Automated system and method for management of digital subscriber lines
View Patent ↗An automatic system for the provisioning, deployment and management of digital subscriber lines (DSL) in a telephone network uses data on loop composition, electromagnetic interference and crosstalk between lines to optimize the performance and correct problems with one or more symmetric and or asymmetric digital subscriber lines in a cable. The system optimizes DSL lines on an individual basis using measurements and data. The optimal transmit power spectral density (PSD) for each DSL can be found in an iterative manner. Starting each DSL with some predetermined starting parameter, the transmit PSD of each DSL is optimized in round-robin fashion. The crosstalk into a given DSL is calculated as the power sum of all transmissions passed through their measured crosstalk couplings. An asymmetric DSL has its transmit PSD optimized by using the “waterfilling” technique. A symmetric or single carrier DSL has its transmit PSD optimized simply as being the PSD corresponding to the maximum bit rate that it can reliably transmit. The joint optimization algorithm converges rapidly to unique values after only a few iterations. Each DSL may also be analyzed by the DSL management system to correct for crosstalk disturbers and electromagnetic interference (EMI) on an individual basis.
1. A method for the automated management of a plurality of digital subscriber lines in a telecommunication network capable of providing broadband data transmission between a central office and one or more subscribers using symmetric and asymmetric transmission comprising the steps of:
selecting an allowed total average transmit power and signal-to-noise ratio margin for each digital subscriber line;
measuring or estimating the crosstalk couplings between digital subscriber lines;
determining the loop response function for each digital subscriber line;
setting the initial transmit power and bit rates for each digital subscriber line;
calculating the sum of all crosstalk into and finding the optimal transmit power for each asymmetric digital subscriber line;
calculating the sum of all crosstalk into and finding the maximum bit rate for each symmetric digital subscriber line; and,
iteratively performing the calculating steps until a predetermined stopping criterion is reached.
2. The method of claim 1 wherein the step of finding the optimal transmit power for each asymmetric digital subscriber line uses the waterfilling technique.
3. The method of claim 1 wherein the predetermined stopping criterion is based on the difference in the maximum bit rates for each digital subscriber line from one iteration to the next.
4. The method of claim 3 wherein the predetermined stopping criterion is when the difference in the maximum bit rates for each digital subscriber line from one iteration to the next is approximately 1 kbps.
5. The method of claim 1 wherein the step of determining the loop response function for each digital subscriber lines further comprises retrieving information from the existing loop database.
6. The method of claim 1 wherein the initial transmit power for each asymmetric digital subscriber line is set to a flat power spectral density across every frequency of transmission at the allowed average power.
7. The method of claim 1 wherein the initial bit rate for each symmetric digital subscriber line is set to approximately twice the bit rate predicted by the worst-case crosstalk model.
8. The method of claim 1 wherein the signal-to-noise ration margin is selected to be approximately 6 dB.
9. A system for the automated management of a plurality of digital subscriber lines in a telecommunication network capable of providing broadband data transmission between a central office and one or more subscribers using symmetric and asymmetric transmission comprising:
means for selecting an allowed total average transmit power and signal-to-noise ratio margin for each digital subscriber line;
means for measuring or estimating the crosstalk couplings between digital subscriber lines;
means for determining the loop response function for each digital subscriber line;
means for setting the initial transmit power and bit rates for each digital subscriber line;
means for iteratively calculating the sum of all crosstalk into and for finding the optimal transmit power for each asymmetric digital subscriber line until a predetermined stopping criterion is reached; and,
means for iteratively calculating the sum of all crosstalk into and for finding the maximum bit rate for each symmetric digital subscriber line until a predetermined stopping criterion is reached.
10. The system of claim 9 wherein the means for finding the optimal transmit power for each asymmetric digital subscriber line uses the waterfilling technique.
11. The system of claim 9 further comprising a means for communicating with automated test equipment capable of determining the composition of one or more digital subscriber lines.
12. The system of claim 9 further comprising a means for communicating with an existing loop database to provide information regarding the composition of one or more digital subscriber lines.
13. The system of claim 9 further comprising a means for communicating with the operations support system.
14. The system of claim 9 wherein at least one of the means for iteratively calculating resides in the subscriber modem.
15. A system for the management of one or more digital subscriber lines for providing communications services from a central office to a subscriber modem comprising:
means for measuring noise on a first digital subscriber line;
means for separating the measured noise into a crosstalk component and an electromagnetic interference (EMI) component;
means for identifying the type of disturber causing the crosstalk component;
means for identifying the identity of the actual crosstalk disturber;
means for communicating with the crosstalk disturber in order to lower the power spectral density of the disturber; and,
means for reassigning the crosstalk disturber in order to reduce crosstalk on the first digital subscriber line.
16. The system of claim 15 further comprising:
means for analyzing the EMI component of the noise;
means for performing electronic EMI remediation.
17. The system of claim 16 wherein the means for performing electronic EMI remediation comprises EMI cancellation.
18. The system of claim 16 further comprising a means for displaying a notification for repair to the unshielded components of the digital subscriber line loop.
19. A method for the management of digital subscriber lines used to provide DSL service comprising the steps of:
measuring the noise on a first digital subscriber line;
separating the noise into a crosstalk component and an EMI component;
identifying the type of crosstalk disturber causing the crosstalk component of the noise;
determining if the crosstalk component of the noise degrades the DSL service on the first digital subscriber line; and,
if the DSL service is degraded by the crosstalk component of the noise, identifying the identity of the crosstalk disturber; and,
lowering the transmit power of the crosstalk disturber so as to reduce the crosstalk component of the noise.
20. The method of claim 19 further comprising the step of reassigning the crosstalk disturber to a different digital subscriber line if the lowering of transmit power does not reduce the crosstalk component of the noise sufficiently.
21. The method of claim 19 further comprising the steps of:
determining if the EMI component of the noise degrades the DSL service on the first digital subscriber line;
if the EMI component degrades the DSL service, reducing the EMI component of the noise through EMI cancellation.
22. The method of claim 21 further comprising the step of communicating a repair notification if the EMI cancellation does not reduce the EMI component of the noise sufficiently.