EP0154565A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Modem
Assignee: General Electric Co
•
Filing: 1985-03-08
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Granted: —
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Expires: 2005-03-08
Abstract
Abstract A modem which includes transmission means for transmitting information signals to a remote device over a channel at any one of a multiplicity of communication rates, reception means for receiving information signals from the remote device over the channel at any one of the communication rates, quality-monitoring means for monitoring the quality of the channel on the basis of the received information signals, and rate control means responsive to the quality-monitoring means for selecting a current communication rate based on the channel quality, the rate control means including fall forward means for indicating that an increase in the current communication rate to a higher communication rate is desired and for implementing the increase when the remote device concurs.
Inventors
- 👤 Shahid U.H. Qureshi
- 👤 Karl W. Seitz
- 👤 Robert M. Wilson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 03:13
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03006; H04L25/03012; H04L25/03019; H04L1/00; H04L1/0001; H04L1/0002; H04L1/0023; H04L1/0025; H04L1/004; H04L1/0045; H04L1/0054; H04L1/20; H04L1/206; H04L2025/03777; H04L2025/03783; H04Q; H04Q2213/00; H04Q2213/13199; H04Q2213/13332; Y; Y02; Y02D; Y02D30/00; Y02D30/50
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
130 words
1 . A modem characterised in that it comprises: transmission means adapted to transmit information signals to a remote device over a channel at any one of a multiplicity of communication rates; reception means adapted to receive information signals from said remote device over said channel at any one of said communication rates; quality-monitoring means adapted to monitor the quality of said channel on the basis of said received infornation signals; and rate control means responsive to said quality-monitoring means and adapted to select a current communi- catio; rate based on said channel quality, said rate contr:l means comprising fall forward means adapted to indicate that a-n increase in said current communication rate to a higher communication rate is desired and to implement said increase when said remote device concurs.
Claim 2
Dependent Claim
130 words
1 . A modem characterised in that it comprises: transmission means adapted to transmit information signals to a remote device over a channel at any one of a multiplicity of communication rates; reception means adapted to receive information signals from said remote device over said channel at any one of said communication rates; quality-monitoring means adapted to monitor the quality of said channel on the basis of said received infornation signals; and rate control means responsive to said quality-monitoring means and adapted to select a current communi- catio; rate based on said channel quality, said rate contr:l means comprising fall forward means adapted to indicate that a-n increase in said current communication rate to a higher communication rate is desired and to implement said increase when said remote device concurs.
Claim 3
Dependent Claim
37 words
A modem according to Claim 1, further characterised in tilt said rate control means further comprises fall back means adapted to make fall back decisions which unilaterally decrease said current communication rate to a lowe communication rate.
Claim 4
Dependent Claim
133 words
' A modem characterised in that it comprises trans- mis: on means adapted to transmit information signals to a remote device over a channel at any one of a multiplicity of transmission rates; reception means adapted to receive information signals from said remote device over said channel at any one of a multiplicity of reception rates; quality-monitoring means adapted to monitor the quality of aid channel on the basis of said received information signals; and rate control means responsive to said quality- monitoring means adapted to select a current reception r e based on said channel quality, said rate control means comprising fall forward means adapted to indicate that an increase in said current reception rate to a higher reception rate is desired and to instruct said remote device to implement said increase.
Claim 5
Dependent Claim
133 words
' A modem characterised in that it comprises trans- mis: on means adapted to transmit information signals to a remote device over a channel at any one of a multiplicity of transmission rates; reception means adapted to receive information signals from said remote device over said channel at any one of a multiplicity of reception rates; quality-monitoring means adapted to monitor the quality of aid channel on the basis of said received information signals; and rate control means responsive to said quality- monitoring means adapted to select a current reception r e based on said channel quality, said rate control means comprising fall forward means adapted to indicate that an increase in said current reception rate to a higher reception rate is desired and to instruct said remote device to implement said increase.
Claim 6
Dependent Claim
46 words
A modem according to Claim 3, further characterised in that said rate control means further comprises fall back means adapted to make fall back decisions to decrease said current reception rate to a lower reception rate and to instruct said remote device to implement said decrease.
Claim 7
Dependent Claim
66 words
A modem according to Claims 3 or 4, further characterised in that said rate control means further comprises means responsive to said remote device and adapted to implement a current transmission rate, said increase in said reception rate being implemented only when said remote device indicates to said modem that said remote device desires an increase in said current transmission rate to a higher transmission rate.
