Method, apparatus and system for carrier frequency offset estimation

A system for carrier frequency offset estimation, comprising:

• a correlator (301), a peak value extraction module (302), a first frequency offset estimation module (303), a second frequency offset estimation module (304) and a frequency offset combination module (305), wherein
• the correlator (301) is configured to receive a preamble sequence rn, and correlate the preamble sequence rn with a locally stored Barker code bn to obtain a calculation result cn;
• the peak value extraction module (302) is configured to extract peak values from every L points in cn and form a peak value sequence xn, L being a length of a Barker code that corresponds to the sampling rate;
• the first frequency offset estimation module (303) is configured to receive xn and calculate a corresponding carrier frequency offset estimate;
• the second frequency offset estimation module (304) is configured to receive xn and calculate another corresponding carrier frequency offset estimate;
• the frequency offset combination module (305) is configured to receive the results output from the first frequency offset estimation module (303) and the second frequency offset estimation module (304), and calculate a final carrier frequency offset estimate, wherein the first and second frequency offset estimation modules adopt different delay parameters D.

An apparatus for carrier frequency offset estimation, comprising:

• a time-delayed conjugate multiplication module (401), a sequence storage module (402), a determination-compensation module (403), an accumulator (404), a phase obtainment apparatus (405) and a multiplication module (406), wherein
• the time-delayed conjugate multiplication module (401) is configured to perform a time-delayed conjugate multiplication to xn to obtain a sequence yn and store the sequence yn on the sequence storage module (402);
• the sequence storage module (402) is configured to receive the sequence yn from the time-delayed conjugate multiplication module (401) and store it;
• the determination-compensation module (403) is configured to determine sequences stored on the sequence storage module (402) and compensate phases thereof;
• the accumulator (404) is configured to accumulate the determination-compensation results and average them;
• the phase obtainment apparatus (405) is configured to receive outputs from the accumulator to obtain a phase and adjust the phase into a range of (−π/2,π/2) by adding or subtracting π thereto or therefrom;
• and
• the multiplication module (406) is configured to multiply the phase with Ki to obtain a carrier frequency offset estimate and output the carrier frequency offset estimate by a corresponding carrier frequency offset estimation apparatus, where Ki=Fs/(2πDi), Fs is the rate of the preamble, and Di is the delay parameter of the i-th frequency offset estimation apparatus.