Maraqa Omar, Siddiqi Umair F, Al-Ahmadi Saad, Sait Sadiq M
Department of Electrical Engineering, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
Center of Communications and IT Research, Research Institute, King Fahd University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia.
Sensors (Basel). 2021 May 26;21(11):3705. doi: 10.3390/s21113705.
Visible light communications (VLC) is gaining interest as one of the enablers of short-distance, high-data-rate applications, in future beyond 5G networks. Moreover, non-orthogonal multiple-access (NOMA)-enabled schemes have recently emerged as a promising multiple-access scheme for these networks that would allow realization of the target spectral efficiency and user fairness requirements. The integration of NOMA in the widely adopted orthogonal frequency-division multiplexing (OFDM)-based VLC networks would require an optimal resource allocation for the pair or the cluster of users sharing the same subcarrier(s). In this paper, the max-min rate of a multi-cell indoor centralized VLC network is maximized through optimizing user pairing, subcarrier allocation, and power allocation. The joint complex optimization problem is tackled using a low-complexity solution. At first, the user pairing is assumed to follow the divide-and-next-largest-difference user-pairing algorithm (D-NLUPA) that can ensure fairness among the different clusters. Then, subcarrier allocation and power allocation are solved iteratively through both the Simulated Annealing (SA) meta-heuristic algorithm and the bisection method. The obtained results quantify the achievable max-min user rates for the different relevant variants of NOMA-enabled schemes and shed new light on both the performance and design of multi-user multi-carrier NOMA-enabled centralized VLC networks.
可见光通信（VLC）作为未来5G网络之外短距离、高数据速率应用的使能技术之一，正日益受到关注。此外，基于非正交多址接入（NOMA）的方案最近已成为这些网络中一种很有前景的多址接入方案，它将实现目标频谱效率和用户公平性要求。将NOMA集成到广泛采用的基于正交频分复用（OFDM）的VLC网络中，需要为共享同一子载波的用户对或用户集群进行最优资源分配。在本文中，通过优化用户配对、子载波分配和功率分配，最大化了多小区室内集中式VLC网络的最大最小速率。使用低复杂度解决方案解决了联合复优化问题。首先，假设用户配对遵循能确保不同集群之间公平性的分而治之与次大差值用户配对算法（D-NLUPA）。然后，通过模拟退火（SA）元启发式算法和二分法迭代求解子载波分配和功率分配问题。所得结果量化了基于NOMA方案的不同相关变体可实现的最大最小用户速率，并为基于NOMA的多用户多载波集中式VLC网络的性能和设计提供了新的思路。