Claim 8
Dependent Claim
31 words
A modem according to Claim 5, further characterised in that said higher reception rate implemented by said remote device is the same as said higher transmission rate implemented by said modem.
Claim 9
Dependent Claim
77 words
A modem according to any preceding claim, further characterised in that said reception means further comprises adaptive equalization and demodulation circuitry for equalizing and demodulating said received information signals using adaptive equalization and demodulation parameters which have initial values, and said rate control means further comprises save equalizer means responsive to said quality-monitoring means and adapted to update said values when said channel quality is good and to reinitialize said values when said channel quality is poor.
Claim 10
Dependent Claim
77 words
A modem according to Claim I or any claim appendent thereto, wherein said information signals comprise signal points, further characterised in that said quality-monitoring means further comprises means adapted to measure the dispersion of said signal points received over said channel around ideal signal points corresponding to said received signal points; and in that said fall forward means further comprises means adapted to indicate that said higher communication rate is desired on the basis of said measure.
Claim 11
Dependent Claim
78 words
A modem according to C laim 3 or any claim appendent thereto, wherein said information signals comprise signal poiits, further characterised in that said quality-monitoring means further comprises means adapted to measure the dispersion of said signal points received over said channel around ideal signal points corresponding to said received signal points; and in that said fall forward means further comprises means adapted to indicate that said higher reception rate is desired on the basis of ;aid measure.
Claim 12
Dependent Claim
20 words
10 A modem according to Claims 8 or 9, further characterised in that said meausre is an average minimum metric.
Claim 13
Dependent Claim
48 words
A modem according to any of Claims 8 to 10,- further characterised in that said fall forward means is arranged to indicate that said higher rate is desired when said measure is less than a predetermined threshold for at least a predetermined percentage of a predetermined time period.
Claim 14
Dependent Claim
45 words
A modem according to Claim 1 or any claim appendent thereto, further characterised in that said information signals include first rate signals corresponding to said current communication rate and second rate signals corres- ponding to said higher communication rate desired by said fall forward means.
Claim 15
Dependent Claim
92 words
A modem according to Claim 12, further characterised in that it comprises memory means adapted to store said first and second rate signals, said transmitted second rate signal transmitted by said transmitting means and said received second rate signal received by said reception means being stored by said memory means; and in that said rate control means further comprises comparison means adapted to compare said transmitted and received second rate signals and means adapted to implement a current communication rate which is the lesser of said transmitted and received second rate signals.
Claim 16
Dependent Claim
96 words
A modem according to Claim 2 or Claim 4, wherein said information signals include data signals corresponding to a data bit pattern being communicated, further characterised in that said reception means further comprises decision means adapted to determine said data bit pattern on the basis of said received data signals; in that said quality-monitoring means further comprises means adapted to estimate the number of errors made by said decision means, said number being the error rate of reception over said channel; and in that said fall back decisions are made on the basis of said estimates.
Claim 17
Dependent Claim
167 words
A modem according to Claim 2 or Claim 4, wherein said information signals include data signals corresponding to a data bit pattern being communicated, and comprising signal points, further characterised in that said reception means further comprises decision means adapted to determine said data bit pattern on the basis of said received data signals using a Viterbi algorithm, said decision means comprising means adapted to make a tentative decision as to the signal points received corresponding to each of said data signals upon receipt of said data signals and a corresponding final decision as to said signal points after a predetermined number of said data signals have been received, and means adapted to detect a discrepancy between said tentative decision and said corresponding final decision; and in that said quality-monitoring means further comprises averaging circuitry for producing an average discrepancy being an estimate of the error rate of transmission over said channel; and in that said fall back decisions are made on the basis of said estimate.
Claim 18
Dependent Claim
32 words
A modem according to either of Claims 14 or 15, further characterised in that said fall back decisions are produced when said estimate exceeds a predetermined threshold for a predetermined time period.
Claim 19
Dependent Claim
47 words
A modem according to either of Claims 14 or 15, further characterised in that said modem is initially trained to receive said information signals over said channel and wherein retraining of said modem is initiated when said estimate exceeds a predetermined threshold for a predetermined time period.
Claim 20
Dependent Claim
31 words
A modem according to Claim 17, further characterised in that said fall back decisions are produced upon the occurrence of a predetermined number of retraining initiations in a predetermined time period.
References Cited (Backward Citations)
No citation records indexed.
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