Optimal link selection for buffer-aided and multicast relay networks

Abstract

In this paper, we study the link selection protocol for the network consisting of two sources, two destinations and one half-duplex decode-and-forward (DF) relay equipped with data buffers. In contrast to most of the existing literature where the buffer-aided relay can only unicast, we introduce the multicast communication into the buffer-aided relay network. With the aid of buffers and multicast communication, the relay can choose links for transmission adaptively based on the channel state information (CSI). An optimal link selection scheme is proposed to maximize the average throughput of the relay network, and it is derived from a throughput maximization problem. Using the Karush-Kuhn-Tucker (KKT) conditions, we obtain the link selection function for Rayleigh fading channels. Numerical results reveal that the proposed scheme achieves significant throughput gain compared with the existing link selection schemes.