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US5799047A
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Carrier synchronization unit and synchronization method
Assignee: NEC Corp
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Filing: 1996-09-12
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Granted: 1998-08-25
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Expires: 2016-09-12
Abstract
Abstract The carrier synchronization unit combines the recursive least square (RLS) type phase and amplitude estimation and the prediction in a decision-directed carrier synchronization strategy. The fading channel multiplicative distortion is estimated using an adaptive recursive least square method which minimizes a time-weighted square error. Combining prediction based on a least-square fading memory curve fit and extrapolation with RLS estimation the tracking delay effect is reduced. Resulting in an improvement of receiver performance. The proposed method minimizes the phenomenon of hang-up allowing rapid phase acquisition with high probability of success.
Inventors
- 👤 Vasic Dobrica
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:41
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/233; H04L27/2332; H04L27/0014; H04L2027/0024; H04L2027/0026; H04L2027/003; H04L2027/0044; H04L2027/0053; H04L2027/0083; H04L2027/0089; H04L2027/0093
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
93 words
The carrier synchronization unit comprising: RLS phase and amplitude estimation means for estimating phase and amplitude of distortion due to fading based on RLS algorithm; prediction means for predicting distortion n symbols (n is an integer) in the future, that is operatively cohering to said RLS phase and amplitude estimation means; compensation means for compensating distortion of a received signal based on said estimated phase and amplitude of distortion; detection means for coherently detecting data symbols based on compensated signal in said compensation means; and means for periodically training said distortion estimation means.
Claim 2
Dependent Claim
93 words
The carrier synchronization unit comprising: RLS phase and amplitude estimation means for estimating phase and amplitude of distortion due to fading based on RLS algorithm; prediction means for predicting distortion n symbols (n is an integer) in the future, that is operatively cohering to said RLS phase and amplitude estimation means; compensation means for compensating distortion of a received signal based on said estimated phase and amplitude of distortion; detection means for coherently detecting data symbols based on compensated signal in said compensation means; and means for periodically training said distortion estimation means.
Claim 3
Dependent Claim
43 words
The carrier synchronization unit of claim 1, wherein said RLS phase and amplitude estimation means comprises means for deriving phase and amplitude from said received signal in a decision-directed configuration by using an RLS adaptive algorithm that minimizes a time-average weighted squared error.
Claim 4
Dependent Claim
28 words
The carrier synchronization unit of claim 2, further comprising means for avoiding hang-up state in decision-directed process using pilot symbols for training indicated by known symbols periodically inserted.
Claim 5
Dependent Claim
46 words
The carrier synchronization unit of claim 2, wherein said RLS phase and amplitude estimation means comprises means for accelerating estimation process during said training intervals by setting internal memory of said RLS estimation means to zero canceling the effect of previous received samples on further estimation.
Claim 6
Dependent Claim
30 words
The carrier synchronization unit of claim 4 comprising: means for generating pilot symbols during training intervals; and multiplexing means for structuring frame multiplexing said pilot symbols and said detected symbols.
Claim 7
Dependent Claim
57 words
The carrier synchronization unit of claim 1, wherein said prediction means comprises means for predicting distortion n symbols (n is an integer) in the future using said current and past distortion values that is estimated by said phase and amplitude estimation means based on RLS algorithm wherein the prediction is based on Morrison's least-square fading-memory prediction algorithm.
Claim 8
Dependent Claim
35 words
The carrier synchronization unit of claim 5, wherein said prediction means comprises predicting distortion n steps in the future and compensating a tracking delay that is introduced by said RLS phase and amplitude estimation means.
Claim 9
Dependent Claim
22 words
The carrier synchronization unit of claim 5, further comprising means for restarting prediction process using updated estimation value during said training intervals.
Claim 10
Dependent Claim
33 words
The carrier synchronization unit of claim 2, wherein said compensation means comprises means for cohering to said RLS phase and amplitude estimation means and responsive for phase and amplitude compensation of received signal.
Claim 11
Dependent Claim
36 words
The carrier synchronization unit of claim 2, wherein said detection means for detecting symbols based on received signal that is phase and amplitude compensated, using phase and amplitude estimation of distortion in a decision-directed carrier synchronization.
Claim 12
Dependent Claim
64 words
A carrier synchronization method comprising the steps of: estimating phase and amplitude distortion due to fading based on RLS algorithm; predicting distortion n symbols (n is an integer) operatively cohering to the RLS estimated phase and amplitude distortion; compensating distortion in a received signal due to fading based on the RLS estimated phase and amplitude distortion; coherently detecting symbols in the compensated received signal.
Claim 13
Dependent Claim
64 words
A carrier synchronization method comprising the steps of: estimating phase and amplitude distortion due to fading based on RLS algorithm; predicting distortion n symbols (n is an integer) operatively cohering to the RLS estimated phase and amplitude distortion; compensating distortion in a received signal due to fading based on the RLS estimated phase and amplitude distortion; coherently detecting symbols in the compensated received signal.
Claim 14
Dependent Claim
18 words
The carrier synchronization method of claim 11, comprising ratios higher than fifteen for detected symbols and pilot symbols.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-24 | 2002-02-23 | 2002-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-24 | 2006-02-23 | 2006-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-24 | 2010-02-23 | 2010-08-25 | $7700.00 | Window Closed / Lapsed |