Section: 4.7.1.7a Intersystem change from S1 mode to A/Gb mode or S1 mode to Iu mode with ISR activated
Content: If ISR is activated and the MS returns from S1 mode to a cell belonging to a RA which is different from the RA where the MS is registered, the MS initiates a normal or combined routing area updating procedure depending on the network operation mode in the current RA. If ISR is activated and the MS returns from S1 mode to a cell belonging to the RA where the MS is registered, the following cases can be distinguished: a) Inter-system change due to PS handover: If the PS handover is to A/Gb mode, the MS initiates a normal or combined routing area updating procedure depending on the network operation mode in the current RA. b) Inter-system change not due to PS handover: 1) If the READY timer is running in the MS after the inters-ystem change occurs, then the MS shall perform a normal or combined routing area updating procedure depending on the network mode of operation in the current RA. 2) If the READY timer is not running in the MS in A/Gb mode or the MS is in PMM-IDLE mode in Iu mode after the intersystem change occurs, unless a routing area updating procedure is required according to subclause 4.7.5.1 and 4.7.5.2.1, the MS shall not perform a routing area updating procedure until uplink user data or signalling information needs to be sent from the MS to the network. - If the MS is in the same access network, (i.e. A/Gb mode or Iu mode), as when it last sent user data or signalling messages in a cell belonging to the RA where the MS is registered, the procedures defined for that access system shall be followed. This shall be sending of an LLC PDU in a A/Gb mode cell or initiating the SERVICE REQUEST procedure in an Iu mode cell. - If the MS is in a different access network (i.e. A/Gb mode or Iu mode), as when it last sent user data or signalling messages in a cell belonging to the RA where the MS is registered, the normal or combined RA update procedure shall be performed depending on the network operation mode in the current RA, before the sending of user data or signalling messages. If the signalling message is a DETACH REQUEST indicating "power off", the routing area updating procedure need not be performed. - If the periodic routing area update timer expires the MS shall initiate the periodic RA update procedure. 3) If the READY timer is not running in the network in A/Gb mode or the network is in PMM-IDLE mode in Iu mode, then the network shall page the MS if downlink user data or signalling information needs to be sent from the network to the MS. This shall include both A/Gb mode and Iu mode cells. - If the MS receives the paging indication in the same access network (i.e. A/Gb mode or Iu mode), as when it last sent user data or signalling information in a cell belonging to the RA where the MS is registered, the MS shall send any LLC PDU in a A/Gb mode cell or shall initiate the service request procedure indicating service type "paging response" in an Iu mode cell. - If the MS receives the paging indication in a different access network (i.e. A/Gb mode or Iu mode), as when it last sent user data or signalling information in a cell belonging to the RA where the MS is registered, the MS shall perform normal or combined routing area updating procedure shall be performed depending on the network operation mode in the current RA.