Cooperative Spectrum Sensing with Distributed Switch and Stay Combining

In this paper, we propose a new cooperative spectrum sensing algorithm using distributed switch and stay combining (DSSC). There are a primary user, one or two relays and a fusion node (FN). Spectrum sensing is performed at FN using the amplify and forwarded signals from the relay. DSSC consists to maintain the chosen relay if the corresponding end-to-end signal to noise ratio is larger than a threshold T. Otherwise, we switch and use the second relay. We derive and optimize the detection probability of DSSC by setting the value of threshold T. We show that the proposed DSSC offers better performance than previous algorithms using all participating (AP) relaying. Furthermore, DSSC is less complex than AP since a single relay is used while both relays are active in AP relaying. DSSC offers close performance to selection combining with optimal selection of relay node.