Systems and methods for avoiding crosstalk

• US 9,294,212 B2
• Filed: 06/07/2013
• Issued: 03/22/2016
• Est. Priority Date: 02/15/2011
• Status: Active Grant

• Current Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Original Assignee: ADTRAN Incorporated (ADTRAN Holdings, Inc.)
• Inventors: Kuipers, Martin, Goodson, Richard L., Chu, Fred
• Primary Examiner(s): GHOWRWAL, OMAR J
• Application Number:
  US13/913,348
• Publication Number:
  US 20130272314A1
• Time in Patent Office: 1,019 Days
• Field of Search: None
• US Class Current: 1/1
• 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 coupled to the first and second DP transceivers, the controller configured to control the first and second DP transceivers such that (1) the first DP transceiver transmits across the first PTP connection a first set of control data for a first frame and (2) the second DP transceiver transmits across the second PTP connection a second set of control data for a second frame that overlaps in time with the first frame, the first set of control data identifying a plurality of downstream time slots allocated to the first DP transceiver for the first frame and a plurality of upstream time slots allocated to the first CP transceiver for the first frame, the second set of control data identifying a plurality of downstream time slots allocated to the second DP transceiver for the second frame and a plurality of upstream time slots allocated to the second CP transceiver for the second frame, wherein the controller is configured to dynamically schedule upstream and downstream transmissions across the first and second PTP connections such that the controller ensures that the upstream time slots and the downstream time slots of the first frame are prevented from overlapping in time with the upstream time slots and the downstream time slots of the second frame, thereby avoiding crosstalk between the first and second PTP connections during communication of the first and second frames across the first and second PTP connections, respectively,

wherein the first set of control data is defined such that the first frame has a first gap between the downstream time slots and the upstream time slots of the first frame thereby preventing the first DP transceiver and the first CP transceiver from transmitting across the first PTP connection during the first gap, wherein the second set of control data is defined such that the second frame has a second gap between the downstream time slots and the upstream time slots of the second frame thereby preventing the second DP transceiver and the second CP transceiver from transmitting across the second PTP connection during the second gap, and wherein the second set of control data is further defined such that the downstream time slots or the upstream time slots of the second frame occur during the first gap thereby permitting the second DP transceiver or the second CP transceiver to transmit across the second PTP connecting during the first gap.

2. The distribution point of claim 1, wherein the first and second sets of control data are simultaneously transmitted across the first and second PTP connections, respectively.

3. The distribution point of claim 2, 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.

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

10. The distribution point of claim 1, wherein the first PTP connection is bound by a binder, and wherein the second PTP connection is bound by the binder.

11. The distribution point of claim 1, wherein the first set of control data has slot indicators for the time slots in the first frame, each of the slot indicators indicating whether a corresponding time slot in the first frame is allocated for upstream communication or downstream communication.

5. 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;

scheduling, with a controller, upstream and downstream transmissions across the first and second PTP connections;

transmitting, by the first DP transceiver, a first set of control data for a first frame across the first PTP connection, the first set of control data identifying a plurality of downstream time slots for the first frame allocated to the first DP transceiver and a plurality of upstream time slots for the first frame allocated to the first CP transceiver;

transmitting, by the second DP transceiver, a second set of control data for a second frame that overlaps in time with the first frame across the second PTP connection, the second set of control data identifying a plurality of downstream time slots for the second frame allocated to the second DP transceiver and a plurality of upstream time slots for the second frame allocated to the second CP transceiver; and

wherein the scheduling comprises ensuring that the upstream time slots and the downstream time slots of the first frame are prevented from overlapping in time with the upstream time slots and the downstream time slots of the second frame, thereby avoiding crosstalk between the first and second PTP connections during communication of the first and second frames across the first and second PTP connections, respectively,

wherein the first set of control data is defined such that the first frame has a first pap between the downstream time slots and the upstream time slots of the first frame thereby preventing the first DP transceiver and the first CP transceiver from transmitting across the first PTP connection during the first gap, wherein the second set of control data is defined such that the second frame has a second gap between the downstream time slots and the upstream time slots of the second frame thereby preventing the second DP transceiver and the second CP transceiver from transmitting across the second PTP connection during the second gap, and wherein the second set of control data is further defined such that the downstream time slots or the upstream time slots of the second frame occur during the first gap thereby permitting the second DP transceiver or the second CP transceiver to transmit across the second PTP connection during the first gap.

