Carrier Frequency Offset Estimation Using Embedded Pseudo Random Sequences

The orthogonal frequency division multiplexing (OFDM) system is widely adopted in high-speed wireless communication systems. Different from the single carrier transmission scheme, OFDM system is extremely sensitive to the carrier frequency offset (CFO). Several frequency estimation methods have been proposed to extract and compensate the CFO. However, conventional estimation methods get some trouble in correctly extracting the integer CFO in strong echo channels. In this paper, a novel frequency estimation method, using PN sequence embedded in frequency domain OFDM data, is introduced for time-domain synchronous OFDM. The method uses correlation result between PN sequence and OFDM data to extract the integer CFO. Simulation result proves that the new method precisely extract the integer CFO in various channels almost without interference on data.