Research And FPGA Implementation Of Adaptive OFDM System’s Channel Error Correction Scheme

OFDM (Orthogonal Frequency Division Multiplexing) orthogonal frequency divisionmultiplexing is a multicarrier digital modulation techniques and it was proposed in the1960s. Thebasic idea of OFDM is dividing the high-speed data into a number of low-speed data by allowingthe subchannel spectrum overlaps but does not produce the mutual influence, and transmitting datain parallel by modulating different carrier frequency. The characteristics of the technology is a highbandwidth utilization,and it can realize high-rate data transmission. Combined with adaptivemodulation, adaptive coding and dynamic subcarrier allocation, dynamic bit allocationtechniques,adaptive OFDM technique combined the advantages of OFDM technology and adaptivetransmission technology natrally and fully,and makes OFDM system get a better performance.In theOFDM communication system, the channel condition has a great influence to the quality ofcommunications, so the channel error correction has become an important research topic.It has agreat significance to study different channel error correction scheme and different types of codingthey used;and then according to the different channel conditions as well as the needs of thecommunication task;finding a appropriate channel error correction coding scheme to improveinterference and error correction capability of the communication system and ensure the reliabilityof the communication.This paper has made a brief introduction of OFDM technology and different kinds of errorcorrection coding scheme at the first.Then, elaborated the development,application and theory ofseveral error correction coding. Several simulations were made on Matlab platform to analysisdifferent correction coding scheme s performance. Proposed fusion frame decoding scheme ofpunctured convolutional code based on the variable puncturing matrix and made the simulation ofthe propesed scheme. A error correction scheme of the adaptive OFDM system was gived.Convolutional coding, Viterbi decoding error correction module, and several modules wereachieved on FPGA platform builded by the third generation of Altera Corporation Cyclone III serieschip and the key models were described in details. The programming mainly used the Veriloghardware description language (HDL).