A reduced complexity adaptive soft-output M-algorithm for turbo-equalization

In this paper we present a reduced complexity soft-output detection algorithm called the adaptive SO-M-algorithm for turbo-equalization, which is a suboptimum version of the Lee algorithm based on the principle of the M-algorithm. In the adaptive SO-M-algorithm, the breadth and depth parameters are adaptively adjusted according to the convergence process of turbo-equalization, and a good performance/complexity ratio is obtained for channels with severe ISI.