Beam Alignment with an Intelligent Reflecting Surface for Integrated Sensing and Communication

Abstract

In a typical communication system, in order to maintain a desired signal-to-noise ratio (SNR) level, initial beam alignment (BA) must be established prior to data transmission. In a setup where a base station (BS) transmitter (Tx) sends data via a digitally modulated waveform, we propose an user equipment (UE) enhanced with an hybrid-intelligent reflective surface (HIRS) to aid beam alignment. A novel multi-slot estimation scheme is developed that alleviates the restrictions imposed by the hybrid digital-analog (HDA) architecture of the HIRS and the BS. To demonstrate the effectiveness of the proposed BA scheme, we derive the Cramér-Rao lower bound (CRLB) of the parameter estimation scheme and provide numerical results.