The OFDM Channel Coding And Modulation Scheme Based On IEEE 802.16d

Consumer requires more and more broadband as the internet is developing quickly. The advantage of broadband become obvious pregressively, and telecom industry has payed more attention to it. Task group of IEEE 802.16 issued the IEEE802.16 2001 standard and gave a wireless metropolitan area network(WMAN) wireless interface criterion to BWA。The standard gives the regulation to MAC and PHY layers of wireless interface. Through the amending to MAC layer and augment to PHY layer, the improvement to 802.16 standard is realized. The wireless interface of this standard can be used as a connection between LAN of 802.11 and internet, the last 1 kilometer solution with the role of extention of cable and DSL. The network based on 802.16d can cover 50 kilometer and communicate with a 70Mb/S speed.This paper focuses on the OFDM channel coding and modulation scheme based on IEEE 802.16d. Actual wireless channel is a conpound channel consisting of random noise and burst noise, So the standard adopt concatenated Reed-Solomon/convolutional code(RS—CC) , which can correct random errors and burst errors simultaneously. And modulation shceme uses the MPSK or MQAM , which have good performance in anti-jamming, error rate and frequenency efficiency. The paper mainly makes a research on the RS codec algrithom and convolution codec algrithom, and gives a analysis of serial performance. It also introduces the constellation map of MPSK and MQAM. A simulation on bit error rate of RS-CC980809 and 16QAM,64QAM based on simulink libaray of MATLAB7.0 has been done。The result indicates that error rate can reach 10e-6 under a 12dB SNR. And the performance of 1/3 convolution code rate outperform that of 1/2 code rate 1dB under the same RS code and length condition. MQAM has a high frequency efficiency, but error rate performance is 2 dB worse than BPSK modulation under the same condition. These result is helpful to the further research of this area.