Design of channel sounder using an agile RF transceiver based USRP3 and Matlab/Simulink

Channel sounders are used to characterize the wireless channels, they work by sounding the channel with known signal and then measure received signal to calculate the channel impulse response. From the channel impulse response the power delay profile of the channel can be obtained and channel parameters such as maximum excessive delay, mean excessive delay and RMS delay spread can be calculated to get more insight into the channel. This helps to do signal design for robust and energy efficient data transfer across wireless channel. This paper presents the design of a channel sounder which uses a wideband 70MHz – 6.0GHz RF agile transceiver based USRP3 B210 board with tunable bandwidth of up to 56MHz. Two USRP3 boards interfaced to the Matlab/Simulink through USB3.0 port; one USRP3 acts as transmit and the other acts as receive. Channel is sounded using an OFDM like signal whose peak-to-average-power is optimized and channel response is measured using Simulink models. Later Matlab scripts are used to post process and extract channel parameters. Channel response of metallic rack is measured and the channel parameters reported.