Main Functions; Physical Layer Processing Function - Samsung Mobile WiMAX Outdoor RAS SPI-2331 System Description

2.2 Main Functions

The main functions of the outdoor SPI-2331 are as follows:

Physical layer processing function

Call processing function
IP processing function
Auxiliary device interface function
Convenient operation and maintenance function
Function of supporting the outdoor environment
2.2.1 Physical Layer Processing Function
OFDMA Ranging
The ranging supported by the OFDMA system is roughly divided by the uplink timing
synchronization method and the contention based bandwidth request method.
Uplink Timing Synchronization
In the uplink timing synchronization method, the outdoor SPI-2331 detects the timing
error of the uplink signal by using the ranging code transmitted from MS and transmits
the timing correction command to each MS to correct the transmission timing of the
uplink.
The uplink timing synchronization method has initial ranging, periodic ranging,
handover ranging, etc.
Contention Based Bandwidth Request
In the contention based bandwidth request method, the outdoor SPI-2331 receives the
bandwidth request ranging code from each MS and allocates uplink resources to the
corresponding MS to enable to transmit the bandwidth request header.
The contention based bandwidth request method has bandwidth request ranging or
something.
Channel Encoding/Decoding
The outdoor SPI-2331 carries out the Forward Error Correction(FEC) encoding for the
downlink packet created in the upper layer by using Conventional Turbo Code(CTC).
On the contrary, it decodes the uplink packet received from the MS after demodulating.
Modulation/Demodulation
The outdoor SPI-2331 carries out the FEC encoding for the downlink packet created in the
upper layer and modulates the encoded packet into the QAM signal. In addition, the
outdoor SPI-2331 demodulates and decodes the uplink packet received from MS.
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Mobile WiMAX Outdoor RAS SPI-2331 System Description/Ed.02
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