Performance Improvement of Non-Regerative Cooperative Relay Networks with Optimal Power Allocation and Adaptive M-QAM/M-PSK Modulation Over Generalized Fading Channels

Abstract

This paper analyzes the performance of Channel Side Information (CSI)-assisted cooperative amplify-andforward (CAF) relay networks that employ both the node placement (i.e., relay position) based optimal power allocation policy among collaborating nodes and adaptive M-ary quadrature amplitude modulation (M-QAM)/ M-ary phase shift keying (M-PSK) techniques in generalized wireless fading environments. In particular, we advocate a simple yet unified numerical approach based on the marginal moment generating function (MGF) of the total received Signal to Noise Ratio (SNR) to derive analytical expressions for the average bit error rate (ABER), mean achievable spectral efficiency, and outage probability performance metrics. The proposed analytical framework is sufficiently general and flexible to characterize the performance of adaptive-link CAF relay networks over a wide range of fading distributions (i.e., not restricted to Rayleigh fading or independent identically distributed (i.i.d) Nakagami-m fading ) with independent but non-identically distributed (i.n.d) fading statistics across the spatially distributed diversity paths. Additionally, we further simplify the computational complexity, by employing the use of an “approximate MGF expression” to compute the system performance metrics over the generalized fading channel. Employing the above novel approach based on “approximate MGF” in conjunction derived analytical frameworks allows us to simplify the computation complexity of achievable spectral efficiency as well as ABER of CAF relay system in the generalized fading environments by simply replacing appropriate single channel MGF which is readily available.