SYSTEMS AND METHODS FOR AVOIDING CROSSTALK

• US 20130272314A1
• Filed: 06/07/2013
• Published: 10/17/2013
• Est. Priority Date: 02/15/2011
• Status: Active Grant

• Current Assignee: Fred Chu, Martin Kuipers, Mr Richard L Goodson
• Original Assignee: Fred Chu, Martin Kuipers, Mr Richard L Goodson
• Inventors: Goodson, Richard L., Chu, Fred, Kuipers, Martin
• Granted Patent: US 9,294,212 B2
• Time in Patent Office: Days
• US Class Current: 370/437
• CPC Class Codes: H04J 3/10 Arrangements for reducing cross-talk between channels
• CPC Class Codes: H04L 12/403 with centralised control, e.g. polling
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 47/52 by attributing bandwidth to queues
• CPC Class Codes: H04L 5/22 using time-division multiplexing

Abstract

A controller at a distribution point (DP) of a communication system is coupled to a plurality of customer premises (CP) transceivers via drop connections. The controller is configured to schedule upstream and downstream data transmissions across the drop connections such that they do not overlap from one drop connection to another thereby avoiding the effects of crosstalk. A flexible frame structure is used to permit dynamic scheduling changes. Overhead for the flexible frame structure is permitted to overlap on the drop connections, and a reduced bit loading is used to communicate the overhead relative to the bit loading used for data transmissions.

Claims

1. A distribution point, comprising:

a first distribution point (DP) transceiver coupled to a first point-to-point (PTP) connection and configured to communicate with a first customer premises (CP) transceiver via the first PTP connection;

a second DP transceiver coupled to a second PTP connection and configured to communicate with a second CP transceiver via the second PTP connection; and

a controller configured to dynamically schedule transmissions across the first and second PTP connections such that the controller ensures, for at least a period of time, that transmissions across the first PTP connection are prevented from overlapping in time with transmissions across the second PTP connection thereby avoiding crosstalk between the first and second PTP connections during the period of time.

2. The distribution point of claim 1, wherein the controller is configured to control the first and second DP transceivers such that the first DP transceiver transmits a first frame across the first PTP connection and the second DP transceiver transmits a second frame across the second PTP connection, wherein the first frame has a first set of control data indicating which time slots of the first frame are allocated to the first DP transceiver and the first CP transceiver, and wherein the second frame has a second set of control data indicating which time slots of the second frame are allocated to the second DP transceiver and the second CP transceiver.

3. The distribution point of claim 2, wherein the first and second sets of control data are simultaneously transmitted across the first and second PTP connections, respectively.

4. The distribution point of claim 3, wherein the first DP transceiver is configured to transmit at least a first discrete multi-tone (DMT) symbol and a second DMT symbol in the first frame, wherein the first DMT symbol includes at least a portion of the first set of control data, and wherein a bit loading for the first DMT symbol is different than a bit loading for the second DMT symbol.

5. The distribution point of claim 1, wherein the controller is configured to schedule the transmissions across the first and second PTP connections such that transmissions of control data across the first PTP connection for indicating time slot allocation for the first PTP connection are prevented from overlapping in time with transmissions of control data across the second PTP for indicating time slot allocation for the second PTP connection.

6. The distribution point of claim 1, wherein the controller is configured to schedule the transmissions across the first and second PTP connections such that for at least one time slot only one of the first DP transceiver, the second DP transceiver, the first CP transceiver, and the second CP transceiver is permitted to transmit across the first and second PTP connections during the time period.

7. A method for use at a distribution point, comprising:

communicating between a first distribution point (DP) transceiver and a first customer premises (CP) transceiver via a first point-to-point (PTP) connection having an end coupled to the first DP transceiver and an end coupled to the first CP transceiver;

communicating between a second DP transceiver and a second CP transceiver via a second PTP connection having an end coupled to the second DP transceiver and an end coupled to the second CP transceiver; and

scheduling transmissions across the first and second PTP connections, wherein the scheduling comprises ensuring, for at least a period of time, that transmissions across the first PTP connection are prevented from overlapping in time with transmissions across the second PTP connection thereby avoiding crosstalk between the first and second PTP connections during the period of time.

8. The method of claim 7, further comprising:

transmitting a first frame from the first DP transceiver across the first PTP connection, wherein the first frame has a first set of control data indicating which time slots of the first frame are allocated to the first DP transceiver and the first CP transceiver; and

transmitting a second frame from the second DP transceiver across the second PTP connection, wherein the second frame has a second set of control data indicating which time slots of the second frame are allocated to the second DP transceiver and the second CP transceiver.

9. The method of claim 8, wherein the first and second sets of control data are simultaneously transmitted across the first and second PTP connections, respectively.

10. The method of claim 9, wherein the first frame includes a first discrete multi-tone (DMT) symbol and a second DMT symbol, wherein the first DMT symbol includes at least a portion of the first set of control data, and wherein a bit loading for the first DMT symbol is different than a bit loading for the second DMT symbol.

11. The method of claim 7, wherein the scheduling comprises permitting only one of the first DP transceiver, the second DP transceiver, the first CP transceiver, and the second CP transceiver to transmit across the first and second PTP connections during the time period.