The soft-output principle - reminiscences and new developments

Kurzfassung

A major breakthrough in digital communications was the provisioning of soft outputs at each processing stage, with appropriate capabilities to use this as soft inputs in the next processing stage. This allowed for much more performant receivers especially in difficult mobile radio channel conditions, and set the stage for iterative processing. This article will outline the development of soft output algorithms over the last two decades along with associated state-of-the-art applications and conclude with an outlook towards novel applications of the soft principle.