Fast retrain based on communication profiles for a digital modem

• US 6,345,071 B1
• Filed: 09/11/1998
• Issued: 02/05/2002
• Est. Priority Date: 07/24/1998
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Hamdi, Rabah S.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): JIANG, LENNY R
• Application Number:
  US09/151,261
• Time in Patent Office: 1,243 Days
• Field of Search: 375/222, 375/224, 375/225, 375/226, 375/227, 375/228, 370/252
• US Class Current: 375/222
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/1438 Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001

Abstract

A digital modem for operating in a splitterless environment that supports fast retrain based on communication profiles. The modem includes a memory that stores a plurality of communication profiles, ADSL communication logic that sends and receives information via a phone line and that operates according to any one of the plurality of communication profiles, and signal quality monitor logic that continuously monitors communication on the phone line. The monitor logic provides a signal change indication if the signal quality changes by at least a predetermined amount. The modem further includes fast retrain logic that selects another one of the profiles stored in the memory in response to the signal change indication, that retrains the communication logic to operate according to the selected profile and that cooperates with the communication logic to transmit a fast retrain indication via the phone line to the central office ADSL modem. The digital modem may also include training or measurement logic that determines the communication characteristics of the phone line, that generates a corresponding profile and that sends the new profile to the other modem via the phone lines.

Claims

1. A digital modem for coupling to a transmission medium, comprising:

a memory that stores a plurality of communication profiles;

communication logic that sends and receives information via the transmission medium and that operates according to any one of the plurality of communication profiles;

monitor logic that continuously monitors communication by the communication logic on the transmission medium according to any one of the plurality of communication profiles and that provides a signal change indication if the communication characteristics change by at least a predetermined amount; and

fast retrain logic that selects another one of the plurality of communication profiles stored in the memory in response to the signal change indication, that retrains the communication logic to operate according to the selected communication profile and that cooperates with the communication logic to transmit a fast retrain indication via the transmission medium.

2. The digital modem of claim 1, further comprising:

measuring logic that cooperates with the communication logic to measure the communication characteristics of the transmission medium and that generates and stores a corresponding communication profile into the memory; and

each of the plurality of communication profiles being measured and stored by the measuring logic in cooperation with the communication logic.

3. The digital modern of claim 2, further comprising:

the fast retrain logic receiving the signal change indication and determining that none of the plurality of communication profiles is valid based on the communication characteristics and providing a new profile indication;

the measuring logic receiving the new profile indication, cooperating with the communication logic to measure the communication characteristics of the transmission medium and generating and storing a corresponding new communication profile into the memory; and

the measuring logic cooperating with the communication logic to send the new communication profile via the transmission medium.

4. The digital modem of claim 1, wherein the fast retrain indication is tone based.

5. The digital modem of claim 4, further comprising:

the fast retrain indication comprising a plurality of tones that provides an index to the plurality of communication profiles.

6. A digital modem system, comprising:

a transmission medium;

a first modem, coupled to the transmission medium, comprising;

a first memory that stores a plurality of communication profiles;

communication logic that sends and receives information via the transmission medium and that operates according to any one of the plurality of communication profiles;

monitor logic that continuously monitors communication by the communication logic on the transmission medium according to any one of the plurality of communication profiles and that provides a signal change indication if the communication characteristics change by at least a predetermined amount; and

first fast retrain logic that selects another one of the plurality of communication profiles stored in the memory in response to the signal change indication, that retrains the communication logic to operate according to the selected communication profile and that cooperates with the communication logic to transmit a fast retrain indication via the transmission medium; and

a second modem, coupled to the transmission medium, comprising;

a second memory that stores the plurality of profiles;

second communication logic that receives and operates according to any communication profile sent by the first modem; and

second fast retrain logic that, upon detecting the fast retrain indication sent by the first modem, retrains the second communication logic to operate according to the selected communication profile.

7. The digital modem system of claim 6, further comprising:

the first memory and the second memory storing at least a first and a second communication profile;

the first and second communication logic operating according to the second communication profile;

the monitor logic detecting the communication characteristics improve by at least the predetermined amount and providing the signal change indication;

the first fast retrain logic retraining the first communication logic to operate according to the first communication profile and cooperating with the first communication logic to transmit a fast retrain indication via the transmission medium to the second modem; and

the second modem receiving the fast retrain indication and the second fast retrain logic retraining the second communication logic to operate according to the first communication profile.

8. The digital modem system of claim 7, further comprising:

the monitor logic detecting the communication characteristics depreciate by at least the predetermined amount and providing the signal change indication;

the first fast retrain logic retraining the first communication logic to operate according to the second communication profile and cooperating with the communication logic to transmit a fast retrain indication via the transmission medium; and

the second modem receiving the fast retrain indication and the second fast retrain logic retraining the second communication logic to operate according to the second communication profile.

9. The digital modem of claim 7, further comprising:

the monitor logic detecting the communication characteristics depreciate by at least the predetermined amount and providing the signal change indication;

the first fast retrain logic determining that that first and second communication profiles are not suitable and providing a new profile indication;

measurement logic, in response to the new profile indication, that cooperates with the first communication logic to measure the communication characteristics of the transmission medium and that generates and stores a corresponding third communication profile into the memory;

the measurement logic training the first communication logic to operate according to the third communication profile and cooperating with the first communication logic to transmit the third communication profile via the transmission medium; and

the second modem receiving and storing the third communication profile into the second memory and retraining the second communication logic to operate according to the third communication profile.

10. The digital modem of claim 9, wherein the third communication profile replaces the second communication profile and wherein the fast retrain indication comprises a single tone.

11. The digital modem of claim 9, wherein the first memory stores the first, second and third communication profiles and wherein the fast retrain indication comprises a plurality of tones to provide a binary index to the plurality of communication profiles.

12. The digital modem of claim 6, further comprising:

the first modem including measuring logic that cooperates with the first communication logic to measure the communication characteristics of the transmission medium upon initialization and that generates and stores a corresponding first communication profile into the first memory;

the measurement logic cooperating with the first communication logic to send the first communication profile to the second modem via the transmission medium;

the measurement logic calculating at least one more communication profile based on the first communication profile and a predetermined cutback amount and storing the at least one more communication profile in the first memory;

the second modem receiving and storing the first communication profile; and

the second modem independently calculating the at least one more communication profile based on the first communication profile and the predetermined cutback amount and storing the at least one more communication profile in the second memory.