Matching Pursuit With Phase Rotation for RIS-Aided mmWave Channel Estimation

This paper presents a channel estimation (CE) solution for Reconfigurable Intelligent Surface (RIS)-assisted systems using compressive sensing (CS) techniques. This estimation is carried out over an adapted redundant dictionary to reconstruct the Base Station (BS) to Reconfigurable Intelligent Surface/User Equipment (BS-RIS/UE-RIS) links in a communication system assisted by RIS. To accomplish this, we employ a CS-based method, specifically, the simultaneous matching pursuit with phase rotation (SMP-PR) technique with the support of a few RIS active elements. The performance and complexity of the proposed method are analyzed in different scenarios and compared against those of several related methods. The effectiveness of the proposed SMP-PR method is demonstrated numerically by its better performance compared to other relevant techniques but with a significant decrease in computational complexity.