METHOD AND APPARATUS FOR GENERATING A LINE IMPAIRMENT LEARNING SIGNAL FOR A DATA COMMUNICATION SYSTEM

US 20010038673A1
Filed: 11/13/1997
Published: 11/08/2001
Est. Priority Date: 09/03/1997
Status: Active Grant

First Claim

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1. A line impairment learning method for use in a data communication system having a first device configured to transmit data to a second device over a communication channel, said method comprising the steps of:

defining a learning sequence descriptor having a training symbol order;

receiving, at said first device, information indicative of said learning sequence descriptor; and

generating a learning signal for transmission from said first device to said second device over said communication channel, said learning signal comprising a number of segments, each of said segments being associated with a sequence of symbols configured in accordance with said learning sequence descriptor;

wherein said training symbol order is indicative of an assignment of a plurality of training symbols to said number of segments.

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Abstract

A modem system includes a programmable synchronization signal format that can be configured at a first modem in response to a request received from a second modem. The synchronization signal format may define a number of parameters of the synchronization signal, such as the sign pattern for symbols transmitted by the first modem during a training sequence. The specific parameters of the synchronization signal format may be associated with the design and operation of the second modem. For example, the particular timing recovery and automatic gain control schemes used by the receiver portion of the second modem may be optimally initialized with a synchronization signal having a specific length, amplitude, or spectrum. In one embodiment, a synchronization signal is configured to convey a single frequency tone for use during a synchronization routine. The modem system may also employ similar techniques to generate, transmit, and analyze a programmable line impairment learning signal. Such a programmable learning signal may be formatted such that characteristics of the communication channel are determined for individual signal points. In response to a particular learning signal, the second modem selects a number of preferred signal points for use by the modem system during subsequent data transmission.

8 Citations

52 Claims

1. A line impairment learning method for use in a data communication system having a first device configured to transmit data to a second device over a communication channel, said method comprising the steps of:
- defining a learning sequence descriptor having a training symbol order;
  
  receiving, at said first device, information indicative of said learning sequence descriptor; and
  
  generating a learning signal for transmission from said first device to said second device over said communication channel, said learning signal comprising a number of segments, each of said segments being associated with a sequence of symbols configured in accordance with said learning sequence descriptor;
  
  wherein said training symbol order is indicative of an assignment of a plurality of training symbols to said number of segments.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18)
- - 2. A method according to claim 1, further comprising the step of transmitting said learning signal over said communication channel from said first device to said second device.
  - 3. A method according to claim 1, further comprising the step of sending said information from said second device to said first device.
  - 4. A method according to claim 1, wherein said receiving step and said generating step are performed during a start-up procedure associated with said data communication system.
  - 5. A method according to claim 1, wherein said defining step defines a sign pattern indicative of the polarity associated with individual symbols within said learning signal.
  - 6. A method according to claim 1, wherein said defining step defines a training pattern indicative of an ordering of a training symbol and a reference symbol within said segments.
  - 7. A method according to claim 6, wherein said defining step defines said reference symbol.
  - 8. A method according to claim 6, wherein said reference symbol is known at said first and second devices prior to said generating step.
  - 9. A method according to claim 6, wherein said reference symbol is associated with a signal point constellation employed by said data communication system for the transmission of data over said communication channel.
  - 10. A method according to claim 1, wherein said defining step defines said training symbol order such that only one training symbol is assigned to each of said segments.
  - 11. A method according to claim 1, wherein said defining step defines said training symbol order such that a unique training symbol is assigned to each of said segments.
  - 12. A method according to claim 1, wherein said training symbols are associated with a signal point constellation employed by said data communication system for the transmission of data over said communication channel.
  - 14. A method according to claim 1, wherein said defining step defines:
    - a number of segments, each of said segments comprising a sequence of symbols in said learning signal;
      
      a length for each of said segments;
      
      a sign pattern indicative of the polarity associated with individual symbols within each of said segments; and
      
      a training pattern indicative of an ordering of one of said training symbols and a reference symbol within each of said segments.
  - 15. A method according to claim 14, wherein at least one of said number, said length, said sign pattern, said training symbol order, and said training pattern is predetermined and known at said first device prior to said receiving step.
  - 16. A method according to claim 14, wherein said length is equal for each of said segments.
  - 17. A method according to claim 14, wherein the length of a current segment is dependent upon the particular one of said training symbols associated with said current segment.
  - 18. A method according to claim 1, wherein said defining step defines a length for each of said segments.

13. A method according to claim i, wherein said defining step defines said learning sequence descriptor such that said learning sequence descriptor is associated with an operational parameter of said second device.

