Apparatus for, and method of, reducing power dissipation in a communications system

• US 6,898,238 B2
• Filed: 08/15/2001
• Issued: 05/24/2005
• Est. Priority Date: 08/28/1998
• Status: Expired due to Fees

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Hatamian, Mehdi, Creigh, John L., Agazzi, Oscar E.
• Primary Examiner(s): Ha, Dac V.
• Application Number:
  US09/930,584
• Publication Number:
  US 20010055335A1
• Time in Patent Office: 1,378 Days
• Field of Search: 375/231, 375/232, 375/346, 375/368, 375/350, 708/322, 708/323
• US Class Current: 375/232
• CPC Class Codes: H04B 3/32 Reducing cross-talk, e.g. by compensating
• CPC Class Codes: H04B 3/487 Testing crosstalk effects

Abstract

A method is provided for reducing power dissipation within a communications system having a plurality of adaptive filters with a plurality of taps, each tap is switchable between an active and an inactive state, each tap also has a coefficient. An acceptable error for the system is specified. This error is typically the mean squared error of the system. A tap threshold is set for each active tap. Those taps having a coefficient with an absolute value less than the tap threshold set for the active tap are deactivated. The error of the system is computed and compared to the acceptable system error. If the computed system error is less than the acceptable system error, the tap threshold for each active tap is increased. The process of comparing the tap coefficients to the tap thresholds, deactivating taps with a coefficient less than the tap threshold and computing the resulting system error is repeated until the computed system error approaches the acceptable system error without exceeding the acceptable system error. In addition, the previously deactivated taps may be periodically activated and their coefficients once again compared to the tap threshold. If a coefficient is less than the tap threshold the tap is again deactivated. If a coefficient is greater than the tap threshold, the tap remains active.

Claims

1. A method of reducing power dissipation in a communications system having at least one adaptive filter having at least one tap, said method comprising:

setting at least one tap threshold; and

dynamically adjusting the at least one tap threshold to allow at least one tap to be activated or deactivated to converge an error to a prespecified acceptable target error;

wherein dynamically adjusting the at least one tap threshold comprises determining whether to deactivate a tap based upon an adjusted tap threshold;

wherein determining whether to deactivate a tap comprises;

determining a filter error; and

if the filter error is less than a prespecified acceptable filter target error, deactivating the tap.

2. A method of reducing power dissipation in a communications system having at least one adaptive filter having at least one tap, said method comprising:

setting at least one tan threshold; and

dynamically adjusting the at least one tan threshold to allow at least one tap to be activated or deactivated to converge an error to a prespecified acceptable target error;

wherein the at least one adaptive filter has a sufficient number of taps to accommodate for delay due to a length of the communications line;

said method further comprising partitioning the taps into a plurality of blocks each having at least one tap and wherein activation and deactivation of adaptive filters is preformed on a block-by-block basis, wherein the blocks are adjusted in a sequential manner starting at an input end of at least one adaptive filter.