Impact of RSU Height on 60 GHz mmWave V2I LOS Communication in Multi-lane Highways

The WiGig Alliance has recently introduced IEEE 802.11ay that standardizes the use of 60 GHz millimeter-wave (mmWave) frequency band for providing Gbps wireless connectivity on the move. However, for vehicle-to-infrastructure (V2I) systems using such standards, network reliability must be ensured when safety-critical signaling information is exchanged. The signals at mmWave frequencies are more prone to attenuation loss, penetration loss, weather effects and blockage. Therefore, placement of road side units (RSUs) is crucial for directional beam alignment, proper signal projection and vehicle tracking. This paper investigates the minimum RSU height required in multi-lane highways to guarantee all-time 60 GHz line of sight (LOS) connectivity for different lanes. The effect of distance of RSU base from highway is also studied. Further, numerical results analyze how both signal strength and overall system data rate wane with RSU height. These results are extended to other mmWave bands as well.