Interference cancellation system
View Patent ↗A DSL or other communication system includes a modem or other communication device having at least one antenna that is configured to collect interference data relating to interference noise affecting communication signals being received by the communication device. The interference may include RF interference, such as AM radio interference, crosstalk and other types of interference from various sources. The interference data collected by the antenna is used by an interference canceller to remove and/or cancel some or all of the interference affecting received signals. In some embodiments of the present invention, more than one antenna may be used, wherein each antenna can collect interference data pertaining to a single source of interference noise. Where a modem or other communication device is coupled to multiple telephone lines, only one of which is being used as the active DSL line, wires in the remaining telephone lines or loops can be used as antennas. Moreover, the antenna may be an antenna, per se, such as a compact AM radio antenna or any other suitable structure or device for collecting the type(s) of interference affecting signals received by the communication device.
1. A system comprising:
a customer premises equipment (CPE) DSL modem coupled to a pedestal via a first active twisted pair telephone DSL line (“first line”) to receive DSL data signals from the pedestal, the CPE DSL modem further coupled to the pedestal via a second inactive twisted pair telephone line (“second line”), wherein the first line and the second line are both part of a single drop segment coupling the CPE DSL modem to the pedestal;
an interference collector coupled to the CPE DSL modem and to the second line to collect interference data from the second line related to interference noise carried by the second line in a frequency range used to carry the DSL data signals on the first line;
an interference canceller coupled to the interference collector, the CPE DSL modem and the first line to subtract from the first line the interference data collected from the second line and thereby remove at least a portion of the interference noise from the first line.
2. The system of claim 1 further comprising a Radio Frequency (RF) antenna coupled to the modem to collect additional interference data.
3. The system of claim 1 further comprising a wire connected to the CPE DSL modem as an additional interference collector and wherein the interference canceller further subtracts from the first line interference data collected from the wire.
4. The system of claim 1 wherein the interference canceller comprises an adaptive filter for configuring the interference data from the second line before subtracting the interference data from the first line.
5. The system of claim 4 wherein the interference canceller further comprises frequency domain processing, and wherein the interference canceller subtracts the interference data from the DSL data signals on the first line in a frequency domain within the frequency range used to carry the DSL data signals on the first line, in accordance with the frequency domain processing.
6. The system of claim 1 wherein the interference noise comprises at least one of:
impulse noise;
man-made electronic radiation;
RF interference; and
crosstalk.
7. The system of claim 1 wherein the interference canceller to subtract from the first line the interference data collected from the second line and thereby remove at least a portion of the interference noise from the first line removes RF interference noise from the DSL data signals received by the CPE DSL modem on the first line.
8. A DSL system comprising:
a Customer Premises Equipment (CPE) DSL modem;
a pedestal
a plurality of wires comprising:
a first active DSL loop coupling the modem and the pedestal, wherein the first active DSL loop is used for transmission arid reception of DSL signals between the modem and pedestal; and
a second loop coupling the modem and the pedestal, wherein the second loop is a member of the same drop segment as the first active DSL loop, and wherein the second loop is to collect interference data from interference sources that affect the first active DSL loop and the second loop; and
wherein the modem comprises an interference canceller coupled to the first active DSL loop and to the second loop to subtract from the first active DSL loop the interference data collected from the second loop and thereby remove at least a portion of the interference noise from the first active DSL loop.
9. The system of claim 8 wherein the second loop is an inactive DSL loop.
10. The system of claim 8 wherein the plurality of wires further comprises an antenna wire coupled to the CPE DSL modem, wherein the antenna wire is configured to function as an antenna to collect interference data from an additional interference source and wherein the interference canceller further subtracts interference data collected from the antenna wire from the first active DSL loop.
11. The system of claim 10 wherein the additional interference source includes a crosstalk source generating crosstalk interference affecting signals on the first active DSL loop.
12. The system of claim 8 wherein the interference sources include a RF interference source generating RF interference affecting signals on the first active DSL loop and wherein the second loop collects RF interference data from the RF interference source.
13. The system of claim 8 wherein the interference canceller is configured for frequency domain processing and to subtract RF interference data from the first active DSL loop using the RF interference data in a frequency domain in accordance with the frequency domain processing.
14. The system of claim 8 wherein the second loop is an active POTS (Plain Old Telephone Service) line.
15. The system of claim 14 further comprising a microfilter between the second loop and a downstream voice telephony subscriber equipment.
16. In a system including a customer premises equipment (CPE) DSL modem coupled to a pedestal via a DSL wired loop to receive a DSL signal from the pedestal, a method comprising:
receiving the DSL signal at the CPE DSL modem from the pedestal coupled to the CPE DSL modem via the DSL wired loop;
receiving interference noise from a second wired loop coupled between the pedestal and the CPE DSL modem the interference noise being in a frequency range used to carry the DSL signal on the DSL wired loop, the DSL wired loop and the second wired loop both being part of a single drop segment coupling the CPE DSL modem and the pedestal; and
subtracting from the received signal on the DSL wired loop the received interference noise collected on the second wired loop and thereby removing at least a portion of the interference noise from the DSL wired loop.
17. The method of claim 16 wherein the second wired loop is a second DSL loop.
18. The method of claim 17 wherein the second DSL loop is active.
19. The method of claim 17 wherein the second DSL loop is inactive.
20. The method of claim 16 further comprising receiving additional interference noise from an RF antenna and subtracting the received additional noise from the received signal on the DSL wired loop.
21. The method of claim 16 wherein the interference noise comprises AM radio interference.
22. The method of claim 16 wherein subtracting the received interference noise is performed by an adaptive filter in the CPE DSL modem.
23. The method of claim 16 wherein the CPE DSL modem comprises time domain processing and further wherein subtracting the interference noise is performed using time domain processing in the DSL modem.
24. The method of claim 16 wherein the CPE DSL modem comprises frequency domain processing and further wherein subtracting the interference noise is performed using frequency domain processing in the DSL modem.
25. The method of claim 16 wherein receiving interference noise comprises receiving RF interference data.
26. The method of claim 16 wherein receiving interference noise comprises receiving crosstalk interference data.
27. The method of claim 16 wherein the second wired loop is an active POTS (Plain Old Telephone Service) line.
28. A system comprising:
a number, N, of twisted pair telephone loops contained in a common binder in a drop segment coupled to a Customer Premises Equipment (CPE) DSL modem from a common pedestal,
wherein a first loop of the N twisted pair telephone loops is a DSL line to carry DSL data in a plurality of frequency ranges
means for collecting interference data on one or more of the remaining N−1 twisted pair telephone loops relating to interference noise in at least one of the frequency ranges used to carry the DSL data on the DSL line, and
means for canceling the interference noise coupled to the DSL line and the means for collecting interference data, the means for canceling interference noise configured to subtract the collected interference data from the DSL line and thereby remove at least a portion of the interference noise from the DSL line.
29. The system of claim 28 wherein the means for collecting interference data comprises a plurality of wires from the N−1 telephone loops and further wherein each wire receives interference noise affecting the DSL signals received by the CPE DSL modem on the first DSL line.
30. The system of claim 29 wherein a source of received interference noise is RF interference.
31. The system of claim 29 wherein a source of received interference noise is crosstalk.
32. The system of claim 29 wherein at least one of the plurality of wires from the N−1 telephone loops is an active POTS (Plain Old Telephone Service) line.