method of any one of claims 21-22, further comprising, in response to transmitting the uplink signal comprising the negative acknowledgement, receiving a second random access response.

38. The method of claim 37, wherein, the second random access response is a retransmission of the random access response.

39. The method of claim 37, wherein, the second random access response comprises a timing advance command MAC CE indicating a timing advance value.

40. A random access method, comprising: transmitting, by a wireless device, a first preamble via a cell; receiving a downlink grant for a random access response; determining a failure to receive the random access response; determining, based on the failure, an uplink signal for transmission via the cell, wherein: the uplink signal comprises a second preamble in response to a time alignment timer not being running in association with the cell; and the uplink signal comprises a negative acknowledgement in response to the time alignment timer being running; and transmitting the uplink signal.

41. The method of claim 40, wherein, the first preamble is transmitted as a first message with a first transport block.

42. The method of claim 41, wherein, the first transport block comprises an identifier of the wireless device.

43. The method of claim 42, wherein, Receiving the downlink grant includes receiving, based on the identifier, a downlink control information including the downlink grant.

44. The method of claim 40, wherein, The downlink control information indicates a wireless resource of an uplink channel for transmission of the uplink signal including the negative acknowledgement.

45. The method of claim 41, wherein, The first transport block includes a cell radio network temporary identifier (C-RNTI) medium access channel (MAC) control element (CE) for indicating an identifier of the wireless device.

46. The method of any one of claims 40 to 45, wherein, Determining the uplink signal is further based on the time alignment timer.

47. The method of claim 40, wherein, The identifier of the wireless device is a C-RNTI of the wireless device.

48. The method of any one of claims 40 to 45, further comprising: Receiving the random access response is based on the downlink grant.

49. The method of any one of claims 40 to 45, wherein, Determining the failure is based on a failure to decode the random access response.

50. The method of any one of claims 40 to 45, wherein, The random access response includes a timing advance command MAC CE indicating a timing advance value.

51. The method of any one of claims 40 to 45, further comprising: Determining that a timing advance value is invalid is in response to the time alignment timer not running.

52. The method of any one of claims 40 to 45, further comprising: Determining that a timing advance value is valid is in response to the time alignment timer running.

53. The method of claim 52, wherein, The timing advance value is for transmission of the uplink signal including the negative acknowledgement.

54. The method of claim 41, wherein, The uplink signal including the second preamble is for retransmission of the first message.

55. The method of any one of claims 40 to 45, wherein, The uplink signal including the second preamble is based on a two-step random access procedure.

56. The method of any one of claims 40 to 45, wherein, The uplink signal including the second preamble further includes a second transport block.

57. The method of any of claims 40-45, further comprising, in response to transmitting the uplink signal including the negative acknowledgement, receiving a second random access response.

58. The method of claim 57, wherein, The second random access response is a retransmission of the random access response.

59. The method of claim 57, wherein, The second random access response includes a timing advance command MAC CE indicating a timing advance value.

60. A random access method comprising: receiving, by a base station, a first message including a first preamble and a first transport block via a cell, wherein the first transport block includes an identifier of a wireless device; transmitting, based on the identifier, a downlink control information indicating a downlink allocation for a random access response to the first message; and receiving, from the wireless device, an uplink signal, wherein: in response to a time alignment timer not running, the uplink signal includes a second preamble; and in response to the time alignment timer running, the uplink signal includes a negative acknowledgement.

61. The method of claim 60, further comprising: transmitting configuration parameters of a two-step random access procedure, wherein the configuration parameters indicate: one or more preambles including the first preamble; a random access channel occasion for transmission of the first preamble; and an uplink channel occasion for transmission of the first transport block.

62. The method of any one of claims 60-61, wherein, The first transport block includes a cell radio network temporary identifier (C-RNTI) medium access channel (MAC) control element (CE) for indicating the identifier of the wireless device.

63. The method of any one of claims 60-61, wherein, The identifier of the wireless device is a C-RNTI of the wireless device.

64. The method of any one of claims 60-61, further comprising: Transmitting the random access response is based on the downlink allocation.

65. The method of any one of claims 60-61, wherein, The negative acknowledgement indicates a failure to transmit the random access response.

66. The method of any one of claims 60-61, wherein, The random access response includes a timing advance command MAC CE indicating a timing advance value.

67. The method of any one of claims 60-61, further comprising: In response to the time alignment timer not running, determining that the timing advance value is invalid.

