Gaussian Broadcast Channels with an Orthogonal and Bidirectional Cooperation Link

TL;DR

This paper analyzes a broadcast system with two receivers connected by an orthogonal bidirectional link, focusing on signal recombination, cooperation rounds, cooperation strategies, and spectral resource impact, using analytical and simulation methods.

Contribution

It provides insights into optimal cooperation strategies and signal processing in Gaussian broadcast channels with orthogonal bidirectional links, considering practical simplified protocols.

Findings

Optimal number of cooperation rounds identified

Impact of cooperation strategy on performance analyzed

Analytical and simulation results compared with discrete models

Abstract

This paper considers a system where one transmitter broadcasts a single common message to two receivers linked by a bidirectional cooperation channel, which is assumed to be orthogonal to the downlink channel. Assuming a simplified setup where, in particular, scalar relaying protocols are used and channel coding is not exploited, we want to provide elements of response to several questions of practical interest. Here are the main underlying issues: 1. The way of recombining the signals at the receivers; 2. The optimal number of cooperation rounds; 3. The way of cooperating (symmetrically or asymmetrically; which receiver should start cooperating in the latter case); 4. The influence of spectral resources. These issues are considered by studying the performance of the assumed system through analytical results when they are derivable and through simulation results. For the particular choices we made, the results sometimes do not coincide with those available for the discrete counterpart of the studied channel.