Design And Simulation Of Concatenated Coded ECS Based On AWGN Channel

The efficiency, reliability and integrality of data in transmitting or saving data become more and more important with the rapid development of information technology. The researchers have been taking their best to find new high performance algorithm, to get more coding gains, better bit error rate and lower computation complexity.Reed-Solomon code is a class of error-correcting codes enjoyed countless applications. As RS codes are symbol based codes, they are quite robust in correcting burst errors. And RS codes are always chose to be the FEC(Forward Error Correction) codes or sub codes when an error control system of data is considered. Hard decision decoding of RS codes have been well developed and widely used. In order to get more coding gains, soft decision decoding technology based on bit reliability or symbol reliability becomes the major interest of researchers. We discussed the soft decision of short RS codes combined with modulation, and presented an improved Chase algorithm and a soft decision algorithm based on modulation signal reliability. The performance was greatly improved while the complexity increased only a little.Coded modulation was first proposed by Ungerboeck in 1982,in which large coding gains can be obtained without compromising efficiency. Based on the Trellis Code Modulation (TCM) theory, we researched a pragmatic TCM(PTCM) mapping method, and designed the structure of the decoder accordingly. We get pretty good BER(Bit Error Rate) and it is also simple to put it into practice.Considering the advantage of the high performance of RS outer codes and low decoding complexity of PTCM inner codes, we concatenated two codes to improve the performance of the system. The design of the inner code was proposed in detail and simulation result of the designed system was presented. It was proved to be feasible.