Impact of Imperfect Time Synchronization on Cooperative Jamming Assisted Slow FH Systems

Abstract

To further enhance the security of the wireless communication systems, an architecture of the cooperative jamming (CJ) assisted slow frequency-hopping (FH) systems is proposed in this paper. Then, after the CJ cancellation operation, the residual CJ raised from synchronization error is analyzed, where the inter-symbol interference (ISI) is employed to depict the time misalignment between the received signal and the local reference CJ at the receiver, and the inter-hop interference (IHI) is introduced to describe the frequency misalignment. In addition, the closed-form expression of the jamming cancellation ratio (JCR) is derived to evaluate the CJ cancellation performance. Theoretical analyses and simulation results show that in the slow FH systems, both the proportions of the ISI and IHI components in the residual CJ are jointly determined by the synchronization error and the hop length. Besides, the JCR increases with the increase of the hop length and the jamming-to-noise ratio (JNR), and decreases with the increase of the synchronization error.