A Spectrum Handoff Scheme by Considering the Interference Probability in Cognitive Radio

In cognitive radio networks, spectrum sensing is used to detect the spectral state of authorized users. In particular, upon detecting primary users (PUs) appearances, Secondary User (SU) vacates the channel and performs the spectrum handoff. In order to protect the PUs, interference constrains and reserved channel are considered. If the SU can’t find any idle channel after the whole spectrum sensing, it carries out spectrum handoff to the reserved channel. In addition, spectrum handoff delay is derived. The nonlinear constrained optimization problem for the presented approach is formulated. In special, the goal is to minimize the SU’s handoff delay while protecting the PU from the interference. Numerical results discuss the impact factors on the handoff delay. Lower interference constrains can not only protect the PUs, but also can provide the lower handoff delay for SUs.