Hybrid Automatic-Repeat-reQuest Systems for Cooperative Wireless Communications

Hybrid-Automatic-Repeat-reQuest H-ARQ has become an indispensable technique in reliable communication systems. Hence, in this paper we review the state-of-art and investigate the performance of H-ARQ in the context of cooperative wireless communications. As a novel advance, we also propose a relay-switching regime based H-ARQ scheme, which is capable of increasing the achievable system throughput as confirmed by both theory and practice. Furthermore, we evaluate the achievable upper-bound performance in the context of perfect Channel State Information CSI. Then we proceed to quantify the performance erosion imposed by realistic CSI-based-coherent detection as well as low complexity non-coherent detection assisted cooperative H-ARQ. Finally, we propose a general design guide-lines for H-ARQ aided cooperative systems.