Maximal Ratio Combiner in Time-Varying Channel Amplify-and-Forward Cooperative Communication Network

Abstract

This manuscript focuses on the Multiple Symbol Double Differential (MSDD) detection scheme in Amplify-and-Forward (AF) cooperative communication network employing Maximal Ratio Combining (MRC) at the receiver. In the wireless communication environment, high mobility, limited bandwidth as well as transmission capacity, and unreliable fading channels affects the channel transmission. Most of the previous works consider a flat-fading scenario, but this assumption is unjustified as cooperative communications are specially utilized in the mobile system, wherein the end users are mobile. As the end user moves under high-velocity environment, the channels experience fast fading which result in performance degradation. Thus, an AF-based cooperative communication method is proposed so as to mitigate the challenges. A comprehensive error probability and outage probability performance analysis are carried through the flat fading Rayleigh environment for the proposed MRC. Specifically, Pairwise Error Probability (PEP) expressions for the proposed MRC detectors are derived based on the Moment Generating Function (MGF). On top of that, Probability Density Function (PDF) analysis expression is derived to obtain the outage probability of the network. It can be observed that the MRC new combining weights that are based on the channel second-order statistic, perform better in terms of error probability as compare to the conventional MRC under time-varying channel environment. Furthermore, the simulations of the proposed MRC and the derived numerical analysis also validated under different faded channel and different number of relays.