Signal sensing for cognitive radios using synthetic multipath

Cognitive radio (CR) is currently being seen as the future for wireless communications. Fundamental to the operation of a CR is the sensing of legacy communication. Energy detector (ED) is a simple and effective signal sensing method. However, the ED requires accurate estimation of the noise power. Any error in the estimation, which is common in practice, affects its performance. Communication signals have temporal correlation due to multipath fading. In this study, we sense a signal by looking at the correlation property. To ensure the correlation we use a simple technique to synthetically introduce multipaths. Thus the need for the estimation of the noise power is avoided. The strength of the correlation is measured using Pearson product moment correlation test. The synthetic multipath scheme is discussed, together with several simulation results, and comparison with the energy detector.