An Achievable Rate Region for the Two-Way Multiple-Relay Channel

TL;DR

This paper introduces a comprehensive achievable rate region for the two-way multiple-relay channel using decode-and-forward coding, addressing the complexity of multiple schemes through a novel ranking concept.

Contribution

It proposes a new ranking-based approach to unify and characterize all decode-forward schemes for the two-way multiple-relay channel, extending existing results.

Findings

Unified rate region encompassing all decode-forward schemes

Introduction of ranking concept for decode-forward coding

Extension of known results to multiple relays

Abstract

We propose an achievable rate-region for the two-way multiple-relay channel using decode-and-forward block Markovian coding. We identify a conflict between the information flow in both directions. This conflict leads to an intractable number of decode-forward schemes and achievable rate regions, none of which are universally better than the others. We introduce a new concept in decode-forward coding called ranking, and discover that there is an underlying structure to all of these rate regions expressed in the rank assignment. Through this discovery, we characterize the complete achievable rate region that includes all of the rate regions corresponding to the particular decode-forward schemes. This rate region is an extension of existing results for the two-way one-relay channel and the two-way two-relay channel.