Section: 5.4.9.2 Group Wake Up Signal
Content: To support the Wake Up Signal (WUS), the WUS Assistance Information is used by the ng-eNB to help determine the WUS group used when paging the UE (see TS 36.300[ Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 ]  [30]). The content of the WUS Assistance Information consists of the paging probability information. The paging probability information provides a metric on the probability of a UE receiving a paging message based on, e.g. statistical information. The UE may in the Registration Request message provide its capability to support receiving WUS Assistance Information. If WUS Assistance Information is supported by the UE, then the UE in the Registration Request message may provide the additional UE paging probability information. The AMF may use the UE provided paging probability, local configuration and/or previous statistical information for the UE, when determining the WUS Assistance Information. If the UE supports WUS Assistance Information, the AMF may assign WUS Assistance Information to the UE, even when the UE has not provided the additional UE paging probability information. If the AMF has determined WUS Assistance Information for the UE, the AMF provides it to the UE in every Registration Accept message. The AMF stores the WUS Assistance Information parameter in the MM context and provides it to the ng-eNB when paging the UE. UE and AMF shall not signal WUS Assistance Information in Registration Request, Registration Accept messages when the UE has an active emergency PDU session.