Adaptive combination of equalization and decoding of error-correcting codes

A combined technique of equalization and decoding of an error-correcting code is introduced. It is very useful for achieving highly reliable communications in channels corrupted by noise and intersymbol interference, such as a telephone subscriber channel and a mobile communications channel. Two types of structures and algorithms for combined equalization and decoding are presented. Equalization can achieve stable adaptation for unknown characteristics and/or variance of a channel by using some information obtained in decoding, while decoding can be modified to adapt to the condition of a channel by exploiting information from equalization. In particular, a method to utilize the reliability of decoded data for equalization and an adaptive decoding scheme based on the combined decoding and equalization are proposed. Theoretical error probability and simulation results are given to evaluate the communication system using the combined technique