Cooperative Jamming Cancellation Analysis Based on RC Shaping Filter in Physical Layer Security

In physical layer secure communications, time synchronization is crucial to cooperative jamming cancellation. However, perfect time synchronization is unrealistic due to inevitable synchronization error in practical communication systems. Consequently, researchers have done some research on the above problem. Unfortunately, the impact of cooperative jamming wave shaping is neglected. In this paper, taking account of transmission signals with raised cosine-rolloff filter, performance of cooperative jamming cancellation with timing errors is studied. By infinite series expansion, an exact analytical expression of the cooperative-jamming-cancellation ratio (CJCR) is derived, which evaluates the performance of the cooperative jamming cancellation. Furthermore, impact of the normalized time synchronization error and the rolloff factor on CJCR is studied. Simulation results show that the normalized time synchronization error of 0.1 causes a loss of 42dB in CJCR, with the ideal received cooperative-jamming-to-noise ratio of 60dB and the rolloff factor of 0.5. Besides, the communication system with a lower rolloff factor and a higher cooperative jamming power is more sensitive to time synchronization error.