Delay Analysis of Cooperative Communication with Opportunistic Relay Access

In this paper we study the delay characteristics of cooperative communications using opportunistic relay access with delay constraints. We consider the scenario where the source node opportunistically tries to access the relay, amongst several Primary Users (PU) of the relay network in the environment, in order to send data across (a fixed) network to its destination. The first-hop connection for the source node to the relay is considered as an opportunistic access link. The traffic from the PUs in the first-hop and the delay associated in getting the data across the network to the destination from the relay node are modeled as random processes. Considering such a link and a random network-delay model we study the probability of successful end-to-end transmission by the source node with a given delay constraint. For the considered model, we present closed form analytical expressions for the success probability, the mean delay and the expected delay jitter for the end-to-end transmission. We also present Monte-Carlo based simulation results to verify our theoretical analysis.