Study of Linear and Decision Feedback Equalizers on Fading Channels

For evaluating the performance of wireless digital communication system the most important part is the simulation of wireless channel, as whole performance of the system is depends upon it. The Band limited communication channel, due to its dispersive time response, may restrict the high data rate, due to Inter symbol Interference (ISI). If the ISI is not taken care off and compensated may cause high Bit Error Rate (BER). Equalizers are used for this purpose. In this paper the performance of Linear and Decision Feedback Equalizers (DFE) are evaluated on three wireless channels i.e. two ray path, Rayleigh and Rician. A model of communication system having Quadrature Amplitude Modulation (QAM) with fading channels is implemented using MATLAB. The performance of Linear and DFE is evaluated on the basis of Bit Error Rate (BER) with varying Signal to Noise Ratio (SNR). The simulation results showed the performance of two equalizers on different channels. The Rayleigh channel model is the most suitable model for urban areas as it is the model which simulates a channel with no Line of Sight (LOS) path and is the most difficult environment. General Terms ISI (Inter-symbol Interference), BER (Bit Error Rate), SNR (Signal to Noise Ratio)