Advanced Detection Techniques for Cognitive Radio

The energy based test is a popular detection scheme for cognitive radio (CR). However, it is infeasible or confronted with difficulty in threshold determination when a reference noise power level is unavailable or inaccurate. In fact, the presence of a primary signal not only changes the received signal energy, but also its correlation structure. In this paper, we show how to exploit information in both the energy and correlation for the detection of CR signals in different operational environments where the reference noise power level can be perfectly known, inaccurate, or completely unavailable. Different types of detectors are derived with emphasis on their philosophy and techniques for their threshold determination. Numerical results are presented for illustration of the theory and performance of the proposed detectors.