Positioning for User Equipment of a mmWave System Using RSSI and Stereo Camera Images

In this paper, we propose a positioning method for user equipment of a mobile millimeter wave (mmWave) communication system. In such a system, a blockage is a cause of a disconnection or a serious degradation of communication. Several techniques to control radio links between multiple base stations have been proposed to avoid these problems. These techniques control radio links by a blockage prediction based on images from a depth camera in a base station. However, those techniques require an accurate position of the user equipment (UE) with a precision of several tens of centimeters. There are methods to obtain accurate UE positions, but they are difficult to apply in real environments because they require particular equipment (e.g., high-precision global navigation satellite systems) and acquisition methods of position information from UEs by a communication system. To solve this problem, we propose the UE positioning method using information only on the base station side. Our proposed method estimates a UE position based on temporal variations in images from a stereo camera and the received signal strength indicator (RSSI) by movements of the UEs and objects. We evaluated our method by experiments in an outside environment, and it achieved an average position accuracy of 0.740 m.