Section: 4.7.13 Service Request procedure (Iu mode only)
Content: The purpose of this procedure is to transfer the PMM mode from PMM-IDLE to PMM-CONNECTED mode, and/or to assign radio access bearer in case of PDP contexts are activated without radio access bearer assigned. In latter case, the PMM mode may be PMM-IDLE mode or may alternatively be the PMM-CONNECTED mode if the MS requires radio access bearer re-establishment. This procedure is used for; - the initiation of CM layer service (e.g. SM or SMS) procedure from the MS in PMM-IDLE mode, - the network to transfer down link signalling, - uplink (in PMM-IDLE or PMM CONNECTED) and downlink (only in PMM-IDLE) user data, - counting the number of mobile stations in a cell which are interested in a specific MBMS service. - requesting the establishment of a point-to-point Radio Bearer for receiving a MBMS service. For downlink transfer of signalling or user data in PMM-IDLE mode, the trigger is given from the network by the paging request procedure, which is out of scope of the present document. For pending downlink user data in PMM-CONNECTED mode, the re-establishment of radio access bearers for all active PDP contexts is done without paging. For counting the number of mobile stations in PMM-IDLE mode interested in a specific MBMS service, the trigger is given from the network by the MBMS notification procedure (see 3GPP TS 25.331[ None ]  [23c]). For establishing a point-to-point radio bearer to allow MBMS service, the trigger is given from the RRC determining this need from the MBMS control parameters broadcasted by the network (see 3GPP TS 25.331[ None ]  [23c]). Service type can take either of the following values; "signalling", "data", "paging response", "MBMS multicast service reception" or "MBMS broadcast service reception". Each of the values shall be selected according to the criteria to initiate the Service request procedure. If the MS is triggered to send a Service Request message for both MBMS multicast service and MBMS broadcast service simultaneously, the MS shall include a Service Type indicating "MBMS multicast service reception". The criteria to invoke the Service request procedure are when: a) the MS has any signalling messages except GMM messages (e.g. for SM or SMS) to be sent to the network in PMM-IDLE mode (i.e., no secure PS signalling connection has been established). In this case, the service type shall be set to "signalling". b) the MS, either in PMM-IDLE or PMM-CONNECTED mode, has pending user data to be sent, no radio access bearer is established for the corresponding PDP context, and timer T3319 (see subclause 4.7.13.3) is not running or, optionally, if timer T3319 is running and the flag in the Uplink data status IE for this PDP context has not been set in the last Service Request. The procedure is initiated by an indication from the lower layers (see 3GPP TS 24.007[ Mobile radio interface signalling layer 3; General Aspects ]  [20]). In this case, the service type shall be set to "data". c) the MS receives a paging request using P-TMSI for PS domain from the network in PMM-IDLE mode. In this case, the service type shall be set to "paging response". d) the MS is in PMM-IDLE mode or PMM-CONNECTED, receives an MBMS notification for an MBMS multicast service for which the MS has activated an MBMS context or for an MBMS broadcast service which has been selected for reception locally by upper layers in the MS, and is prompted by the contents of the notification to establish a PS signalling connection (see 3GPP TS 25.346[ None ]  [110]). In this case, the service type shall be set to "MBMS multicast service reception" or "MBMS broadcast service reception", respectively. e) the MS in PMM-IDLE mode or PMM-CONNECTED, determines from the broadcast MBMS control parameters that there is a need to establish a point-to-point Radio Bearer to enable MBMS reception (see 3GPP TS 25.346[ None ]  [110]). In this case, the service type shall be set to "MBMS multicast service reception" or "MBMS broadcast service reception", respectively. If one of the above criteria to invoke the Service request procedure is fulfilled, then the Service request procedure may only be initiated by the MS when the following conditions are fulfilled: - its GPRS update status is GU1 UPDATED and the stored RAI is equal to the RAI of the current serving cell; and - no GMM specific procedure is ongoing (see subclause 4.1.1.1). If a GMM specific procedure is ongoing at the time a request from CM sublayer, the RRC or the RABM (see 3GPP TS 24.007[ Mobile radio interface signalling layer 3; General Aspects ]  [20]) is received and the ATTACH REQUEST or ROUTING AREA UPDATE REQUEST message has been sent, then, depending on implementation, the MS shall abort the received request or delay it until the GMM specific procedure is completed. If the ATTACH REQUEST or ROUTING AREA UPDATE REQUEST message has not been sent, the MS may indicate "follow-on request pending" in the message (i.e. the MS wishes to prolong the established PS signalling connection after the GMM specific procedure). Then, the MS shall delay the Service request procedure until the GMM specific procedure is completed. If the network indicates "follow-on proceed" in the ATTACH ACCEPT or ROUTING AREA UPDATE ACCEPT message and the MS has a service request pending, the MS shall react depending on the service type. If the service type is: - "signalling": the MS shall abort the Service request procedure and send the pending signalling messages immediately; - "data": the MS shall immediately perform the pending Service request procedure using the current PS signalling connection; - "paging response": the MS shall abort the Service request procedure. No further specific action is required from the MS. If the network indicates "follow-on proceed" and the MS has no service request pending, then no specific action is required from the MS. As an implementation option, the MS may start timer T3340 as described in subclause 4.7.1.9 if no user plane radio access bearers are set up. If the network indicates "no follow-on proceed" in the ATTACH ACCEPT or ROUTING AREA UPDATE ACCEPT message, the MS shall not initiate the pending Service request procedure until the current PS signalling connection is released. NOTE: The "follow-on proceed" indication was not defined in earlier versions of the protocol. A network that is compliant with the earlier versions of the protocol will always encode the respective bit as zero, i.e. as "follow-on proceed", even if it does not prolong the PS signalling connection. After completion of a Service request procedure but before re-establishment of radio access bearer, if the PDP and MBMS context status information elements are included, then the network shall deactivate all those PDP and MBMS contexts locally (without peer to peer signalling between the MS and the network), which are not in SM state PDP-INACTIVE on network side but are indicated by the MS as being in state PDP-INACTIVE. After completion of a Service request procedure, the pending service is resumed and uses then the connection established by the procedure. If the service type is indicating "data", then the radio access bearers for all activated PDP contexts are re-established by the network, except for those activated PDP contexts having maximum bit rate value set to 0 kbit/s for both uplink and downlink and as an option those which have no pending user data. The re-establishment of radio access bearers for those PDP contexts is specified in subclause 6.1.3.3. A service request attempt counter is used to limit the number of service request attempts and no response from the network. The service request attempt counter shall be incremented as specified in subclause 4.7.13.5. The service request attempt counter shall be reset when: - an attach or combined attach procedure is successfully completed; - a normal or periodic routing area updating or a combined routing area updating procedure is successfully completed; - a service request procedure is successfully completed ; or - the UE moves to GMM-DEREGISTERED state.