RFWiMAX Timers T1-T27: Comprehensive Guide
wimax
timers
network operation
base station
subscriber station
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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 Timer | Function | Value |
|---|---|---|
| T1 | Used at the Subscriber Station (SS), this timer waits for the Downlink Channel Descriptor (DCD) timeout. | Max. value is 5 * DCD interval. |
| T2 | Used at the SS, this timer waits for the broadcast ranging timeout. | Max. value is 5 * ranging interval. |
| T3 | Ranging Response (RNG-RSP) reception timeout, triggered after the transmission of a ranging request. | Default and max. value is 200ms. |
| T4 | Used 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. |
| T5 | Used at the Base Station (BS), this timer waits for an uplink channel change response. | Max. value is 2 s. |
| T6 | Used at the SS, this timer waits for a registration response. | Max. value is 3 s. |
| T7 | Used 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. |
| T8 | Used at the SS/BS, this timer waits for a DSA/DSC acknowledge timeout. | Max. value is 300ms. |
| T9 | Used 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. |
| T10 | Used at the SS/BS, this timer waits for a transaction end timeout. | Max. value is 3 s. |
| T12 | Used at the SS, this timer waits for an Uplink Channel Descriptor (UCD). | Max. value is 5 * UCD interval. |
| T13 | Used 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. |
| T14 | Used at the SS, this timer waits for a DSX-RVD timeout. | Max. value is 200ms. |
| T15 | Used at the BS, this timer waits for an MCA-RSP message. | Min. and default value is 20ms. |
| T16 | Used at the SS, this timer waits for a bandwidth request grant. | Min. is 10ms, Max. value is QoS dependent. |
| T17 | Used 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. |
| T18 | Used at the SS, this timer waits for an SBC-RSP timeout. | Default is 50ms and Max. is less than T9. |
| T19 | Used at the SS, this timer represents the time the DL channel remains unstable. | N/A |
| T20 | Used at the SS, this timer represents the time the SS searches for preambles on a given channel. | Min. value is equivalent to MAC frames. |
| T21 | Used at the SS, this timer represents the time the SS searches for DLMAP on a given channel. | Max. value is 10s. |
| T22 | Used at the SS/BS, this timer waits for an ARQ reset. | Max. value is 0.5s. |
| T23 | Used in mesh node systems during network entry, this timer detects the network. | Min. value is 1 sec. |
| T24 | Used in mesh node systems during network entry, this timer accumulates MSH-NCFG messages. | Default value is 120s. |
| T25 | Used in mesh node systems during network entry, this timer waits for MSH-NENT/MSH-NCFG messages. | Default value is 1 s. |
| T26 | Used 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. |
