US5835731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Technique for improving the blind convergence of a two-filter adaptive equalizer
Assignee: Nokia of America Corp
•
Filing: 1996-09-18
•
Granted: 1998-11-10
•
Expires: 2016-09-18
Abstract
Abstract A blind equalization cost function called the "constrained Hilbert cost function" (CHCF) provides for reliable blind convergence of a two-filter equalizer structure. In particular, the CHCF cost function is designed in such a way that the two filters are constrained to be a Hilbert pair. Advantageously, this technique can be used with any blind equalization algorithms, such as RCA, CMA, and MMA.
Inventors
- 👤 Jean-Jacques Werner
- 👤 Jian Yang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:15
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L25/03038; H04L25/0305; H04L25/38; H04L25/40; H04L25/49; H04L25/4917; H04L25/4919; H04L25/4921; H04L2025/0335; H04L2025/03375; H04L2025/0342; H04L2025/03433; H04L2025/03439; H04L2025/03445; H04L2025/03471; H04L2025/03477; H04L2025/03592; H04L2025/03598; H04L2025/03611; H04L2025/03617
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
36 words
An improved equalizer for use in a receiver for performing blind equalization; the improvement comprising: a processor that adapts coefficients of the equalizer using a blind equalization algorithm modified to include a constrained Hilbert cost function.
Claim 2
Dependent Claim
36 words
An improved equalizer for use in a receiver for performing blind equalization; the improvement comprising: a processor that adapts coefficients of the equalizer using a blind equalization algorithm modified to include a constrained Hilbert cost function.
Claim 3
Dependent Claim
13 words
The improvement of claim 1 wherein the processor is a digital signal processor.
Claim 4
Dependent Claim
27 words
The improvement of claim 1 wherein the blind equalization algorithm is a reduced constellation algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 5
Dependent Claim
28 words
The improvement of claim 1 wherein the blind equalization algorithm conforms to a constant modulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 6
Dependent Claim
27 words
The apparatus of claim 1 wherein the blind equalization algorithm conforms to a multimodulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 7
Dependent Claim
54 words
Apparatus for use in a receiver, the apparatus comprising: an equalizer having a set of tap coefficient values and for providing an equalized version of an applied input signal; and a processor for adapting the set of tap coefficients as a function of a blind equalization algorithm that incorporates a constrained Hilbert cost function.
Claim 8
Dependent Claim
54 words
Apparatus for use in a receiver, the apparatus comprising: an equalizer having a set of tap coefficient values and for providing an equalized version of an applied input signal; and a processor for adapting the set of tap coefficients as a function of a blind equalization algorithm that incorporates a constrained Hilbert cost function.
Claim 9
Dependent Claim
27 words
The apparatus of claim 6 wherein the blind equalization algorithm is a reduced constellation algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 10
Dependent Claim
28 words
The apparatus of claim 6 wherein the blind equalization algorithm conforms to a constant modulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 11
Dependent Claim
27 words
The apparatus of claim 6 wherein the blind equalization algorithm conforms to a multimodulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 12
Dependent Claim
51 words
An improved equalizer for use in a receiver for performing blind equalization; the improvement comprising: a processor a) for providing an equalizer function for equalizing a received signal, and b) for adapting coefficients of the equalizer function by using a blind equalization algorithm modified to include a constrained Hilbert cost function.
Claim 13
Dependent Claim
51 words
An improved equalizer for use in a receiver for performing blind equalization; the improvement comprising: a processor a) for providing an equalizer function for equalizing a received signal, and b) for adapting coefficients of the equalizer function by using a blind equalization algorithm modified to include a constrained Hilbert cost function.
Claim 14
Dependent Claim
13 words
The apparatus of claim 10 wherein the processor is a digital signal processor.
Claim 15
Dependent Claim
27 words
The apparatus of claim 10 wherein the blind equalization algorithm is a reduced constellation algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 16
Dependent Claim
28 words
The apparatus of claim 10 wherein the blind equalization algorithm conforms to a constant modulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 17
Dependent Claim
27 words
The apparatus of claim 10 wherein the blind equalization algorithm conforms to a multimodulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 18
Independent Claim
62 words
A method for use in a communications receiver, the method comprising the steps of: adaptively filtering a received signal as a function of a set of tap coefficient values to provide a filtered signal; and using a blind equalization algorithm to adapt the set of tap coefficient values; wherein the blind equalization algorithm is a function of a constrained Hilbert cost function.
Claim 19
Independent Claim
62 words
A method for use in a communications receiver, the method comprising the steps of: adaptively filtering a received signal as a function of a set of tap coefficient values to provide a filtered signal; and using a blind equalization algorithm to adapt the set of tap coefficient values; wherein the blind equalization algorithm is a function of a constrained Hilbert cost function.
Claim 20
Dependent Claim
28 words
The method of claim 15 wherein the blind equalization algorithm conforms to a reduced constellation algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 21
Dependent Claim
28 words
The method of claim 15 wherein the blind equalization algorithm conforms to a constant modulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 22
Dependent Claim
27 words
The method of claim 15 wherein the blind equalization algorithm conforms to a multimodulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 23
Dependent Claim
37 words
The method of claim 15 further comprising the step of switching to an unconstrained decision directed adaptation algorithm for adjusting the set of tap coefficient values when a calculated error rate is less than a predetermined value.
Claim 24
Dependent Claim
20 words
The method of claim 19 wherein the unconstrained decision directed adaptation algorithm uses a least means squared tap updating algorithm.