6. The method of claim 5, wherein the first and second sets of control data are simultaneously transmitted across the first and second PTP connections, respectively.

7. The method of claim 6, 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.

12. The method of claim 5, wherein the first PTP connection is bound by a binder, and wherein the second PTP connection is bound by the binder.

13. The method of claim 5, wherein the first set of control data has slot indicators for the time slots in the first frame, each of the slot indicators indicating whether a corresponding time slot in the first frame is allocated for upstream communication or downstream communication.

8. 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 coupled to the first DP transceiver and the second DP transceiver, the controller configured to provide control data to the first DP transceiver and the second DP transceiver such that the first DP transceiver is configured to transmit a first frame across the first PTP connection to the first CP transceiver and the second DP transceiver is configured to transmit a second frame that overlaps in time with the first frame across the second PTP connection to the second CP transceiver, 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 for downstream communications across the first PTP connection and which time slots of the first frame are allocated to the first CP transceiver for upstream communications across the first PTP connection, 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 for downstream communications across the second PTP connection and which time slots of the second frame are allocated to the second CP transceiver for upstream communications across the second PTP connection, wherein the first set of control data and the second set of control data indicate a transmission schedule for the first and second PTP connections such that the controller ensures that the time slots of the first frame allocated for upstream and downstream communications across the first PTP connection are prevented from overlapping in time with the time slots of the second frame allocated for upstream and downstream communications across the second PTP connection thereby avoiding crosstalk between the first and second PTP connections during communication of the first and second frames across the first and second PTP connections, respectively,

wherein the first set of control data is defined such that the first frame has a first gap between the time slots allocated to the first DP transceiver and the slots allocated to the first CP transceiver thereby preventing the first DP transceiver and the first CP transceiver from transmitting across the first PTP connection during the first gap, wherein the second set of control data is defined such that the second frame has a second gap between the time slots allocated to the second DP transceiver and the time slots allocated to the second CP transceiver thereby preventing the second DP transceiver and the second CP transceiver from transmitting across the second PTP connection during the second gap, and wherein the second set of control data is further defined such that the time slots allocated to the second DP transceiver or the time slots allocated to the second CP transceiver occur during the first gap thereby permitting the second DP transceiver or the second CP transceiver to transmit across the second PTP connection during the first gap.

9. A communication system, comprising:

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

a controller coupled to the first transceiver and the second transceiver, the controller configured to control the first and second transceivers such that (1) the first transceiver transmits across the first PTP connection a first set of control data for a first frame and (2) the second transceiver transmits across the second PTP connection a second set of control data for a second frame that overlaps in time with the first frame, the first set of control data identifying a plurality of downstream transmission slots allocated to the first transceiver for the first frame and a plurality of upstream transmission slots allocated to the first CP transceiver for the first frame, the second set of control data identifying a plurality of downstream transmission slots allocated to the second transceiver for the second frame and a plurality of upstream transmission slots allocated to the second CP transceiver for the second frame, wherein the controller is configured to schedule communications across the first and second PTP connections such that the controller ensures that the upstream transmission slots and the downstream transmission slots of the first frame are prevented from overlapping in time with the upstream transmission slots and the downstream transmission slots of the second frame, thereby avoiding crosstalk between the first and second PTP connections during communication of the first and second frames across the first and second PTP connections, respectively,

wherein the first set of control data is defined such that the first frame has a first gap between the downstream transmission slots and the upstream transmission slots of the first frame thereby preventing the first transceiver and the first CP transceiver from transmitting across the first PTP connection during the first gap, wherein the second set of control data is defined such that the second frame has a second gap between the downstream transmission slots and the upstream transmission slots of the second frame thereby preventing the second transceiver and the second CP transceiver from transmitting across the second PTP connection during the second gap, and wherein the second set of control data is further defined such that the downstream transmission slots or the upstream transmission slots of the second frame occur during the first gap thereby permitting the second transceiver or the second CP transceiver to transmit across the second PTP connection during the first gap.