Simulative Analysis of Turbo Codes with Block Interleaver using Different Modulation Schemes on Rayleigh Channel

Turbo codes can be achieved by parallel concatenation of two or more codes. These codes have been the subject of intense research as they are producing results very close to the theoretical limits set by Shannon. These are forward error correction (FEC) codes developed within Shannon limits. These codes have been successfully implemented in 3G mobile systems and satellite communication systems as well as other applications where designer seek to achieve reliable information transfer over bandwidth or latency constrained communication link in the presence of noise that can cause errors in the transmitted information. In this paper work is outlined using recursive convolutional encoder with fixed constraint length and block interleaver with different modulation schemes such a BPSK,QPSK,QAM to modulate the data and then this data is transferred using Rayleigh channel with additive white Gaussian noise and viterbi iterative decoding algorithm is used at decoding process. The focus of the work in this paper is based on the performance of turbo codes in terms of bit error rate (BER) vs Eb/N0. Then comparison of these techniques is done. This whole system is simulated using MATLAB.