Performance study of opportunistic scheduling in multiuser cognitive relay network

In this paper, we investigate the theoretical performance analysis of opportunistic scheduling for dual-hop cognitive relay network with multiuser in the secondary system. Different from the existing work, we take the consideration of primary user's interference with opportunistic scheduling technique and theoretically derive the influence of the interference from primary transmitter for the scenario. The cumulative distribution function (CDF) of signal-to-noise ratio (SNR) is formulated and the exact close-form expression of the cognitive relay network outage probability is derived. After calculating the asymptotic outage probability in high SNR regime and asymptotic error probability, we provide an adaptive power allocation scheme in the secondary system to optimize the capacity of system. It is confirmed that the opportunistic scheduling technique for multiuser has a positive influence on the performance of cognitive networks. Moreover, the adaptive power allocation can also promote system performance. Finally, numerical simulations are provided to support and directly reflect the correctness of our analytic results.