Method and apparatus for offset frequency estimation for a coherent receiver

A receiver for coherent reception of a first signal having known reference information and an extractor for extracting the reference information from the first signal, the receiver including an offset frequency estimator comprising:

• (a) filtering means for filtering the reference information to output a filtered reference sequence;
• (c) correlating means for correlating the filtered reference sequence against a predetermined reference signal to form correlation values, the predetermined reference signal being a sequence of noiseless candidates, each candidate of the sequence of noiseless candidates having a greater increase in phase per a predetermined unit of time than a preceding candidate;
• and
• (d) determining means for determining an offset signal characteristic estimate from the correlation values.

A receiver for coherent reception of a first signal having known reference information and an extractor for extracting the reference information from the first signal, the receiver including an offset frequency estimator comprising:

• (a) a filter coupled to the reference signal extractor being operable for filtering the reference information to output a filtered reference sequence;
• (b) a correlator coupled to the filter being operable for correlating each of a sequence of candidates, each candidate having a greater increase in phase per a predetermined unit of time than a preceding candidate, against the filtered reference sequence to form a correlation value for each corresponding candidate;
• and
• (c) a peak detector coupled to the correlator being operable for determining a peak correlation value from the correlation values and determining an offset frequency estimate based on a predetermined value of the candidate corresponding to the peak correlation value.