US RE45,794 E1Granted

Crosstalk cancellation using sliding filters

AssigneeMarvell International Ltd.

InventorGavin D. Parnaby

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Abstract

A crosstalk cancellation system and method is disclosed for use in a multi-channel communication system. Crosstalk which couples between channels is cancelled through use of an in-line FFE filter and in-line delay. A cross-connect system associated with each channel includes a cross-connect delay and cross-connect filter. The cross-connect system generates a cancellation signal for each of the channels, which is routed into a junction. The junction subtracts the cancellation signal from the received signal, which has also been delayed and filtered, to remove unwanted cross-talk. During training, cancellation magnitude is monitored at various delay offsets to determine which offset and corresponding filter coefficients, for each delay, maximizes cancellation. The filters are set with filter coefficients that maximize cancellation. The cross-connect delay with the maximum offset is set to zero and its calculated offset amount is established as the in-line delay offset. The other cross-connect delay offsets are adjusted accordingly.

Claims25

Dependent claims

A method for training a crosstalk cancellation system that comprises one or more in-line filters, one or more in-line delays, one or more cross-connect filters, and one or more cross-connect delays, the method comprising, for each channel the method comprising:

providing a crosstalk cancellation system comprising one or more in-line filters, one or more in-line delays, one or more cross-connect filters, one or more cross-connect delays and a memory;
setting one or more in-line delays and one or more cross-connect delays to zero delay;
training the one or more in-line filters;
training the one or more cross-connect filters to generate cross-connect filter coefficients;
store storing the cross-connect filter coefficients;
continue continuing to adapt the one or more in-line filters and store resulting in-line filter coefficients with the cross-connect filter coefficient as filter coefficient sets;
establishing an offset in one or more in-line delays;
retraining the one or more in-line filters and the one or more cross-talk filters with the established offset to establish new coefficient set;
storing the new coefficient set;
establishing additional offsets and for each additional offset:
retraining the one or more in-line filters and the one or more cross-talk filters to create a filter coefficient set associated with each offset;
storing the additional filter coefficients sets associated with each offset;
analyze analyzing the filter coefficient sets to determine which offset maximizes cancellation to thereby identify a maximum cancellation offset;
establish establishing one or more in-line filters with coefficient set which corresponds to maximum cancellation offset;
establish establishing one or more in-line delays with offset which corresponds to maximum cancellation offset for victim-interferer pair that needs the largest delay to maximize its cancellation;
establish establishing one or more cross-connect filters with a coefficient set which corresponds to maximum cancellation offset;
and
establish establishing one or more cross-connect delays with offset which corresponds to maximum cancellation offset.

15 more elements

A crosstalk cancellation system comprising:

a plurality of receivers corresponding to a plurality of respective communication channels, wherein each receiver in the plurality of receivers includes
an in-line filter,
an in-line delay, and
a cross-connect system that includes, for each other receiver in the plurality of receivers, (i) a cross-connect filter in a path coupled to the other receiver and (ii) a cross-connect delay in the path coupled to the other receiver;
and
a processor configured to, for each receiver in the plurality of receivers, establish settings for (i) the in-line filter, (ii) the in-line delay, (iii) each of the cross-connect filters, and (iv) each of the cross-connect delays, at least in part by
iteratively training, with a different one of a plurality of in-line delay values being applied to the in-line delay during each iteration, (i) the in-line filter and (ii) at least one of the cross-connect filters to generate a plurality of sets of filter coefficients,
identifying (i) a first in-line delay value of the plurality of in-line delay values, and (ii) a first set of filter coefficients, of the plurality of sets of filter coefficients, that maximize crosstalk cancellation,
setting the in-line filter based at least in part on the first set of filter coefficients, and
setting the in-line delay based at least in part on the first in-line delay value.

7 more elements

A method for training a crosstalk cancellation system, wherein the crosstalk cancellation system comprises a plurality of receivers corresponding to a plurality of respective communication channels, wherein each receiver in the plurality of receivers includes (i) an in-line filter, (ii) an in-line delay, and (iii) a cross-connect system that includes, for each other receiver in the plurality of receivers, a cross-connect filter in a path coupled to the other receiver and a cross-connect delay in the path coupled to the other receiver, the method comprising, for each receiver in the plurality of receivers:

establishing settings for (i) the in-line filter, (ii) the in-line delay, (iii) each of the cross-connect filters, and (iv) each of the cross-connect delays, wherein establishing the settings includes
iteratively training, with a different one of a plurality of in-line delay values being applied to the in-line delay during each iteration, (i) the in-line filter and (ii) at least one of the cross-connect filters to generate a plurality of sets of filter coefficients,
identifying (i) a first in-line delay value of the plurality of in-line delay values, and (ii) a first set of filter coefficients, of the plurality of sets of filter coefficients, that maximize crosstalk cancellation,
setting the in-line filter based at least in part on the first set of filter coefficients;
and
setting the in-line delay based at least in part on the first in-line delay value.

3 more elements

A tangible, non-transitory computer-readable medium storing instructions that, when executed by a processor in a crosstalk cancellation system that comprises a plurality of receivers corresponding to a plurality of respective communication channels, wherein each receiver in the plurality of receivers includes (i) an in-line filter, (ii) an in-line delay, and (iii) a cross-connect system that includes, for each other receiver in the plurality of receivers, a cross-connect filter in a path coupled to the other receiver and a cross-connect delay in the path coupled to the other receiver, cause the processor to, for each receiver in the plurality of receivers:

establish settings for (i) the in-line filter, (ii) the in-line delay, (iii) each of the cross-connect filters, and (iv) each of the cross-connect delays, wherein the instructions cause the processor to establish the settings at least by
identifying (i) a first in-line delay value of the plurality of in-line delay values, and (ii) a first set of filter coefficients, of the plurality of sets of filter coefficients, that maximize crosstalk cancellation,
setting the in-line filter based at least in part on the first set of filter coefficients, and
setting the in-line delay based at least in part on the first in-line delay value.

1 more element

Dependencies are inferred from the claim text.