On the Effective Capacity of Delay Constrained Cognitive Radio Networks with Relaying Capability

In this paper we analyze the performance of a secondary link in a cognitive radio relaying system operating under a statistical quality of service (QoS) delay constraint. In particular, we quantify analytically the Effective Capacity improvement for the secondary user when it offers a packet relaying service to the primary user packets that are lost under the SINR interference model. Towards this objective, we utilize the concept of Effective Capacity introduced earlier in the literature as a metric to quantify the wireless link throughput under statistical QoS delay constraints, in an attempt to support real-time applications using cognitive radios. We study a two-link network, a single secondary link and a primary network abstracted to a single primary link, with and without relaying capability. We analytically prove that exploiting the packet relaying capability at the secondary transmitter improves the Effective Capacity of the secondary user. Finally, we present numerical results that support our theoretical findings.