Space–Time Diversity Enhancements Using Collaborative Communications

TLDR

The use of the spatial dimension is known to greatly increase the reliability of quasi‑static (i.e., nonergodic) wireless channels. The study demonstrates that most of the spatial diversity gain can be achieved via collaborative communications among single‑antenna/multiple‑antenna nodes with a single receiver. The authors analyze single‑antenna collaboration by modeling communication between clusters of nearby nodes. Collaborative codes exist that incur only a small intra‑cluster negotiation penalty, enabling almost all of the traditional space‑time diversity gain, as illustrated by a negligible penalty when a single transmitter with two collaborators outperforms a receiver by 10 dB.

Abstract

The use of the spatial dimension is known to greatly increase the reliability of quasi-static (i.e., nonergodic) wireless channels. In this paper, it is demonstrated that most of this gain can also be achieved through collaborative communications with single-antenna/multiple-antenna nodes when there is one receiving agent. In particular, for the single-antenna case, communication is considered to take place between clusters of nearby nodes. The existence of collaborative codes for which the intra-cluster negotiation penalty is, in principle, small (and almost all the diversity gain of traditional space-time codes may be realized) is shown. For example, for a single transmitter node with two collaborators and one receiver node, if the collaborators have as little as a 10-dB path loss advantage over the receiver, the penalty for collaboration over traditional space-time systems is negligible.