Telephonic communications – Diagnostic testing – malfunction indication – or electrical... – Testing of subscriber loop or terminal
Reexamination Certificate
2000-07-10
2004-11-16
Kuntz, Curtis (Department: 2643)
Telephonic communications
Diagnostic testing, malfunction indication, or electrical...
Testing of subscriber loop or terminal
C379S001040, C379S027010, C379S029090
Reexamination Certificate
active
06819746
ABSTRACT:
FIELD OF THE INVENTION
The concepts involved in the present invention relate to automated techniques for qualifying subscriber loops for digital subscriber line (DSL) services, based on the learning capabilities of an expert system. Preferably, the inventive techniques classify loops by prediction of performance metrics indicating that loop performance falls within ranges of data rate corresponding to different xDSL service grades offered by a carrier or other service provider.
BACKGROUND
Modern society continues to create exponentially increasing demands for digital information, and the communication of such information creates increasing needs for ever-faster data communication speeds. To meet the demand for speed, a number of technologies are being developed and are in early stages of deployment, for providing substantially higher rates of data communication, for example ranging from 640 kb/s to several Mb/s. In particular, a number of the local telephone carriers are working on enhancements to their existing copper-wire loop networks, based on various xDSL technologies. xDSL here is used as a generic term for a group of higher-rate digital subscriber line communication schemes capable of utilizing twisted pair wiring from an office or other terminal node of a telephone network to the subscriber premises. Examples under various stages of development include ADSL (Asymmetrical Digital Subscriber Line), HDSL (High data rate Digital Subscriber Line) and VDSL (Very high data rate Digital Subscriber Line). As one example, ADSL modems today are typically providing downstream data rates in ranges of 640 kb/s, 1.6 Mb/s and 7.1 Mb/s.
Installation, operating and maintenance of xDSL data services, however, pose a number of problems. These problems may be particularly acute where a carrier is considering upgrading to an xDSL service on an existing subscriber's line circuit. The precise data rate of any xDSL service depends on many factors, such as line length, copper wire gauge, cross-coupled interference, and the like. As a general rule, the shorter the distance and/or the larger the diameter of the wire (smaller the gauge), the higher the rate can be on the particular telephone line. If the wiring has been in place and used for Plain Old Telephone Service (POTS) there may be load coils on the line, which prevent xDSL services. Bridged-taps, which are common in telephone loop plant, also cause severe performance problems.
To provide service to a customer seeking to upgrade to an xDSL service, the carrier must determine if the loop to that customer's premises can support the desired xDSL grade of service, and if not, what lower rate service the loop might support. Loop Qualification refers to the task of pre-determining the data rate capacities of loops for high-speed services. For example, a current ADSL Loop Qualification process may focus on which one of three service ranges a customer's loop can support. The three service grades refer to ranges of data described by upper limits of 640 kb/s, 1.6 Mb/s or 7.1 Mbps. Customers are charged based on which range data rate range they choose, predicated on the loop's ability to support it. The fourth possibility, however, is that the loop cannot support any DSL service.
Loop qualification often relies on parameters culled from existing databases regarding cable make-ups of a carrier's outside loop plant. Cable make-up refers to information such as wire gauges, loop lengths and load coils. Sources of cable make-up information include legacy databases and test systems. These sources, however, are notorious for containing incomplete and erroneous information. Further, the quality of databases vary from region to region, telephone company to telephone company and even from wire-center to wire-center. The problems with such information is further increased by the spate of mergers involving regional telephone companies, particularly when each party to the merger has its own legacy and test systems with varying degrees of accuracy and completeness.
The Loop Qualification process to this point has focused primarily on human expert experience in quantifying loop capacity, using established criteria for determining data rates. Some Loop Qualification processes, for example, rely primarily on manually weeding out obvious high power interference sources located in the same binder group, such as T
1
disturbers. In most other cases, loop qualification is based solely on the distance of the customer from the CO. The.process is intensely manual and often requires many truck rolls to confirm or repair service. Due to the inaccuracies or incompleteness of the data used or the limitations of the human expert, the current qualification processes produce two basic types of errors.
Type A errors occur when the carrier qualifies a loop, certifying that it can support a desired grade of service, but when actually used by the subscriber, the loop does not support that grade of service. This generates a complaint by the customer, and the carrier often will send personnel to try to test the line and fix the problem. Sometimes, repairs are possible but require considerable labor. At other times, the repairs may not even be feasible. The subscriber, of course, will not pay for the service that the carrier fails to deliver. The attempts to make manual repairs incur considerable expense, in terms of truck rolls, even if the repairs ultimately fail to deliver the service that the carrier stated that the line could deliver.
The other type of errors, Type B, occur when the carrier decides that a line will not support a desired grade of service, when in fact it could. In this case, the subscriber may obtain a lower grade service over the line, but of course, the subscriber will pay a lower rate than would otherwise have been the case. In many instances, the qualification process may indicate that the line will not support any kind of DSL service at all, in which case the carrier completely loses the opportunity to sell a subscription for such a service to the would-be customer. All such errors essentially cost the carrier opportunities to sell a service or to sell an even higher grade of service and result in lost revenue.
Hence, both errors result in quantifiable economic costs that are borne by the exchange carrier. Failure to mitigate these errors results in reduced revenues and increased expenses. More specifically, Type A errors result in increased expenses due to the dispatch of unnecessary truck rolls. Type B errors translate into lost revenue. Both error types lead to a reduced profitability of xDSL services. Additional expenses also accrue, directly and indirectly, from the increased ‘bad will’ of customers towards the carrier, an increase in unsatisfied customers, greater scrutiny by regulatory agencies, and an eroded corporate image. Other service offerings may also suffer reduced profitability since customer dissatisfaction with xDSL could lead to disconnects by dissatisfied customers who then seek broadband and other services from competitors, and so lead to a hemorrhaging of current revenue and profit streams or the DSL carrier.
Predictive models have been developed in a first effort to automate the task of predicting the level of service that a loop might support. Any such model is only a first order approximation of reality and is only as good as the assumptions incorporated into the model. For example, several existing models predict service level or throughput for xDSL service as a function of loop length. For lines under otherwise equal conditions, these models adequately approximate the values of performance metrics as a function of the variable loop length. However, such models can not account for other variable conditions, particularly locally unique conditions, that may effect xDSL performance. For example, two lines of the same overall length may support radically different levels of xDSL service. One may support a high-rate service, and the other may not support any DSL service, because of differences in the bridged tap cond
Dagen Aaron
Grinbaum Zinovy
Schneider Allan
Kuntz Curtis
Rader & Fishman & Grauer, PLLC
Suchyta, Esq. Leonard C.
Taylor Barry W
Verizon Services Corp.
LandOfFree
Expert system for loop qualification of XDSL services does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Expert system for loop qualification of XDSL services, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Expert system for loop qualification of XDSL services will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3354877