Method and apparatus for quick modem reconnect

• US 6,768,791 B1
• Filed: 09/10/1999
• Issued: 07/27/2004
• Est. Priority Date: 04/12/1999
• Status: Expired due to Fees

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: PCTEL, Inc.
• Inventors: Beadle, Burk, Olafsson, Sverrir
• Primary Examiner(s): Eng, George
• Application Number:
  US09/394,018
• Time in Patent Office: 1,782 Days
• Field of Search: 379/93.01, 379/93.05, 379/93-8-, 379/93-1-, 379/100.15, 375/222, 375/231, 348/14.01
• US Class Current: 379/93.32
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation
• CPC Class Codes: H04L 27/02 Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence
• CPC Class Codes: H04L 5/1438 Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 11/00 Telephonic communication systems specially adapted for combination with other electrical systems
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 11/066 Telephone sets adapted for data transmision

Abstract

A quick startup procedure for a modem system utilizes known characteristics of a previously established communication channel to reduce the initialization period associated with subsequent connections over the same channel. In response to the establishment of a call, the modem devices determine whether the quick connect protocol is supported. If so, then the called modem transmits a modified answer tone to the calling modem. The calling modem analyzes the signal received in response to the modified answer tone to determine whether characteristics of the current channel are similar to stored characteristics associated with a previous connection over the same channel. If a channel “match” is found, then the modem devices carry out a quick initialization routine that eliminates, abbreviates, or modifies a number of procedures or protocols that are carried out in conventional modem startup processes. The general quick startup techniques may also be applied in the context of a quick reconnect procedure that can be performed in response to a temporary pausing or disconnecting of the data modem mode.

Claims

1. A method of reducing time for use by a first modem to connect to a second modem via a communication channel, said method comprising the steps of:

receiving a first digital impairment learning sequence from said second modem over said communication channel;

determining first one or more digital impairment attributes of said communication channel based on analyzing said first digital impairment learning sequence;

storing said first one or more digital impairment attributes of said communication channel at said first modem;

obtaining one or more parameters for initializing said first modem for connection over said communication channel;

storing said one or more parameters at said first modem;

interrupting said communication channel;

terminating said interrupting;

receiving an ANSpcm signal from said second modem;

determining second one or more digital impairment attributes of said communication channel based on analyzing said ANSpcm signal; and

initializing said first modem with said one or more parameters to reconnect to said second modem if said first one or more digital impairment attributes are similar to corresponding said second one or more digital impairment attributes.

2. The method according to claim 1, wherein said interrupting disconnects said first modem from said second modem.

3. The method according to claim 2, wherein said terminating includes dialing a phone number associated with said second modem.

4. The method according to claim 1, wherein said interrupting places communication between said first modem and second modem on hold.

5. The method according to claim 4, wherein said terminating is performed without dialing a phone number associated with said second modem.

6. The method according to claim 1, wherein said first one or more digital impairment attributes include first points/levels, and second one or more digital impairment attributes include second points/levels, wherein similarity is determined by comparing said first points/levels with said second points/levels.

7. The method according to claim 1, wherein said one or more of parameters comprise data associated with a signal point constellation for said first modem.

8. The method according to claim 1, wherein said one or more of parameters comprise data associated with echo canceler settings for said first modem.

9. The method according to claim 1, wherein said one or more of parameters comprise data associated with power level settings for said first modem.

10. The method according to claim 1, wherein said one or more of parameters comprise data associated with equalizer settings for said first modem.

11. A method of reducing time for use by a first modem to connect to a second modem via a communication channel, said first modem being configured to maintain one or more initialization parameters associated with said communication channel, said method comprising the steps of:

receiving a first digital impairment learning sequence from said second modem over said communication channel;

determining first one or more digital impairment attributes of said communication channel based on analyzing said first digital impairment learning sequence;

storing said first one or more digital impairment attributes of said communication channel;

interrupting said communication channel;

transmitting a reconnect indication after said interrupting;

receiving an ANSpcm signal from said second modem in response to said reconnect indication;

determining second one or more digital impairment attributes of said communication channel based on analyzing said ANSpcm signal; and

initializing said first modem with said one or more parameters to reconnect to said second modem if said first one or more digital impairment attributes are similar to corresponding said second one or more digital impairment attributes.

12. The method according to claim 11 further comprising a step of receiving a reply signal prior to said receiving said ANSpcm signal, wherein said reply signal comprising a transition sequence configured to enable said first modem to determined robbed bit signaling characteristics of said communication channel.

13. The method according to claim 12, wherein said determining step further determines said second one or more digital impairment attributes of said communication channel based on analyzing a signal point sequence of said reply signal.

14. The method according to claim 13, wherein said signal point sequence comprises a sequence of pulse code modulation signal points.

15. The method according to claim 12, wherein said transition sequence comprises positive and negative value of at least one signal point.

16. The method according to claim 11, wherein said first one or more digital impairment attributes includes first points/levels, and second one or more digital impairment attributes include second points/levels, wherein similarity is determined by comparing said first points/levels with said second points/levels.

17. The method according to claim 11, wherein said one or more of initialization parameters comprises data associated with a signal point constellation for said first modem.

