This paper studies joint source and relay beamforming optimization and time allocation for a wireless powered multi-relay multi-user network, where a multi-antenna base station (BS) transmits information to users with the assistance of multiple single-antenna relays. Considering that the relays are energy-constrained, which are powered by the BS wirelessly, we aim to maximize the minimum rate among the users by jointly optimizing the information and energy beamforming at the BS, the distributed beamforming at the relays, and the time allocation under the power constraints and the energy causality constraints at the BS and relays, respectively. In order to tackle the formulated optimization problem, we propose an iterative algorithm by alternatively solving two subproblems. Numerical results show that the proposed joint optimization scheme obviously outperforms other schemes.

本文研究了无线多中继多用户网络的联合源和中继波束成形优化和时间分配，其中多天线基站（BS）借助多个单天线中继向用户发送信息。考虑到中继是受能量限制的，由BS无线供电，我们的目标是通过共同优化BS的信息和能量波束成形，中继的分布式波束成形以及时间分配来最大化用户中的最小速率。分别在基站和中继站受到功率约束和能量因果约束。为了解决公式化的优化问题，我们通过交替解决两个子问题提出了一种迭代算法。