User's Manual

Mobile WiMAX RAS SPI-2213 System Description/Ed.00

The SPI-2213 carries out the related call processing function by receiving/sending the

signaling message required for the status transition into Sleep Mode of MS and the return

from the Sleep Mode to Awake Mode of MS.

Admission Control (CAC) Function

If the SPI-2213 receives the call setup request, such as network entry, Quick Connection

Setup (QCS) and handover, from an MS, it monitors the traffic and signaling load for each

subcell and the number of user in Active/Sleep Mode and performs the AC function to

prevent the system overload.

AC can be roughly divided into AC by MS and AC by service flow.

y AC by MS

If the number of users who the subcell is in Active/Sleep Mode exceeds the threshold

when the SPI-2213 receives the call setup request from an MS, it rejects the call setup

request of the MS.

y AC by service flow

When service flow is added, the SPI-2213 checks if the air resources of the requested

subcell exceed the threshold and determines the creation of the service

MAC ARQ Function

The SPI-2213 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 SPI-2213 carries out the following function for the service flows applying ARQ:

y MAC Management creation and transmission concerned with ARQ operation

y Feedback processing depending on ARQ types

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

y ARQ timer/window management

QoS Support Function

The packet traffic exchanged between ACR and SPI-2213 is delivered to the modem in the

SPI-2213. At this time, the SPI-2213 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 SPI-2213 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.