In a device-to-device communication scenario, the number of far users (FUs) is higher than the near users (NUs) in each cluster. In such a scenario, the paired NUs and FUs communicate through non-orthogonal multiple access (NOMA), and the remaining FUs communicate through orthogonal multiple accesses (OMA) schemes. This system is called as hybrid-NOMA (HNOMA). This letter proposes a reconfigurable intelligent surface (RIS)-assisted HNOMA system to enhance the energy and spectral efficiencies of the conventional HNOMA. In this proposed RIS-assisted HNOMA (PR-HNOMA) system, the NU is paired with multiple FUs with allocations of different bandwidths. The PR-HNOMA system’s sum rate is maximized by considering joint beamforming at BS and RIS via semidefinite relaxation (SDR) and alternatively optimization (AO) techniques. Further, the sum rate of the PR-HNOMA under imperfect successive interference cancellation (ISIC) is analyzed and compared with different NOMA and OMA schemes. Simulation results show that the PR-HNOMA achieves better sum-rate performance than the conventional RIS assisted HNOMA (R-HNOMA), and RIS assisted NOMA (R-CNOMA), and OMA (R-OMA).

中文翻译：

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基于信誉的联盟区块链网络中的任务卸载游戏


在设备到设备通信场景中，每个集群中远用户（FU）的数量高于近用户（NU）。在这种情况下，配对的NU和FU通过非正交多址(NOMA)进行通信，而其余的FU通过正交多址(OMA)方案进行通信。该系统称为混合 NOMA (HNOMA)。这封信提出了一种可重构智能表面（RIS）辅助的 HNOMA 系统，以提高传统 HNOMA 的能量和频谱效率。在这个提出的 RIS 辅助 HNOMA (PR-HNOMA) 系统中，NU 与分配不同带宽的多个 FU 配对。 PR-HNOMA 系统的总速率通过半定松弛 (SDR) 和交替优化 (AO) 技术考虑 BS 和 RIS 处的联合波束成形来最大化。进一步分析了PR-HNOMA在不完美连续干扰消除(ISIC)下的总速率，并与不同的NOMA和OMA方案进行了比较。仿真结果表明，PR-HNOMA比传统RIS辅助HNOMA（R-HNOMA）、RIS辅助NOMA（R-CNOMA）和OMA（R-OMA）实现了更好的总速率性能。