68. The method of any one of claims 60-61, further comprising: In response to the time alignment timer running, determining that the timing advance value is valid.

69. The method of claim 68, wherein, The timing advance value is used for receiving the uplink signal including the negative acknowledgement.

70. The method of any one of claims 60-61, wherein, The downlink control information indicates a wireless resource of an uplink channel used for receiving the uplink signal including the negative acknowledgement.

71. The method of any one of claims 60-61, wherein, The uplink signal including the second preamble is used for retransmission of the first message.

72. The method of any one of claims 60-61, wherein, The uplink signal including the second preamble is based on a two-step random access procedure.

73. The method of any one of claims 60-61, wherein, The uplink signal including the second preamble further includes a second transport block.

74. The method of any one of claims 60-61, further comprising: In response to receiving the uplink signal including the negative acknowledgement, starting a time window for transmission of a second random access response that is a retransmission of the random access response.

75. The method of any one of claims 60-61, further comprising: In response to the negative acknowledgement, determining a second random access.

76. The method of any of claims 60-61, further in response to receiving the uplink signal including the negative acknowledgement, transmitting a second random access response.

77. The method of claim 76, wherein, The second random access response is a retransmission of the random access response.

78. The method of claim 76, further comprising: Based on combining the random access response and the second random access response, determining to decode the second random access response.

79. The method of claim 76, wherein, The random access response includes a timing advance command MAC CE indicating a timing advance value.

80. A random access method, comprising: receiving, by a base station, a first preamble via a cell; transmitting a downlink grant for a random access response; and receiving an uplink signal, wherein the uplink signal includes one of a second preamble and a negative acknowledgement based on a failure to transmit the random access response and a time alignment timer of the cell; wherein the uplink signal includes the negative acknowledgement in response to the time alignment timer running.

81. The method of claim 80, wherein, In response to the time alignment timer associated with the cell not running, the uplink signal includes the second preamble.

82. The method of any one of claims 80-81, wherein, The first preamble is received as a first message with a first transport block.

83. The method of claim 82, wherein, The first transport block includes an identifier of a wireless device.

84. The method of claim 82, wherein, The first transport block includes a cell radio network temporary identifier (C-RNTI) medium access channel (MAC) control element (CE) to indicate an identifier of a wireless device.

85. The method of claim 83, wherein, Transmitting the downlink grant includes transmitting a downlink control information including the downlink grant based on the identifier.

86. The method of claim 83, wherein, The identifier of the wireless device is a C-RNTI of the wireless device.

87. The method of any one of claims 80-81, further comprising: Transmitting the random access response based on the downlink grant.

88. The method of any one of claims 80-81, wherein, The uplink signal including the negative acknowledgement indicates the failure to transmit the random access response.

89. The method of any one of claims 80-81, wherein, The random access response includes a timing advance command MAC CE indicating a timing advance value.

90. The method of any one of claims 80-81, further comprising: In response to the time alignment timer not running, determining that the timing advance value is invalid.

91. The method of any one of claims 80-81, further comprising: In response to the time alignment timer running, determining that the timing advance value is valid.

92. The method of any one of claims 80-81, wherein, The downlink grant indicates radio resources of an uplink channel for receiving the uplink signal comprising the negative acknowledgement.

93. The method of any one of claims 80-81, wherein, The uplink signal comprising the second preamble: an indication of a failure to transmit the random access response; and is received as a retransmission of the first preamble.

94. The method of any one of claims 80-81, wherein, The uplink signal comprising the second preamble is based on a two-step random access procedure.

95. The method of any one of claims 80-81, wherein, The uplink signal comprising the second preamble further comprises a second transport block.

96. The method of any one of claims 80-81, further in response to receiving the uplink signal comprising the negative acknowledgement, transmitting a second random access response.

97. The method of claim 96, wherein, The second random access response is a retransmission of the random access response.

98. The method of claim 96, wherein, The second random access response comprises a timing advance command MAC CE indicating a timing advance value.

99. A wireless device 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 one of claims 1-59.

100. A base station comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the base station to perform the method of any one of claims 60-98.

101. 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 one of claims 1-59.

102. A mobile communication system comprising: a base station; and a wireless device 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 one of claims 1-59.

103. A mobile communication system comprising: a wireless device; and a base station comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the base station to perform the method of any one of claims 60-98.

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