Telephonic communications – Transmission line conditioning – Interference suppression
Reexamination Certificate
2000-11-10
2004-12-21
Bui, Bing Q. (Department: 7642)
Telephonic communications
Transmission line conditioning
Interference suppression
C379S417000, C375S254000, C375S278000, C375S284000, C375S285000, C375S296000, C375S346000
Reexamination Certificate
active
06834109
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention pertains to the field of communication systems. More specifically, the present invention relates to a method and apparatus for mitigating disturbers in communication systems.
2. Background Information
The speed at which data is transmitted or received in digital communication systems is significantly impaired by the level of background noise, impulse noise, cross-talk interference, ingress noise coming from appliances, AM radio, and other communication devices.
For example, in Digital Subscriber Line (DSL) configurations, cross-talk interference arises from electromagnetic coupling of physically proximate channels. In DSLsystems, a data signal running along a telephone wire may be diminished by the noise that is injected by the other signals running on adjacent wires. The cross-coupling between two channels can create a highly correlated noise source that can degrade the performance of the transceiver and, in severe instances, completely disable the main communication channel. Cross-talk interference degrades the signal-to-noise ratio (SNR) of a data signal. Cross-talk interference may also shorten the distance the signal can be received reliably, i.e., it may limit loop reach. Additionally, cross-talk interference limits the bit rate for a given maximum allowable transmit power. Such limitations may lower the number of users for a particular system and may limit the deployment of communication systems in certain regions.
When analyzing a single line in a network system, the cross-talk from adjacent lines is considered a disturber or noise. If a modem operating on an impaired line has access to the disturber, it may be able to cancel the interference through adaptive filtering techniques. Such measurements, however, are not always possible due to the lack of physical proximity of modems within a network.
Other factors that influence the data transmission through a network are: the large number of network users, the large amount of data collected from the deployed lines, and the presernce of competing providers in the same physical line plant. The coexistence of ILECs (Incumbent Local Exchange Carriers) and CLECs (Competitive Local Exchange Carriers) in the same cable binders, brought about by the federally mandated deregulation of local telecommunication markets, implies that services deployed by one carrier may be disturbing the users of another carrier, who has no information about the source of this disturbance.
Thus, it is highly desirable to sort through the collected data and determine whether a specific line is being disturbed by external interference and whether that offending service belongs to the same carrier or not. Specifically, it is necessary to diagnose where the cross-talk problems are originating, predict how cross-talk affects services, and optimize the use of the system based on these predictions.
SUMMARY OF THE INVENTION
The present invention includes a method and system for compensating for cross-talk interference in communication systems. The method includes determining an estimation of at least one interfering signal and performing a compensation operation on the at least one interfering signal.
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Erickson Mark Alan
Galarza Cecilia Gabriela
Gu Ming
Hernandez Daniel Joseph
Kanellakopoulos Ioannis
Blakely , Sokoloff, Taylor & Zafman LLP
Bui Bing Q.
Tokyo Electron Limited
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