DMT of parallel-path and layered networks under the half-duplex constraint

Abstract—In this paper, we study the diversity-multiplexing-gain tradeoff (DMT) of wireless relay networks under the half-duplex constraint. It is often unclear what penalty if any, is imposed by the half-duplex constraint on the DMT of such networks. We study two classes of networks; the first class, called KPP(I) networks, is the class of networks with the relays organized in parallel paths between the source and the destination. While we assume that there is no direct source-destination path, the relaying paths can interfere with each other. The second class, termed as layered networks, is comprised of relays organized in layers, where links exist only between adjacent layers. We present a communication scheme based on static schedules and amplify-and-forward relaying for these networks. We also show that for KPP(I) networks with, the proposed schemes can achieve full-duplex DMT performance, thus demonstrating that there is no performance hit on the DMT due to the half-duplex constraint. We also show that, for layered networks, a linear DMT of between the maximum diversity and the maximum MG, is achievable. We adapt existing DMT optimal coding schemes to these networks, thus specifying the end-to-end communication strategy explicitly. Index Terms—Amplify-and-forward protocols, cooperative diversity, diversity-multiplexing gain tradeoff, explicit codes, KPP networks, layered networks, multi-antenna networks, multi-hop networks, relay networks. I