Section: 4.4.2 Periodic updating
Content: Periodic updating may be used to notify periodically the availability of the mobile station to the network. Periodic updating is performed by using the location updating procedure. The location updating type information element in the LOCATION UPDATING REQUEST message shall indicate periodic updating. The procedure is controlled by the timer T3212 in the mobile station. The MS indicates in the MS network feature support IE whether it supports the extended value for timer T3212. If the MS receives the Per MS T3212 IE in the LOCATION UPDATING ACCEPT message, the MS shall use this IE to determine the value of T3212 instead of the value of T3212 that is broadcast. If the MS does not receive the Per MS T3212 IE in the LOCATION UPDATING ACCEPT message, the MS shall use the value of T3212 that is broadcast . If the timer is not already started, the timer is started each time the mobile station enters the MM IDLE substate NORMAL SERVICE or ATTEMPTing TO UPDATE. When the MS leaves the MM Idle State the timer T3212 shall continue running until explicitly stopped. The timer is stopped (shall be set to its initial value for the next start) when: - a LOCATION UPDATING ACCEPT or LOCATION UPDATING REJECT message is received; - an AUTHENTICATION REJECT message is received; - the first MM message is received, or security mode setting is completed in the case of MM connection establishment, except when the most recent service state is LIMITED SERVICE; - the mobile station has responded to paging and thereafter has received the first correct layer 3 message except RR message; - the mobile station is deactivated (i.e. equipment powered down or SIM/USIM removed). When the timer T3212 expires, the location updating procedure is started and the timer shall be set to its initial value for the next start. If the mobile station is in other state than MM Idle when the timer expires the location updating procedure is delayed until the MM Idle State is entered. The conditions under which the periodic location updating procedure is used by a mobile station in the MM IDLE state are defined for each service state in subclause 4.2.2. If the mobile station is in service state NO CELL AVAILABLE, LIMITED SERVICE, PLMN SEARCH or PLMN SEARCH-NORMAL SERVICE when the timer expires the location updating procedure is delayed until this service state is left. In A/Gb mode and GERAN Iu mode, the (periodic) location updating procedure is not started if the BCCH information at the time the procedure is triggered indicates that periodic location shall not be used. The timeout value is broadcasted in the L3-RR SYSTEM INFORMATION TYPE 3 message on the BCCH, in the Control channel description IE, see 3GPP TS 44.018[ None ]  [84] subclause 10.5.2.11. In UTRAN Iu mode, the (periodic) location updating procedure is not started if the information on BCCH or in the last received dedicated system information at the time the procedure is triggered indicates that periodic location shall not be used. The timeout value is included in the CS domain specific system information element. The T3212 timeout value shall not be changed in the NO CELL AVAILABLE, LIMITED SERVICE, PLMN SEARCH and PLMN SEARCH-NORMAL SERVICE states. If the MS, configured to use CS fallback and SMS over SGs, or SMS over SGs only, enters a GERAN or UTRAN cell after intersystem change from S1 mode to Iu or A/Gb mode in NMO II, the TIN indicates "GUTI", and the location area of the current cell is the same as the stored location area, the MS shall start timer T3212, with a value set to the shorter of the values of the remaining value of timer T3412, and the broadcast T3212 timeout value. When the MS supporting N1 mode in MS operation modes A or B moves from NG-RAN coverage to GERAN coverage, or from NG-RAN coverage to UTRAN coverage, the network operates in network operation mode II, the location area of the current cell is the same as the stored location area, the broadcast value of T3212 does not indicate "deactivated" and the T3212 has expired, the MS may intiate the periodic location updating procedure. When a change of the broadcast T3212 timeout value has to be taken into account and the timer is running (at change of the serving cell or, change of the broadcast value of T3212), the MS shall behave as follows: let t1 be the new T3212 timeout value and let t be the current timer value at the moment of the change to the new T3212 timeout value; then the timer shall be restarted with the value t modulo t1. When the mobile station is activated, or when a change of the broadcast T3212 timeout value has to be taken into account and the timer is not running, the mobile station shall behave as follows: let t1 be the new T3212 timeout value, the new timer shall be started at a value randomly, uniformly drawn between 0 and t1.