Method and apparatus for fast V.90 modem startup

• US 20040146148A1
• Filed: 01/08/2004
• Published: 07/29/2004
• Est. Priority Date: 04/12/1999
• Status: Active Grant

• Current Assignee: Modern Telecom Systems, LLC (Ideahub, Inc.)
• Original Assignee: Mindspeed Technologies Inc. (MACOM Technology Solutions Holdings, Inc.)
• Inventors: Beadle, Burk, Chu, Keith, Olafsson, Sverrir
• Granted Patent: US 7,062,022 B2
• Time in Patent Office: Days
• 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 fast 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 fast 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 fast initialization routine that eliminates, abbreviates, or modifies a number of procedures or protocols that are carried out in conventional modem startup processes.

Claims

1. A method for reducing startup latency associated with a data transmission system having a first device configured to communicate with a second device over a communication channel, said method comprising the steps of:

establishing a call between said first device and said second device;

determining whether a characteristic of said communication channel is similar to a corresponding characteristic associated with a previously established communication channel; and

initializing at least one of said first and second devices in response to a number of stored parameters associated with said previously established communication channel, said initializing step being performed if said determining step determines that said characteristic is similar to said corresponding characteristic.

2. A method according to claim 1, further comprising the step of ascertaining, for said call, whether said first device and said second device support a fast connect protocol, said ascertaining step being performed prior to said determining and initializing steps.

3. A method according to claim 1, wherein said determining step comprises the steps of:

transmitting a signal point sequence from said first device to said second device;

obtaining a received sequence at said second device, said received sequence being related to said signal point sequence; and

comparing attributes of said received sequence with stored attributes of a previously received sequence associated with said previously established communication channel.

4. A method according to claim 3, wherein said signal point sequence comprises a sequence of pulse code modulation signal points.

5. A method according to claim 3, wherein said signal point sequence is predetermined and known at said first device and at said second device.

6. A method according to claim 1, wherein:

at least a portion of said initializing step is performed at an initial data rate; and

said method further comprises the step of entering a data mode at a full data rate, said entering step being performed after said initializing step.

7. A method according to claim 1, further comprising the step of identifying at least one signal point for use by said first device in a transition sequence, said at least one signal point being capable of highlighting the presence of digital impairments in said communication channel.

8. A method according to claim 1, further comprising the steps of:

conducting final training of at least one of said first and second devices during a time period, said conducting step being performed after said determining step; and

exchanging authentication information between said first and second devices during said time period.

9. A method according to claim 8, wherein said exchanging step is performed in accordance with the Password Authentication Protocol (“

PAP”

) or in accordance with the Challenge Handshake Authentication Protocol (“

CHAP”

).

10. A method according to claim 1, wherein said determining step determines whether digital impairments associated with said communication channel are similar to digital impairments associated with said previously established communication channel.

11. A method for reducing startup latency associated with a data transmission system having a first device configured to communicate with a second device over a communication channel, said method comprising the steps of:

establishing a call between said first device and said second device;

determining whether a characteristic of said communication channel is similar to a corresponding characteristic associated with a previously established communication channel;

training at least one of said first and second devices at an initial data rate during a first time period; and

exchanging authentication information between said first and second devices during said time period, said exchanging step being performed if said determining step determines that said characteristic is similar to said corresponding characteristic.

12. A method according to claim 11, further comprising the step of initializing at least one of said first and second devices in response to a number of stored parameters associated with said previously established communication channel, said initializing step being performed if said determining step determines that said characteristic is similar to said corresponding characteristic.

13. A method according to claim 11, further comprising the step of ascertaining, for said call, whether said first device and said second device support a fast connect protocol, said ascertaining step being performed prior to said determining, training, and exchanging steps.

14. A method according to claim 11, wherein said determining step comprises the steps of:

transmitting a signal point sequence from said first device to said second device;

obtaining a received sequence at said second device, said received sequence being related to said signal point sequence; and

comparing attributes of said received sequence with stored attributes of a previously received sequence associated with said previously established communication channel.

15. A method according to claim 11, further comprising the step of identifying at least one signal point for use by said first device in a transition sequence, said at least one signal point being capable of enabling said second device to detect digital impairments present in said communication channel.

16. A method according to claim 11, wherein said exchanging step is performed in accordance with the Password Authentication Protocol (“

PAP”

) or in accordance with the Challenge Handshake Authentication Protocol (“

CHAP”

).

