Turning interference weakness into PHY security enhancement for cognitive radio networks

Traditionally, the transmitting power of secondary users (SUs) in the cognitive radio (CR) network is limited under a certain threshold, since it is harmful for primary user's (PU) channel capacity. However, when it comes to PU's secrecy capacity, the transmitting power may be either harmful or beneficial. On one hand, the attendance of SUs in the CR network can be threatened to PU's main channel and decreases PU's secrecy capacity. On the other hand, the signals transmitted by SUs can also decrease the wire-tap channel capacity, and therefore improves PU's secrecy capacity. In order to find the tradeoff, by modeling this scenario as a coalition formation game, we apply the “merge” and “split” algorithm to select the appropriate SUs which are beneficial to PU's secrecy capacity. The simulation results verify the efficiency of the proposed algorithm in various scenarios.