60 GHz V2I Channel Variability for Different Elevation Angle Switching Strategies

We report results based on millimeter wave vehicle-to-infrastructure (V2I) channel measurements carried out in an urban street environment, down-town Vienna, Austria. Signal to noise ratios (SNRs) have been acquired at 60 GHz with 100 MHz bandwidth. Two horn antennas were used on a moving transmitter vehicle: one horn emitted a beam towards the horizon and the second horn emitted an elevated beam at 15-degrees up-tilt. This configuration was chosen to assess the impact of beam elevation on V2I communication channel variability. The variability of the V2I channel is shown by density estimates of the channel transfer function magnitudes. The channel changes severely along the vehicle trajectory in an urban street scenario. Density estimates in the region with clear wide-angle view are bimodal and motivate a two-wave with diffuse power (TWDP) fading model for V2I communication with horizontal and elevated antenna beams. We compare three different strategies for beam switching: fixed, geometry-based, and SNR-based.