High bit error rates of the wireless communication system require employing forward error correction (FEC) methods on the data transferred to reducing the error in transmission. In this paper, the performance of OFDM- BPSK,-QPSK and -QAM system by using forward error correcting codes as concatenated codes schemes that are used to encode the data stream in wireless communications Nakagami-m fading channel has been reported here . Our approach is based on decomposition of Nakagami random variable into orthogonal random variables with Gaussian distribution envelopes. Results have been presented by using optimum value of m based on BER and SNR We present OFDM for wireless communications .We address basic OFDM and related modulations, as well as techniques to improve the performance of OFDM for wireless communications (OFDM). we performed simulations to find out the best BER performance using RS-CC concatenated codes. By concatenating two different codes we can get the effect of improving the total BER due to benefits of RS codes correcting burst errors while convolutional codes are good for correcting random errors that are caused due to a noisy channel.
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