In this letter, we investigate the reconfigurable intelligent surface (RIS) assisted multi-cell downlink multi-input single-output system under the assumption of only statistical channel state information at the base stations and RIS. Firstly, a closed-form ergodic weighted sum rate approximation is obtained. Then, based on this approximation, we propose an approximate optimal joint beamforming vectors and RIS phase shift matrix design algorithm utilizing the fractional programming and complex circle manifold. Simulation results show that the proposed low-complexity algorithm performs well.

中文翻译：

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利用统计 CSI 的可重构智能表面辅助多小区 MISO 通信系统


在这封信中，我们在基站和RIS仅统计信道状态信息的假设下研究了可重构智能表面（RIS）辅助的多小区下行链路多输入单输出系统。首先，获得封闭式遍历加权和速率近似。然后，基于该近似，我们利用分数规划和复圆流形提出近似最优联合波束形成向量和RIS相移矩阵设计算法。仿真结果表明，所提出的低复杂度算法表现良好。