19. A line impairment learning system for use in a data communication system having a first device configured to transmit data to a second device over a communication channel, said line impairment learning system comprising:
- means for storing a learning sequence descriptor at said second device, said learning sequence descriptor conveying a training symbol order;
  
  means for sending information indicative of said learning sequence descriptor from said second device to said first device;
  
  means for generating a learning signal at said first device, said learning signal comprising a number of segments, each of said segments being associated with a sequence of symbols configured in accordance with said learning sequence descriptor, wherein said training symbol order is indicative of an assignment of a plurality of training symbols to said number of segments; and
  
  means for transmitting said learning signal from said first device over said communication channel.
- View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
- - 20. A system according to claim 19, wherein said learning sequence descriptor comprises a sign pattern associated with individual symbols within said sequence of symbols.
  - 21. A system according to claim 20, wherein said sign pattern comprises a number of bits indicating positive polarity and a substantially equal number of bits indicating negative polarity.
  - 22. A system according to claim 19, wherein said learning sequence descriptor comprises a training pattern indicative of an ordering of a training symbol and a reference symbol within said sequence of symbols.
  - 23. A system according to claim 22, wherein said training pattern comprises a number of repeated sub-patterns.
  - 24. A system according to claim 22, wherein said reference symbol is associated with a signal point constellation employed by said data communication system for the transmission of data over said communication channel.
  - 25. A system according to claim 19, wherein said training symbol order is configured such that only one training symbol is assigned to each of said segments.
  - 26. A system according to claim 19, wherein said training symbol order is configured such that a unique training symbol is assigned to each of said segments.
  - 27. A system according to claim 19, wherein said training symbols are associated with a signal point constellation employed by said data communication system for the transmission of data over said communication channel.

28. A receive modem for use in a data communication system having a corresponding transmit modem configured to transmit data to said receive modem over a communication channel, said receive modem comprising:
- means for storing a learning sequence descriptor associated with a predetermined learning signal compatible with said receive modem, wherein said predetermined learning signal comprises a sequence of symbols and said learning sequence descriptor comprises a training pattern indicative of an ordering of a training symbol and a reference symbol within said sequence of symbols;
  
  means for transmitting information indicative of said learning sequence descriptor in response to a control signal received by said receiver unit;
  
  a receiver circuit for receiving at least a portion of a learning signal at said receiver unit, said learning signal being initialized in accordance with said learning sequence descriptor; and
  
  means for analyzing said portion of said learning signal with respect to said predetermined learning signal to thereby obtain data associated with characteristics of said communication channel.
- View Dependent Claims (29, 30, 31, 32)
- - 29. A receive modem according to claim 28, wherein said learning sequence descriptor comprises a sign pattern associated with individual symbols within said sequence of symbols.
  - 30. A receive modem according to claim 28, wherein said reference symbol is associated with a signal point constellation employed by said data communication system for the transmission of data over said communication channel.
  - 31. A receive modem according to claim 28, wherein said learning sequence descriptor comprises a training symbol order indicative of an assignment of a plurality of training symbols to said segments.
  - 32. A receive modem according to claim 31, wherein said training symbols are associated with a signal point constellation employed by said data communication system for the transmission of data over said communication channel.

33. A transmit modem for transmitting data over a communication channel to a corresponding receive modem, said transmit modem comprising:
- means for generating a learning signal in accordance with a learning sequence descriptor, said learning signal comprising a number of segments, each of said segments being represented by a sequence of symbols;
  
  a training symbol assigner configured to assign, in accordance with said leaning sequence descriptor, one of a plurality of training symbols to each of said segments; and
  
  a transmitter for transmitting said learning signal over said communication channel to said receive modem.
- View Dependent Claims (34, 35, 36, 37, 38, 39)
- - 34. A transmit modem according to claim 33, further comprising:
    - a receiver for receiving information associated with said learning sequence descriptor; and
      
      means for recovering said learning sequence descriptor from said information.
  - 35. A transmit modem according to claim 33, wherein said learning sequence descriptor comprises a training pattern indicative of an ordering of a respective training symbol and a reference symbol within each of said sequence of symbols.
  - 36. A transmit modem according to claim 35, wherein said reference symbol is associated with a signal point constellation employed by said transmit modem for the transmission of data over said communication channel.
  - 37. A transmit modem according to claim 33, wherein said learning sequence descriptor comprises a training symbol order indicative of an assignment of said training symbols to said segments.
  - 38. A transmit modem according to claim 37, wherein said training symbol order is configured such that a unique training symbol is assigned to each of said segments.
  - 39. A transmit modem according to claim 33, wherein said training symbols are associated with a signal point constellation employed by said transmit modem for the transmission of data over said communication channel.

