US6064873A
Expired / Lapsed
US
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Method and apparatus for controlling echo on both sides of a connection
Assignee: Telefonaktiebolaget LM Ericsson AB
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Filing: 1997-03-26
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Granted: 2000-05-16
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Expires: 2017-03-26
Abstract
Abstract A single two-ended echo canceller is provided that uses an adaptive FIR filter to model the impulse response of the echo path and cancel the echo originating from the PSTN side of the connection, and a non-linear processor controlled by input signal levels to cancel the echo originating from the mobile phone side of the connection. Since the linear processing function is not used for cancelling echoes of the mobile phone side, the algorithms directed to estimating and cancelling echoes on the two sides of the connection can be executed in a single DSP, with all of the attendant advantages.
Inventors
- 👤 Gunnar Eriksson
- 👤 Tonu Trump
- 👤 Tommy Svensson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:59
CPC Classifications
H; H04; H04B; H04B3/00; H04B3/02; H04B3/20; H04B3/23; H04M; H04M9/00; H04M9/08; H04M9/082
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
81 words
An echo canceller for use in cancelling echoes from two sides of a connection, comprising: a first part comprising an FIR filter-based echo canceller for use in cancelling a network echo received from one side of the connection; and a second part coupled to said first part, said second part comprising a non-linear processor and a delay and level estimator connected to said non-linear processor for use in cancelling a second echo received from a digital mobile side of the connection.
Claim 2
Dependent Claim
81 words
An echo canceller for use in cancelling echoes from two sides of a connection, comprising: a first part comprising an FIR filter-based echo canceller for use in cancelling a network echo received from one side of the connection; and a second part coupled to said first part, said second part comprising a non-linear processor and a delay and level estimator connected to said non-linear processor for use in cancelling a second echo received from a digital mobile side of the connection.
Claim 3
Dependent Claim
19 words
The echo canceller of claim 1, wherein said connection comprises a switching connection in a mobile services switching center.
Claim 4
Dependent Claim
19 words
The echo canceller of claim 1, wherein said connection comprises a switching connection in a long distance traffic system.
Claim 5
Dependent Claim
17 words
The echo canceller of claim 1, further comprising a comfort noise generator connected to said non-linear processor.
Claim 6
Dependent Claim
16 words
The echo canceller of claim 1, wherein said one side of the connection comprises a PSTN.
Claim 7
Dependent Claim
19 words
The echo canceller of claim 1, wherein said digital mobile side of the connection comprises a digital mobile phone.
Claim 8
Dependent Claim
17 words
The echo canceller of claim 1, wherein said connection comprises a direct connection to a trunk line.
Claim 9
Dependent Claim
53 words
The echo canceller of claim 1 wherein the delay and level estimator estimates an echo path delay on the digital mobile side of the connection and estimates a relationship between a signal power of a signal transmitted towards the digital mobile side of the connection and a signal power of the second echo.
Claim 10
Dependent Claim
39 words
The echo canceller of claim 1 wherein the non-linear processor is activated for a selected amount of time after a threshold amount of signal power of a signal transmitted towards the digital mobile side of the connection is detected.
Claim 11
Independent Claim
85 words
An apparatus for use in cancelling an echo originating from a digital mobile phone, comprising: a non-linear processor; a comfort noise generator coupled to said non-linear processor, for generating a comfort noise signal in response to an estimated background noise level; and an echo delay and power level estimator coupled to said non-linear processor for at least estimating a relationship between a power level of a signal transmitted toward the digital mobile phone and the power of the echo originating from the digital mobile phone.
Claim 12
Independent Claim
85 words
An apparatus for use in cancelling an echo originating from a digital mobile phone, comprising: a non-linear processor; a comfort noise generator coupled to said non-linear processor, for generating a comfort noise signal in response to an estimated background noise level; and an echo delay and power level estimator coupled to said non-linear processor for at least estimating a relationship between a power level of a signal transmitted toward the digital mobile phone and the power of the echo originating from the digital mobile phone.
Claim 13
Dependent Claim
11 words
The apparatus of claim 10, further comprising a digital signal processor.
Claim 14
Dependent Claim
19 words
The apparatus of claim 10, further comprising an echo canceller for use in cancelling echoes originating from a PSTN.
Claim 15
Independent Claim
146 words
A method for use in cancelling echoes from two sides of a switch connection, comprising the steps of: transmitting a first signal from a first side of the switch connection; estimating an impulse response for a first echo signal originating on said first side of the switch connection, wherein said first echo signal comprises a reflection of said first signal; cancelling said first echo signal; transmitting a second signal from a second side of the switch connection; detecting a second echo signal originating on the second side of the switch connection, wherein said second echo signal comprises a reflection of said second signal; estimating a delay for said second echo signal; estimating a relationship between a first power signal directed toward said second side of said switch connection and said second echo signal; and cancelling said second echo signal responsive to said delay and said relationship.
Claim 16
Independent Claim
146 words
A method for use in cancelling echoes from two sides of a switch connection, comprising the steps of: transmitting a first signal from a first side of the switch connection; estimating an impulse response for a first echo signal originating on said first side of the switch connection, wherein said first echo signal comprises a reflection of said first signal; cancelling said first echo signal; transmitting a second signal from a second side of the switch connection; detecting a second echo signal originating on the second side of the switch connection, wherein said second echo signal comprises a reflection of said second signal; estimating a delay for said second echo signal; estimating a relationship between a first power signal directed toward said second side of said switch connection and said second echo signal; and cancelling said second echo signal responsive to said delay and said relationship.
Claim 17
Dependent Claim
18 words
The method of claim 13, wherein said first echo signal comprises an echo signal originating from a PSTN.
Claim 18
Dependent Claim
20 words
The method of claim 13, wherein said second echo signal comprises an echo signal originating from a digital mobile phone.
Claim 19
Dependent Claim
23 words
The method of claim 13, wherein the step of cancelling a second echo signal comprises the step of injecting a comfort noise signal.
Claim 20
Dependent Claim
19 words
The method of claim 13, wherein said switch connection comprises a switch connection in a mobile services switching center.
Claim 21
Dependent Claim
19 words
The method of claim 13, wherein said switch connection comprises a switch connection in a long distance traffic system.
Claim 22
Dependent Claim
30 words
The method of claim 13, wherein the step of cancelling the second echo signal is responsive to a detection of a threshold amount of signal power for said second signal.
Claim 23
Dependent Claim
29 words
The method of claim 13, further comprising the step of calculating an amount of time for performing the step of cancelling the second echo signal responsive to said relationship.
References Cited (Backward Citations)
US4629829A
Cited
US4935919A
Cited
JPH03159423A
Cited
EP0439139A2
Cited
US5283784A
Cited
GB2256351A
Cited
DE4216911A1
Cited
US5477535A
Cited
US5295136A
Cited
US5559881A
Cited
US5323459A
Cited
JPH07288493A
Cited
US5587998A
Cited
US5610909A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-05-16 | 2003-11-15 | 2004-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-16 | 2007-11-15 | 2008-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-16 | 2011-11-15 | 2012-05-16 | $7700.00 | Window Closed / Lapsed |