Mitigation of UE Antenna Calibration Errors via Differential STBC in Cell-Free Massive MIMO
For cell-free massive MIMO systems, this work addresses the practical problem of UE antenna calibration errors, offering a calibration-free solution.
This letter proposes differential space-time block coding (DSTBC) to mitigate antenna calibration errors at multi-antenna user equipment in cell-free massive MIMO downlink, achieving reliable communication without explicit calibration or channel phase knowledge. Simulations show near-coherent performance restoration.
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.