User's Manual

CHAPTER 2. Overview of SPI-2213

2-8

Support of Sleep Mode

Sleep Mode is the mode defined to save the MS power under IEEE 802.16 standard and

indicates the status that air resources allocated to an MS are released when the MS does not

need traffic reception/transmission temporarily. If the MS in Sleep Mode needs the traffic

reception/transmission, the MS returns to the normal status immediately.

Both Idle Mode and Sleep Mode are modes to save the MS power. The Idle Mode release

all service flows allocated to an MS, while the Sleep Mode releases only the air resources

between the MS and RAS temporarily, continuously keeping the service flow information

allocated to the MS.

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