Design, Simulation and Evaluation of SISO/MISO/MIMO-OFDM Systems

Abstract— In this paper an endeavour is made to design and simulate SISO, MISO and MIMO OFDM systems. We have analysed and compared the performance of these systems for image transmission over AWGN and Rayleigh channels. The effect of LS channel estimation on the BER over a range of SNR for MIMO(2X2) systems is examined. We have also compared the performance based on various M-ary PSK modulation techniques for image transmission over Rayleigh channel in MIMO-OFDM system. The system performance is simulated in Matlab. The results of the simulation show that as the antenna diversity increases, the BER decreases and the channel capacity increases. Also, the BER obtained in MIMO-OFDM system is less when LS estimation is used.

Keywords— OFDM, MIMO, Rayleigh, AWGN, BER, channel capacity

I. INTRODUCTION

The demand for maximum achievable data rate, less delay time, efficient modulation technique, less interference, reduced effect of multipath propagation and Doppler shift, high picture and voice quality, etc. are increasing day by day in wireless technology. These demands can be met by technologies like multicarrier systems (OFDM), MIMO, CDMA etc. The main advantages of multicarrier systems are its robustness in frequency selective channels and less signal processing complexity as equalization is done in frequency domain. OFDM is amalgamation of modulation and multiplexing. It helps in reducing Inter Symbol Interference for frequency selective channels by adding cyclic prefix. MIMO transforms single point to point channel into multiple parallel channels thus offering higher channel capacity and reduced Bit Error Rate (BER) [4][10]. Here, we attempt to analyze the performance of the three systems namely SISO-OFDM, MISO(1X2)-OFDM and MIMO(2X2) OFDM for image transmission over Rayleigh and AWGN channels. We have also examined the effect of using LS channel estimation technique in MIMO-OFDM system over Rayleigh channel. Matlab simulation results are compared for parameters such as BER and channel capacity.
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