Terminology » Mobile Communication » UE WCDMA/UMTS Timers Explained

UE WCDMA/UMTS Timers Explained

wcdma umts timer ue mobile communication

This tutorial section on UMTS basics covers the following sub topics:

  • Main Page
  • Architecture
  • Stack channel types
  • Bands
  • UARFCN
  • Frame
  • Timers

This page covers timers used in 3G/WCDMA/UMTS compatible UE which include T300, T302, T304, T305, T307, T308, T309, T310, T311, T312, T313, T314, T315 and T316 timers.

WCDMA/UMTS TimerFunctionWhen Start/Stop/at expiry
T300Starts at the transmission of RRC CONNECTION REQStops at the receipt of RRC Connection setup. At expiry, re-transmits RRC CONNECTION REQ if V300<=N300, ELSE go to IDLE Mode
T302Starts at the transmission of Cell Update or URA UpdateStops at the receipt of Cell Update Confirm or URA Update Confirm. At expiry, re-transmits Cell Update/URA Update if V302<= N302 Else goto IDLE Mode
T304Starts at the transmission of UE Capability InfoStops at the receipt of UE capability Information Confirm. At Expiry, re-transmits UE capability information if V304<=N304, Else initiate a Cell Update proc
T305Starts upon entering CELL_FACH/URA_PCH/CELL_PCH state OR upon receipt of CELL Update Confirm/URA Update ConfirmStops upon entering another state. At expiry, transmits CELL Update if T307 is not activated and UE detects “In Service Area”. Otherwise If T307 is not active, initiate starting of timer T307
T307Starts when timer T305 has been expired and UE detects the ” Out of Service Area”Stops when UE detects “In Service Area”. At Expiry it transit to the IDLE MODE
T308Starts at the transmission of RRC Connection Release CompleteNot Stopped. At Expiry, transmits RRC connection Release Complete IF V308<=N308 ELSE GOTO IDLE MODE
T309Starts upon receipt of Cell Change Order from UTRAN messageStops upon successful response to a CONNECTION ESTABLISHMENT REQUEST in a new CELL. At Expiry, resumes the Connection to UTRAN network
T310Starts upon transmission of PUSCH Capacity Request messageStops upon receipt of Physical Shared Channel Allocation. At expiry transmits PUSCH Capacity Request if V310 <= N310 ELSE stops the procedure
T311Starts upon reception of Physical Shared Channel Allocation (When “PUSCH ALLOCATION” set to “PUSCH ALLOCATION pending”)Stops upon receipt of Physical Shared Channel Allocation (When “PUSCH allocation” set to “PUSCH allocation assignment”). At Expiry, UE initiate a PUSCH CAPACITY REQUEST procedure
T312Starts When UE starts to establish dedicated channel modeStops When UE detects N312 “in sync” indication from Layer-1(PHY). Timer expires when criteria for physical channel establishment failure is fulfilled
T313Timer Starts when UE detects consecutive N313 “out of sync” indication from Layer-1(PHY)Stops when UE detects consecutive N315 “in sync” indication from Layer-1(PHY). Timer expires when the criteria for Radio Link failure is fulfilled
T314Starts after the criteria for radio link failure have been fulfilled, and if radio bearers associated with T314 exists.Stops when the cell update procedure completes. REFER 8.3.1.13 in 3GPP TS 25.331 Specification
T315Starts after the criteria for radio link failure have been fulfilled, and if radio bearers associated with T315 exists.Stops when the cell update procedure completes. REFER 8.3.1.14 in 3GPP TS 25.331 Specification
T316Starts when UE detects “out of service area” in the URA_PCH or CELL_PCH stateStops when UE detects “in service area”. At expiry, initiates cell update procedure if “in service area” is detected, OTHERWISE starts timer T317, transit to CELL_FACH state and initiate cell update procedure when the UE detects “in service area”
T317Starts when timer T316 expires OR when in CELL_FACH state, UE detects “out of service area”Stops when UE detects “in service area”. At Expiry, transits to IDLE MODE

V300, V302, V304, V308 and V310 are counters used in UE.

N300, N302, N304, N308, N310, N312, N313 and N315 are constants used in UE.

For information refer 3GPP TS 25.331 Specification .