Protecting physical layer synchronization: mitigating attacks against OFDM acquisition

Orthogonal Frequency Division Multiplexing (OFDM) has become an integral physical layer feature of 4G systems, and will continue to be utilized in future communications standards. In systems that utilize OFDM, synchronization between the transmitter and the receiver is paramount. However, many current acquisition algorithms and implementations are susceptible to corruption by adversarial communications systems. This paper outlines two improvements to OFDM timing and frequency offset estimation; sync-amble randomization and Cross Ambiguity Function (CAF) acquisition. Both analysis and simulation results are provided which suggest that both of these strategies offer improvements in physical layer security to OFDM synchronization in the presence of attacking communication systems, with minimal impact on overall performance.