18. The method according to claim 11, wherein said one or more of initialization parameters comprises data associated with echo canceler settings for said first modem.

19. The method according to claim 11, wherein said one or more of initialization parameters comprises data associated with power level settings for said first modem.

20. A first modem configured to communicate with a second modem over a communication channel, said first modem comprising:

a memory element configured to store first one or more digital impairment attributes of said communication channel and further store one or more parameters for initializing said first modem for connection over said communication channel;

a receiver section configured to receive a first digital impairment learning sequence from said second modem, and further receive an ANSpcm signal from said second modem over said communication channel in response to a request transmitted by said first modem over said communication channel to terminate a temporary interruption in said communication channel; and

a processor element configured to analyze said first digital impairment learning sequence to determine said first one or more digital impairment attributes of said communication channel and store said one or more digital impairment attributes in said memory, and to initialize said first modem with said one or more parameters in response to said ANSpcm signal if said processor determines that second one or more digital impairment attributes of said communication channel based on analyzing said ANSpcm signal are similar to said first one or more digital impairment attributes.

21. The first modem according to claim 20, wherein said first one or more digital impairment attributes include first points/levels, and said second one or more digital impairment attributes include second points/levels, and wherein said processor element determines similarity by comparing said first points/levels with said second points/levels.

22. The first modem according to claim 20, wherein said first modem is compatible with ITU-T Recommendation V.90.

23. The method according to claim 20, wherein said one or more of parameters comprise data associated with a signal point constellation for said first modem.

24. The first modem according to claim 20, wherein said one or more of parameters comprise data associated with echo canceler settings for said first modem.

25. The first modem according to claim 20, wherein said one or more of parameters comprise data associated with power level settings for said first modem.

26. The first modem according to claim 20, wherein said one or more of parameters comprise data associated with equalizer settings for said first modem.

27. A computer readable medium including computer software program executable by a processor in a first modem for implementing a method of reducing time for use by the first modem to connect with a second modem over a communication channel, said computer software program comprising

code for receiving a first digital impairment learning sequence from said second modem;

code for determining first one or more digital impairment attributes of said communication channel based on analyzing said first digital impairment learning sequence;

code for storing said first one or more digital impairment attributes of said communication channel;

code for obtaining one or more parameters for initializing said first modem for connection over said communication channel;

code for storing said one or more parameters associated with initializing said first modem;

code for interrupting said communication channel;

code for terminating said interrupting;

code for receiving an ANSpcm_signal over said communication channel in response to said terminating;

code for determining second one or more digital impairment attributes of said communication channel based on analyzing said ANSpcm signal; and

code for initializing said first modem with said one or more parameters to reconnect to said second modem if said first one or more digital impairment attributes are similar to corresponding said second one or more digital impairment attributes.

28. The computer software program of claim 27, wherein said code for interrupting disconnects said first modem from said second modem.

29. The computer software program of claim 28, wherein said code for terminating includes dialing a phone number associated with said second modem.

30. The computer software program of claim 27, wherein said code for interrupting places communication between said first modem and said second modem on hold.

31. The computer software program of claim 30, wherein said code for terminating is performed without dialing a phone number associated with said second modem.

32. The computer software program of claim 27, wherein said one or more parameters include a receiver parameter.

33. The computer software program of claim 27, wherein said one or more stored parameters include a parameter associated with said communication channel.

34. A first modem configured to communicate with a second modem over a communication channel, said first modem comprising:

a memory element configured to store first one or more digital impairment attributes of said communication channel and further store one or more parameters for initializing said first modem for connection over said communication channel;

a receiver section configured to receive a first digital impairment learning sequence from said second modem, and further receive an ANSpcm signal from said second modem over said communication channel in response to terminating an interruption in said communication channel by said first modem; and

a processor element configured to analyze said first digital impairment learning sequence to determine said first one or more digital impairment attributes of said communication channel and store said one or more digital impairment attributes in said memory, and to initialize said first modem with said one or more parameters in response to said ANSpcm signal if said processor determines that second one or more digital impairment attributes of said communication channel based on analyzing said ANSpcm signal are similar to said first one or more digital impairment attributes.

35. The first modem according to claim 34, wherein said interruption disconnects said first modem from said second modem.

36. The first modem according to claim 35, wherein said terminating includes dialing a phone number associated with said second modem.

37. The first modem according to claim 34, wherein said interruption places communication between said first modem and second modem on hold.

38. The first modem according to claim 34, wherein said terminating is performed without dialing a phone number associated with said second modem.

39. The first modem according to claim 34, wherein said first one or more digital impairment attributes include first points/levels, and second one or more digital impairment attributes include second points/levels, wherein similarity is determined by comparing said first points/levels with said second points/levels.

40. The first modem according to claim 34, wherein said one or more of parameters comprise data associated with a signal point constellation for said first modem.

41. The first modem according to claim 34, wherein said one or more of parameters comprise data associated with echo canceler settings for said first modem.

42. The first modem according to claim 34, wherein said one or more of parameters comprise data associated with power level settings for said first modem.

43. The first modem according to claim 34, wherein said one or more of parameters comprise data associated with equalizer settings for said first modem.