A probabilistic detect-and-forward relay selection policy for cooperative device-to-device wireless systems

We consider a four-node cooperative, detect-and-forward (DaF) relay-assisted device-to-device (D2D) system. For it, we propose a simple, novel, and intuitive probabilistic relay selection policy. We analyze fading-averaged symbol error rate (FASER) of the policy. Specifically, we derive closed form expressions of FASER for two different constellations, namely, M-ary phase shift keying (MPSK) and M-ary quadrature amplitude modulation (MQAM). Besides the FASER analysis, we also analyze fading-averaged spectral efficiency. We extend our analysis and present an insightful result on the diversity order of the proposed relay selection policy. In order to validate our theoretical derivations, we present numerical results. For the in-depth analysis of the proposed probabilistic relay selection policy, various effects like small scale fading, large scale fading, and the combination of both small and large scale fading are considered with path loss. The proposed relay selection policy and its performance analysis are useful for cooperative D2D wireless DaF relay systems and networks. (C) 2019 Elsevier B.V. All rights reserved.