Performance Bounds of Secondary User's Transmission Under Fading Channel

Cognitive radio (CR) is a promising technology to improve the spectrum utilization in that it allows secondary users (SUs) to transmit over the spectrum holes by spectrum sensing. Though the SUs are with low priority to access to the channel, the QoS guarantees are critical for their transmissions. In this paper, we construct a cross-layer based model to analyze the performance bounds for SUs, by which we investigate how different factors jointly influence the transmission of SUs, including PU activity, number of SUs and channel fading, etc. To this end, the stochastic network calculus is employed as a basic tool, where impairment process is introduced to construct the service process for SUs. Then, the delay bound and throughput bound are derived for given arrival process. Numerical results demonstrate that PU activity has a dominant impact on the performance of the transmission for SUs.