Broadcast Approach and Oblivious Cooperative Strategies for the Wireless Relay Channel - Part I: Sequential Decode-and-Forward (SDF)

TL;DR

This paper introduces a broadcast approach combined with sequential decode-and-forward strategies for the wireless relay channel, analyzing achievable rates under various channel conditions and proposing oblivious cooperative protocols.

Contribution

It develops a novel broadcast-based cooperative strategy for relay channels, deriving rate expressions and bounds for multiple configurations including MISO and oblivious scenarios.

Findings

Achievable rate expressions for SDF with broadcast approach are derived.

Continuous broadcasting lower bounds are established for MISO and oblivious cooperation.

The approach improves adaptation to channel conditions in relay networks.

Abstract

In this two part paper we consider a wireless network in which a source terminal communicates with a destination and a relay terminal is occasionally present in close proximity to the source without source's knowledge, suggesting oblivious protocols. The source-relay channel is assumed to be a fixed gain AWGN due to the proximity while the source-destination and the relay-destination channels are subject to a block flat Rayleigh fading. A perfect CSI at the respective receivers only is assumed. With the average throughput as a performance measure, we incorporate a two-layer broadcast approach into two cooperative strategies based on the decode-and-forward scheme - Sequential Decoded-and Forward (SDF) in part I and the Block-Markov (BM) in part II. The broadcast approach splits the transmitted rate into superimposed layers corresponding to a "bad" and a "good" channel states, allowing better adaptation to the actual channel conditions In part I, the achievable rate expressions for the SDF strategy are derived under the broadcast approach for multiple settings including single user, MISO and the general relay setting using successive decoding technique, both numerically and analytically. Continuous broadcasting lower bounds are derived for the MISO and an oblivious cooperation scenarios.