PERFORMANCE ANALYSIS OF COMPOSITE FADING CHANNELS

Abstract

The presence of both the fading and shadowing effects (also called composite multipath/shadowed fading) is often encountered in a realistic radio propagation scenario, thus, making it necessary to consider the simultaneous effect of fading and shadowing on the received signal. The performance of L-Hoyt/gamma and L-Hoyt/lognormal composite fading channels with Maximum Ratio Combining (MRC) employing micro-diversity is analyzed. Closed-form expressions for distribution function, moments, outage probability and channel capacity are derived using the probability density function (PDF) of the received instantaneous signal to noise ratio (SNR) in terms of hypergeometric functions. The detailed analysis of communication system in terms of average bit/symbol error probability (ABEP/ASEP) for both coherent and non-coherent modulation techniques are performed. The performance of energy detector over L-Hoyt/gamma and L-Hoyt/lognormal channel is also performed. The analytical expressions of average probability of detection and the average area under the receiver operating characteristic over the composite fading channel are derived. In addition, the optimized threshold has been incorporated to overcome the problem of spectrum sensing (SS) at low signal to noise ratio. For independent diversity receivers the analysis has been carried out for the arbitrary number of input branches. The effect of diversity order and fading parameters on the performance measures are studied. For the expressions with infinite series, the convergence is observed and wherever possible the expressions for upper bound on truncation error have been provided. To validate the accuracy of the derived expressions Monte-Carlo/Exact simulations are performed. The results are useful for system design engineers and can be vi directly used in several wireless applications such as cooperative and non-cooperative cognitive radio networks.