Contribution based cooperative spectrum sensing against malfunction nodes in cognitive radio networks

In cognitive radio networks, secondary users can cooperate based on their own sensing observations so as to detect the primary user more accurately. However, since of location disadvantage, multipath fading or shadowing, sensing contribution of some secondary users may be untrustworthy, which are termed malfunction nodes in this paper. To mitigate this problem we propose a contribution based cooperative spectrum sensing scheme for cognitive radio networks. By assigning different sensing time to each secondary user based on their historic contribution to the global decision, the new scheme can exploit the merit of spatial advantage and save more energy for them when they are in a severe fading or shadowing environment. Numerical results show that the sensing performance is improved significantly as opposed to conventional spectrum sensing.