Network-Coding-based Jamming With Triple Transmission Time Slots: A Method To Secure Transmission In An Extreme Case of Source-Wiretapping and Unshared Jamming Signal

This article resolves an extreme case in physical layer security: an eavesdropper, located near to a source, can spy on the jamming-seed if it is just cryptographically shared. The direct link between the source and destination is even unavailable. The system is proposed to operate in triple transmission phases (timeslots). In the first phase, jamming signal is proposed to carry a random binary network-coding-based jamming (NCJ )message, transmitted by an active jammer. As NCJ cannot be just cryptographically protected, we propose a solution of using physical layer security to secure this message. As a result, a network-coding method can be employed in which NCJ acts as a key to protect the source message from this extreme case of wiretapping. The spatial diversities in both jamming and legitimate transmission is fully exploited to overcome this challenge with high performance. Analysis and simulation of the outage performance and comparison with current methods are provided to validate the performance of the proposed method.