On Throughput-Reliability-Delay Tradeoffs in Wireless Networks
Young‐Han Nam · OhioLink ETD Center (Ohio Library and Information Network) · 2008
In wireless communication networks, performance goals are often conflicting with each other.For example, in point-to-point multi-input-multi-output (MIMO) links, spectrum efficiency and reliability are in a tradeoff relation; in ad-hoc wireless networks, we need to sacrifice throughput to decrease packet delay.In this dissertation, we investigate problems on the diversity-multiplexing tradeoff (DMT) in cellular wireless communication networks and problems on the throughput-delay tradeoff in adhoc wireless networks.We first consider two topics on the DMT in cellular uplinks (or multiple-access channels, MACs): (1) the diversity-multiplexing-delay tradeoff (DMDT) in a randomaccess scenario and (2) an explicit construction of space-time coding scheme achieving the DMT.For the random-access scenario, we propose an incremental-redundancy automatic repeat request (IR-ARQ) scheme.We prove that our scheme successfully exploits both ARQ diversity and joint-decoding advantage, and achieves a better DMT than other existing protocols, such as Tsatsanis et al.'s network-assisted diversity multiple-access (NDMA) and Gallager tree algorithm.Next, we propose a latticespace time (LAST) coding/decoding scheme in MACs and prove that it achieves the optimal DMT in MACs.Although our result is established using a random coding argument, it is important to note that the proposed scheme is explicit in a sense that