Effects of Mobility and Primary Appearance Probability on Spectrum Handoff

This paper is an attempt to understand better the impact of users mobility and primary appearance on the spectrum handoff rate and connection reliability for the Cognitive Radio (CR) Ad hoc Network. Spectrum handoff is a new type of handoff caused by the appearance of the original user of the spectrum or simply by the movement of a cognitive user to an area where its currently used band is in use. We exploit the spectrum sensing capability in each CR and we propose three random techniques to access free channels while avoiding/minimizing the hidden terminal problem. Extensive simulation experiments have been conducted to evaluate the system performance, in particular, handoff rate, session continuity distribution, and missing handoff. Furthermore, a simple queuing model is suggested. Finally, simulation results are compared with analytical results which show a good matching.