40. A line impairment learning arrangement for use in a data communication system having a first device configured to transmit data to a second device over a communication channel, said line impairment learning arrangement comprising:
- first means for transmitting a learning signal from said first device to said second device over said communication channel, said learning signal comprising data points selected from a signal point constellation employed by said data communication system;
  
  means for receiving at least a portion of said learning signal at said second device;
  
  means for analyzing characteristics of said portion of said learning signal received at said second device, said means for analyzing being configured to determine a plurality of preferred data points on a point-by-point basis, said preferred data points being used by said data communication system during transmission of data over said communication channel; and
  
  second means for transmitting information indicative of said preferred data points from said second device to said first device.
- View Dependent Claims (41, 42, 43, 44, 45)
- - 41. A learning arrangement according to claim 40, further comprising means for generating said learning signal at said first device in accordance with a learning sequence descriptor.
  - 42. A learning arrangement according to claim 41, further comprising means for storing said learning sequence descriptor at said second device, wherein said second means for transmitting is further configured to transmit information indicative of said learning sequence descriptor from said second device to said first device.
  - 43. A learning arrangement according to claim 40, wherein:
    - said learning signal comprises a number of segments, each of said segments comprising a sequence of symbols; and
      
      each of said segments contains a single training symbol utilized by said means for analyzing to determine said preferred data points.
  - 44. A learning arrangement according to claim 43, wherein each of said segments contains a reference symbol.
  - 45. A learning arrangement according to claim 40, wherein:
    - said learning signal comprises a number of segments, each of said segments comprising a sequence of symbols; and
      
      each of said segments contains a unique training symbol utilized by said means for analyzing to determine said preferred data points.

46. A synchronization method for use in a pulse code modulation (PCM) data communication system having a first device configured to transmit data at a symbol rate to a second device, said method comprising the steps of:
- generating a synchronization signal segment at said first device for transmission to said second device, said synchronization signal segment comprising a repetitive sequence of symbols associated with a signal point constellation employed by said PCM data communication system, said synchronization signal segment being configured to convey a single frequency tone;
  
  receiving said synchronization signal segment at said second device; and
  
  performing a synchronization routine at said second device in response to said synchronization signal segment.
- View Dependent Claims (47, 48, 49, 50, 51, 52)
- - 47. A synchronization method according to claim 46, further comprising the steps of:
    - generating a secondary synchronization signal segment at said first device for transmission to said second device after said synchronization signal segment;
      
      receiving said secondary synchronization signal segment at said second device; and
      
      performing a secondary synchronization routine at said second device in response to said secondary synchronization signal segment.
  - 48. A synchronization method according to claim 46, wherein said preliminary synchronization signal segment is configured to convey a single frequency tone combined with a single frequency band-edge tone different than said single frequency tone.
  - 49. A synchronization method according to claim 46, wherein:
    - said sequence of symbols contains four symbols;
      
      said sequence of symbols is defined by a symbol pattern +A, +A, −
      
      A, −
      
      A; and
      
      A represents the amplitude of one symbol contained in said signal point constellation.
  - 50. A synchronization method according to claim 46, wherein:
    - said sequence of symbols contains four symbols;
      
      said sequence of symbols is defined by a symbol pattern +A, B, −
      
      A, B;
      
      A and B represent the amplitudes of a first symbol and a second symbol, respectively, contained in said signal point constellation; and
      
      B is approximately equal to zero.
  - 51. A synchronization method according to claim 46, wherein:
    - said sequence of symbols contains four symbols;
      
      said sequence of symbols is defined by a symbol pattern +A, +C, −
      
      C, −
      
      A;
      
      A and C represent the amplitudes of a first symbol and a second symbol, respectively, contained in said signal point constellation; and
      
      C is approximately equal to 3A.
  - 52. A synchronization method according to claim 46, wherein:
    - said sequence of symbols contains six symbols;
      
      said sequence of symbols is defined by a symbol pattern +A, +A, +A, −
      
      A, −
      
      A, −
      
      A; and
      
      A represents the amplitude of one symbol contained in said signal point constellation.

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Current Assignee
Modern Telecom Systems, LLC (Ideahub, Inc.)
Original Assignee
Conexant Systems Incorporated (Synaptics Incorporated)
Inventors
OLAFSSON, SVERRIR

Granted Patent

US 6,332,009 B2
Time in Patent Office

Days
Field of Search
US Class Current

375/354
CPC Class Codes

H04L 25/4927 using levels matched to the...

METHOD AND APPARATUS FOR GENERATING A LINE IMPAIRMENT LEARNING SIGNAL FOR A DATA COMMUNICATION SYSTEM

First Claim

11 Assignments

0 Petitions

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Abstract

8 Citations

52 Claims

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METHOD AND APPARATUS FOR GENERATING A LINE IMPAIRMENT LEARNING SIGNAL FOR A DATA COMMUNICATION SYSTEM

First Claim

11 Assignments

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0 Petitions

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Accused Products

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Abstract

8 Citations

52 Claims

Specification

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Solutions

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