Method and apparatus for offset frequency estimation for a coherent receiver
First Claim
1. A method for offset frequency estimation of a received signal having known reference information, the method comprising:
- (a) extracting the reference information from the received signal;
(b) filtering the reference information to output a filtered reference sequence;
(c) 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 an offset signal characteristic estimate from the correlation values.
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Abstract
A method and apparatus for improved offset frequency estimation includes in a first embodiment a receiver (100) for coherent reception of a signal having known reference information, the receiver including an extractor (106) for extracting the reference information (107) from the signal, and an offset frequency estimator (110). The offset frequency estimator (110) includes a filter (121) for filtering the reference information and outputting a filtered reference sequence; a correlator (122, 124) for correlating the filtered reference sequence against a predetermined reference signal to form correlation values; and a peak detector (126) for determining an offset frequency estimate (131) from the correlation values. Other embodiments are also shown.
107 Citations
20 Claims
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1. A method for offset frequency estimation of a received signal having known reference information, the method comprising:
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(a) extracting the reference information from the received signal; (b) filtering the reference information to output a filtered reference sequence; (c) 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 an offset signal characteristic estimate from the correlation values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. 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:
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(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. - View Dependent Claims (15, 16, 17, 18, 19)
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20. 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:
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(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.
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Specification