In this paper, the diversity gain of a Maximal Ratio Combiner (MRC) has been investigated for Orthogonal Frequency Division Multiplexing (OFDM) by varying the number of receiving antennas. Different modulation schemes namely 64-PSK, 64-QAM, 16-PSK, 16-QAM and QPSK have been used in OFDM technique. The simulation results show that the performance (SNR) of an OFDM system can be significantly improved by using MRC. We have also derived average Symbol Error Rate (SER) of M-ary Quadrature Amplitude (M-QAM) and M-ary Phase Shift Keying (M-PSK) modulations for N-branch MRC space diversity reception scheme. In this paper, it is shown that M-QAM based OFDM technique outperforms M-PSK based OFDM technique. The comparison of the performances of the Signal-to-Noise Ration (SNR) ofM-PSK and M-QAM based OFDM technique has been presented in this paper. It is also shown that SNR can be improved further if the number of receiving antennasis increased.
|Journal||International Journal of Distributed and Parallel Systems (IJDPS)|