Performance Analysis of Different M-ary Modulation Techniques in Fading Channels Using Different Diversity

The comparison of symbol error probability(SEP) for different M-ary modulation techniques over slow, flat, identically independently distributed Rician fading channel is presented in this paper. Because fading is one of the major limitations in wireless communication, so modulation technique with diversity is used to transmit message signal efficiently. Exact analysis of symbol error probability for M-ary differentially encoded or differentially decoded phase shift keying(PSK) and coherent M-ary phase shift keying, transmitted over Rician fading channel has been performed with N branch receive diversity using maximalratio-combining(MRC) where channel side information known at the receiver. Also the performance of Mary quadrature amplitude modulation (QAM) over Rician fading channel has been analyzed here. Approximate formula has been used to represent symbol error probability for M-ary quadrature amplitude modulation over a Gaussian channel. The boundary condition for approximation is M > 4 and 0 ≤ SNR ≤ 30 dB.