Movable antenna (MA) is an emerging technology which enables a local movement of the antenna in the transmitter/receiver region for improving the channel condition and communication performance. In this paper, we study the deployment of multiple MAs at the base station (BS) for enhancing the multiuser communication performance. First, we model the multiuser channel in the uplink to characterize the wireless channel variation due to MAs' movements at the BS. Then, an optimization problem is formulated to maximize the minimum achievable rate among multiple users for MA-aided uplink multiuser communications by jointly optimizing the MAs' positions, their receive combining at the BS, and the transmit power of users, under the constraints of finite moving region for MAs, minimum inter-MA distance, and maximum transmit power of each user. To solve this challenging non-convex optimization problem, a two-loop iterative algorithm is proposed by leveraging the particle swarm optimization (PSO) method. Specifically, the outer-loop updates the positions of a set of particles, where each particle's position represents one realization of the antenna position vector (APV) of all MAs. The inner-loop implements the fitness evaluation for each particle in terms of the max-min achievable rate of multiple users with its corresponding APV, where the receive combining matrix of the BS and the transmit power of each user are optimized by applying the block coordinate descent (BCD) technique. Simulation results show that the antenna position optimization for MAs-aided BSs can significantly improve the rate performance as compared to conventional BSs with fixed-position antennas (FPAs).

翻译：可移动天线（MA）是一种新兴技术，它允许天线在发射器/接收器区域内进行局部移动，以改善信道条件和通信性能。本文研究了在基站（BS）部署多个可移动天线以提升多用户通信性能的方法。首先，我们建立了上行链路中的多用户信道模型，以刻画由于基站处可移动天线移动引起的无线信道变化。然后，构建了一个优化问题，旨在通过联合优化可移动天线位置、基站的接收合并以及用户的发射功率，在可移动天线有限移动区域、最小天线间距以及每个用户最大发射功率的约束下，最大化多用户中最小可达速率。为解决这一具有挑战性的非凸优化问题，提出了一种基于粒子群优化（PSO）方法的两层迭代算法。具体而言，外层循环更新一组粒子的位置，每个粒子的位置代表所有可移动天线的一个天线位置向量（APV）实现。内层循环针对每个粒子，根据其对应的APV评估多用户的最大最小可达速率作为适应度，其中基站的接收合并矩阵和每个用户的发射功率通过应用块坐标下降（BCD）技术进行优化。仿真结果表明，与采用固定位置天线（FPA）的传统基站相比，可移动天线辅助基站的天线位置优化能显著提升速率性能。