An Information-Theoretic Analysis of the Gaussian Multicast Channel with Interactive User Cooperation

TL;DR

This paper analyzes the Gaussian multicast channel with interactive user cooperation, proposing a new three-receiver scheme that combines compress-forward and decode-forward strategies, leading to improved transmission rates over existing methods.

Contribution

It introduces a novel three-receiver interactive cooperation scheme (3FC) that enhances multicast transmission rates by combining CF and DF techniques with receiver interaction.

Findings

The 3FC scheme outperforms existing schemes in Gaussian multicast channels.

Interaction among receivers significantly improves achievable rates.

The analysis provides a closed-form expression for practical evaluation.

Abstract

We consider the transmission of a common message from a transmitter to three receivers over a broadcast channel, referred to as a multicast channel in this case. All the receivers are allowed to cooperate with each other over full-duplex bi-directional non-orthogonal cooperation links. We investigate the information-theoretic upper and lower bounds on the transmission rate. In particular, we propose a three-receiver fully interactive cooperation scheme (3FC) based on superpositions of CF and DF at the receivers. In the 3FC scheme, the receivers interactively perform compress-forward (CF) simultaneously to initiate the scheme, and then decode-forward (DF) sequentially to allow a correlation of each layer of the DF superposition in cooperation with the transmitter toward the next receiver in the chain to improve the achievable rate. The analysis leads to a closed-form expression that allows for numerical evaluation, and also gives some insight on key points to design interactive schemes. The numerical results provided in the Gaussian case show that the proposed scheme outperforms existing schemes and show the benefit of interaction.