-MODELLING OF FADING AND SHADOWING ASPECTS IN WIRELESS COMMUNICATION CHANNELS: AN ANALYTICAL PERSPECTIVE

Abstract

The dissertation addresses the issue of modelling randomness of the signal envelope arising from fading-shadowing phenomenon. The emphasis in the work done is on modelling these aspects using analytical framework to gain insight into the performance measures associated with wireless, channel characteristics. The fading and shadowing aspects in wireless channels are generally captured through composite Rayleigh-lognormal distribution (RLD) which suffers from the limitation that no closed form solution exists. To overcome this difficulty, a composite distribution Rayleigh-gamma distribution (RGD) is used in the literature which yields a closed form referred to as K-distribution. A new composite distribution Rayleigh-Inverse Gaussian distribution (RIGD) (having closed form) is.proposed by replacing lognormal with inverse Gaussian distribution in RLD. It is found that RIGD outperforms RGD in terms of closeness to RLD and QOS parameters like average bit error rate (BER) of DPSK and MSK schemes. Analytical results predicting BER of DPSK and MSK schemes for RLD shows that RIGD performs better than K-distribution. We have succeeded in obtaining the analytic closed form expressions for intractable BER of DPSK and MSK schemes for Rayleigh lognormal distribution by using n-point distributions,