A test signal is transmitted over a communication channel and the signal is received by a receiver. The temporal evolution of the test signal is represented in a matrix and the inverse of the test signal evolution matrix is stored in the receiver. Samples of the received signal and the test signal evolution...http://www.google.com/patents/US5047859?utm_source=gb-gplus-sharePatent US5047859 - Method and apparatus for communication channel identification and signal restoration
