چكيده به لاتين
The focus of this thesis in on cooperative spectrum sensing and related issues regarding the security of multi-channel cognitive radio networks (MCCRN). Here, the aim is cooperative spectrum sensing for channel assignment in MCCRNs, so that the number of available channels is maximized in the presence of attackers. At the first, for cooperative spectrum sensing, two centralized and distributed scenarios are considered, which distributed scenario is based on coalition game theories. Then, security of physical layer is analyzed for cooperative spectrum sensing in MCCRNs. after that, the major issue of key management and distributed ID-based and certificate-based key management schemes are discussed. Implementation of distributed key management schemes require distributed private key generators (DPKG). Furthermore, security-based and energy-based DPKG selection are analyzed and simulated to energy-efficiency.
Due to simulation of cooperative spectrum sensing regarding distributed scenario and related issues of its security, a more powerful and intelligent distributed cooperative Byzantine attack on the multi-channel cooperative spectrum sensing is implemented, where attackers collude by applying coalition game theory among themselves to maximize the number of invaded channels in distributed manner. Then, to remedy such attacks, a hierarchical identity-base key management scheme is adopted, in which CRs can only play on a certain number of requested channels and channel access for sensing is restricted to the honest CR selected in the coalition game. The simulation results show that this scheme can significantly improve cooperative spectrum sensing and secure the system against Byzantine attacks.
Finally, to improve sensing and increasing available channels, a scheme based on decreasing number of coalition members is proposed, which the effect of decreasing number of coalition members is analyzed and simulated. Simulation results indicate that this scheme leads to increase in available channels in the presence of attackers and is more energy efficient and cause an increase in the battery lifetime.
