Enhancing Security in Random Wireless Network with the Aid of Friendly Jammers

This thesis investigates the use of friendly jammers against adaptive and active eavesdroppers in wireless networks. The adaptive and active eavesdroppers are capable of both eavesdropping and jamming, thus disrupting the reliability and security of the communications. The friendly jammers jam only the eavesdroppers. The legitimate entities remain unaffected by the friendly jammers. The adaptive eavesdroppers are half-duplex and fail to jam while listening to the source-like signal by the friendly jammers. Again, the active or full-duplex eavesdroppers are also affected because of the interference from this friendly jamming. The numerical results show that friendly jammers can improve the secrecy performance by investigating two of the major secrecy metrics in the field of physical layer security, namely the secrecy capacity and the secrecy outage probability.