Claim 25
Dependent Claim
79 words
Apparatus for use in performing blind equalization in a receiver, the apparatus comprising: a memory for storing a blind equalization algorithm that incorporates a constrained Hilbert cost function and for storing a set of tap coefficient values; and a processor a) for filtering an input signal as a function of the set of stored tap coefficient values to provide an output signal, and b) for executing the blind equalization algorithm to adapt the set of stored tap coefficient values.
Claim 26
Dependent Claim
79 words
Apparatus for use in performing blind equalization in a receiver, the apparatus comprising: a memory for storing a blind equalization algorithm that incorporates a constrained Hilbert cost function and for storing a set of tap coefficient values; and a processor a) for filtering an input signal as a function of the set of stored tap coefficient values to provide an output signal, and b) for executing the blind equalization algorithm to adapt the set of stored tap coefficient values.
Claim 27
Dependent Claim
27 words
The apparatus of claim 21 wherein the blind equalization algorithm is a reduced constellation algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 28
Dependent Claim
28 words
The apparatus of claim 21 wherein the blind equalization algorithm conforms to a constant modulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 29
Dependent Claim
27 words
The apparatus of claim 21 wherein the blind equalization algorithm conforms to a multimodulus algorithm modified to include an orthogonal error term and an equal energy condition.
Claim 30
Dependent Claim
65 words
An improved adaptive filter for performing blind equalization in a receiver, the improvement comprising: an adaptive filter having a two-filter structure, where each of the two filters further comprises a respective set of tap coefficient values, and wherein a blind equalization algorithm adapts each set of tap coefficient values for each filter as a function of an orthogonal error term and an equal energy condition.
Claim 31
Dependent Claim
65 words
An improved adaptive filter for performing blind equalization in a receiver, the improvement comprising: an adaptive filter having a two-filter structure, where each of the two filters further comprises a respective set of tap coefficient values, and wherein a blind equalization algorithm adapts each set of tap coefficient values for each filter as a function of an orthogonal error term and an equal energy condition.
Claim 32
Dependent Claim
16 words
The improvement of claim 25 wherein the blind equalization algorithm is a modified reduced constellation algorithm.
Claim 33
Dependent Claim
16 words
The improvement of claim 25 wherein the blind equalization algorithm conforms to a constant modulus algorithm.
Claim 34
Dependent Claim
15 words
The improvement of claim 25 wherein the blind equalization algorithm conforms to a multimodulus algorithm.
Claim 35
Dependent Claim
72 words
Apparatus for use in a receiver, the apparatus comprising: an adaptive filter having a two-filter structure, where each of the two filters further comprises a respective set of tap coefficient values; and circuitry for adapting each set of tap coefficient values in accordance with a blind equalization algorithm that adapts each set of tap coefficient values for each filter as a function of an orthogonal error term and an equal energy condition.
Claim 36
Dependent Claim
72 words
Apparatus for use in a receiver, the apparatus comprising: an adaptive filter having a two-filter structure, where each of the two filters further comprises a respective set of tap coefficient values; and circuitry for adapting each set of tap coefficient values in accordance with a blind equalization algorithm that adapts each set of tap coefficient values for each filter as a function of an orthogonal error term and an equal energy condition.
Claim 37
Dependent Claim
16 words
The apparatus of claim 29 wherein the blind equalization algorithm is a modified reduced constellation algorithm.
Claim 38
Dependent Claim
16 words
The apparatus of claim 29 wherein the blind equalization algorithm conforms to a constant modulus algorithm.
Claim 39
Dependent Claim
15 words
The apparatus of claim 29 wherein the blind equalization algorithm conforms to a multimodulus algorithm.
Claim 40
Independent Claim
69 words
A method for use in a communications receiver, the method comprising the steps of: using a two-filter structure for adaptively filtering a received signal, the two filter structure including a corresponding set of tap coefficient values for each filter; and using a blind equalization algorithm to adapt each set of tap coefficient values for each filter as a function of an orthogonal error term and an equal energy condition.
Claim 41
Independent Claim
69 words
A method for use in a communications receiver, the method comprising the steps of: using a two-filter structure for adaptively filtering a received signal, the two filter structure including a corresponding set of tap coefficient values for each filter; and using a blind equalization algorithm to adapt each set of tap coefficient values for each filter as a function of an orthogonal error term and an equal energy condition.
Claim 42
Dependent Claim
17 words
The method of claim 33 wherein the blind equalization algorithm otherwise conforms to a reduced constellation algorithm.
Claim 43
Dependent Claim
17 words
The method of claim 33 wherein the blind equalization algorithm otherwise conforms to a constant modulus algorithm.
Claim 44
Dependent Claim
16 words
The method of claim 33 wherein the blind equalization algorithm otherwise conforms to a multimodulus algorithm.
Claim 45
Dependent Claim
14 words
The method of claim 33 wherein the two-filter structure is a fractionally-spaced linear equalizer.
Claim 46
Dependent Claim
37 words
The method of claim 33 further comprising the step of switching to an unconstrained decision directed adaptation algorithm for adjusting the set of tap coefficient values when a calculated error rate is less than a predetermined value.
Claim 47
Dependent Claim
20 words
The method of claim 38 wherein the unconstrained decision directed adaptation algorithm uses a least means squared tap updating algorithm.
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) | 2001-11-09 | 2002-05-11 | 2002-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-09 | 2006-05-11 | 2006-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-09 | 2010-05-11 | 2010-11-10 | $7700.00 | Window Closed / Lapsed |