17. A method according to claim 11, wherein:

said training step comprises the step of transmitting scrambled digital data between said first and second devices; and

said authentication information exchanged during said exchanging step is associated with said scrambled digital data.

18. A method according to claim 17, wherein said scrambled digital data comprises said authentication information.

19. A method according to claim 11, wherein said determining step determines whether digital impairments associated with said communication channel are similar to digital impairments associated with said previously established communication channel.

20. A data transmission device comprising:

a receiver section configured to receive communication signals transmitted by a remote device;

a transmitter section configured to transmit communication signals to said remote device and to transmit a fast connect identifier in response to the establishment of a call associated with a current communication channel, said current communication channel having a first channel characteristic associated therewith;

a memory element configured to store a second channel characteristic associated with a previously established communication channel; and

a processor element configured to determine whether said first channel characteristic is similar to said second channel characteristic, said processor being further configured to trigger a fast startup routine in response to a validation of said first channel characteristic with said second channel characteristic.

21. A device according to claim 20, wherein:

said receiver section is configured to obtain a received sequence related to a signal point sequence transmitted by said remote device; and

said processor element is configured to compare attributes of said received sequence with stored attributes of a previously received sequence associated with said previously established communication channel.

22. A device according to claim 20, wherein said transmitter is further configured to transmit a signal point identifier that identifies at least one signal point for use by said remote device in a transition sequence, said at least one signal point being capable of highlighting the presence of digital impairments in said current communication channel.

23. A device according to claim 22, wherein said transmitter is configured to transmit said fast connect identifier and said signal point identifier as one sequence.

24. A device according to claim 20, wherein said receiver is further configured to receive a fast connect acknowledgment from said remote device, said fast connect acknowledgment being generated in response to said fast connect identifier.

25. A device according to claim 20, wherein said processor element is further configured to initialize said receiver section in response to a number of stored parameters associated with said previously established communication channel, wherein an initialization of said receiver section occurs if said processor element determines that said first channel characteristic is similar to said second channel characteristic.

26. A device according to claim 20, wherein said processor element is further configured to train said receiver section at an initial data rate and to exchange authentication information with said remote device during a first time period, wherein an exchange of authentication information with said remote device occurs if said processor element determines that said first channel characteristic is similar to said second channel characteristic.

27. A device according to claim 26, wherein said exchange of authentication information is performed in accordance with the Password Authentication Protocol (“

PAP”

) or in accordance with the Challenge Handshake Authentication Protocol (“

CHAP”

).

28. A method according to claim 26, wherein:

said receiver section is trained in response to scrambled digital data transmitted by said remote device; and

said authentication information is associated with said scrambled digital data.

29. A data transmission device comprising:

a receiver section configured to receive communication signals transmitted by a remote device and to receive a fast connect identifier in response to the establishment of a call associated with a current communication channel, said current communication channel having a first channel characteristic associated therewith;

a transmitter section configured to transmit communication signals to said remote device and to transmit a signal point sequence if said receiver section receives said fast connect identifier, said signal point sequence being configured to identify said first channel characteristic to said remote device; and

a processor element configured to trigger a fast startup routine in response to a validation of said first channel characteristic with a second channel characteristic associated with a previously established communication channel.

30. A device according to claim 29, wherein said receiver section is further configured to receive a signal point identifier that identifies at least one signal point for use in a transition sequence, said at least one signal point being capable of illuminating digital impairments present in said current communication channel.

31. A device according to claim 29, wherein said transmitter section is further configured to transmit said transition sequence, said transition sequence comprising positive and negative values of said at least one signal point.

32. A device according to claim 29, wherein said signal point sequence transmitted by said transmitter section comprises a sequence of pulse code modulation signal points.

33. A device according to claim 29, wherein:

said transmitter section is further configured to transmit a training sequence to said remote device at an initial data rate during a first time period;

said processor element is further configured to exchange authentication information with said remote device during said first time period; and

an exchange of authentication information with said remote device occurs if said processor element determines that said first channel characteristic is similar to said second channel characteristic.

34. A device according to claim 33, wherein said exchange of authentication information is performed in accordance with the Password Authentication Protocol (“

PAP”

) or in accordance with the Challenge Handshake Authentication Protocol (“

CHAP”

).