Increasing the Secrecy Capacity by Cooperation in Wireless Networks

Physical layer security is an emerging security field that explores the possibilities of achieving perfect secrecy data transmission between the intended network nodes, while possible malicious nodes that eavesdrop the communication obtain zero information. In this paper, we observe how node cooperation improves the physical layer security of a simple wireless network by reducing the surface of the geographical area in which the malicious nodes can listen to the transmitted data from the source to the destination. Our analysis and simulation results show a dramatic improvement even by cooperation with only one relay node. The improvement gets better by adding more cooperating nodes. We also observe that if cooperating nodes are closer to the line that connects the source and the destination node, the region in which the malicious node can profit from the eavesdropping gets smaller.