Six-dimensional movable antenna (6DMA) is an effective solution for enhancing wireless network capacity through the adjustment of both 3D positions and 3D rotations of distributed antennas/antenna surfaces. Although freely positioning/rotating 6DMA surfaces offers the greatest flexibility and thus highest capacity improvement, its implementation may be challenging in practice due to the drastic architecture change required for existing base stations (BSs), which predominantly adopt fixed-position antenna (FPA) arrays (e.g., sector antenna arrays). Thus, we introduce in this letter a new BS architecture called hybrid fixed and movable antennas (HFMA), which consists of both conventional FPA arrays and position/rotation-adjustable 6DMA surfaces. For ease of implementation, we consider that all 6DMA surfaces can rotate along a circular track above the FPA arrays. We aim to maximize the network capacity via optimizing the rotation angles of all 6DMA surfaces based on the users' spatial distribution. Since this problem is combinatorial and its optimal solution requires prohibitively high computational complexity via exhaustive search, we propose an alternative adaptive Markov Chain Monte Carlo based method to solve it more efficiently. Finally, we present simulation results that show significant performance gains achieved by our proposed design over various benchmark schemes.

翻译：六维可移动天线（6DMA）通过调整分布式天线/天线面的三维位置和三维旋转，是增强无线网络容量的有效解决方案。尽管自由定位/旋转的6DMA面能提供最大灵活性和最高容量提升，但在实践中，由于现有基站（BS）主要采用固定位置天线（FPA）阵列（如扇区天线阵列），其实现可能面临重大架构变革的挑战。因此，本文提出一种名为混合固定与可移动天线（HFMA）的新型基站架构，该架构同时包含传统FPA阵列和位置/旋转可调的6DMA面。为便于实现，我们假定所有6DMA面可在FPA阵列上方的圆形轨道上旋转。目标是基于用户空间分布，通过优化所有6DMA面的旋转角度来最大化网络容量。由于该问题具有组合特性，且通过穷举搜索求最优解会导致过高的计算复杂度，我们提出一种基于自适应马尔可夫链蒙特卡洛的替代方法，以更高效地求解。最后，仿真结果表明，我们所提设计相比各类基准方案取得了显著的性能增益。