Adaptive equalizers and methods for carrying out equalization with a precoded transmitter

A communication system, comprising:

• a transmitter coupled to a first end of a communication channel, the transmitter transmitting data signals over the communication channel, the transmitter further comprising a precoder using transmitter coefficients for pre-equalizing the channel for post-cursor intersymbol interference;
• and
• a receiver, coupled to a second end of the communication channel, the receiver further comprising:
• a feed forward equalizer receiving a signal from the communication channel, the feed forward equalizer equalizing variations in pre-cursor intersymbol interference resulting from changes in characteristics of the channel and providing an output signal to an error correction decoder;
• a decision circuit, coupled to the feed forward equalizer, for generating error vectors in response to the output signal of the feed forward equalizer;
• and
• a decision feedback equalizer, coupled to the decision circuit, the decision feedback equalizer monitoring the pre-cursor intersymbol interference of the channel, determining when the transmitter coefficients to the precoder warrant updating, and generating a signal indicating that an update to the transmitter coefficients to the precoder is warranted.

A method for performing equalization of a communication channel having a transmitter with a precoder coupled thereto, the precoder using transmitter coefficients for pre-equalizing the communication channel for post-cursor intersymbol interference, the method comprising the steps of:

• receiving a signal from the communication channel;
• equalizing variations in pre-cursor intersymbol interference in the signal resulting from changes in characteristics of the channel using a feed forward equalizer and providing an output signal to an error correction decoder;
• generating error vectors in response to the output signal of the feed forward equalizer by a decision circuit;
• monitoring the pre-cursor intersymbol interference of the channel by the decision feedback equalizer;
• determining when the transmitter coefficients to the precoder warrant updating based upon the monitored pre-cursor intersymbol interference;
• and
• generating a signal indicating that an update to the transmitter coefficients to the precoder is warranted.