Method and apparatus for adaptive dual decision equalization in multipath fading channels

摘要

An adaptive equalization method and device which provides for the equalization of symbol sequences sent through fading multipath channels with time and frequency dispersion. By using a trainer system to supply an estimate of the received symbol sequence to a trainee system, equalization of the received symbol sequences is accomplished without the need for training sequences and with the ability of compensating for spectral nulls without a substantial increase in the noise in the system. The trainer system is configured as a decision directed equalizer with a feed forward filter having the received symbol sequence as input and connected to a decision element that outputs decided symbols. The trainee system is similar to decision feed back equalization in that it has a feed forward filter, a feedback filter and a decision element but, differs in that the input to the feed back filter is provided by the trainer system. The feed forward filter of the trainee system takes received symbol sequence as input. The output of the feed forward filter and the feedback filter of the trainee system is provided to the decision element which outputs the equalized symbol sequences.