Joint Source-Channel Cooperative Transmission over Relay-Broadcast Networks

TL;DR

This paper investigates reliable joint source-channel transmission over relay-broadcast networks with correlated side information, proposing two decode-and-forward schemes that achieve the source-channel capacity under specific network conditions.

Contribution

It introduces two novel achievability schemes for cooperative relay networks with side information, demonstrating their optimality in certain degraded network scenarios.

Findings

Both schemes achieve the same source-channel code rate.

The schemes are optimal for physically degraded relay networks with correlated side information.

The schemes are effective in relay-broadcast networks where all terminals aim to reconstruct the source.

Abstract

Reliable transmission of a discrete memoryless source over a multiple-relay relay-broadcast network is considered. Motivated by sensor network applications, it is assumed that the relays and the destinations all have access to side information correlated with the underlying source signal. Joint source-channel cooperative transmission is studied in which the relays help the transmission of the source signal to the destinations by using both their overheard signals, as in the classical channel cooperation scenario, as well as the available correlated side information. Decode-and-forward (DF) based cooperative transmission is considered in a network of multiple relay terminals and two different achievability schemes are proposed: i) a regular encoding and sliding-window decoding scheme without explicit source binning at the encoder, and ii) a semi-regular encoding and backward decoding scheme with binning based on the side information statistics. It is shown that both of these schemes lead to the same source-channel code rate, which is shown to be the "source-channel capacity" in the case of i) a physically degraded relay network in which the side information signals are also degraded in the same order as the channel; and ii) a relay-broadcast network in which all the terminals want to reconstruct the source reliably, while at most one of them can act as a relay.