Scheduling Quantum Annealing for Active User Detection in a NOMA Network

TL;DR

This paper introduces a quantum annealing method for active user detection in NOMA networks, transforming the problem into an Ising Hamiltonian ground state and optimizing the annealing schedule for efficiency and robustness.

Contribution

It proposes a quantum annealing approach with a universal control function for efficient, high-probability detection in NOMA networks, even with network imperfections.

Findings

The maximum a posteriori decoder corresponds to the ground state of an Ising Hamiltonian.

The proposed control function improves annealing efficiency over linear schedules.

The method maintains high success probability despite network imperfections.

Abstract

Active user detection in a non-orthogonal multiple access (NOMA) network is a major challenge for 5G/6G applications. However, classical algorithms that can perform this task suffer either from complexity or reduced performances. This work aims at proposing a quantum annealing approach to overcome this trade-off. Firstly, we show that the maximum a posteriori decoder of the activity pattern of the network can be seen as the ground state of an Ising Hamiltonian. For N users in a network with perfect channels, we propose a universal control function to schedule the annealing process. Our approach avoids to continuously compute the optimal control function but still ensures high success probability while demanding a lower annealing time than a linear control function. This advantage holds even in the presence of imperfections in the network.