Outage Performance of Statistical CSI Assisted Cognitive Relay with Interference from Primary User

This work has studied the outage performance of amplify-and-forward (AF) relaying in underlay spectrum sharing systems with interference from primary user (PU). To reduce the complexity and improve the feasibility, two schemes using statistical channel state information (CSI) of interference links are proposed. For each scheme, the closed-form expressions for outage probability of secondary user (SU) and PU are derived, as well as the asymptotic expressions and diversity order. The impact of using statistical CSI instead of instantaneous CSI has been evaluated through the comparison with existing scheme. The analytical results and the simulation results are in excellent agrement confirming the effectiveness of the analysis in this work.