Analysis of system outage probability in underlay cognitive two-way amplify-and-forward relay networks

摘要

Several works have studied relaying in cognitive radio networks in terms of outage probability. The main challenge in such works is finding a mathematical expression for this performance metric under different system models. This expression can be employed in studying and designing more related systems. In this paper, we consider an underlay cognitive communication system, where each of the primary and secondary networks has two communicating nodes. The secondary nodes communicate, in two directions, through a relay node that employs half-duplex amplify-and-forward relaying scheme. In our study, we presumed having free-space path loss over the channels between the primary and secondary nodes as well as having Nakagami-m fading over the channels between the secondary nodes. To the best of our knowledge, there are no prior works which are similar to ours. In particular, we thoroughly study the proposed model and mathematically derive the outage probability for the whole two-way system in the secondary network under different communication schemes: two time slots, three time slots and four time slots schemes. To verify our mathematical derivations, we conduct thorough simulations under different scenarios. Interestingly, the simulation results show the correctness of our derivation.