Multi-Cell 6DMA: Cooperative Interference Management and Antenna Rotation Optimization

2026-05-21

AI Summary

This work addresses the challenge in multi-cell six-dimensional movable antenna (6DMA) networks where antenna rotation simultaneously enhances desired signals and leaks interference to neighboring cells, creating strong coupling between rotation design and precoding that complicates joint optimization. To tackle this, the authors propose a distributed dual-timescale joint optimization framework: 6DMA rotation angles are updated over the long term using statistical channel state information, while precoding is designed in the short term based on instantaneous CSI, coordinated through an edge-level interference power constraint mechanism. A one-dimensional grid search combined with a randomized maximum matching algorithm maximizes the weighted sum rate under antenna geometric constraints. The proposed scheme significantly reduces inter-base-station signaling overhead, achieves performance close to centralized benchmarks across diverse interference scenarios, and demonstrates excellent network scalability.

Abstract

In this paper, we investigate a multi-cell six-dimensional movable antenna (6DMA) network for enhancing downlink communication performance under inter-cell interference (ICI). Each base station (BS) is equipped with multiple 6DMA surfaces, and the 6DMA rotations affect both the desired-signal enhancement for in-cell users and the interference leakage toward neighboring cells, which makes the antenna-rotation design and transmit precoding intrinsically coupled across BSs. To address this issue, we formulate an average weighted sum-rate maximization problem for the multi-cell system by jointly optimizing the short-term downlink precoders and long-term 6DMA rotations under practical antenna geometric constraints. To tackle the resulting nonconvex problem, we propose a distributed two-timescale design based on inter-cell interference power constraint (IPC) coordination among neighboring BSs, under which each BS performs local short-term precoder optimization based on instantaneous channel state information (CSI) and long-term 6DMA rotation update according to statistical CSI with limited inter-BS information exchange. In particular, an edge-wise IPC coordination mechanism based on two-stage one-dimensional grid search and random maximal matching is developed to enable scalable distributed implementation. A centralized offline benchmark is also provided for performance comparison. Numerical results show that the proposed distributed design achieves performance close to the centralized benchmark under different interference conditions, while maintaining favorable scalability as the network size increases.

Problem

• multi-cell
• 6DMA
• inter-cell interference
• antenna rotation
• precoding

Innovation

• 6DMA
• inter-cell interference management
• two-timescale optimization
• distributed coordination
• antenna rotation