Outage Performance of Cognitive Relay Networks Using Interweave-Underlay Approach

In this paper, we consider the cognitive relay network in which secondary users employ interweave-underlay approach to access to the unoccupied band of the primary user. In the network, relay nodes decode and forward the received signal to the destination in a repetition-based scheme. We define the average outage probability of the cognitive relay network, which is different from the opportunistic relaying network or cognitive relay network with interference constraints. We derive the average outage probability of the source node in the cognitive relay network. There is an interesting phenomenon that the average probability does not always decrease as spectrum sensing accuracy increases. We also show that the full diversity can also be achieved in the cognitive relay network.