Chirp sounder measurements for broadband wireless networks and cognitive radio

This paper presents a channel sounder based on the digital chirp technique which enables both active and passive measurements of the radio channel in the 2-6 GHz band. Active measurements using both single antenna and multiple antenna configurations provide estimation of channel parameters such as delay spread, frequency selectivity, angle of arrival/angle of departure and channel capacity. WiMAX simulations using measured data illustrate the relationship between frequency selectivity and error rate. Passive measurements sense the occupancy of the spectrum and are essential for the assessment of cognitive radio. High repetition rates achieved with the digital sweep are shown to capture frequency hopping signals with the SIMO architecture providing estimation of the angle of arrival.