System for low complexity adaptive ECHO and NEXT cancellers

A communications transceiver comprising:

• i. N transmitters, where N is a positive integer greater than 1, each containing a precoder to process an input signal and compute a compensation signal;
• ii. N receivers, each comprising:
• (a) a first filter used as a NEXT canceller, to filter a sum of the input signal and the compensation signal of the precoder of a near-end transmitter;
• (b) a weight update block to compute a set of tap weights for the NEXT canceller, coupled to either the compensation signal or the input signal of the precoder of the corresponding near-end transmitter or to the sum of these two signals;
• (c) a second filter with transfer function 1/H(z), coupled to the output of the NEXT canceller;
• (d) computing the difference between the output of the second filter and the received signal to generate an error signal;
• (e) filtering the error signal by a third filter H(z), whose transfer function is the reciprocal of that of the second filter, and using the output of the third filter as an input to the corresponding weight update block.

An integrated circuit implementing a communications transceiver comprising:

• i. N transmitters, where N is a positive integer, each containing a precoder to process an input signal and compute a compensation signal;
• ii. N receivers, each comprising:
• (a) a first filter used as an echo canceller, to filter a sum of the input signal and the compensation signal of the precoder of the corresponding transmitter;
• (b) a weight update block, coupled to either the compensation signal or the input signal of the precoder of the corresponding transmitter or the sum of these two signals;
• (c) a second filter with transfer function 1/H(z), coupled to the output of the echo canceller;
• (d) a subtractor to compute the difference between the output of the second filter and the received signal to generate an error signal;
• (e) a third filter H(z), whose transfer function is reciprocal of that of the second filter, to filter the error signal and using the output of the this filter as an input to the corresponding weight update block.

An integrated circuit implementing a communications transceiver comprising:

• i. N transmitters, where N is a positive integer greater than 1, each containing a precoder to process an input signal and compute a compensation signal;
• ii. N receivers, each comprising:
• (a) a first filter used as a NEXT canceller, to filter a sum of the input signal and the compensation signal of the precoder of a corresponding near-end transmitter;
• (b) a weight update block, coupled to either the compensation signal or the input signal of the precoder of the corresponding near-end transmitter or the sum of these two signals;
• (c) a second filter with transfer function 1/H(z), coupled to the output of the NEXT canceller;
• (d) a subtractor to compute the difference between the output of the second filter and the received signal to generate an error signal;
• (e) a third filter H(z), whose transfer function is reciprocal of that of the second filter, to filter the error signal and using the output of the this filter as an input to the corresponding weight update block.

An echo canceller in a precoded communications transceiver, comprising:

• a transmitter, comprising a precoder, to process an input signal and compute a compensation signal;
• a receiver comprising:
• a received signal;
• a first filter loop comprising:
• a first filter, with a transfer function H(z), to filter a first error signal;
• a second filter coupled to the output of the first error signal to compute a set of tap weights;
• a third filter to filter a sum of the compensation signal and the input signal of the precoder of the transmitter using the tap weights computed by the second filter;
• and
• a fourth filter with transfer function 1/H(z), the reciprocal of that of the first filter, to filter the output of the third filter;
• where the first error signal is computed by taking a difference of the received signal and the output of the fourth filter.

A near-end cross-talk canceller in a multiple-input multiple-output precoded communication transceiver, comprising:

• a first transmitter, comprising a first precoder, to process a first input signal and compute a first compensation signal;
• a second transmitter, comprising a second precoder, to process a second input signal and compute a second compensation signal;
• a first receiver comprising a first received signal;
• and a second receiver comprising a second received signal;
• the first receiver further comprising:
• a first loop comprising:
• a first filter, with a transfer function H(z), to filter a first error signal;
• a second filter coupled to the output of the first error signal to compute a set of tap weights;
• a third filter to filter a sum of the compensation signal and the input signal of the second precoder of the second transmitter using the tap weights computed by the second filter;
• and
• a fourth filter with a transfer function 1/H(z), the reciprocal of that of the first filter, to filter the output of the third filter;
• where the first error is computed by taking the difference of the first received signal and the output of the fourth filter.