Improving the Physical Layer Security in Cooperative Networks with Multiple Eavesdroppers

Physical layer security is an efficient technique to realize security in wireless network without relying on conventional cryptographic techniques. In cooperative networks with secrecy constraints, joint relay and jammer selection is a promising approach for improving the security of wireless communications. We need to apply more techniques in order to achieve more effective security in contrast to the mentioned method. In this paper, we propose three techniques to increase the secrecy as follows: Firstly, we introduce a new criterion which decreases the rate at the eavesdroppers. Next, a new relay selection schemes are proposed, where two of the available relays are selected for data transmission. Therefore, the secrecy rate is increased considerably. Finally, we propose a sub-optimal power allocation solution for jammer nodes. Sub-optimal power of the jammer nodes vary according to the type of scenario, location of the eavesdroppers, and the destination. The sub-optimal power allocation to the jammer nodes causes more eavesdroppers confusion. As a result, the total secrecy rate is increased. Simulation and analytical results demonstrate the performance improvement of the proposed techniques.