Method and apparatus for transmitting data in differential and phantom mode in vectoring DSL

Patent metadata

Field	Value
Publication number	US-10097236-B2
Application number	US-201615552957-A
Country	US
Kind code	B2
Filing date	Feb 26, 2016
Priority date	Mar 2, 2015
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A transmitter device 16 for transmitting data to a plurality of receiver devices 51, 52, 53 , each of which is connected to the transmitter device via at least one respective pair of wires 21, 22, 23 , each receiver device being operable to receive signals detected as a change over time in the potential difference across the local ends of each respective pair of wires extending between the receiver device and the transmitter device, the transmitter device being operable to transmit signals onto the wires extending between the transmitter device and the plurality of receiver devices in a plurality of different modes, over a plurality of different channels, the different modes including phantom and differential modes and the different channels including a first set of phantom channels, the transmitter comprising a phantom channel selector 1690 for selecting a second set of one or more phantom channels from the first set, the second set being a proper subset of the first set comprising one or more of the phantom channels of the first set, the selection being made in dependence upon the cross-talk coupling between the phantom channels of the first set and the reception of signals at each of the receivers detected as a change over time in the potential difference across the local ends of the respective pair of wires extending between the respective receiver device and the transmitter device; and a connector 1670 for connecting the selected phantom channels to the transmitter such that the transmitter is able to transmit signals from the transmitter onto the phantom channel or channels of the second set of phantom channels.

First claim

The invention claimed is:

1. A method of transmitting data from a transmitter device to a plurality of receiver devices, each of which is connected to the transmitter device via at least one respective pair of wires, each receiver device being operable to receive signals detected as a change over time in the potential difference across the local ends of each respective pair of wires extending between the receiver device and the transmitter device, the transmitter device being operable to transmit signals onto the wires extending between the transmitter device and the plurality of receiver devices in a plurality of different modes, over a plurality of different channels, the different modes including phantom and differential modes and the different channels including a first set of phantom channels, the method comprising:
selecting a second set of phantom channels from the first set, the second set being a proper subset of the first set comprising one or some of the phantom channels of the first set, the selection being made in dependence upon the cross-talk coupling between the phantom channels of the first set and the reception of signals at each of the receiver devices detected as a change over time in the potential difference across the local ends of the, or each, respective pair of wires extending between the respective receiver device and the transmitter device, and
connecting the selected phantom channels to the transmitter device and transmitting signals from the transmitter device onto the phantom channels of the second set of phantom channels.

2. A method according to claim 1 wherein:
the selected phantom channels include at least a first single ended phantom mode channel;
the signals transmitted by the transmitter device include at least:
a first signal transmitted via a first direct differential mode channel to a first receiver device connected to the transmitter device by a first twisted metallic pair over which the first signal is carried;
a second signal transmitted via a second direct differential mode channel to a second receiver device connected to the transmitter device by a second twisted metallic pair over which the second signal is carried; and
a phantom signal transmitted via the first single ended phantom mode channel and received by both the first and the second receiver devices in the differential mode; and

the phantom signal comprises a weighted summation of the first and second signals, the weighting being made in accordance with a set of weighting values calculated in dependence upon measurements or estimations of the extent of mode conversion coupling between the single ended phantom channel and the first and second direct differential mode channels as detected by the first and second receiver devices respectively.

3. A method according to claim 2 wherein the first signal is generated in dependence upon:
user data to be transmitted to the first receiver device;
channel estimations of the first direct differential mode channel;
channel estimations of the indirect channel between the transmitter device and the first receiver via the second direct differential mode channel;
channel estimations of the extent of mode conversion coupling between the single ended phantom channel and the first direct differential mode channel as detected by the first receiver; and
at least some of the weighting values.

4. A method according to claim 2 wherein at least some of the weighting values take values intermediate between zero and one.

5. A method according to claim 1 wherein the transmitter device transmits a single common signal over plural channels between the transmitter device and the receiver devices, the plural channels including the second set of phantom channels, and wherein a multiple access technique is used to provide overlaid virtual channels by which different data is directed to different ones of the receiver devices.

6. Processor implementable instructions for causing a processor to carry out the method of claim 1 during execution of the instructions.

7. A non-transitory computer readable medium storing processor implementable instructions which upon execution by a computer perform the method of claim 1 .

8. A transmitter device for transmitting data to a plurality of receiver devices, each of which is connected to the transmitter device via at least one respective pair of wires, each receiver device being operable to receive signals detected as a change over time in the potential difference across the local ends of each respective pair of wires extending between the receiver device and the transmitter device, the transmitter device being operable to transmit signals onto the wires extending between the transceiver device and the plurality of receiver devices in a plurality of different modes, over a plurality of different channels, the different modes including phantom and differential modes and the different channels including a first set of phantom channels, the transmitter device comprising:
a phantom channel selector for selecting a second set of phantom channels from the first set, the second set being a proper subset of the first set comprising one or some of the phantom channels of the first set, the selection being made in dependence upon the cross-talk coupling between the phantom channels of the first set and the reception of signals at each of the receiver devices detected as a change over time in the potential difference across the local ends of the respective pair of wires extending between the respective receiver device and the transmitter device; and
a connector for connecting the selected phantom channels to the transmitter device such that the transmitter device is able to transmit signals from the transmitter device onto the phantom channels of the second set of phantom channels.

9. A transmitter device according to claim 8 , wherein:
the selected phantom channels include at least a first single ended phantom mode channel;
the transmitter device is operable to transmit at least the following signals:
a first signal transmitted via a first direct differential mode channel to a first receiver device connected to the transmitter device by a first twisted metallic pair over which the first signal is carried;
a second signal transmitted via a second direct differential mode channel to a second receiver device connected to the transmitter device by a second twisted metallic pair over which the second signal is carried; and
a phantom signal transmitted via the first single ended phantom mode channel and received by both the first and the second receiver devices in the differential mode; and

the transmitter device is further operable to generate the phantom signal as a weighted summation of the first and second signals, the weighting being made in accordance with a set of weighting values calculated in dependence upon measurements or estimations of the extent of mode conversion coupling between the single ended phantom channel and the first and second direct differential mode channels as detected by the first and second receiver devices respectively.

10. A phantom channel connector for connecting a transmitter device to a selected set of phantom channels carried over a plurality of pairs of wires extending between the transmitter device and a plurality of receiver devices, the phantom channel connector comprising:
a phantom channel selection signal receiver for receiving a phantom channel selection signal specifying a set of one or more phantom channels,
the set of selected phantom channels comprising a subset of the total number of possible phantom channels to which the connector is operable to connect to the transmitter device,
a set of one or more pairs

Assignees

• British Telecomm
• British Telecomm

Inventors

• Al Rawi Anas
• Humphrey Leslie

Classifications

• H04L25/03006

  Arrangements for removing intersymbol interference · CPC title

• H04L25/0228

  with direct estimation from sounding signals · CPC title

• H04L25/03885

  adaptive · CPC title

• H04J3/10

  Arrangements for reducing cross-talk between channels · CPC title

• H04B3/32 Primary

  Reducing cross-talk, e.g. by compensating · CPC title