Effect of scattering-matrix mismatches

Investigate the effect of scattering-matrix mismatches, including calibration, modeling, and hardware-induced drift deviations from the nominal scattering matrix, on the proposed mutual-coupling-aware channel-estimation method.

Background

The proposed estimator assumes that the base station has prior knowledge of the neighboring active RIS scattering matrix and the average RIS amplification factor. The paper notes that the scattering matrix is predominantly determined by the RIS physical architecture and is therefore quasi-static, but calibration and modeling errors, as well as hardware-induced drift, can cause deviations from the nominal stored matrix. The impact of these mismatches on the proposed sensing-matrix design and channel-estimation accuracy is not analyzed in the paper and is explicitly deferred to future work.