Method of establishing signaling rate for single-line digital subscriber link providing extended range ADSL service with auxiliary pots channel

• US 6,539,081 B2
• Filed: 07/20/2001
• Issued: 03/25/2003
• Est. Priority Date: 07/20/2001
• Status: Expired due to Term

• Current Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Original Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Inventors: Zakrzewski, Jon Thomas, Barrett, Robert Allen, Ballard, Thomas L. III, Wilkes, John B. Jr.
• Primary Examiner(s): Ramakrishnaiah, Melur
• Application Number:
  US09/910,699
• Publication Number:
  US 20030016797A1
• Time in Patent Office: 613 Days
• Field of Search: 379/93.32, 379/93.33, 379/93.28, 379/90.01, 379/93.01, 379/93.05, 379/93.08, 379/93.09, 375/222, 375/225
• US Class Current: 379/93.32
• CPC Class Codes: H04L 47/10 Flow control; Congestion control

Abstract

An autobaud mechanism is executed by transceivers coupled to opposite ends of a communication loop, such as an extended range SDSL loop, to resolve the maximum data rate that can be supported by the loop, using signal power and quality measurements to first estimate the length of the SDSL loop and thereafter iteratively adjust baud rate and/or number of bits/per baud, as necessary, to realize an SDSL baud rate that will ensure error-free transmission over the loop.

Claims

1. For use with a telecommunication network, a method of establishing the baud rate of data communications over a communication link between said first and second sites comprising the steps of:

(a) at said first site, applying a stimulus to said communication link;

(b) at said second site, estimating an initial baud rate to be employed for a data communication session between said first and second sites in accordance with a response of said communication link to said stimulus being applied thereto in step (a);

(c) conducting a link-training communication session between said first and second sites, beginning with said initial baud rate estimated in step (b), and proceeding through one or more lower baud rates, as necessary, until said communication link exhibits an acceptable performance at the baud rate employed;

(d) in response to said communication link exhibiting an acceptable performance in step (c), measuring signal quality of said communication link; and

(e) in response to the signal quality measured in step (d) being at least a prescribed signal quality, establishing the baud rate realized in step (c) to be used for data communications between said first and second sites, and wherein

step (a) comprises transmitting a predetermined signal over said communication link from said first site to said second site, and step (b) comprises measuring an attribute of said predetermined signal as received at said second site, and estimating said initial baud rate to be employed for a data communication session between said first and second sites in accordance with the measured attribute of said predetermined signal,

step (b) comprises determining the length of said communication link between said first and second sites in accordance with the measured attribute of said predetermined signal as received at said second site, and estimating said initial baud rate to be employed for a data communication session between said first and second sites in accordance with the determined length of said communication link,

step (c) comprises conducting a link-training communication session between said first and second sites, beginning with a first baud rate, and proceeding through one or more lower baud rates, as necessary, until said communication link exhibits an acceptable performance at the baud rate employed, and wherein step (e) comprises, in response to the signal quality measured in step (d) being at least said prescribed signal quality, establishing the baud rate to be used for data communications between said first and second sites as that for which said communication link exhibits an acceptable performance at the baud rate employed,

step (e) further includes in response to the signal quality measured in step (d) being less than said prescribed signal quality, modifying an attribute of said baud rate, and repeating steps (c)-(d), as necessary, until the measured signal quality is at least said prescribed signal quality, and establishing the baud rate to be used for data communications between said first and second sites, as the baud rate at which at least said prescribed signal quality has been realized, and

step (e) comprises, in response to the signal quality measured in step (d) being less than said prescribed signal quality, modifying the number of bits per baud and repeating steps (c)-(d), as necessary, until the measured signal quality is at least said prescribed signal quality, and establishing the baud rate to be used for data communications between said first and second sites, as the baud rate at which at least said prescribed signal quality has been realized.

2. The method according to claim 1, further including the step (f) of conducting a data communication session between said first and second sites at the baud rate established in step (e).

3. The method according to claim 2, wherein said communication link comprises a single-line digital subscriber line (SDSL) link, and wherein step (f) comprises conducting said data communication session by transporting asymmetric digital subscriber line (ADSL) and digital plain old telephone service (POTS) data signals over said SDSL link.

