This article aims to improve spectrum efficiency (SE) for the unmanned aerial vehicle (UAV)-relayed cellular uplinks, through distinguishing both line-of-sight (LoS) and non-LoS (NLoS) links. Meanwhile, aiming to accommodate the air-to-ground (A2G) cooperative nonorthogonal multiple access (NOMA)-based cellular users (CUs) with a high energy efficiency (EE), a joint resource allocation (RA) problem is further considered for the UAV and the CUs. To solve the problem, first, an access-priority-based receiver determination (RD) method is derived. According to the RD result, the heuristic user association (UA) strategies are given. Then, based on the UA result, transmission powers of the CUs and the UAV are initialized based on their quality-of-service (QoS) demands. Furthermore, the subchannels are assigned to the associated CUs and the UAV with the reweighted message-passing algorithm. Finally, the transmission power of the CUs and the UAV is jointly fine-tuned with the proposed access control schemes. Compared with the traditional orthogonal frequency-division multiple access (OFDMA) scheme and the traditional ground-to-ground (G2G) NOMA scheme, simulation results confirm that the UAV-aided NOMA with the proposed joint RA scheme yields better performances in terms of the SE, the EE, and the access ratio of the CUs.

中文翻译：

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无人机辅助的空对地合作非正交多路访问

本文旨在通过区分视线（LoS）和非视距（NLoS）链路，提高无人飞行器（UAV）中继蜂窝上行链路的频谱效率（SE）。同时，为了容纳具有高能效（EE）的基于空对地（A2G）协作非正交多址（NOMA）的蜂窝用户（CU），针对该问题进一步考虑了联合资源分配（RA）问题。无人机和CU。为了解决该问题，首先，推导基于访问优先级的接收器确定（RD）方法。根据RD结果，给出了启发式用户关联（UA）策略。然后，基于UA结果，根据CU和UAV的服务质量（QoS）要求初始化其传输功率。此外，子信道通过重新加权的消息传递算法分配给相关联的CU和UAV。最后，CU和UAV的传输功率与提出的访问控制方案共同进行了微调。与传统的正交频分多址（OFDMA）方案和传统的地对地（G2G）NOMA方案相比，仿真结果证实，采用拟议的联合RA方案的无人驾驶飞机辅助NOMA在性能方面具有更好的性能。 SE，EE和CU的访问率。