Decentralized Two-Hop Opportunistic Relaying With Limited Channel State Information

TL;DR

This paper analyzes the throughput scaling laws of decentralized two-hop relaying protocols in large networks with limited channel state information, demonstrating that the optimal throughput scales as log n.

Contribution

It introduces a decentralized opportunistic relaying scheme that achieves the optimal log n throughput scaling with limited CSI and no relay cooperation.

Findings

Throughput scales as log n in large networks.

Decentralized scheme achieves optimal throughput scaling.

Limited CSI at transmitters suffices for optimal performance.

Abstract

A network consisting of $n$ source-destination pairs and $m$ relays is considered. Focusing on the large system limit (large $n$), the throughput scaling laws of two-hop relaying protocols are studied for Rayleigh fading channels. It is shown that, under the practical constraints of single-user encoding-decoding scheme, and partial channel state information (CSI) at the transmitters (via integer-value feedback from the receivers), the maximal throughput scales as $\log n$ even if full relay cooperation is allowed. Furthermore, a novel decentralized opportunistic relaying scheme with receiver CSI, partial transmitter CSI, and no relay cooperation, is shown to achieve the optimal throughput scaling law of $\log n$.