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US5754599A
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Method and apparatus for coherent channel estimation in a communication system
Assignee: Google Technology Holdings LLC
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Filing: 1996-01-04
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Granted: 1998-05-19
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Expires: 2016-01-04
Abstract
Abstract Generally stated, a receiver in a communication system implements coherent channel estimation by first receiving an encoded signal and then generating a complex channel estimate from the encoded signal. The receiver then combines the complex channel estimate with the encoded signal to produce a coherent demodulated signal. After combining, the receiver decodes a version of the coherent demodulated signal to produce an estimate of the encoded signal prior to encoding.
Inventors
- 👤 Fuyun Ling
- 👤 Terry Michael Schaffner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:03
CPC Classifications
H; H03; H03D; H03D1/00; H04; H04L; H04L25/00; H04L25/02; H04L25/0202; H04L25/0224; H04L25/0228; H04L25/023; H04L25/0236; H04L25/0212; H04L25/0214
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
132 words
A method of coherent channel estimation in a communication system, the method comprising the steps of: (a) receiving an encoded signal; (b) processing the encoded signal into its in-phase and quadrature digital signal components: (c) generating an orthogonally demodulated in-phase digital signal and an orthogonally demodulated quadrature digital signal from the in-phase and quadrature digital signal components; (d) generating an in-phase complex channel estimate and a quadrature complex channel estimate from the orthogonally demodulated in-phase digital signal and orthogonally demodulated quadrature digital signal; (e) generating a complex coherent orthogonally demodulated signal from the in-phase and quadrature channel estimates; (f) generating a real coherent orthogonally demodulated signal from the complex coherent orthogonally demodulated signal; and (g) decoding the real coherent orthogonally demodulated signal to produce an estimate of the encoded signal before encoding.
Claim 2
Independent Claim
132 words
A method of coherent channel estimation in a communication system, the method comprising the steps of: (a) receiving an encoded signal; (b) processing the encoded signal into its in-phase and quadrature digital signal components: (c) generating an orthogonally demodulated in-phase digital signal and an orthogonally demodulated quadrature digital signal from the in-phase and quadrature digital signal components; (d) generating an in-phase complex channel estimate and a quadrature complex channel estimate from the orthogonally demodulated in-phase digital signal and orthogonally demodulated quadrature digital signal; (e) generating a complex coherent orthogonally demodulated signal from the in-phase and quadrature channel estimates; (f) generating a real coherent orthogonally demodulated signal from the complex coherent orthogonally demodulated signal; and (g) decoding the real coherent orthogonally demodulated signal to produce an estimate of the encoded signal before encoding.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein the step of receiving the encoded signal is performed by a RAKE receiver having a plurality of fingers.
Claim 4
Dependent Claim
63 words
The method of claim 2, further comprising the steps of: (h) repeating steps (a)-(f) for each finger of the RAKE receiver: (i) summing the real coherent orthogonally demodulated signal generated in each finger of the RAKE receiver to form an aggregate coherently orthogonally demodulated signal; and (j) decoding the aggregate coherent orthogonally demodulated signal to produce an estimate of the signal before encoding.
Claim 5
Dependent Claim
20 words
The method of claim 1, wherein the step of generating a complex channel estimate is performed by a channel estimator.
Claim 6
Dependent Claim
23 words
The method of claim 1, wherein the version of the coherent demodulated signal further comprises a real part of the coherent demodulated signal.
Claim 7
Dependent Claim
26 words
The method of claim 1, wherein the step of decoding further comprises decoding an aggregate of the real part of a plurality of coherent demodulated signals.
Claim 8
Dependent Claim
156 words
The method of claim 1, wherein the step of generating an in-phase and quadrature complex channel estimate comprise the steps of: (a) generating a summed energy value for each of a plurality of FHT outputs with a same Walsh symbol index value, keeping only N largest summed energy values; (b) calculating N 2 summations from the FHT output of a first and a second Walsh symbol in a block such that c m .sup.(1) (i(1),i(2))=W m i (1) (1)+W m i (2) (2); (c) sorting the N 2 summations by their relative energy values, retaining only the largest N summed energy values denoted as; c m .sup.(1) (i(1),i(2)) (d) forming summations of c m .sup.(1) (i(1),i(2)) and W m i (3) (3) as in (b) keeping only the N largest summations; and (e) repeating (d) for n=4,5,6 until the largest summation, denoted as C4 m =C m .sup.(5) (i(1),i(2),i(3),i(4),i(5component for the corresponding respective input signal component.
Claim 9
Independent Claim
129 words
An apparatus for coherent channel estimation in a communication system, the apparatus comprising: receiver which receives an encoded signal; processor which processes the encoded signal into its in-phase and quadrature digital signal components, generates an orthogonally demodulated in-phase digital signal and an orthogonally demodulated quadrature digital signal from the in-phase and quadrature digital signal components, generates an in-phase complex channel estimate and a quadrature complex channel estimate from the orthogonally demodulated in-phase digital signal and orthogonally demodulated quadrature digital signal, generates a complex coherent orthogonally demodulated signal from the in-phase and quadrature channel estimates and generates a real coherent orthogonally demodulated signal from the complex coherent orthogonally demodulated signal; and decoder which decodes real coherent orthogonally demodulated signal to produce an estimate of the encoded signal prior to encoding.
Claim 10
Independent Claim
129 words
An apparatus for coherent channel estimation in a communication system, the apparatus comprising: receiver which receives an encoded signal; processor which processes the encoded signal into its in-phase and quadrature digital signal components, generates an orthogonally demodulated in-phase digital signal and an orthogonally demodulated quadrature digital signal from the in-phase and quadrature digital signal components, generates an in-phase complex channel estimate and a quadrature complex channel estimate from the orthogonally demodulated in-phase digital signal and orthogonally demodulated quadrature digital signal, generates a complex coherent orthogonally demodulated signal from the in-phase and quadrature channel estimates and generates a real coherent orthogonally demodulated signal from the complex coherent orthogonally demodulated signal; and decoder which decodes real coherent orthogonally demodulated signal to produce an estimate of the encoded signal prior to encoding.
Claim 11
Dependent Claim
18 words
The apparatus of claim 8, wherein the receiver further comprises a RAKE receiver having a plurality of fingers.
Claim 12
Dependent Claim
19 words
The apparatus of claim 9, wherein each finger of the RAKE receiver produces a real coherent orthogonally demodulated signal.
Claim 13
Dependent Claim
35 words
The apparatus of claim 10, further comprising a summer for summing the real coherent orthogonally demodulated signal from each finger of the RAKE receiver to form an aggregate of the real coherent orthogonally demodulated signals.
Claim 14
Dependent Claim
19 words
The apparatus of claim 11 wherein the decoder further decodes the aggregate of the real coherent orthogonally demodulated signals.
Claim 15
Dependent Claim
30 words
The apparatus of claim 8, wherein the function of the apparatus may be performed within a very large scale integration (VLSI) integrated circuit or, an application specific integrated circuit (ASIC).
Claim 16
Dependent Claim
17 words
The apparatus of claim 8, wherein the decoder further comprises a maximum likelihood sequence estimator (MLSE) decoder.
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) | 2001-05-18 | 2001-11-17 | 2002-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-18 | 2005-11-17 | 2006-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-18 | 2009-11-17 | 2010-05-19 | $7700.00 | Window Closed / Lapsed |