LAUSR

In this article, we suggest a new Spectrum Sensing (SS) algorithm using Incremental Relaying (IR). In previous studies, the relays always cooperate in the SS process. However, sometimes the Signal to Noise Ratio (SNR) of the direct link between the Primary User (PU) and the Fusion Node (FN) is high and cooperation is not required. We suggest to activate the relays only when the SNR of direct link is lower than a predefined threshold T . Otherwise, the relays should be idle. In the proposed SS algorithm with IR, all relays can amplify the PU signal to FN only when the SNR of direct link is lower than T. We can also implement IR with relay selection techniques. When the SNR of direct link is lower than T, we select the best relay. Three relay selection algorithms are investigated such as opportunistic amplify and forward, partial and reactive relay selection.