In this letter, we investigate the joint beamforming and power splitting design problem in a base station (BS) cluster-based cloud radio access network (C-RAN) with multicast fronthaul, where users are jointly served by BSs within each cluster. Meanwhile, each user can simultaneously obtain information and energy from received signals. On this basis, under predefined minimum harvested energy of each user and maximum transmit power of each BS and central processor, we formulate a sum rate maximization problem by jointly optimizing multicast fronthaul beamforming, cooperative access beamforming and power split ratios. Due to the difficulty in solving the formulated problem, we first transform it into a convex one by successive convex approximate and semidefinite program (SDP) relaxation techniques, and then propose an effective iterative algorithm. Moreover, we design a randomization method that can always obtain the rank-one solution. Finally, numerical results are conducted to validate the effectiveness of our proposed algorithm.

中文翻译：

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具有组播前传的 C-RAN 联合波束成形和功率分配设计

在这封信中，我们研究了具有多播前传的基于基站 (BS) 集群的云无线接入网络 (C-RAN) 中的联合波束成形和功率分配设计问题，其中用户由每个集群内的 BS 联合服务。同时，每个用户可以同时从接收到的信号中获取信息和能量。在此基础上，在预定义的每个用户的最小收获能量和每个基站和中央处理器的最大发射功率下，通过联合优化组播前传波束成形、协作接入波束成形和功率分流比，我们制定了总速率最大化问题。由于求解公式化问题的难度，我们首先通过逐次凸近似半定规划（SDP）松弛技术将其转化为凸问题，然后提出一种有效的迭代算法。此外，我们设计了一种总是可以得到秩一解的随机化方法。最后，通过数值结果验证了我们提出的算法的有效性。