System and method for bit loading with optimal margin assignment

• US 6,205,410 B1
• Filed: 10/13/1998
• Issued: 03/20/2001
• Est. Priority Date: 06/01/1998
• Status: Expired due to Term

• Current Assignee: Synaptics Incorporated
• Original Assignee: GlobeSpan Semiconductor, Inc. (Synaptics Incorporated)
• Inventors: Cai, Lujing
• Primary Examiner(s): Hoff, Marc S.
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US09/170,749
• Time in Patent Office: 889 Days
• Field of Search: 702/191, 370/476, 370/252, 370/506, 370/343, 370/431, 370/464, 375/295, 375/220, 375/260, 375/377, 709/190, 709/195, 709/189
• US Class Current: 702/191
• CPC Class Codes: H04L 5/0044 allocation of payload

Abstract

A system and method which establishes an optimum margin for each channel in a discrete multi-tone (DMT) transceiver. The present system entails a discrete multi-tone transceiver which comprises a processor and a memory. Stored on the memory is operating logic which directs the function of the processor. The operating logic includes bit allocation logic and signal-to-noise (SNR) variation logic. The SNR variation logic determines an variation in the signal-to-noise ratio for each channel. The bit loading logic then determines a bit loading configuration based upon the variation in the signal-to-noise ratio ascertained by the SNR variation logic. The SNR variation logic preferably includes logic to determine the variation in the signal-to-noise ratio by means of statistical analysis, however, other approaches to determining the variation in the signal-to-noise ratio may be employed.

Claims

1. A bit loading system in a discrete multi-tone (DMT) transceiver having a plurality of channels, the bit loading system comprising:

at least one processor;

a memory;

operating logic stored on the memory, the processor operating according to the operating logic, the operating logic comprising;

signal-to-noise variation logic to determine a variation in a signal-to-noise ratio for each of the channels; and

bit loading logic to determine a bit loading configuration for each of the channels based on the variation in the signal-to-noise ratio for each of the channels.

2. The system of claim 1, wherein the signal-to-noise variation logic further comprises logic to calculate a statistical variation of the signal-to-noise ratio based on a mean average of the signal-to-noise ratio, the mean average being calculated from a predetermined number of signal-to-noise ratio measurements.

3. The system of claim 1, wherein the signal-to-noise variation logic further comprises logic to calculate a statistical estimate of the variation of the signal-to-noise ratio for each of the channels based upon an initially determined mean signal-to-noise ratio.

4. The system of claim 1, wherein the signal-to-noise variation logic further comprises:

logic to maintain a highest signal-to-noise ratio for each of the channels;

logic to maintain a lowest signal-to-noise ratio for each of the channels; and

logic to calculate the maximum variation based on the highest and the lowest signal-to-noise ratios.

5. The system of claim 2, wherein the signal-to-noise variation logic further comprises

logic to measure the signal-to-noise ratio of each channel;

logic to store a predetermined number of signal-to-noise ratio measurements for each channel on a first-in-first-out basis.

6. A bit loading system in a discrete multi-tone (DMT) transceiver having a plurality of channels, the bit loading system comprising:

means for determining a variation in a signal-to-noise ratio for each of the channels; and

means for determining a bit loading configuration for each of the channels based on the variation in the signal-to-noise ratio for each of the channels.

7. The system of claim 6, wherein the means for determining a variation in a signal-to-noise ratio for each of the channels further comprises means for calculating a statistical variation of the signal-to-noise ratio based on a mean average of the signal-to-noise ratio, the mean average being calculated from a predetermined number of signal-to-noise ratio measurements.

8. The system of claim 6, wherein the means for determining a variation in a signal-to-noise ratio for each of the channels further comprises means for calculating a statistical estimate of the variation of the signal-to-noise ratio for each of the channels based upon an initially determined mean signal-to-noise ratio for each of the channels.

9. The system of claim 6, wherein the means for determining a variation in a signal-to-noise ratio for each of the channels further comprises:

means for maintaining a highest signal-to-noise ratio for each of the channels;

means for maintaining a lowest signal-to-noise ratio for each of the channels; and

means for calculating the maximum variation based on the highest and the lowest signal-to-noise ratios.

10. The system of claim 7, wherein the means for determining a variation in a signal-to-noise ratio for each of the channels further comprises:

means for measuring the signal-to-noise ratio of each channel; and

means for storing a predetermined number of signal-to-noise ratio measurements for each channel on a first-in-first-out basis.

11. A method for establishing the bit loading configuration of a discrete multi-tone (DMT) transceiver having a plurality of channels, comprising the steps of:

determining a variation in a signal-to-noise ratio for each of the channels; and

determining a bit loading configuration for each of the channels based on the a variation in the signal-to-noise ratio for each of the channels.

12. The method of claim 11, wherein the step of determining a variation in a signal-to-noise ratio for each of the channels further comprises the step of calculating a statistical variation of the signal-to-noise ratio based on a mean average of the signal-to-noise ratio, the mean average being calculated from a predetermined number of signal-to-noise ratio measurements.

13. The method of claim 11, wherein the step of determining a variation in a signal-to-noise ratio for each of the channels further comprises the step of calculating a statistical estimate of the variation of the signal-to-noise ratio for each of the channels based upon an initially determined mean signal-to-noise ratio for each of the channels.

14. The method of claim 11, wherein the step of determining a variation in a signal-to-noise ratio for each of the channels further comprises the steps of:

maintaining a highest signal-to-noise ratio for each of the channels;

maintaining a lowest signal-to-noise ratio for each of the channels; and

calculating the maximum variation based on the highest and the lowest signal-to-noise ratios.

15. The method of claim 12, wherein the step of determining a variation in a signal-to-noise ratio for each of the channels further comprises the steps of:

measuring the signal-to-noise ratio of each channel; and

storing a predetermined number of signal-to-noise ratio measurements for each channel on a first-in-first-out basis.