4. The method according to claim 1, wherein step (e) further includes, in response to the signal quality measured in step (d) being less than said prescribed signal quality, modifying an attribute of the baud rate, repeating steps (c)-(d), as necessary, until the measured signal quality is at least said prescribed signal quality, and establishing the baud rate to be used for data communications between said first and second sites, as the baud rate at which at least said prescribed signal quality has been realized.

5. The method according to claim 4, further including the step (f) of conducting a data communication session between said first and second sites at the baud rate established in step (e).

6. The method according to claim 1, wherein said communication link comprises a single-line digital subscriber line (SDSL).

7. The method according to claim 1, wherein step (e) further includes measuring signal quality of said communication link during said data communication session and in responsive to the signal quality measured during said data communication session being less than said prescribed signal quality, modifying an attribute of the baud rate and repeating steps (c)-(d), as necessary, until the measured signal quality is at least said prescribed signal quality, and establishing the baud rate for a communication session between said first and second sites as the baud rate exhibiting at least said prescribed signal quality.

8. The method according to claim 7, wherein step (e) comprises, in response to the signal quality measured during said data communication session being less than said prescribed signal quality, modifying the number of bits per baud and repeating steps (c)-(d), as necessary, until the measured signal quality is at least said prescribed signal quality, and conducting said data communication session at the baud rate and number of bits per baud exhibiting at least said prescribed signal quality.

9. For use with an asymmetrical digital subscriber line (ADSL) communication system, having an upstream transceiver coupled to an upstream ADSL communication device that provides access to one or more digital communication resources of a telecommunication network, said upstream transceiver being coupled over a communication link to a downstream transceiver, said downstream transceiver being coupled to a customer premises equipment ADSL communication device, a method of establishing a communication baud rate to be employed by said upstream and downstream transceivers for digital communications over said communication link, said method comprising the steps of:

(a) transmitting a signal from one of said upstream and downstream transceivers over said communication link to the other of said upstream and downstream transceivers;

(b) at said other transceiver, estimating an initial baud rate capable of being supported by said communication link in accordance with a property of said signal as received by said other receiver;

(c) conducting a link-training communication session between said one and other transceivers, beginning with said initial baud rate estimated in step (b), and proceeding through one or more lower baud rates, as necessary, until said communication link exhibits an acceptable performance at the signaling rate employed;

(d) in response to said communication link exhibiting an acceptable performance in step (c), measuring signal quality of said communication link; and

(e) in response to the signal quality measured in step (d) being at least a prescribed signal quality, establishing the baud rate realized in step (c) to be used for data communications between said upstream and downstream transceivers, and wherein

step (e) further includes, in response to the signal quality measured in step (d) being less than said prescribed signal quality, modifying the number of bits per baud and repeating steps (c)-(d), as necessary, until the measured signal quality is at least said prescribed signal quality, and establishing the baud rate to be used for data communications between said upstream and downstream transceivers, as the baud rate at which at least said prescribed signal quality has been realized.

10. The method according to claim 9, wherein step (b) comprises estimating the length of said communication link between said first and second sites in accordance with a measured attribute of said signal as received by said other transceiver, and estimating a baud rate supportable by said communication link in accordance with the estimated length of said communication link.

11. The method according to claim 9, wherein said communication link comprises a single-line digital subscriber line (SDSL) link, and further including the step (f) of transporting, over said SDSL link between said upstream and downstream transceivers, a digital data signal containing a composite of an asymmetric digital subscriber line (ADSL) channel and a digital plain old telephone service (POTS) channel, at the baud rate established in step (e).

12. The method according to claim 11, wherein said communication link comprises a single-line digital subscriber line (SDSL) link, said upstream transceiver is adapted to combine a downstream ADSL channel provided by an upstream ADSL communication device with a downstream digital plain old telephone system (POTS) channel into a composite downstream digital signal for transmission at said established baud rate over said communication link from an upstream site thereof, and wherein said downstream transceiver is coupled to a dowmstream site of said communication link that is remote with respect to said upstream site, and is adapted to receive said composite downstream digital signal transmitted over said communication link from said upstream transceiver at said established baud rate, and to extract from said composite downstream digital signal said downstream digital POTS channel for delivery to a downstream POTS device, and said downstream ADSL channel for delivery to a downstream ADSL communication device.