The movable antenna (MA) technology enables flexible reconfiguration of wireless channels through adaptive antenna deployment, offering significant potential for enhancing communication performance. However, antenna movement requires a certain duration within which communication may be compromised due to factors such as channel fluctuation and Doppler effect. This leads to a fundamental tradeoff: A longer movement duration allows antennas to reach more favorable positions for better channel conditions, but it inevitably reduces the time available for data transmission. To characterize the aforementioned tradeoff, we focus on the MAs-enabled multiuser downlink scenario, and jointly optimize the movement duration and antenna deployment at the base station to maximize the effective throughput. The formulated problem is highly non-convex. The general solutions require an one-dimensional search over movement durations, each with optimized antenna deployment. To reduce complexity, we propose a fitting method that samples only a few rate-duration pairs, yielding a closed-form expression that captures the rate trend and enables a favorable solution immediately. We further derive a closed-form condition on the maximum antenna movement speed: When the speed is below a certain threshold, the optimal strategy is to keep antennas stationary throughout the transmission period. The fundamental tradeoff and the effectiveness of the proposed solutions are examined in a special case with two MAs and two users. Finally, numerical simulations validate the efficacy of the proposed schemes.

翻译：可移动天线（MA）技术通过自适应天线部署实现无线信道的灵活重构，为提升通信性能提供了重要潜力。然而，天线移动需要一定时间，在此期间通信可能因信道波动和多普勒效应等因素而受损。这导致了一个基本权衡：更长的移动时间允许天线到达更有利的位置以获得更好的信道条件，但不可避免地减少了可用于数据传输的时间。为表征上述权衡，我们关注MA支持的多用户下行链路场景，联合优化基站处的移动持续时间和天线部署以最大化有效吞吐量。所构建的问题高度非凸。通用解法需要对移动持续时间进行一维搜索，每次搜索对应优化的天线部署。为降低复杂度，我们提出一种仅采样少量速率-时间对的拟合方法，得到捕捉速率趋势的闭式表达式，从而能立即获得有利解。我们进一步推导出最大天线移动速度的闭式条件：当速度低于某阈值时，最优策略是在整个传输期间保持天线静止。通过两个MA和两个用户的特例检验了基本权衡及所提方案的有效性。最后，数值仿真验证了所提方案的性能优势。