Experimental Study of Fading using Alamouti Space-Time Block Code

In wireless communication system, transmitted signal is received at the receiver from various paths. This happens because of scattering object which are present in the Line of Sight (LOS) path in wireless communication channel. Due to this multipath reception of the signal at the receiver, there occurs constructive or destructive interference which gives rise to fading. In this paper, the problem of fading in the multipath system is studied using simple models for multipath propagation. Extensive SIMULINK® models are presented to show the cases where a transmitted signal is traveling through multipath trajectories and reaches at receiver. A Rayleigh fading channel is modelled to show this multipath effect. A comparison is made between the performance of AWGN channel and Rayleigh fading channel keeping Bit Error Rate (BER) as a parameter. It is also observed that by using more number of receivers, the BER of the fading channel can be brought closer to the ideal situation. Further, it is shown that effective use of Alamouti Space-Time Block code improves BER significantly in MIMO system considering multiple receivers in comparison with Rayleigh fading channel.