Differential Modulation for Buffer-Aided Cooperative Relaying using Priority-Based Link Selection

In this paper, we employ a differential modulation technique for a butter-aided cooperative network. A differential decode-and-forward relaying protocol is proposed for transmission with priority-based link selection. The proposed technique does not require channel state information at any node of the buffer-aided cooperative network. A Markov chain-based approach is used to analyze the state transition matrix which models the evolution of butter status. An analytical expression for the steady state probability is derived, and with the help of that, analytical expressions of outage probability and average bit error rate (ABER) are obtained. The performance gap between the considered system and coherent butter-aided system is observed through the derived analytical results. The considered differential system suffers a signal-to-noise ratio penalty of 1 dB at the ABER level of 10
^-4
with a two-bit butter, which is a significant improvement over non-butter-aided networks; which offer a performance gap of 3 dB between coherent and differential relaying.