Multi-carrier communication using adaptive tone-pruning

• US 20060002457A1
• Filed: 06/30/2004
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: 2Wire, Inc. (CommScope Holding Company, Inc.)
• Inventors: Romano, Pasquale, Fisher, Kevin, Sedarat, Hossein
• Granted Patent: US 7,502,336 B2
• Time in Patent Office: Days
• US Class Current: 375/222
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling

Abstract

An apparatus, system, and method are described for multi-carrier communication using adaptive tone-pruning. The method may include transmitting a data-bearing signal over a plurality of tones on a communication loop within a plurality of communication loops and calculating a minimum tone cost according to a tone cost algorithm. The tone cost algorithm defines a tone cost associated with a selected tone within the plurality of tones. The tone cost of the selected tone is based on a predefined loading frequency and a signal-to-noise ration (SNR) of the selected tone. The method also may include determining a bit loading pattern for the data-bearing signal according to the minimum tone cost. This determination may occur in response to a determination that a minimum allowable transmission power is greater than a minimum required transmission power for the data-bearing signal.

Claims

1. An apparatus, comprising:

a modem configured to transmit a data-bearing signal over a plurality of tones on a communication loop within a plurality of communication loops;

a cost calculation module configured to calculate a minimum tone cost according to a tone cost algorithm, the tone cost algorithm defining a tone cost associated with a selected tone of the plurality of tones based on a predefined loading frequency and a signal-to-noise ratio (SNR) of the selected tone; and

a bit loading module configured to determine a bit loading pattern for the data-bearing signal according to the minimum tone cost in response to a determination that a minimum allowable transmission power is greater than a minimum required transmission power for the data-bearing signal.

2. The apparatus of claim 1, wherein the tone cost algorithm is as follows:

3. The apparatus of claim 2, further comprising a training module configured to facilitate a training communication between the modem and a second modem to determine the signal-to-noise (SNR) ratio of the selected tone.

4. The apparatus of claim 1, further comprising a power monitor module configured to determine if the minimum allowable transmission power is greater than the minimum required transmission power for the data-bearing signal.

5. The apparatus of claim 1, wherein:

the communication loop carries the data-bearing signal between the modem located at a remote terminal and a second modem located at an end user location; and

the predefined loading frequency comprises an upper frequency within an allowable frequency spectrum.

6. The apparatus of claim 5, wherein the predefined loading frequency comprises an uppermost frequency within the allowable frequency spectrum.

7. The apparatus of claim 1, wherein the communication loop is a short loop and the bit loading module is further configured to determine the bit loading pattern to reduce cross-talk noise on a long loop within the plurality of communication loops, the cross-talk noise caused by the data-bearing signal on the short loop on the long loop.

8. The apparatus of claim 1, wherein the bit loading module is further configured to determine the bit loading pattern to eliminate the cross-talk noise in the plurality of communication loops in a near proximity to one another, wherein the communication loop comprises a first loop between a remote terminal and a first end user location, the plurality of communication loops further comprising a second loop between a central office and a second end user location.

9. The apparatus of claim 1, wherein the bit loading module is further configured to determine the bit loading pattern to create a disjoint spectrum with a second bit loading pattern of a second data-bearing signal on a second communication loop within the plurality of communication loops.

10. The apparatus of claim 1, wherein the modem comprises a digital subscriber line (DSL) modem.

11. The apparatus of claim 1, wherein the bit loading module is further configured to determine a bottom-pruning bit loading pattern and deactivate a lower frequency within an allowable frequency spectrum for the communication loop, wherein the communication loop comprises a short loop.

12. A system, comprising:

a first transmitter configured to transmit a first data-bearing signal over a first plurality of tones on a short loop within a plurality of communication loops;

a second transmitter configured to transmit a second data-bearing signal over a second plurality of tones on a long loop within the plurality of communication loops; and

a first bit loading module configured to determine a first bit loading pattern for the first data-bearing signal according to a first minimum tone cost, the first minimum tone cost calculated according to a tone cost algorithm defining a tone cost associated with a selected tone of the first plurality of tones based on a predefined loading frequency and a signal-to-noise ratio (SNR) of the selected tone.

13. The system of claim 12, further comprising a cost calculation module configured to calculate the minimum tone cost, wherein the tone cost algorithm is as follows:

14. The system of claim 12, further comprising a power monitor module configured to determine if a minimum allowable transmission power is greater than a minimum required transmission power for the first data-bearing signal and wherein the first bit loading module is further configured to determine the first bit loading pattern in response to a determination that the minimum allowable transmission power is greater than the minimum required transmission power for the first data-bearing signal.

15. A system, comprising:

a first modem configured to transmit a first data-bearing signal over a first plurality of tones over a long loop within a plurality of communication loops, the first plurality of tones selected from an allowable plurality of tones according to a first tone cost algorithm dependent on a signal-to-noise ratio (SNR) of a first selected tone within the first plurality of tones; and

a second modem configured to transmit a second data-bearing signal over a second plurality of tones over a short loop within the plurality of communication loops, the second plurality of tones selected from the allowable plurality of tones according to a second tone cost algorithm dependent on a predefined loading frequency and a signal-to-noise ratio (SNR) of a second selected tone within the second plurality of tones.

