ISI Cancellation with Iterative Processing and Selective Decisions

This paper presents a computationally efficient linear inter-symbol interference (ISI) canceller (LIC) algorithm using turbo-processing methods and selective decision (SD). The proposed algorithm is based on simple and efficient hard decision processing methods augmented by a simple decision selection device that uses stop-and-go (SAG) type criterion [1] to assess the reliability of the transmit signal estimate produced by channel decoder. When the transmit signal estimate is deemed reliable, it is selected as feedback to LIC. Otherwise, a more reliable replacement is used in the next iteration that will result in reduction of error propagation and hence improvement of LIC performance. The new algorithm is shown to outperform its counterpart that does not use selective decisions in term of BER for distorted communication channels.