Outage analysis of cognitive Z-interference channel with two-path cognitive relaying

In this paper, we analyze the outage performance of cognitive Z-interference channel where two-path cognitive relaying is used to improve bandwidth utilization efficiency of cognitive user transmission while simultaneously leading to improvement in outage performance of primary user. Cognitive relays have non-causal message knowledge of cognitive user and use interference pre-cancellation scheme to cancel interference due to cognitive transmission at primary receiver. We derive analytical results for outage probability and diversity-multiplexing tradeoff to prove the efficiency of proposed protocol. Simulations results demonstrate that the proposed protocol achieves large outage capacity, ergodic capacity and diversity gain for primary user while achieving improved outage capacity for cognitive user.