Cooperative HARQ Assisted NOMA Scheme in Large-scale D2D Networks

TL;DR

This paper proposes an interference-aware cooperative HARQ assisted NOMA scheme for large-scale D2D networks, improving throughput and reducing outage probability by accounting for spatial and temporal interference correlations.

Contribution

It introduces a stochastic geometry-based design framework that jointly considers interference correlations, enhancing NOMA performance analysis and optimization in D2D networks.

Findings

Interference-aware design significantly improves LTAT and ASE.

Cooperative HARQ reduces outage probability by 32%.

Proposed scheme achieves 47% higher throughput than HARQ-assisted OMA.

Abstract

This paper develops an interference aware design for cooperative hybrid automatic repeat request (HARQ) assisted non-orthogonal multiple access (NOMA) scheme for large-scale device-to-device (D2D) networks. Specifically, interference aware rate selection and power allocation are considered to maximize long term average throughput (LTAT) and area spectral efficiency (ASE). The design framework is based on stochastic geometry that jointly accounts for the spatial interference correlation at the NOMA receivers as well as the temporal interference correlation across HARQ transmissions. It is found that ignoring the effect of the aggregate interference, or overlooking the spatial and temporal correlation in interference, highly overestimates the NOMA performance and produces misleading design insights. An interference oblivious selection for the power and/or transmission rates leads to violating the network outage constraints. To this end, the results demonstrate the effectiveness of NOMA transmission and manifest the importance of the cooperative HARQ to combat the negative effect of the network aggregate interference. For instance, comparing to the non-cooperative HARQ assisted NOMA, the proposed scheme can yield an outage probability reduction by $32$%. Furthermore, an interference aware optimal design that maximizes the LTAT given outage constraints leads to $47$% throughput improvement over HARQ-assisted orthogonal multiple access (OMA) scheme.