I. Introduction
The fifth generation (5G) and beyond wireless systems show the potential to simultaneously achieve high-rate communications and high-accuracy positioning performance. For one reason, with the deployment of large antenna arrays at both transmitter and receiver sides, the system spectrum and energy efficiency of the massive multiple-input multiple-output (MIMO) systems can be significantly improved [1], [2]. The large available bandwidth over millimeter wave (mmWave) frequency can boost the communication rate [3]. Moreover, massive MIMO enables the high angular resolution of the propagation multipath. The wide-band mmWave signals allow high delay resolutions. Therefore, significant improvement of the localization performance can be achieved [1], [4].