Priority-based max-link relay selection scheme for buffer-aided DF cooperative networks

Abstract

In this paper, we propose, for decode-and-forward cooperative networks, a relaying scheme which is based on giving a priority to the status of relay buffers along with the highest channel gain of wireless links. Specifically, we divide the set of relay buffer status into three priority classes: i) the first priority is given to relay buffers which are full, ii) the second priority to relay buffers which are empty, and iii) the third priority to relay buffers which are neither full nor empty. Within a priority class, a relay node is selected corresponding to the link having the highest channel gain. We adopt a Markov chain approach to analyze the state transition matrix that models the evolution of the relay buffer status. Analytical expressions for the outage probability and the diversity order are derived. The proposed scheme is illustrated with an example and analytical expressions for the steady-state probability vector are obtained. It is also shown that the states having the same probabilities can be grouped. Furthermore, we explain the construction of the reduced state transition matrix. Our analytical and simulation results demonstrate that the proposed scheme has the potential to provide better outage performance over the conventional maxlink scheme.