Geo-location-assisted real time in-band spectrum sensing for cognitive radio networks

A geo-location assisted real-time in-band spectrum sensing scheme is proposed to carry out the spectrum sensing and secondary transmissions in parallel. It is able to avoid the widely used “quiet periods,” which have at least the following two disadvantages. First, periodical interruption of the secondary transmissions will degrade the QoS of secondary networks (e.g., decreased system capacity, increased packet delay, etc.). Second, tight synchronization becomes necessary but very difficult to implement in the distributed networks. With the assistance of geolocations of the primary transmitters and the secondary users, the proposed method is able to differentiate the target primary signal power from the co-channel and adjacent-channel interference produced by the simultaneous data transmissions in the secondary networks. Then, the interference can be cancelled when constructing the test statistic for the energy detectors. Both analyzing and simulation results show that the proposed method is able to successfully cancel the interference and can achieve a good performance.