Linear Attention for Joint Power Optimization and User-Centric Clustering in Cell-Free Networks
This work addresses the challenge of efficient and flexible network management for cell-free systems, though it is incremental as it builds on existing transformer-based approaches with specific adaptations.
The paper tackles the problem of optimizing access point clustering and power allocation in user-centric cell-free massive MIMO systems, achieving near-optimal performance in maximizing minimum spectral efficiency with linear scalability in dynamic scenarios.
Optimal AP clustering and power allocation are critical in user-centric cell-free massive MIMO systems. Existing deep learning models lack flexibility to handle dynamic network configurations. Furthermore, many approaches overlook pilot contamination and suffer from high computational complexity. In this paper, we propose a lightweight transformer model that overcomes these limitations by jointly predicting AP clusters and powers solely from spatial coordinates of user devices and AP. Our model is architecture-agnostic to users load, handles both clustering and power allocation without channel estimation overhead, and eliminates pilot contamination by assigning users to AP within a pilot reuse constraint. We also incorporate a customized linear attention mechanism to capture user-AP interactions efficiently and enable linear scalability with respect to the number of users. Numerical results confirm the model's effectiveness in maximizing the minimum spectral efficiency and providing near-optimal performance while ensuring adaptability and scalability in dynamic scenarios.