Non-orthogonal multiple-access for coherent-state optical quantum communications under lossy photon channels
Abstract
Coherent states have been increasingly considered in optical quantum communications (OQCs).With the inherent non-orthogonality of coherent states, non-orthogonal multiple-access (NOMA) naturally lends itself to the implementation of multi-user OQC. However, this remains unexplored in the literature. This paper proposes a novel successive interference cancellation (SIC)-based photon-number-resolving detection (PNRD)-Kennedy receiver for uplink NOMA-OQC systems, along with a new approach for power allocation of the coherent states emitted by users. The key idea is to rigorously derive the asymptotic sum-rate of the considered systems, taking into account the impact of atmospheric turbulence, background noise, and lossy photon channel. With the asymptotic sum-rate, we optimize the average number of photons (or powers) of the coherent states emitted by the users. Variable substitution and successive convex approximation (SCA) are employed to convexify and maximize the asymptotic sum-rate iteratively. A new coherent-state power allocation algorithm is developed for a small-to-medium number of users. We further develop its low-complexity variant using adaptive importance sampling, which is suitable for scenarios with a medium-to-large number of users. Simulations demonstrate that our algorithms significantly enhance the sum-rate of uplink NOMA-OQC systems using coherent states by over 20%, compared to their alternatives.
Document Type
Journal Article
Date of Publication
1-1-2025
Publication Title
IEEE Transactions on Communications
Publisher
IEEE
School
School of Engineering
Funders
National Natural Science Foundation of China (62571137, 62231010) / Natural Science Foundation of Shanghai (24ZR1407100)
Copyright
subscription content
Comments
Dong, Z., Zhou, X., Chen, Y., Ni, W., Hossain, E., & Wang, X. (2025). Non-orthogonal multiple-access for coherent-state optical quantum communications under lossy photon channels. IEEE Transactions on Communications, 74, 2548–2563. https://doi.org/10.1109/TCOMM.2025.3646885