  IEEE 802.22 standard utilizes cognitive radio (CR) techniques to allow
sharing unused spectrum band. The cognitive radio is vulnerable to various
attacks such as jamming attacks. This paper has focused on coordinated jamming
attacks. A simple strategy for secondary users is to change their bands and
switch to other appropriate bands when the jamming attack is occurred. Also,
the malicious users should switch to other bands in order to jam the secondary
users. To address this problem, a game theoretical method is proposed to
analyze coordinated jamming attacks in CR. Then, using Nash equilibrium on the
proposed game, the most appropriate bands have been found to switch as well as
the optimal switching probabilities for both secondary and malicious users.
Meanwhile, effects of different parameters like the number of malicious users
are investigated in changing the optimal switching probabilities by analysis on
the model.
