Efficient and unrecognizable OFDM jamming by failing the cyclic prefix functionality

Abstract

Listen

Translate article

In order to counteract hostile communication based on the advanced Orthogonal Frequency Division Multiplexing (OFDM) technology, an efficient and unrecognizable jamming technique by failing the OFDM cyclic prefix (CP) functionality is developed in the paper. CP is introduced into OFDM systems to prevent interference caused by the multipath fading, as long as it is no shorter than the channel delay spread. The basic principle of the proposed approach is to destroy this CP validity condition by constructing a path of the target signal with a delay larger than the CP length. Specifically, the jammer captures the ongoing OFDM signal and then forwards it with an intended delay. The aggregation of the target and jamming signals is thus equivalent to a faded target signal suffering a multipath channel of an overlong delay spread that cannot be absorbed by the CP. Both inter-symbol interference (ISI) and inter-carrier interference (ICI) are induced. The OFDM transmission can therefore be disrupted due to the loss of subcarrier orthogonality. Moreover, as the jamming signal is actually a delayed version of the target signal, the jamming attack is hard to be detected. Compared with the existing OFDM jamming methods, the proposed scheme can be easily implemented without synchronization to the target signal or detailed frame structure of the target system.