Newmann Series-Based Precoding Weight Design for Multi-User Massive MIMO Null-Space Expansion

This paper proposes a low-complexity precoding weight suitable for multi-user massive multiple-input multiple-output (MU-mMIMO) in user terminals' (UTs') mobility environ-ment. Null-space expansion (NSE) achieves better inter-user in-terference (IUI) suppression performance than channel prediction schemes by steering several nulls for interfering UTs in the high mobility environment. However, NSE faces challenges in effectively managing the computation complexity of precoding. Focusing on the singularity of the Gram matrix in NSE, we incorporate Ridge regression into the Newmann series (NS) to achieve a low-complexity weight design optimized for NSE. Computer simulation demonstrates the superiority of the proposed scheme in terms of IUI suppression performance and computation complexity.