ARQ Control

The functions in this service are used to set parameters of Automatic Repeat reQuest (ARQ) which is one of the MAC level data connection's error control mechanisms used by the basestation.

The arq service has the following functions:

<service name="arq">
  <info>Set ARQ parameters</info>
  <args>
    <arg name="ackproctime" isRequired="false" value="[ackproctime]">
      <info>ACK proc time [] (0)</info>
    </arg>
    <arg name="blockltm" isRequired="false" value="[blockltm]">
      <info>ARQ block lifetime [] (5000)</info>
    </arg>
    <arg name="txackdelay" isRequired="false" value="[txackdelay]">
      <info>Tx ACK delay [] (100)</info>
    </arg>
    <arg name="sltmo" isRequired="false" value="[sltmo]">
      <info>Sync loss timeout [] (10000)</info>
    </arg>
    <arg name="dlvrorder" isRequired="false" value="[dlvrorder]">
      <info>Delivery in order: true/false (true)</info>
    </arg>
    <arg name="wsize" isRequired="false" value="[wsize]">
      <info>ARQ window size [0..1024] (1024)</info>
    </arg>
    <arg name="rxpurgetmo" isRequired="false" value="[rxpurgetmo]">
      <info>RX purge timeout [] (5000)</info>
    </arg>
    <arg name="enable" isRequired="false" value="[enable]">
      <info>Enable ARQ: true/false (false)</info>
    </arg>
    <arg name="rtmotx" isRequired="false" value="[rtmotx]">
      <info>TX retry timeout [] (1000)</info>
    </arg>
    <arg name="bloksize" isRequired="false" value="[blocksize]">
      <info>ARQ block size [0..(ARQ windows size/2)] (256)</info>
    </arg>
    <arg name="rtmorx" isRequired="false" value="[rtmorx]">
      <info>RX retry timeout [] (1000)</info>
    </arg>
  </args>
</service>

ARQ Functions

ackproctime

ACK proc time.

blockltm

ARQ block lifetime. This is the maximum time interval an ARQ block shall be managed by te transmitter ARQ state machine, once initial transmission of the block has occurred. If transmission (or subsequent retransmission) of the block is not acknowledged by the receiver before the time limit is reach, the block is discarded.

txackdelay

Tx ACK delay. This is the time delay before receiver sends of an acknowledgement. Default: 100.

sltmo

Sync loss timeout. This is the maximum time interval ARQ_TX_WINDOW_START or ARQ_RX WINDOW_START parameters can stay at the same value before declaring a loss of synchronization between transmitter and receiver.

dlvrorder

Deliver in order on/off. This option tells received to forward SDUs in same order as sent by transmitter. Default: on

wsize

Transmission window size. This is the number of queued ARQ acknowledgement blocks at any given time for a connection. Default: 1024

rxpurgetmo

RX purge timeout. This is the time interval the receiver shall wait after successful reception of a block that does not result in advancement of ARQ_RX_WINDOW_START value, before advancing to a new ARQ_RX_WINDOW_START.

enable

Indicates if ARQ is enabled for connection. Default: false

rtmotx

TX retry timeout. The minimum time interval a transmitter shall wait before retransmission of an unacknowledged block for retransmission. The interval begins when the ARQ block was last transmitted.

bloksize

ARQ block size in bytes. Before transmission each SDU block is partitioned into a sequence of ARQ blocks of this size. Default: 1024

rtmorx

RX retry timeout.

References

1. ​http://wiki.hsc.com/wiki/Main/WimaxArq
2. ​http://www.simet.com.tr/documents/product/F83D610A-B7F6-ADBD-907AB9D8F8708319.pdf
3. Performance Analysis of the IEEE 802.16 ARQ Mechanism. Sayenko, Tykhomyrov, Martikainen, Alanen.