The Three Node Wireless Network: Achievable Rates and Cooperation Strategies

TL;DR

This paper analyzes a three-node wireless network, proposing new cooperation strategies for relay, multicast, and conference channels, demonstrating how feedback and source coding enhance achievable rates under practical constraints.

Contribution

It introduces a novel cooperation scheme for the relay channel that leverages wireless feedback without ideal assumptions and develops a greedy cooperation framework for multicast and conference channels.

Findings

Proposed a new relay cooperation scheme exploiting feedback gain.

Identified diminishing feedback benefits at extreme SNR regimes.

Developed a greedy cooperation approach emphasizing source-channel coding.

Abstract

We consider a wireless network composed of three nodes and limited by the half-duplex and total power constraints. This formulation encompasses many of the special cases studied in the literature and allows for capturing the common features shared by them. Here, we focus on three special cases, namely 1) Relay Channel, 2) Multicast Channel, and 3) Conference Channel. These special cases are judicially chosen to reflect varying degrees of complexity while highlighting the common ground shared by the different variants of the three node wireless network. For the relay channel, we propose a new cooperation scheme that exploits the wireless feedback gain. This scheme combines the benefits of decode-and-forward and compress-and-forward strategies and avoids the idealistic feedback assumption adopted in earlier works. Our analysis of the achievable rate of this scheme reveals the diminishing feedback gain at both the low and high signal-to-noise ratio regimes. Inspired by the proposed feedback strategy, we identify a greedy cooperation framework applicable to both the multicast and conference channels. Our performance analysis reveals several nice properties of the proposed greedy approach and the central role of cooperative source-channel coding in exploiting the receiver side information in the wireless network setting. Our proofs for the cooperative multicast with side-information rely on novel nested and independent binning encoders along with a list decoder.