Relaying Simultaneous Multicast Messages

TL;DR

This paper investigates the capacity and achievable rates for a relay-assisted multicast system where the relay may have its own message, introducing new bounds and strategies for this complex communication scenario.

Contribution

It characterizes the capacity region of a relay-assisted multicast channel with cognitive relay and proposes achievable rate regions using decode-and-forward and compress-and-forward strategies.

Findings

Capacity region of the cognitive relay model is characterized.

Achievable rate regions for cMACr are developed.

Numerical results demonstrate the bounds for Gaussian channels.

Abstract

The problem of multicasting multiple messages with the help of a relay, which may also have an independent message of its own to multicast, is considered. As a first step to address this general model, referred to as the compound multiple access channel with a relay (cMACr), the capacity region of the multiple access channel with a "cognitive" relay is characterized, including the cases of partial and rate-limited cognition. Achievable rate regions for the cMACr model are then presented based on decode-and-forward (DF) and compress-and-forward (CF) relaying strategies. Moreover, an outer bound is derived for the special case in which each transmitter has a direct link to one of the receivers while the connection to the other receiver is enabled only through the relay terminal. Numerical results for the Gaussian channel are also provided.