Robust Least Squares Power Allocation in User-Centric Cell-Free Massive MIMO Systems

IEEE Wireless Communications Letters, vol. 15, pp. 1598–1602

Abstract

In cell-free massive multiple-input multiple-output (MIMO) networks, robust resource allocation is critical to ensure reliable system performance in the presence of channel uncertainties resulting from imperfect channel state information (CSI). In this work, we propose a robust power allocation method that formulates the power optimization problem into a least-squares framework, enhanced by Tikhonov regularization to mitigate the adverse effects of channel estimation errors. We integrate our approach with zero-forcing precoding, enabling a design that is both computationally efficient and resilient to CSI imperfections. Numerical results indicate that the proposed method outperforms existing non-robust techniques while benefiting from low computational overhead, making it well-suited for large-scale deployments under CSI uncertainty.

Authors 6

1. Saeed Mashdour

   Pontifícia Universidade Católica do Rio de Janeiro

   Affiliation as printed

   Department of Electrical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil

2. Saeed Mohammadzadeh

   University of York

   Affiliation as printed

   School of Physics, Engineering and Technology, University of York, York, U.K

3. André R. Flores

   Pontifícia Universidade Católica do Rio de Janeiro

   Affiliation as printed

   Department of Electrical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil

4. Shirin Salehi Aachen Chair of Information Theory and Data Analytics

   RWTH Aachen University

   Affiliation as printed

   Chair of Information Theory and Data Analytics, RWTH Aachen University, Aachen, Germany

5. Rodrigo C. de Lamare

   Pontifícia Universidade Católica do Rio de Janeiro

   Affiliation as printed

   Department of Electrical Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil

6. Anke Schmeink Aachen Chair of Information Theory and Data Analytics

   RWTH Aachen University

   Affiliation as printed

   Chair of Information Theory and Data Analytics, RWTH Aachen University, Aachen, Germany