Signal-to-channel mapping for multi-channel, multi-signal transmission systems

• US 5,991,271 A
• Filed: 12/20/1995
• Issued: 11/23/1999
• Est. Priority Date: 12/20/1995
• Status: Expired due to Term

• Current Assignee: Comcast MO Group Incorporated (Comcast Corporation)
• Original Assignee: US West, Inc. (Lumen Technologies, Inc.)
• Inventors: Jones, David C., Lee, Youngho, Phillips, Bruce A.
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): YAO, KWANG BIN
• Application Number:
  US08/575,402
• Time in Patent Office: 1,434 Days
• Field of Search: 370/252, 370/430, 370/437, 370/464, 370/465, 370/480, 370/486, 370/490, 370/496, 370/333, 370/466, 370/467, 348/14, 348/15, 348/16, 379/414, 379/416, 379/417
• US Class Current: 370/252
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04J 3/22 in which the sources have different rates or codes simultaneous speech and digital data or video transmission H04M11/06; see provisional also H04J3/16

Abstract

A system and method for allocating signal types to transmission channels in a multi-channel, multi-signal transmission system uses one or more decision rules to determine a signal-to-channel mapping based on a predetermined performance criterion, such as signal-to-noise ratio (SNR), SNR margin, or target transport margin at a particular bit error rate (BER), rather than random assignment. The system and method improve overall performance of a transmission system carrying multiple signal types, such as telephony, compressed digital video, broadcast video, and low and high speed data. The decision rules are implemented over the entire transmission system to simplify recordkeeping and associated aspects of network operations.

Claims

1. A method for improving performance of a transmission system used for communicating a plurality of signal types over a plurality of communication channels extending between at least one transmitter and at least one receiver, the method comprising:

selecting at least one performance criterion indicative of signal quality at the at least one receiver;

associating each of the plurality of signal types with a corresponding one of the plurality of communication channels so as to define a plurality of available signal-to-channel maps;

evaluating the selected criterion for each of the plurality of associated signal types and communication channels in a particular signal-to-channel map;

storing a lowest value of the selection criterion for the particular signal-to-channel map;

repeating the steps of evaluating and identifying for each of the plurality of available signal-to-channel maps; and

selecting the signal-to-channel map based on the stored values.

2. The method of claim 1 further comprising:

transmitting each of the plurality of signal types over a corresponding assigned communication channel.

3. The method of claim 1 wherein the step of selecting comprises selecting signal to noise ratio as the at least one performance criterion.

4. The method of claim 1 wherein the step of selecting comprises selecting signal to noise ratio margin relative to a set of signal to noise ratio references corresponding to the set of signal types as the at least one performance criterion.

5. The method of claim 1 wherein the plurality of signal types includes a digital signal type and wherein the step of selecting includes selecting transmission margin at a predetermined bit error rate as the at least one performance criterion.

6. The method of claim 1 wherein the step of selecting the signal-to-channel map comprises selecting the signal-to-channel map having the highest stored value.

7. The method of claim 1 wherein the step of selecting comprises selecting at least one performance criterion indicative of near-end crosstalk and far-end crosstalk.

8. A method for improving performance of a transmission system used for communicating a plurality of signal types over a distribution cable having a plurality of twisted pairs extending between at least one transmitter and at least one receiver, the method comprising:

associating each of the plurality of signal types with a corresponding one of the plurality of twisted pairs so as to define a plurality of available signal-to-pair mappings;

measuring pair to pair electromagnetic coupling for at least two of the plurality of twisted pairs;

selecting the signal-to-lair mapping which improves system performance as determined by the measured pair to pair electromagnetic coupling; and

assigning each of the plurality of signal types to one of the plurality of twisted pairs based on the selected signal-to-pair mapping.

9. The method of claim 8 further comprising:

transmitting each of the plurality of signal types over a corresponding assigned twisted pair.

10. The method of claim 9 wherein the plurality of twisted pairs is separated into a plurality of binder groups, the plurality of signal types includes an upstream signal traveling in a direction opposite to a downstream signal, and wherein the step of assigning comprises:

assigning the upstream signal to a first one of the plurality of binder groups and assigning the downstream signal to a second one of the plurality of binder groups.

11. The method of claim 10 wherein the upstream and downstream signals are digital signals.

12. The method of claim 8 wherein the plurality of signal types includes at least one digital signal and wherein the step of measuring comprises:

computing the near end crosstalk and far end crosstalk power sums as a function of frequency; and

computing transmission margin for each of the at least one digital signal types for a predetermined error rate.

13. The method of claim 12 wherein the step of assigning comprises assigning each of the plurality of signal types to one of the plurality of twisted pairs based on the signal-to-pair mapping which maximizes the minimum transmission margin at a predetermined bit error rate.

14. The method of claim 12 wherein the step of assigning comprises assigning each of the plurality of signal types to one of the plurality of twisted pairs based on the signal-to-pair mapping which optimizes signal to noise margin.

15. The method of claim 12 wherein the step of assigning comprises assigning each of the plurality of signal types to one of the plurality of twisted pairs based on the signal-to-pair mapping which optimizes signal to noise ratio.

16. Apparatus for improving performance of a transmission system used for communicating a plurality of signal types over a plurality of communication channels extending between at least one transmitter and at least one receiver, the apparatus comprising:

control logic for selecting at least one performance criterion indicative of signal quality at the at least one receiver, evaluating at least one rule of decision based on the at least one performance criterion,

associating each of the plurality of signal types with a corresponding one of the plurality of communication channels so as to define a plurality of available signal-to-channel maps,

evaluating the selected criterion for each of the plurality of associated signal types and communication channels in a particular signal-to-channel map,

storing a lowest value of the selection criterion for the particular signal-to-channel map,

repeating the steps of evaluating and identifying for each of the plurality of available signal-to-channel maps,

selecting the signal-to-channel map based on the stored values.

17. The apparatus of claim 16 wherein the control logic selects the signal-to-channel map having the highest stored value.

18. The apparatus of claim 16 wherein the control logic selects signal-to-noise ratio margin as the at least one performance criterion.

19. The apparatus of claim 16 wherein the control logic evaluates at least one rule of decision based on mathematical optimization which maximizes a minimum value of the at least one performance criterion.