Performance Comparison of Turbo Code in WIMAX System with Various Detection Techniques

The different FEC techniques like convolution code, RS code and turbo code are used to improve the performance of communication system. In this paper, we study the performance of the MAP, Log-MAP, Max-Log-MAP and APP decoding algorithms for turbo codes, in terms of the a priori information, a posteriori information, extrinsic information and channel reliability. We also analyze how important an accurate estimate of channel reliability factor is to the good performances of the iterative turbo decoder. The simulations are made for parallel concatenation of two recursive systematic convolution codes with a block interleaver at the transmitter, AWGN channel and iterative decoding with different algorithms at the receiver side. The comparison of these detection techniques in term of BER performance is discussed in result section.