Fast Double-Directional Full Azimuth Sweep Channel Sounder Using Low-Cost COTS Beamforming RF Transceivers

This paper presents a multipath component (MPC) parameter estimator that uses a double-directional (D-D) channel sounding system in WiGig millimeter-wave bands. It employs low-cost commercial-off-the-shelf (COTS) RF transceivers capable of beam steering within an azimuth angle range of +/- 45 degrees; the transmit power is approximately 31 dBm, equivalent isotropic radiated power (EIRP), including a total antenna gain of approximately 19 dBi. The half-power beam widths in the azimuth and elevation planes are 6 degrees and 45 degrees, respectively. A fast D-D channel acquisition in 360 degrees full azimuth range can be achieved by developing a 4 x 4 multiple-input-multiple-output (MIMO) time division-multiplexing (TDM) scheme that enables simultaneous use of four antenna arrays at both sides of the transmitter and receiver. The beam switching for all combinations (48 x 48 = 2304) with 12 beams at each array requires less than 200 ms, excluding optional procedure related to data storage. A high-resolution MPC extraction method was developed from the D-D angular delay power spectra obtained using the sub-grid CLEAN algorithm, which is applicable when phase coherence among multiple snapshots obtained via the beam-switching measurement cannot be guaranteed. Furthermore, the operation of the developed system was validated via a measurement at 58.32 GHz in an office floor of a university laboratory. From the data analysis, the cluster properties and the corresponding scattering processes were identified.

Automated summary

This study introduces a method for estimating multipath component parameters using a double-directional channel sounding system in WiGig millimeter-wave bands, enabling fast channel acquisition over a full 360-degree range with low-cost commercial-off-the-shelf RF transceivers. The research successfully validates the system operation and data analysis through a high-resolution MPC extraction method in a laboratory setting.