A Fast Spectrum Sensing and Revocation Testbed Based on USRP and GNU Radio for Cognitive Radio Networks

Since the use of wireless devices in the already overcrowded licensed and unlicensed bands had been further growing recently. Realization of wireless communications in Cognitive Radio (CR) is one of the most urgent research and development issues to accommodate rapidly increasing wireless access. In order to ensure avoidance of interference from Secondary Users (SUs) to Primary Users (PUs), adoption of White Space Database (WSDB) is one of the important strategies. In this paper, we have implemented the PAWS API and WSDB for spectrum allocation and show that mechanism operations with an experimental DSA network, which enables the SUs to share the White Space (WS) of PUs in a fine geolocation and timescale. In the experimental setup, the DSA network consists of the secondary transmitter node (STN) and secondary receiver node (SRN), a sensing node (SN), and primary transmitter node (PTN). The network is constructed by using the proposed spectrum sensing and revocation testbed. The testbed employs the Universal Software Radio Peripheral (USRP) devices and open source software, named GNU radio, to develop the spectrum sensing and revocation mechanism. We demonstrate the communication between the STN and the SRN, while avoiding interference to PTN which operates in the same spectrum. The experimental shows that the network is capable of detecting PTN in real time and revocation spectrum adaptively to avoid interference to primary receiver node (PRN). The experimental results are presented to show that the performance of proposed mechanism in terms of the expending time of sensing available channels and revocation spectrum.