Relay-assisted Multiple Access with Full-duplex Multi-Packet Reception

TL;DR

This paper analyzes the impact of full-duplex relaying with self-interference on multiuser network throughput and delay, revealing that perfect self-interference cancelation can sometimes degrade performance due to queue instability.

Contribution

It provides analytical models for relay queue dynamics and performance metrics considering self-interference, a novel analysis in full-duplex multi-packet reception networks.

Findings

Perfect self-interference cancelation can worsen throughput and delay at low SINR thresholds.

Queue stability at the relay is affected by self-interference levels and transmission probabilities.

Full-duplex relaying can outperform half-duplex under certain conditions, but may also cause instability.

Abstract

The effect of full-duplex cooperative relaying in a random access multiuser network is investigated here. First, we model the self-interference incurred due to full-duplex operation, assuming multi-packet reception capabilities for both the relay and the destination node. Traffic at the source nodes is considered saturated and the cooperative relay, which does not have packets of its own, stores a source packet that it receives successfully in its queue when the transmission to the destination has failed. We obtain analytical expressions for key performance metrics at the relay, such as arrival and service rates, stability conditions, and average queue length, as functions of the transmission probabilities, the self interference coefficient, and the links' outage probabilities. Furthermore, we study the impact of the relay node and the self-interference coefficient on the per-user and aggregate throughput, and the average delay per packet. We show that perfect self-interference cancelation plays a crucial role when the SINR threshold is small, since it may result to worse performance in throughput and delay comparing with the half-duplex case. This is because perfect self-interference cancelation can cause an unstable queue at the relay under some conditions.