A sign-bit auto-correlation architecture for fractional frequency offset estimation in OFDM

This paper presents an architecture of an autocorrelator for Orthogonal Frequency Division Multiplexing systems. The received signal is quantized to only the sign-bit, which dramatically simplifies the frequency offset estimation. Hardware cost is reduced under the assumption that synchronization during acquisition does not have to be very accurate, but sufficient for coarse estimation. The architecture is synthesized towards a 65nm low-leakage high threshold standard cell CMOS library. The proposed architecture results in area reduction of 93% if compared to typical 8-bit implementation. The area occupied by the architecture is 0.063 mm². The architecture is evaluated for WLAN, LTE and DVB-H. Power simulations for DVB-H transmission shows a power consumption of 4.8μW per symbol.