Method and apparatus for sensing noise signals in a wireline communications environment
The present invention relates to methods and apparatuses for sensing noise sources in a wireline communications environment such as a customer premises environment in a DSL system. In embodiments, the invention includes an additional sensor that is connected to power mains in a DSL customer premises environment either to characterize, at their source, noises coupling into the DSL lines, and/or to mitigate their impact into the DSL lines. One objective is associated with diagnostics that help to better characterize the noise signals themselves and derive correlation of signals sensed from the power mains and their possible projection onto the DSL line. Another objective makes use of these power line sensor signals to mitigate or to eliminate power line noises that make their way onto the DSL line. Example embodiments further include and exploit signals from additional secondary sensors such as secondary common mode, differential mode and phantom mode sensors.
1. An apparatus in a customer premises environment of a wireline communication system, comprising:
a primary sensor coupled to receive data signals of the wireline communication system; and
a power line sensor coupled to receive power line signals corresponding to noise source interferences originating from power mains in the customer premises environment, wherein the power line sensor is used with the primary sensor to characterize the noise source interferences.
2. The apparatus of claim 1 , wherein the wireline communication system is a Digital Subscriber Line (DSL) system, a Multi-Media over Coaxial Cable (COAX) system, a Home Phoneline Networking Alliance (HPNA) based network, or an International Telecommunication Union (ITU) Telecommunication home network standard (ITU-T G.hn) based network.
3. The apparatus of claim 1 , further comprising a power supply unit, wherein the power line signals are derived from the power supply unit.
4. The apparatus of claim 1 , wherein the power line sensor includes an external probe coupled to the power mains.
5. The apparatus of claim 1 , wherein the power line signals are derived from a combination of one or more of hot and neutral wires, neutral and ground wires, and hot and ground wires of the power mains.
6. The apparatus of claim 1 , wherein the power line signals comprise one or more of a differential mode signal between hot and neutral wires and a common mode signal between hot and neutral and ground wires of the power mains.
7. The apparatus of claim 1 , further comprising a canceller adapted to cancel noise affecting the data signals using the power line signals.
8. The apparatus of claim 7 , wherein the canceller is configured to perform a cancellation using a combination of outputs from the primary sensor and the powerline sensor as a linearly weighted sum.
9. The apparatus of claim 7 , wherein the canceller comprises a digital signal processor configured to perform adaptive linear filtering on the data signals and the power line signals.
10. The apparatus of claim 7 , wherein the wireline communication system is a multitone system and wherein the canceller is configured to operate on a per tone basis in a frequency domain.
11. The apparatus of claim 7 , wherein the canceller is configured to operate in order to complement another cancellation process that is performed using a secondary sensor.
12. The apparatus of claim 11 , further comprising a selector for conditionally selecting output from one of the cancellers.
13. The apparatus of claim 1 , wherein the power line sensor is used in conjunction with other sensors to characterize noise in the customer premises environment and sources thereof, and associated impact on the wireline communication system.
14. The apparatus of claim 13 , wherein characterization is performed using the primary sensor, the powerline sensor, and a secondary common mode sensor.
15. The apparatus of claim 13 , wherein characterization includes determining a coupling between at least two of the primary sensor, the powerline sensor, and a secondary common mode sensor.
16. The apparatus of claim 13 , wherein the characterization is performed by estimating noise source power on the sensors and noise correlation across the sensors.
17. The apparatus of claim 16 , wherein a determination of number and relative location of the noise sources is based at least in part on the characterization.
18. An apparatus in a customer premises environment of a wireline communication system, comprising:
a primary sensor coupled to receive data signals of the wireline communication system;
a powerline sensor coupled to receive power line signals corresponding to noise impacting the data signals and originating from power mains in the customer premises environment; and
an embedded noise analysis engine that performs characterization of the noise based at least in part on the received data signals and the received power line signals.
19. The apparatus of claim 18 , wherein the embedded noise analysis engine collects information regarding the noise while transmissions to and from the apparatus using the wireline communication system are not in service.
20. The apparatus of claim 18 , wherein the embedded noise analysis engine collects information regarding the noise while transmissions to and from the apparatus using the wireline communication system are in service.