Joint Communication and Trajectory Design for Movable Antenna Systems

TL;DR

This paper proposes a joint communication and trajectory optimization for movable antennas to maximize data rates, using graph theory and closed-form solutions for special cases, with significant performance improvements shown in simulations.

Contribution

It introduces a novel joint optimization framework for movable antennas, transforming a complex problem into a shortest path problem for efficient solution.

Findings

Optimized trajectories significantly increase data rates.

The reformulation into a shortest path problem enables optimal solutions.

Simulation results outperform baseline schemes.

Abstract

Movable antennas (MAs) have attracted significant attention in wireless communications due to their ability to reconfigure channel conditions by flexibly adjusting the antenna positions within a confined region. However, MA movement generally incurs a non-negligible delay, which may significantly limit the data transmission time at optimized positions. To tackle this challenge, this paper investigates a new joint communication and trajectory optimization problem, where each MA transmits while moving along an optimized trajectory to prolong the effective data transmission time. Focusing on a single-MA system, our goal is to maximize the average data rate by optimizing the MA's positions over time, subject to its maximum velocity constraints. However, this continuous-time antenna position optimization problem is highly non-convex and challenging to solve. To tackle this challenge, we first consider a special case with two channel paths and derive the optimal MA trajectory in closed form. For other general cases, we ingeniously reformulate the average rate maximization problem into a fixed-hop shortest path problem in graph theory by sampling the antenna movement region into a multitude of discrete points, and solve it optimally. Simulation results demonstrate that our proposed algorithm can significantly improve the data rate compared to other baseline schemes.