Performance evaluation of a wireless Orthogonal Frequency Division Multiplexing system under various concatenated FEC channel-coding schemes

Abstract

In this paper, we study the effect of various concatenated forward error correction (FEC) codes on the performance of a wireless orthogonal frequency division multiplexing (OFDM) system. In FEC concatenated channel code, the OFDM system incorporates Reed-Solomon (RS) encoder of (255,239,8), Cyclic Encoder of (15,11), Bose-Chadhuri-Hocquenghem (BCH) encoder of (127,64) with Convolution encoder of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> / <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and frac34-rated codes under different combinations of digital modulation (QPSK, 8PSK, 32-QAM and 64-QAM). The simulation study is made with the development of a computer program written in Matlab source code on the processing of recorded audio signal under additive white Gaussian noise (AWGN) channel. The simulation results of estimated Bit error rate (BER) show that the implementation of concatenated RS(255,239,8) code with frac34-rated Convolutional code under QPSK modulation technique is highly effective to combat inherent interference in the communication system. Due to constraint in data handling capability of the Matlab editor, a segment of the recorded audio signal is used for analysis. The transmitted audio message is found to have retrieved effectively under noisy situation.