Phase warping and differential scrambling attacks against OFDM frequency synchronization

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) is used in many modern communications systems. Timing and frequency synchronization in an OFDM system are critical to performance and must be carried out early and often. Current synchronization methods, such as those developed by Schmidl and Cox [1], were not designed to be robust to adversarial signals. A series of attacks against the preamble synchronization stage have been developed and demonstrated to debilitate OFDM receivers. Multiple attacks against the frequency offset error estimation stage are discussed, and some possible improvements to OFDM synchronization algorithms are suggested.