System and method for reducing power consumption by spectral shaping of signals

• US 7,133,419 B1
• Filed: 05/03/2002
• Issued: 11/07/2006
• Est. Priority Date: 05/04/2001
• Status: Expired due to Fees

• Current Assignee: Ikanos Communications Incorporated (Qualcomm, Inc.)
• Original Assignee: Conexant Incorporated (Synaptics Incorporated)
• Inventors: Hendrichs, Laurent, Scholtz, William
• Primary Examiner(s): To, Doris H.
• Assistant Examiner(s): SHAH, CHIRAG G
• Application Number:
  US10/138,365
• Time in Patent Office: 1,649 Days
• Field of Search: None
• US Class Current: 370/468
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data

Abstract

The present invention provides a system and method for reducing power consumption by shaping the spectrum of a downstream signal. Incremental improvements in power consumption due to spectral shaping produces a noticeable reduction in the aggregate power consumed at a central office in asymmetric digital subscriber line (ADSL) systems.

Claims

1. A method for reducing power consumption in downstream transmission of signals in asymmetric digital subscriber line (ADSL) systems, comprising the steps of:

beginning an exchange of first initialization messages between a central office ADSL transceiver unit (ATU-C) and a remote ADSL transceiver unit (ATU-R), wherein the first initialization messages are carried in discrete bins;

receiving a R-B&

G message and a R-MSG2 message at the ATU-C during the exchange of the first initialization messages;

aborting the exchange of the first initialization messages in response to the receiving of the R-B&

G message at the ATU-C;

extracting a number of bits, b_i, allocated to each bin, i, from the R-B&

G message;

extracting a scaling factor, g_i, associated with each bin, i, from the R-B&

G message;

extracting performance margin information, M, from the R-MSG2 message;

calculating a signal-to-noise ratio (SNR) associated with each bin, i, from the extracted number of bits, the extracted scaling factor, and the extracted performance margin information as;

2. A method for reducing power consumption in signal transmission systems, comprising the steps of:

calculating a bandwidth for a transmission of a signal;

determining a spectral shape for the calculated bandwidth, wherein the spectral shape is configured to substantially minimize power consumption during the transmission of the signal;

initializing a signal transmission system using the determined spectral shape and the calculated bandwidth; and

transmitting data within the initialized signal transmission system;

wherein the step of calculating the bandwidth comprises the steps of;

exchanging a first set of initialization messages between a transmitter and a receiver, wherein the first set of initialization messages are exchanged using discrete bins;

determining a bin signal-to-noise ratio (SNR) associated with each of the discrete bins using information included within the first set of initialization messages;

comparing the determined bin SNR with a predetermined threshold SNR; and

designating the discrete bins having a greater bin SNR than the predetermined threshold SNR as bins configured to carry data.

3. The method of claim 2, wherein the transmitter is a central office ADSL transceiver unit (ATU-C) and the receiver is a remote ADSL transceiver unit (ATU-R).

4. The method of claim 3, wherein the step of exchanging a first set of initialization messages comprises the steps of:

beginning an exchange of first initialization messages between the central office ADSL transceiver unit (ATU-C) and the remote ADSL transceiver unit (ATU-R), wherein the first initialization messages are carried in discrete bins;

receiving a R-B&

G message and a R-MSG2 message at the ATU-C during the exchange of the first initialization messages; and

aborting the exchange of the first initialization messages in response to the receiving of the R-B&

G message at the ATU-C.

5. The method of claim 4, wherein the step of receiving the R-B&

G message and the R-MSG2 message comprises the steps of;

receiving information indicative of a number of bits allocated to each bin;

receiving information indicative of a scaling factor associated with each bin; and

receiving performance margin information.

6. The method of claim 5, wherein the step of determining the bin signal-to-noise ratio (SNR) comprises the steps of:

extracting the number of bits, b_i, allocated to each bin, i, from the R-B&

G message;

extracting the scaling factor, g_i, associated with each bin, i, from the R-B&

G message;

extracting the performance margin, M, from the R-MSG2 message; and

calculating a signal-to-noise ratio (SNR) associated with each bin, i, from the extracted number of bits, the extracted scaling factor, and the extracted performance margin as;

7. The method of claim 6, wherein the SNR gap is 9.55.

8. The method of claim 2, wherein the step of determining the spectral shape comprises the steps of:

exchanging a first set of initialization messages between a transmitter and a receiver, wherein the first set of initialization messages are exchanged using discrete bins;

determining a bin signal-to-noise ratio (SNR) associated with each of the discrete bins using information included within the first set of initialization messages;

calculating a transmission power output associated with each bin using the determined bin SNR.

9. The method of claim 8, wherein the transmitter is a central office ADSL transceiver unit (ATU-C) and the receiver is a remote ADSL transceiver unit (ATU-R).

10. The method of claim 9, wherein the step of exchanging a first set of initialization messages comprises the steps of:

beginning an exchange of first initialization messages between the central office ADSL transceiver unit (ATU-C) and the remote ADSL transceiver unit (ATU-R), wherein the first initialization messages are carried in discrete bins;

receiving a R-B&

G message and a R-MSG2 message at the ATU-C during the exchange of the first initialization messages; and

aborting the exchange of the first initialization messages in response to the receiving of the R-B&

G message at the ATU-C.

11. The method of claim 10, wherein the step of receiving the R-B&

G message and the R-MSG2 message comprises the steps of;

receiving information indicative of a number of bits allocated to each bin;

receiving information indicative of a scaling factor associated with each bin; and

receiving performance margin information.

12. The method of claim 11, wherein the step of determining the bin signal-to-noise ratio (SNR) comprises the steps of:

extracting the number of bits, b_i, allocated to each bin, i, from the R-B&

G message;

extracting the scaling factor, g_i, associated with each bin, i, from the R-B&

G message;

extracting the performance margin, M, from the R-MSG2 message; and

calculating a signal-to-noise ratio (SNR) associated with each bin, i, from the extracted number of bits, the extracted scaling factor, and the extracted performance margin as;

13. The method of claim 8, wherein the step of calculating the transmission power output comprises the steps of:

determining a target bit allocation;

determining a threshold total power level; and

iteratively computing a bin bit allocation and a bin power level for each bin until either a sum of the bin bit allocation exceeds the target bit allocation or a sum of the bin power level exceeds the threshold total power level.

14. The method of claim 13, wherein the step of iteratively computing the bin bit allocation comprises the steps of:

determining a bin bit allocation for each bin; and

summing each of the determined bin bit allocations to produce the sum of the bin bit allocation.

15. The method of claim 13, wherein the step of iteratively computing the bin power level comprises the steps of:

determining a spectral density for each bin; and

summing each of the determined spectral densities to produce the sum of the bin power level.

16. The method of claim 2, wherein the signal communication system is an asymmetric digital subscriber line (ADSL) system employing discrete multi-tone (DMT) technology, wherein data is transmitted in discrete bins.

17. The method of claim 16, wherein the step of initializing of the signal communication system further comprises the steps of:

loading a second set of initialization messages into each of the discrete bins within the calculated bandwidth;

setting a transmission power of each of the loaded bins, wherein the transmission power is a function of the determined spectral shape;

transmitting the second set of initialization messages in each of the loaded bins using the set transmission power for each of the loaded bins.