Half-duplex multiple-relay multiple-antenna diamond networks with perfect full-duplex performance

Abstract

Diversity-multiplexing tradeoff (DMT) of a full-duplex diamond network where the inter-relay interference (IRI) is suppressed, global channel state information (CSI) is available in all nodes, and perfect self-interference cancellation (SIC) technique is used, which we call it the perfect full-duplex diamond network, is an upper bound for the DMT of the equivalent half-duplex diamond network, i.e., the perfect full-duplex diamond network outperforms the half-duplex case. Nevertheless, the implementation of the perfect full-duplex diamond network is a high-cost operation and requires significant hardware changes in current systems. The main question addressed in this paper is: under which condition (or perhaps conditions) does a prevalent half-duplex diamond network provide the same performance as the perfect full-duplex one? In this regard, first, we calculate the DMT of a perfect full-duplex multiple-relay and multiple-antenna (MRMA) symmetric diamond network. Then, we demonstrate that for the same network but with half-duplex relays, when the number of antennas in relays satisfies a specific condition, there exists a fixed listen-transmit schedule combined with quantize-map-and-forward (QMF) relaying to achieve the optimal DMT. Also, we attain a lower bound for the total number of antennas of the MRMA symmetric diamond network to achieve the optimal DMT.