Incentive design for collaborative jamming using contract theory in physical layer security

Cooperative jamming is a promising technology for improving information secrecy at the physical layer. The increase of secrecy capacity heavily depends on the participation of the jammer and its geographical locations. However, the jammer's geographical location might not be known to others such as the source node due to privacy, and the asymmetric information will lead to inefficiency in jamming. Thus, incentive mechanisms for cooperative jamming are on demand. In this paper, a solution based on contract theory is proposed to solve the problem of motivating efficient friendly jamming. First, we classify the diverse potential locations of the jammer into a finite number of types under the framework of contract theory. Second, we analyze the feasible conditions which guarantee that a jammer will provide service and select the contract bundle designed only for its corresponding type. Finally, an optimal contract is proposed targeting to maximize the source node's utility. Numerical results verify the performances of our proposed scheme.