Section: 4.7.9.1.1 Paging for GPRS services using P-TMSI
Content: The network shall initiate the paging procedure for GPRS services using P-TMSI when GMM signalling messages or user data is pending to be sent to the MS while the mobile reachable timer is running. The network may page only GPRS MSs which are GMM-REGISTERED and identified by a local P-TMSI. In Iu mode, for the MS using eDRX, the network initiates the paging procedure when the paging trigger is received within the paging time window. If the paging trigger is received outside the paging time window, the network initiates the paging procedure at T time ahead of the beginning of the next paging time window. NOTE: T time is a short time period based on implementation. The operator can take possible imperfections in the synchronization between the CN and the MS into account when choosing T time. In Iu mode, to initiate the procedure the GMM entity in the network requests the lower layer to start paging (see 3GPP TS 25.331[ None ]  [23c] and 3GPP TS 25.413[ UTRAN Iu interface Radio Access Network Application Part (RANAP) signalling ]  [19c]) and shall start the timer: - T3315 for this paging procedure, if the network accepted to use eDRX for the MS. - Otherwise T3313 for this paging procedure. In Iu mode, if the network starts the timer T3315, the network shall set the timer T3315 to a value smaller than the value of timer T3-RESPONSE (see 3GPP TS 29.274[ 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3 ]  [16D] for further details on timer T3-RESPONSE). In Iu mode, the GMM entity in the network may provide the lower layer with a list of CSG IDs, including the CSG IDs of both the expired and the unexpired subscriptions. If there is a PDN connection for emergency bearer services established, the GMM entity in the network shall not provide the list of CSG IDs to the lower layer. Upon reception of a paging indication, the MS shall stop the timer T3346, if running, and: - initiate a service request procedure to respond to the paging, the MS shall set the service type to "paging response" in the SERVICE REQUEST message (see 3GPP TS 24.007[ Mobile radio interface signalling layer 3; General Aspects ]  [20], 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74], 3GPP TS 25.331[ None ]  [23c] and 3GPP TS 25.413[ UTRAN Iu interface Radio Access Network Application Part (RANAP) signalling ]  [19c]); or - initiate a routing area update procedure as specified in subclauses 4.7.5.1 and 4.7.5.2.1. If the paging request for GPRS services was received during an ongoing MS initiated GMM specific procedure, then the MS shall progress the GMM specific procedure, and the network shall proceed with the GMM specific procedure. In A/Gb mode, to initiate the procedure the GMM entity requests the RR sublayer to start paging (see 3GPP TS 44.018[ None ]  [84], 3GPP TS 44.060[ None ]  [76]), and shall start the timer: - T3315 for this paging procedure, if the network accepted to use eDRX for the MS. - Otherwise T3313 for this paging procedure. In A/Gb mode, if the network starts the timer T3315, the network shall set the timer T3315 to a value smaller than the value of timer T3-RESPONSE (see 3GPP TS 29.274[ 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for Control plane (GTPv2-C); Stage 3 ]  [16D] for further details on timer T3-RESPONSE). In A/Gb mode, upon reception of a paging indication, the MS shall respond to the paging with any LLC frame (see 3GPP TS 44.064[ Mobile Station - Serving GPRS Support Node (MS-SGSN); Logical Link Control (LLC) Layer Specification ]  [78a], 3GPP TS 24.007[ Mobile radio interface signalling layer 3; General Aspects ]  [20], 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74]). At intersystem change, an MS not having the READY timer running in A/Gb mode or an MS in PMM-IDLE mode in Iu mode, being paged in a different access network as when it last sent user data or signalling message, uses the ROUTING AREA UPDATE REQUEST message as paging response, i.e. the routing area updating procedure shall be performed instead according to the selective routing area updating procedure. The network shall stop the timer for the paging procedure (i.e. either timer T3313 or timer T3315) when a response is received from the MS. Upon expiry ofthe timer T3313, the network may re-initiate paging. Upon expiry of the timer T3315, the network shall abort the paging procedure and shall proceed as specified in 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74]. In Iu mode, when a response is received from the MS, the network shall change from PMM-IDLE mode to PMM-CONNECTED mode. In A/Gb mode, when a response different from an LLC NULL frame is received from the MS, the network shall start the READY timer.