Reducing fading effects in mobile communications

This dissertation is aimed at research on mitigation techniques to reduce the negative effects in a wireless communication system. We analyze and calculate the numerical relationship between bit error rate and signal-to-noise ratio. We also simulate and observe various multipath propagations over a wireless fading channel. Horizontal and vertical comparison of the improvements brought about by different diversity combining techniques is listed. Firstly, conventional diversity combining techniques including selection combining, maximum-ratio combining, and equal-gain combining, are applied. Meanwhile, we state the optimum combining technique for different modulation and demodulation schemes, especially refers to the coherent and non-coherent modulation. Then the generalization selection combining is proposed, by plotting the second-order selection combining, both in theoretical and simulated results, to achieve the sub-optimum performance with less system complexity. Based on the theoretical analysis which was published by the recent researchers, we do a complete comparison in this dissertation depending on the simulations, and as a result, this dissertation investigates the feasibility of the second-order selection combining as an alternative of the optimum diversity combining in simulated results.Master of Science (Communications Engineering