Content for  TS 23.287  Word version:  18.4.0

For UE in limited service state, as defined in TS 23.122, V2X communication is only allowed over PC5 reference point. UEs that are authorized to use V2X communication over PC5 reference point shall be able to use V2X communication over PC5 reference point when in limited service state following the principles defined in clause 5.1.2.2 for V2X communication over PC5 reference point when the UE enters in limited service state in 5GS:

• because UE cannot find a suitable cell of the selected PLMN as described in TS 23.122; or
• as the result of receiving one of the following reject reasons defined in TS 23.122:
  • a "PLMN not allowed" response to a registration request or;
  • a "5GS services not allowed" response to a registration request or service request.

A UE in limited service state shall only use the radio resources and procedure available in CM-IDLE mode for V2X communication over PC5 reference point, for details see TS 36.300 and TS 38.300. UEs shall not use V2X communication over PC5 reference point using the "operator-managed" radio resources, as specified in clause 5.1.2.1, if the UE has entered in limited service state due to all other situations (e.g. no SIM in the MS, an "illegal MS" or "illegal ME" response to a registration request, or an "IMSI unknown in HLR" response to a registration request) defined in TS 23.122, where the UE is unable to obtain normal service from a PLMN. The UEs may use V2X communication over PC5 reference point using the "non-operator-managed" radio resources, as specified in clause 5.1.2.1, according to the principles defined in clause 5.1.2.2.

For NR based unicast, groupcast and broadcast mode communication over PC5 reference point, PC5 DRX operations are supported to enable pedestrian UE power saving. The V2X layer determines the respective V2X service types, and derives the corresponding PC5 QoS parameters based on either the mapping of V2X service types to PC5 QoS parameters, or the V2X Application Requirements for the V2X service type provided by the application layer. The V2X layer passes the PC5 QoS parameters and destination Layer-2 ID to the AS layer as specified in clauses 6.3.1, 6.3.2 and 6.3.3. When the V2X layer derives new PC5 QoS parameters for a destination Layer-2 ID that has been provided to the AS layer, i.e. due to changes of V2X service types or V2X Application Requirements, the V2X layer provides the new PC5 QoS parameters for the destination Layer-2 ID to the AS layer. For broadcast or groupcast, the V2X layer maintains a list of all V2X service types, i.e. activated V2X service types and/or V2X service types that the UE is interested for reception, for a given destination Layer-2 ID and determines the NR Tx Profile available to be mapped for the respective V2X service type based on the configuration described in clause 5.1.2.1. Whenever the list of the V2X service types for a given destination Layer-2 ID changes, the V2X layer updates the AS layer for the NR Tx Profiles information. The V2X layer determines whether and how to provide the NR Tx Profiles for the given destination Layer-2 ID to the AS layer as below:

• If all the V2X service types have mapped NR Tx Profiles, the V2X layer provides all the mapped NR Tx Profiles to the AS layer for the given destination Layer-2 ID, e.g. when providing other information such as the destination Layer-2 ID, PC5 QoS parameters;
• If any of the V2X service types does not have mapped NR Tx Profile, the V2X layer does not provide any NR Tx Profile to the AS layer for the given destination Layer-2 ID, e.g. when providing other information such as the destination Layer-2 ID, PC5 QoS parameters.

For broadcast, the mapping from destination Layer-2 ID to NR Tx Profile is configured in the NG-RAN. The NG-RAN may derive the NR Tx Profile from the destination Layer-2 ID to perform the network scheduled operation mode, alignment of Uu DRX and PC5 DRX, etc. Support for PC5 DRX operations in the AS layer is specified in TS 38.300. When the PC5 DRX operation is needed, e.g. based on the NR Tx Profile in case of broadcast or groupcast, the AS layer determines the PC5 DRX parameter values for V2X communication over PC5 reference point, taking into account, e.g., PC5 QoS parameters and/or destination Layer-2 ID provided by the V2X layer. For unicast, two UEs may negotiate the PC5 DRX configuration in the AS layer, and the PC5 DRX parameter values can be configured per pair of source and destination Layer-2 IDs and per direction in the AS layer. For transmitting and receiving Direct Communication Request messages, a default PC5 DRX configuration is used when the PC5 DRX operation is needed, e.g. based on the NR Tx Profile as specified in clause 5.1.2.1. For broadcast and groupcast when the UE is "not served by E-UTRA" and "not served by NR", the UE uses the provisioned PC5 DRX configuration for PC5 DRX operation as specified in clause 5.1.2.1.