Method and apparatus for mitigating the residual CFO effect on channel estimation for OFDM receivers

摘要

A CFO tracking loop module comprises: a numerically-controlled oscillator (NCO) that calculates a phase output; a CFO phase error block that generates a corrected NCO phase output by subtracting half of residual CFO phase error from the NCO phase output; a multiplier that corrects pilot subcarrier's phase by multiplying complex values of the pilot subcarriers by a conjugated complex value of the corrected NCO phase output; a pilot processor that generates a phase error by averaging phases over pilot subcarriers; and a loop filter that filters phase error from the pilot processor and updates the NCO with the filtered phase error.