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Experimental study of dynamic spectrum access for opportunistic mobile communications using USRP devices

Opportunistic spectrum access is regarded as an emerging technique to utilize scarce RF spectrum efficiently. The performance study of opportunistic spectrum often overlooks the impact of unlicensed SU mobility. Many of the methods assume secondary users stationary or with low mobility. In this paper, we investigate the impact of mobility of wireless devices for opportunistic spectrum access and communications using National Instrument Universal Software Radio Peripherals (USPR) 292x devices. Each USRP device sends its geolocation to query the spectrum database for idle channels using dedicated links such as cellular link periodically. If the USRP user is within the contour of idle channels, it gets a list of channels. Then, transmitter and receiver with their respective lists of channels choose a common channel for communications using quorum based rendezvous. Numerical results obtained from experiments are presented to evaluate the proposed approach and we found that the longer (shorter) query interval results in higher (lower) false list of channels for the users.