16. The system of claim 15, wherein the second tone cost algorithm is as follows:

17. A method, comprising:

transmitting a data-bearing signal over a plurality of tones on a communication loop within a plurality of communication loops;

calculating a minimum tone cost according to a tone cost algorithm, the tone cost algorithm defining a tone cost associated with a selected tone of the plurality of tones based on a predefined loading frequency and a signal-to-noise ratio (SNR) of the selected tone; and

determining a bit loading pattern for the data-bearing signal according to the minimum tone cost in response to a determination that a minimum allowable transmission power is greater than a minimum required transmission power for the data-bearing signal.

18. The method of claim 17, wherein the tone cost algorithm is as follows:

19. The method of claim 17, further comprising facilitating a training communication between the modem and a second modem to determine the signal-to-noise (SNR) ratio of the selected tone.

20. The method of claim 17, further comprising reducing cross-talk noise on a long loop within the plurality of communication loops, the cross-talk noise caused by the data-bearing signal on a short loop.

21. The method of claim 20, further comprising eliminating the cross-talk noise on the long loop.

22. The method of claim 17, further comprising creating a disjoint spectrum with a second bit loading pattern of a second data-bearing signal on a second communication loop within the plurality of communication loops.

23. The method of claim 17, further comprising:

transmitting the data-bearing signal between a remote terminal (RT) modem and an end user (EU) modem;

determining a bottom-pruning bit loading pattern; and

deactivating a lower frequency within an allowable frequency spectrum.

24. A machine-readable medium storing executable instructions to cause a device to perform operations, comprising:

transmit a data-bearing signal over a plurality of tones on a communication loop within a plurality of communication loops;

calculate a minimum tone cost according to a tone cost algorithm, the tone cost algorithm defining a tone cost associated with a selected tone of the plurality of tones based on a predefined loading frequency and a signal-to-noise ratio (SNR) of the selected tone; and

determine a bit loading pattern for the data-bearing signal according to the minimum tone cost in response to a determination that a minimum allowable transmission power is greater than a minimum required transmission power for the data-bearing signal.

25. The machine-readable medium of claim 24, wherein the tone cost algorithm is as follows:

26. The machine-readable medium of claim 24, further comprising executable instructions to cause the device to reduce cross-talk noise on a long loop within the plurality of communication loops, the cross-talk noise caused by the data-bearing signal on a short loop.

27. The machine-readable medium of claim 26, further comprising executable instructions to cause the device to eliminate the cross-talk noise on the long loop.

28. The machine-readable medium of claim 24, further comprising executable instructions to cause the device to create a disjoint spectrum with a second bit loading pattern of a second data-bearing signal on a second communication loop within the plurality of communication loops.

29. An apparatus, comprising:

means for transmitting a data-bearing signal over a plurality of tones on a communication loop within a plurality of communication loops;

means for calculating a minimum tone cost according to a tone cost algorithm, the tone cost algorithm defining a tone cost associated with a selected tone of the plurality of tones based on a predefined loading frequency and a signal-to-noise ratio (SNR) of the selected tone; and

means for determining a bit loading pattern for the data-bearing signal according to the minimum tone cost in response to a determination that a minimum allowable transmission power is greater than a minimum required transmission power for the data-bearing signal.

30. The apparatus of claim 29, wherein the tone cost algorithm is as follows:

31. The apparatus of claim 29, further comprising means for reducing cross-talk noise on a long loop within the plurality of communication loops, the cross-talk noise caused by the data-bearing signal on a short loop.

32. The apparatus of claim 31, further comprising means for eliminating the cross-talk noise on the long loop.

33. The apparatus of claim 29, further comprising means for creating a disjoint spectrum with a second bit loading pattern of a second data-bearing signal on a second communication loop within the plurality of communication loops.

34. The apparatus of claim 29, further comprising means for limiting a percentage loss of a bit rate on a second communication loop, the percentage loss defined by a loss algorithm as follows:

35. An apparatus, comprising:

a modem configured to transmit a data-bearing signal over a plurality of tones on a communication loop within a plurality of communication loops;

a cost calculation module configured to calculate a minimum tone cost according to a tone cost algorithm, the tone cost algorithm defining a tone cost associated with a selected tone of the plurality of tones based on a predefined loading frequency of the selected tone; and

a bit loading module configured to determine a bit loading pattern for the data-bearing signal according to the minimum tone cost.

36. The apparatus of claim 35, wherein the tone cost algorithm is as follows:

37. The apparatus of claim 36, wherein:

the communication loop comprises a short loop; and

the predefined loading frequency is an upper frequency, within an allowable frequency spectrum, that is higher than a transmission frequency of a second data bearing signal on a long loop within the plurality of communication loops.

38. A method, comprising:

establishing a training sequence for a multi-carrier communication system;

determining a bit loading pattern for a plurality of tones in a frequency spectrum;

determining if the bit loading pattern for the plurality of tones is limited by a minimum allowable transmission power level;

selecting a first segment of tones of the plurality of tones to load with data if a second segment of tones of the plurality of tones is limited by the minimum allowable transmission power level; and

selecting the first segment of tones to load with data based upon a predefined loading frequency and a signal-to-noise ratio (SNR) of each tone.

39. The method of claim 38, further comprising calculating a minimum tone cost according to a tone cost algorithm, the tone cost algorithm defining a tone cost associated with a selected tone of the plurality of tones based on the predefined loading frequency and the signal-to-noise ratio (SNR) of the selected tone.