Testbed verification of spectrum access opportunity detection in cognitive radio networks

Detecting the spectrum access opportunity (OP) of a secondary user is a key technique in cognitive radio (CR) networks. Especially in a CR scenario where dedicated spectrum sensors are installed to check the spectrum utilization, the OP at locations where the sensor is not installed cannot be estimated. To cope with the issue, this paper proposes an OP map, in which a centralized server estimates the OP of secondary users based on the interference measurements of sensors. The OP is estimated by analyzing the spatial correlation of interference. The accuracy of OP detection is validated through the MATLAB simulations in conjunction with testbed experiments using universal software radio peripherals (USRPs) in Yonsei university, Seoul, South Korea.