This paper studies the problem of joint relay selection and power allocation (J-RS-PA) for non-orthogonal multiple-access (NOMA)-based multicast cognitive radio networks with energy-harvesting (EH) relays. Particularly, the primary and secondary transmitters communicate with their receivers over EH amplify-and-forward relays, with the aim of simultaneously maximizing the network sum-rate, minimizing energy consumption, and satisfying quality-of-service (QoS) constraints. The formulated J-RS-PA problem happens to be non-convex and computationally-intensive. Alternatively, it is solved via a low-complexity solution procedure, which optimally solves the power allocation problem over each relay, and then selects the relay that maximizes the network objective function. Additionally, the proposed solution procedure can be used to tradeoff spectrum- and energy-efficiencies. Simulation results are presented to evaluate the proposed solution procedure, which is shown to efficiently yield the optimal network sum-rate and energy consumption solutions, in agreement with the J-RS-PA scheme (solved via a global optimization package), but with lower computational complexity, while satisfying the QoS requirements at the primary and secondary receivers.

本文研究了基于非正交多址（NOMA）的具有能量收集（EH）中继的多播认知无线电网络的联合中继选择和功率分配（J-RS-PA）问题。特别地，主要和次要发送器通过EH放大转发中继器与其接收器通信，目的是同时最大化网络总速率，最小化能耗并满足服务质量（QoS）约束。制定的J-RS-PA问题恰好是非凸的并且计算量很大。可替代地，通过低复杂度的解决过程来解决该问题，该过程最优地解决了每个中继器上的功率分配问题，然后选择使网络目标函数最大化的中继器。另外，所提出的解决方案可用于权衡频谱效率和能量效率。给出了仿真结果，以评估所提出的解决方案过程，该过程证明与J-RS-PA方案（通过全局优化包解决）相一致，可以有效地产生最佳的网络总速率和能耗解决方案。计算复杂度，同时满足主要和次要接收器的QoS要求。