Tackling the physical layer secrecy issue, existing studies on cooperative jamming generally assume the persistent jamming and perfect channel estimation at the receiver side. However, these two assumptions are incompatible since jamming signals can corrupt the pilot symbols. In addition, due to the energy budget limitation, persistent jamming is burdensome to the cooperative jammers. To address these issues, we propose a cooperative jamming strategy that designs the jamming symbols aiming only at the pilot signals to attain security improvement by manipulating the channel estimations at the authorized receiver and the eavesdropper simultaneously. Via computer simulations, we compare the performance of the proposed strategy with that of a conventional persistent artificial noise-aided strategy, and these results demonstrate that the proposed strategy achieves substantial secrecy rate gain in wide region, especially at the low data transmission power regime and at the rank-deficient environment.
['Sungjun Ahn', 'Wonju Lee', 'Kwang Eog Lee', 'Joonhyuk Kang']
Deterministic pilot jamming symbol design for enhanced physical layer secrecy