  Wireless communication in millimeter wave spectrum is poised to provide the
latency and bandwidth needed for advanced use cases unfeasible at lower
frequencies. Despite the market potential of vehicular communication networks,
investigations into the millimeter wave vehicular channel are lacking. In this
paper, we present a detailed overview of a novel 1 GHz wide, multi-antenna
vehicle to vehicle directional channel sounding and measurement platform
operating at 28 GHz. The channel sounder uses two 256-element phased arrays at
the transmitter vehicle and four 64-element arrays at the receiver vehicle,
with the receiver measuring 116 different directional beams in less than 1
millisecond. By measuring the full multi-beam channel impulse response at large
bandwidths, our system provides unprecedented insight in instantaneous mobile
vehicle to vehicle channels. The system also uses centimeter-level global
position tracking and 360 degree video capture to provide additional contextual
information for joint communication and sensing applications. An initial
measurement campaign was conducted on highway and surface streets in Austin,
Texas. We show example data that highlights the sensing capability of the
system. Preliminary results from the measurement campaign show that bumper
mounted mmWave arrays provide rich scattering in traffic as well a provide
significant directional diversity aiding towards high reliability vehicular
communication. Additionally, potential waveguide effects from high traffic in
lanes can also extend the range of mmWave signals significantly.
