Method and apparatus for transmitting data from a transmitter device to a plurality of receiver devices

Patent metadata

Field	Value
Publication number	US-10069617-B2
Application number	US-201615552932-A
Country	US
Kind code	B2
Filing date	Mar 2, 2016
Priority date	Mar 2, 2015
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

Apparatus for communicating data between a transmitter device 16 and a first 51 and a second 52 receiver device, the receiver devices being connected, in use, to the transmitter device via a first 21 and a second 22 pair of wires respectively. Each receiver device is 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 respective receiver device and the transmitter device, and the transmitter device is operable to transmit signals onto the wires at the transmitter ends thereof in order to transmit signals via a direct differential mode to each respective receiver via its respective pair of wires. The transmitter device is additionally operable to transmit signals to both receivers via a single common indirect channel and comprises: a channel estimator 1670, 1680, 1690 for estimating the extent of coupling between the common indirect channel and each of the receiver devices based on readings received by the transmitter device from the receiver devices; and a processor 1690 for determining a plurality of weighting values in dependence upon the estimated extents of the couplings; the transmitter 16 being operable to transmit a first signal via the direct differential mode over the first pair 21 , to transmit a second signal via the direct differential mode over the second pair 22 and to transmit a combined signal onto the indirect channel, wherein the combined signal comprises a weighted sum of the first and second signals, the weighting being done in accordance with the determined weighting values; and wherein the transmitter further comprises a precoder 1640 for precoding the first, second and combined signals to pre-compensate them for the expected effects of cross-talk from the other ones of these signals, wherein the pre-coding of each signal, including the first and the second signals, is performed in dependence upon the determined weighting values.

First claim

The invention claimed is:

1. A method of transmitting data from a transmitter device to a first, a second and a third receiver device, the receiver devices being connected to the transmitter device via a first, a second and a third pair of wires respectively, 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 and the transmitter devices, the transmitter device being operable to transmit signals onto the wires extending between the transmitter device and the receiver devices in order to transmit signals via the direct differential mode to each respective receiver, and is additionally operable to transmit signals to both receivers via a single common indirect channel, the method comprising:
measuring the extent of coupling between the common indirect channel and each of the receiver devices,
determining a plurality of weighting values in dependence upon the measured extent of the couplings,
transmitting a first signal via the direct differential mode over the first pair and a second signal via the direct differential mode over the second pair, and transmitting a combined signal onto the indirect channel, the combined signal comprising a weighted sum of the first and second signals, the weighting being done in accordance with the determined weighting values, and
wherein each of the signals is precoded prior to being transmitted in order to pre-compensate for the expected effects of cross-talk from the other signals, and
wherein the pre-coding of each signal, including the first and the second signal, is performed in dependence upon the determined weighting values,
wherein a first phantom mode channel is formed using a differential signal between signals of the first and second receiver devices, a second phantom mode channel is formed using a differential signal between signals of the first and third receiver devices, and a third phantom mode channel is formed using a differential signal between signals of the second and third receiver devices, and
wherein the common indirect channel is a single ended phantom mode channel selected from a set of possible phantom mode channels formed by the first, second and third phantom mode channels.

2. A method according to claim 1 wherein the weighting values are determined additionally in dependence upon the instantaneous level of demand for data to be transmitted to a respective receiver.

3. A method according to claim 2 wherein the transmitter device and the receiver devices are operating in accordance with a physical layer retransmission scheme whereby a receiver requests retransmission of received data which is irreparably damaged because of errors in the received signals or in the detected or recovered data upon receipt.

4. A method according to claim 3 wherein the demand used in determining the weighting values reflects the demand for physical layer re-transmission of data caused by errors in received data.

5. A method of transmitting data from a transmitter device to a first and a second receiver device, the receiver devices being connected to the transmitter device via a first and a second pair of wires respectively, 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 and the transmitter devices, the transmitter device being operable to transmit signals onto the wires extending between the transmitter device and the receiver devices in order to transmit signals via the direct differential mode to each respective receiver, and is additionally operable to transmit signals to both receivers via a single common indirect channel, the method comprising:
measuring the extent of coupling between the common indirect channel and each of the receiver devices,
determining a plurality of weighting values in dependence upon the measured extent of the couplings,
transmitting a first signal via the direct differential mode over the first pair and a second signal via the direct differential mode over the second pair, and
transmitting a combined signal onto the indirect channel, the combined signal comprising a weighted sum of the first and second signals, the weighting being done in accordance with the determined weighting values, and
wherein each of the signals is precoded prior to being transmitted in order to pre-compensate for the expected effects of cross-talk from the other signals, and
wherein the pre-coding of each signal, including the first and the second signal, is performed in dependence upon the determined weighting values,
wherein the method further comprises monitoring one or more metrics associated with the operation of the system and performing a redetermination of at least some of the weighting values and associated precoding coefficients in the event that, as a result of the monitoring, one or more monitored metric is observed to have changed by more than a predetermined threshold amount since last determining or re-determining the weighting values.

6. A method according to claim 5 wherein the monitored metric comprises one or more of channel transfer function estimations and levels of demand for data to be transmitted.

7. A method of transmitting data from a transmitter device to a first and a second receiver device, the receiver devices being connected to the transmitter device via a first and a second pair of wires respectively, 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 and the transmitter devices, the transmitter device being operable to transmit signals onto the wires extending between the transmitter device and the receiver devices in order to transmit signals via the direct differential mode to each respective receiver, and is additionally operable to transmit signals to both receivers via a single common indirect channel, the method comprising:
measuring the extent of coupling between the common indirect channel and each of the receiver devices,
determining a plurality of weighting values in dependence upon the measured extent of the couplings,
transmitting a first signal via the direct differential mode over the first pair and a second signal via the direct differential mode over the second pair, and
transmitting a combined signal onto the indirect channel, the combined signal comprising a weighted sum of the first and second signals, the weighting being done in accordance with the determined weighting values, and
wherein each of the signals is precoded prior to being transmitted in order to pre-compensate for the expected effects of cross-talk from the other signals,
wherein the pre-coding of each signal, including the first and the second signal, is performed in dependence upon the determined weighting values, and
wherein the manner in which the weighting values are used to affect the first and second signals and the manner in which the combined signal is generated for transmission over the common indirect channel is performed in such a way that by assigning zero to all of the weighting values for a particular tone, the method reverts to a vectoring technique, for any such tone, in which the first and second signals are transmitted only onto their respective direct differential mode channels, and those signals are pre-coded to pre-compensate for the expected cross-talk effects of the signal being transmitted onto the other direct differential mode channel associated with the respective other pair of wires.

8. A method according to claim 1 wher

Assignees

• British Telecomm

Inventors

• Al Rawi Anas
• Humphrey Leslie
• Linney Trevor

Classifications

• H04M11/062

  using different frequency bands for speech and other data · CPC title

• H04L2025/0342

  QAM · CPC title

• H04L5/20 Primary

  using different combinations of lines, e.g. phantom working · CPC title

• H04L25/03343

  Arrangements at the transmitter end · CPC title

• H04B3/50

  Systems for transmission between fixed stations via two-conductor transmission lines (H04B3/54 takes precedence) · CPC title