US5541964A
Expired / Lapsed
US
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Distortion compensation technique
Assignee: AT&T Inc
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Filing: 1995-09-25
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Granted: 1996-07-30
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Expires: 2015-09-25
Abstract
Abstract Symbols which are representative of customer data are transmitted in bursts. In the idle mode, i.e., the time intervals between bursts, symbol sequences which are a priori known to the receiver are transmitted. Such idle mode symbols maintain adaptive apparatus, such as NEXT cancellers and equalizers, in their properly converged state. To reduce crosstalk and spectral emissions, the idle mode symbols are selected to be the innermost symbols in the signal constellation encompassing the ensemble of all symbols.
Inventors
- 👤 Eran Cohen
- 👤 Andrew T. Weitzner
- 👤 Jean-Jacques Werner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:49
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/32; H04L27/34; H04L7/00; H04L7/04; H04L7/041; H04L2007/045
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
129 words
Apparatus utilizing busy and idle modes wherein in said busy mode information represented by symbols in a signal constellation is to be transmitted over a bidirectional communications channel and in said idle mode said information symbols are not transmitted, said apparatus comprising: first means responsive to an indication of said busy mode for generating a plurality of first symbols in said signal constellation, each of said first symbols being representative of associated information; and second means responsive to an indication of said idle mode for generating only at least one second symbol, each at least one second symbol being an innermost symbol in said signal constellation, said first symbols not being generated in response to said indication of said idle mode, wherein crosstalk is reduced in said communications channel.
Claim 2
Dependent Claim
129 words
Apparatus utilizing busy and idle modes wherein in said busy mode information represented by symbols in a signal constellation is to be transmitted over a bidirectional communications channel and in said idle mode said information symbols are not transmitted, said apparatus comprising: first means responsive to an indication of said busy mode for generating a plurality of first symbols in said signal constellation, each of said first symbols being representative of associated information; and second means responsive to an indication of said idle mode for generating only at least one second symbol, each at least one second symbol being an innermost symbol in said signal constellation, said first symbols not being generated in response to said indication of said idle mode, wherein crosstalk is reduced in said communications channel.
Claim 3
Dependent Claim
51 words
The apparatus of claim 1 wherein said first and second symbols are, coupled to a bidirectional communications channel and said idle mode corresponds to an arrival of predetermined ones of said first symbols from said communications channel, wherein said predetermined ones of said first symbols are outermost symbols in said constellation.
Claim 4
Dependent Claim
24 words
The apparatus of claim 1 wherein said busy mode corresponds to an arrival of said at least one second symbol from said communications channel.
Claim 5
Dependent Claim
42 words
The apparatus of claim 1 wherein said first means transmits a packet premable a plurality of times and said first means transmits a preamble indicating a change from said idle mode to said busy mode at each of said plurality of times.
Claim 6
Dependent Claim
16 words
The apparatus of claim 4 wherein said preamble includes an outermost symbol in said symbol constellation.
Claim 7
Dependent Claim
43 words
The apparatus of claim 5 wherein said outermost symbol is used to represent data when not in said preamble, and said outermost symbol does not represent data and indicates a change from said idle mode to said busy mode when in said preamble.
Claim 8
Dependent Claim
19 words
The apparatus of claim 5 wherein said preamble also includes at least one symbol other than said outermost symbol.
Claim 9
Dependent Claim
120 words
Apparatus utilizing busy and idle modes wherein symbols in a signal constellation are received from a communications channel that are representative of information in said busy mode and the symbols received from said communications channel in said idle mode are not representative of said information, said apparatus comprising means for receiving said symbols from said communications channel; and means responsive an indication of said busy mode for decoding said received symbols into an associated plurality of bits and for passing without decoding at least one received symbol which is an innermost symbol in said constellation, which is representative of an idle control symbol in response to an indication of said idle mode, wherein crosstalk is reduced in said communications channel.
Claim 10
Dependent Claim
120 words
Apparatus utilizing busy and idle modes wherein symbols in a signal constellation are received from a communications channel that are representative of information in said busy mode and the symbols received from said communications channel in said idle mode are not representative of said information, said apparatus comprising means for receiving said symbols from said communications channel; and means responsive an indication of said busy mode for decoding said received symbols into an associated plurality of bits and for passing without decoding at least one received symbol which is an innermost symbol in said constellation, which is representative of an idle control symbol in response to an indication of said idle mode, wherein crosstalk is reduced in said communications channel.
Claim 11
Dependent Claim
62 words
The apparatus of claim 8 further including means for encoding information into symbols at certain times and transmitting at least one innermost symbol at other times, said innermost symbol not being representative of said information at said other times and wherein each of said certain times corresponds to a receipt of received symbols from said communications channel which are representative of information.
Claim 12
Dependent Claim
28 words
The apparatus of claim 9 wherein each of said other times corresponds to a receipt of innermost symbols from said communications channel which are not representative of information.
Claim 13
Dependent Claim
37 words
The apparatus of claim 8 wherein a transition from said idle mode to said busy mode is indicated by a receipt of an ensemble of symbols including one which is an outermost symbol in said signal constellation.
Claim 14
Dependent Claim
16 words
The apparatus of claim 11 wherein said ensemble also includes symbols other than said outermost symbol.
Claim 15
Independent Claim
116 words
A method for use in apparatus utilizing busy and idle modes wherein in said busy mode information represented by symbols in a signal constellation is transmitted over a communications channel and in said idle mode said information symbols are not transmitted, said method comprising the steps of: generating a plurality of first symbols in a signal constellation in response to an indication of said busy mode, each of said first symbols being representative of associated information; and generating only at least one second symbol and no first symbols in response to an indication of said idle mode, each second symbol being an innermost symbol in said signal constellation, wherein crosstalk is reduced in said communications channel.
Claim 16
Independent Claim
116 words
A method for use in apparatus utilizing busy and idle modes wherein in said busy mode information represented by symbols in a signal constellation is transmitted over a communications channel and in said idle mode said information symbols are not transmitted, said method comprising the steps of: generating a plurality of first symbols in a signal constellation in response to an indication of said busy mode, each of said first symbols being representative of associated information; and generating only at least one second symbol and no first symbols in response to an indication of said idle mode, each second symbol being an innermost symbol in said signal constellation, wherein crosstalk is reduced in said communications channel.
Claim 17
Independent Claim
127 words
A method for use in apparatus utilizing busy and idle modes wherein symbols in a signal constellation are received from a communications channel that are representative of information in said busy mode and the symbols received from said communication channel in said idle mode are not representative of said information, said method comprising the steps of: receiving said symbols from said communications channel; and decoding said received symbols into an associated plurality of bits in response to an indication of said busy mode and passing without decoding at least one of said received symbols which is an innermost symbol in said constellation, which is representative of an idle control symbol in response to an indication of said idle mode, wherein crosstalk is reduced in said communications channel.
Claim 18
Independent Claim
127 words
A method for use in apparatus utilizing busy and idle modes wherein symbols in a signal constellation are received from a communications channel that are representative of information in said busy mode and the symbols received from said communication channel in said idle mode are not representative of said information, said method comprising the steps of: receiving said symbols from said communications channel; and decoding said received symbols into an associated plurality of bits in response to an indication of said busy mode and passing without decoding at least one of said received symbols which is an innermost symbol in said constellation, which is representative of an idle control symbol in response to an indication of said idle mode, wherein crosstalk is reduced in said communications channel.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-07-30 | 2000-01-29 | 2000-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-07-30 | 2004-01-29 | 2004-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-07-30 | 2008-01-29 | 2008-07-30 | $7700.00 | Window Closed / Lapsed |