MIMO Multiway Distributed-Relay Channel with Full Data Exchange: An Achievable Rate Perspective

TL;DR

This paper introduces a novel physical-layer network coding scheme for MIMO multiway distributed relay channels with full data exchange, achieving near-capacity sum rates at high SNR through advanced precoding and coding techniques.

Contribution

It proposes a new PNC-based scheme combining linear precoding, nested lattice coding, and lattice-based interference mitigation, achieving asymptotic capacity within a constant gap.

Findings

Achieves the same sum-rate as cooperative relaying at high SNR.

Attains the asymptotic sum capacity within a constant gap.

Outperforms existing decode-and-forward and amplify-and-forward schemes.

Abstract

We consider efficient communications over the multiple-input multiple-output (MIMO) multiway distributed relay channel (MDRC) with full data exchange, where each user, equipped with multiple antennas, broadcasts its message to all the other users via the help of a number of distributive relays. We propose a physical-layer network coding (PNC) based scheme involving linear precoding for channel alignment nested lattice coding for PNC, and lattice-based precoding for interference mitigation, We show that, with the proposed scheme, distributed relaying achieves the same sum-rate as cooperative relaying in the high SNR regime. We also show that the proposed scheme achieve the asymptotic sum capacity of the MIMO MDRC within a constant gap at high SNR. Numerical results demonstrate that the proposed scheme considerably outperforms the existing schemes including decode-and-forward and amplify-and-forward.