DMT of Wireless Networks: An overview

The efficient operation of single-source, single-sink wireless networks is considered with the diversity-multiplexing gain tradeoff (DMT) as the measure of performance. Whereas in the case of a point-to-point MIMO channel the DMT is determined by the fading statistics, in the case of a network, the DMT is additionally, a function of the time schedule according to which the network is operated, as well as the protocol that dictates the mode of operation of the intermediate relays. In general, it is only possible at present, to provide upper bounds on the DMT of the network in terms of the DMT of the MIMO channel appearing across cuts in the network. This paper presents a tutorial overview on the DMT of half-duplex multi-hop wireless networks that also attempts to identify where possible, codes that achieve the DMT. For example, it is shown how one can construct codes that achieve the DMT of a network under a given schedule and either an amplify-and-forward or decode-and-forward protocol. Also contained in the paper, are discussions on the DMT of the multiple-access channel as well as the impact of feedback on the DMT of a MIMO channel.