Terminology » WiMAX » WiMAX Timers T1-T27: Comprehensive Guide

WiMAX Timers T1-T27: Comprehensive Guide

wimax timers network operation base station subscriber station

This document outlines the various timers used in WiMAX (Worldwide Interoperability for Microwave Access) technology, specifically T1 through T27. These timers play a crucial role in managing network operations, ensuring reliable communication, and handling various procedures such as ranging, registration, and service flow management.

WiMAX Timer Details

The following table provides a detailed description of each WiMAX timer, its function, and its typical value or range:

WiMAX TimerFunctionValue
T1Used at the Subscriber Station (SS), this timer waits for the Downlink Channel Descriptor (DCD) timeout.Max. value is 5 * DCD interval.
T2Used at the SS, this timer waits for the broadcast ranging timeout.Max. value is 5 * ranging interval.
T3Ranging Response (RNG-RSP) reception timeout, triggered after the transmission of a ranging request.Default and max. value is 200ms.
T4Used at the SS, this timer waits for a unicast ranging opportunity. If the “pending until complete” field was used earlier by this SS, then the value of that field shall be added to this interval.Min. is 30 s, max. is 35 sec.
T5Used at the Base Station (BS), this timer waits for an uplink channel change response.Max. value is 2 s.
T6Used at the SS, this timer waits for a registration response.Max. value is 3 s.
T7Used at the SS/BS, this timer waits for a Dynamic Service Addition (DSA), Dynamic Service Change (DSC), or Dynamic Service Deletion (DSD) response timeout.Max. value is 1 s.
T8Used at the SS/BS, this timer waits for a DSA/DSC acknowledge timeout.Max. value is 300ms.
T9Used at the BS, this timer represents the registration timeout, the time allowed between the BS sending a RNG-RSP (success) to an SS and receiving a SBC-REQ from that same SS.Min. and default value is 300ms.
T10Used at the SS/BS, this timer waits for a transaction end timeout.Max. value is 3 s.
T12Used at the SS, this timer waits for an Uplink Channel Descriptor (UCD).Max. value is 5 * UCD interval.
T13Used at the BS, this timer represents the time allowed for an SS following receipt of a REG-RSP message to send a TFTP-CPLT message to the BS.Min. and default value is 15 min.
T14Used at the SS, this timer waits for a DSX-RVD timeout.Max. value is 200ms.
T15Used at the BS, this timer waits for an MCA-RSP message.Min. and default value is 20ms.
T16Used at the SS, this timer waits for a bandwidth request grant.Min. is 10ms, Max. value is QoS dependent.
T17Used at the BS, this timer represents the time allowed for the SS to complete SS authorization and key exchange.Min. is 5 min and default value is 5 min.
T18Used at the SS, this timer waits for an SBC-RSP timeout.Default is 50ms and Max. is less than T9.
T19Used at the SS, this timer represents the time the DL channel remains unstable.N/A
T20Used at the SS, this timer represents the time the SS searches for preambles on a given channel.Min. value is equivalent to MAC frames.
T21Used at the SS, this timer represents the time the SS searches for DLMAP on a given channel.Max. value is 10s.
T22Used at the SS/BS, this timer waits for an ARQ reset.Max. value is 0.5s.
T23Used in mesh node systems during network entry, this timer detects the network.Min. value is 1 sec.
T24Used in mesh node systems during network entry, this timer accumulates MSH-NCFG messages.Default value is 120s.
T25Used in mesh node systems during network entry, this timer waits for MSH-NENT/MSH-NCFG messages.Default value is 1 s.
T26Used at the SS, this timer waits for a TFTP-RSP.Min. = 10ms, Default = 200ms, Max. = 200ms.
T27 (Idle)Used at the BS, this timer represents the maximum time between unicast grants to the SS when the BS believes the SS uplink transmission quality is good enough.Min. value is equal to SS Ranging Response processing time.
T27 (Active)Used at the BS, this timer represents the maximum time between unicast grants to the SS when the BS believes the SS uplink transmission quality is not good enough.Min. value is equal to SS Ranging Response processing time.