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CHAPTER 2. Overview of Outdoor SPI-2331
Support of Sleep Mode
Sleep mode is the mode defined to save the MS power under IEEE 802.16e 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 outdoor SPI-2331 carries out the related call processing function by receiving/sending
the signaling message required for the MS's status transition into Sleep Mode and the MS
return from the Sleep Mode to Awake Mode.
Call Admission Control (CAC) Function
If the outdoor SPI-2331 receives the call setup request, such as network entry, 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 CAC function to prevent the system
overload.
CAC can be roughly divided into CAC by MS and CAC by service flow.
CAC by MS
If the number of users who the subcell is in Active/Sleep Mode exceeds the threshold
when the outdoor SPI-2331 receives the call setup request from an MS, it rejects the
call setup request of the MS.
CAC by service flow
When service flow is added, the outdoor SPI-2331 checks if the air resources of the
requested subcell exceed the threshold and determines the creation of the service
MAC ARQ Function
The outdoor SPI-2331 carries out the ARQ function of the MAC layer. In packet data
exchange, ARQ transmits SDU from the transmission side to the ARQ block 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-2331 carries out the following function for the service flows applying ARQ:
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-2331 is delivered to the
modem in the outdoor SPI-2331. At this time, the outdoor SPI-2331 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.
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© SAMSUNG Electronics Co., Ltd.
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