Two Birds One Stone: Blind Beamforming for Integrated Communications and Localization

This paper considers a typical application case of the integrated sensing and communications (ISAC) in which the receiver wishes to not only enhance its channel capacity but also localize the transmitter in aid of metasurfaces (MTSs). In view of practical situations, we assume that the MTSs consist of lowresolution (e.g., 1-bit) phase shifters and that the channel state information (CSI) is completely unknown. The key step in the proposed method is to retrieve the phase difference information from the received signal strength (RSS) through a novel technique called blind beamforming. We then utilize the phase difference information to align the reflected channels and thereby enhance signal-to-noise ratio (SNR), and also recover the position of the target with the MTSs treated as anchors. According to our field tests carried out at 2.6 GHz frequency band, the proposed method gives much more precise localization than the benchmarks, aside from increasing the SNR by up to around 10 dB.