An optimal spectrum handoff scheme for cognitive radio mobile Ad hoc networks

Spectrum handoff procedures occur when the primary users appear in the licensed band temporary occupied by the cognitive radio (CR) users and aim to help the CR users to vacate the spectrum rapidly and find available channel to resume the transmission. However, a spectrum handoff scheme that comprehensively considers channel selection, handoff decision as well as space domain handoff is yet undeveloped. In this paper we present a complete optimal spectrum handoff scheme for cognitive radio mobile ad hoc networks. First, we design a spectrum selection mechanism to allow CR users optimally choose the appropriate channel. The spectrum idleness prediction algorithm is utilized based on developing a cooperative spectrum searching approach. Through combining the estimated transmission time, the PU appearance probability and the mean spectrum availability time are integrated to develop the optimal spectrum handoff scheme. Moreover, as one part of the proposed scheme, a geo-location approach is utilized to deal with the space domain handoff. The complete scheme is evaluated through a comprehensive simulation study, and results reveal significant improvements in handoff times and transmission efficiency over conventional approaches.