User's Manual

Mobile WiMAX Outdoor RAS SPI-2210 System Description/Ed.05

MAC ARQ Function

The outdoor SPI-2210 carries out the ARQ function of the MAC layer. In packet data

exchange, the transmission side transmits ARQ block which SDU is divided into, and

retransmits the packet according to the ARQ feedback information received from the

reception side to raise the reliability of data communication.

The outdoor SPI-2210 carries out the following function for the service flows applying

ARQ:

 MAC Management creation and transmission concerned with ARQ operation

 Feedback processing depending on ARQ types

 Block processing (fragmentation/reassemble/retransmission) depending on ARQ types

 ARQ timer/window management

QoS Support Function

The packet traffic exchanged between ACR and Outdoor SPI-2210 is delivered to the

modem in the outdoor SPI-2210. At this time, the outdoor SPI-2210 allocates the queue in

the modem to each service flow that QoS type is specified to observe the QoS constraint

given for each QoS class or service flow and performs the strict-priority scheduling

according to the priority.

The modem that receives the packet traffic performs the scheduling by using the

uplink/downlink algorithm, such as Proportional Fair (PF) or Round Robin (RR) and

transmits the scheduled allocation information to an MS through DL/UL MAP.

The MS receiving the DL/UL MAP checks the air resources allocated to the MS and

modulates/demodulates the downlink packet or transmits the uplink packet from the

allocated uplink area.

Since the outdoor SPI-2210 provides the QoS monitoring function, it can compile statistics

on packets unsatisfying the latency requested from the QoS parameter according to TDD

frames and report the statistics to an operator via the OAM interface.