Section: 4.7.2.9 Power saving mode
Content: The MS can request the use of power saving mode (PSM) during an attach or routing area updating procedures (see 3GPP TS 23.682[ Architecture enhancements to facilitate communications with packet data networks and applications ]  [133A] and 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74]). The MS shall not request the use of PSM during: - an attach for emergency bearer services procedure; - a routing area updating procedure for initiating a PDN connection for emergency bearer services; or - a routing area updating procedure when the MS has a PDN connection established for emergency bearer services. The network accepts the use of PSM by providing a specific value for timer T3324 when accepting the attach or routing area updating procedure. The MS may use PSM only if the network has provided the T3324 value IE during the last attach or routing area updating procedure with a value different from "deactivated". Upon expiry of the timer T3324 or if the T3324 value provided by the network is zero, the MS may deactivate the AS layer and activate PSM by entering the state GMM-REGISTERED.NO-CELL-AVAILABLE if: a) the MS is not attached for emergency bearer services; b) the MS has no PDN connection for emergency bearer services; c) the MS is in PMM-IDLE mode (in Iu mode) or the READY timer is not running (in A/Gb mode); d) the MS is in the GMM-REGISTERED.NORMAL-SERVICE state; and e) no RR connection exists. If conditions a, b, c and e are fulfilled, but the MS is in a state other than GMM-REGISTERED.NORMAL-SERVICE when timer T3324 expires, the MS may activate PSM when the MS returns to state GMM-REGISTERED.NORMAL-SERVICE. If conditions a, b, c and d are fulfilled, but an RR connection exists, the MS may activate PSM when the RR connection has been released. An MS that has already been allocated timer T3324 with a value different from "deactivated" and the timer T3324 has expired, may activate PSM if it receives an "Extended wait time" from lower layers. When PSM is activated all NAS timers are stopped and associated procedures aborted except for timers T3312, T3346, T3396, any backoff timers, and the timer T controlling the periodic search for HPLMN or EHPLMN (if the EHPLMN list is present) or higher prioritized PLMNs (see 3GPP TS 23.122[ Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode ]  [14]). If the MS is attached for emergency bearer services or has a PDN connection for emergency bearer services, the MS shall not activate PSM. The MS may deactivate PSM at any time (e.g. for transfer of mobile originated signalling or user data, or to initiate a mobile originated circuit-switched transaction), by activating the AS layer before initiating the necessary GMM or MM procedures (if any).