Dynamic User Pairing for Non-Orthogonal Multiple Access in Downlink Networks

TL;DR

This paper proposes a joint optimization approach for user pairing and beamforming in downlink NOMA systems to enhance fairness and throughput, employing a relaxation and iterative algorithm to find local optima.

Contribution

It introduces a novel joint optimization framework for dynamic user pairing and beamforming in downlink NOMA, with an iterative algorithm that outperforms existing strategies.

Findings

Proposed algorithm achieves higher minimum throughput.

Outperforms conventional beamforming and heuristic pairing.

Effective in maximizing user fairness.

Abstract

This paper considers a downlink (DL) system where non-orthogonal multiple access (NOMA) beamforming and dynamic user pairing are jointly optimized to maximize the minimum throughput of all DL users. The resulting problem belongs to a class of mixed-integer non-convex optimization. To solve the problem, we first relax the binary variables to continuous ones, and then devise an iterative algorithm based on the inner approximation method which provides at least a local optimal solution. Numerical results verify that the proposed algorithm outperforms other ones, such as conventional beamforming, NOMA with random-pairing and heuristic-search strategies.