  This paper shows how an ultrawideband channel sounder can be built with the
latest National Instruments (NI) Universal Software Radio Peripheral (USRP)
equipment, featuring onboard FPGA processing and utilizing open-source tools.
Compared to other USRP-based channel sounders, our design is versatile, eases
the requirements on the data link between the USRPs and the host, limits the
measurement data size, and increases the signal-to-interference-plus-noise
ratio due to averaging. Furthermore, this paper serves as a proof-of-concept
for other researchers seeking to build a channel sounder based on the USRP
equipment.
