Mitigation of UE Antenna Calibration Errors via Differential STBC in Cell-Free Massive MIMO

2026-03-09

AI Summary

This work addresses the performance degradation in cell-free massive MIMO downlink systems caused by antenna calibration errors at multi-antenna user equipment. To mitigate this issue, the paper introduces differential space–time block coding (DSTBC) into the system architecture for the first time. The proposed approach eliminates the need for explicit antenna calibration or channel phase information at the user side, thereby effectively circumventing the adverse effects of phase errors across the antenna array. By formulating a phase error model and integrating it with the DSTBC transmission mechanism, the scheme significantly reduces system implementation complexity. Simulation results demonstrate that the method effectively suppresses antenna-correlated phase offsets and recovers near-coherent transmission performance under non-ideal calibration conditions.

Technology Category

• Machine Learning: Calibration & Uncertainty Quantification
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Security and Privacy: Large-scale security measurements

Abstract

This letter investigates the use of differential space-time block coding (DSTBC) to address antenna array calibration impairments at multi-antenna user equipment (UE) in the downlink (DL) of cell-free massive MIMO (CF-mMIMO) systems. We show that, by exploiting DSTBC, reliable DL communication can be achieved without explicit UE-side calibration or channel phase knowledge. Simulation results demonstrate that the proposed DSTBC-based transmission effectively mitigates the impact of antenna-dependent phase offsets, restoring near-coherent performance in CF-mMIMO networks.

Problem

• antenna calibration
• cell-free massive MIMO
• phase offset
• user equipment
• downlink communication

Innovation

• Differential STBC
• Cell-Free Massive MIMO
• Antenna Calibration
• Phase Offset Mitigation
• Downlink Transmission