Omnidirectional Channel Sounder With Phased-ArrayAntennas for 5G Mobile Communications

We describe a 60-GHz channel sounder with phased-array antennas and 1-GHz bandwidth. It estimates the angle of departure (AoD)/angle of arrival (AoA) of channel multipath components (MPCs) by sweeping the antenna space of the transmitter/receiver through 5.6° electronically steerable beams. The associated 26.1-dBi gain and resultant 36-dBm EIRP of the beams enable sounding up to hundreds of meters. Both ends integrate multiple arrays to extend the ±45° field of view (FoV) of the individual arrays to an omnidirectional view; the additional advantage of integrating multiple arrays is to quicken the channel sweep period to just 262 μs, corresponding to a maximum closing velocity of 33 km/h for vehicle-to-vehicle (V2V) scenarios. The receiver is mounted on a mobile robot whose navigational system enables rapid, autonomous, and untethered data collection. Overthe-air (OTA) methods to characterize the array beams patterns, calibrate the system impulse response, and compensate for clock drift are proposed such that properties of the MPCs can be extracted with high fidelity through super-resolution techniques. To substantiate the latter, we compare estimated properties against ground-truth values from extensive field measurements. The mean absolute error in angle was reported as 2.87°.