Cross–Bearing based Positioning as a Feature of 5G Millimeter Wave Beam Alignment

In the context of vehicle–to–everything (V2X) communications, a mobile subscriber positioning service is beneficial for locating e.g. motor vehicles on the road or unmanned aerial vehicles (UAVs) in the air. Current mobile networks process metrics like the receive power or the propagation delay to determine terminals’ positions. With the introduction of millimeter wave (mmWave) communications, the electrically steerable directivity of phased arrays not only procure high gains on the radio link but also offer a direction finding (DF) to the terminals. Several DFs of located base stations could be merged in a cross–bearing manner to indicate the position of mobile devices. In this work, the suitability of DF for positioning of mobile subscribers is discussed based on latest standardization efforts and experimentally evaluated. Our extensive laboratory system consists of three software–defined radio mmWave transceiver platforms, phased array antennas and a tailored rail system allowing for reproducible mobility emulation, positioning and over–the–air testing at 28 GHz. The results show, that considering information about the directivity, a DF can be estimated precisely via the beam pointing direction. The mmWave V2X communications offer a possibility for a precise positioning service for mobile devices as well as to applications in the edge–cloud on the infrastructure side.