Movable antenna (MA) technology, which can reconfigure wireless channels by flexibly moving antenna positions in a specified region, has great potential for improving communication performance. In this paper, we consider a new setup of MAs-enabled multicasting, where we adopt a simple setting in which a linear MA array-enabled source (${\rm{S}}$) transmits a common message to two single-antenna users ${\rm{U}}_1$ and ${\rm{U}}_2$. We aim to maximize the minimum rate among these two users, by jointly optimizing the transmit beamforming and antenna positions at ${\rm{S}}$. Instead of utilizing the widely-used alternating optimization (AO) approach, we reveal, with rigorous proof, that the above two variables can be optimized separately: i) the optimal antenna positions can be firstly determined via the successive convex approximation technique, based on the rule of maximizing the correlation between ${\rm{S}}$-${\rm{U}}_1$ and ${\rm{S}}$-${\rm{U}}_2$ channels; ii) afterwards, the optimal closed-form transmit beamforming can be derived via simple arguments. Compared to AO, this new approach yields the same performance but reduces the computational complexities significantly. Moreover, it can provide insightful conclusions which are not possible with AO.

翻译：可移动天线（MA）技术通过在指定区域内灵活移动天线位置来重构无线信道，具有提升通信性能的巨大潜力。本文考虑了一种全新的MA组播场景，采用线性MA阵列的源节点（${\rm{S}}$）向两个单天线用户${\rm{U}}_1$和${\rm{U}}_2$传输公共信息。我们通过联合优化源节点的发射波束赋形与天线位置，旨在最大化两个用户中的最小速率。不同于广泛使用的交替优化（AO）方法，我们通过严格证明揭示了上述两个变量可分离优化：i) 基于最大化${\rm{S}}$-${\rm{U}}_1$与${\rm{S}}$-${\rm{U}}_2$信道相关性的准则，首先利用逐次凸逼近技术确定最优天线位置；ii) 随后通过简单推导获得闭合形式的最优发射波束赋形。与AO相比，该方法在保持相同性能的同时显著降低了计算复杂度，并能得出AO无法提供的深刻结论。