On APP Decoding

Carlos R.P. Hartmann, Syracuse University
Luther D. Rudolph, Syracuse University
Kishan Mehrotra, Syracuse University, Department of Electrical Engineering and Computer Science
Guy J. Snedeker, Syracuse University

SU-CIS-81-05

Description/Abstract

In this paper we show that APP decoding for a linear code C is optimum not for C, but for a minimum-distance-2 code which contains C as a subcode when the codewords of are transmitted with equal probability. However, APP decoding is shown to be a symptotically optimum for C for high SNR when C is a binary one-step orthogonolizable code with equiprobable codewords transmitted over the AWGN channel.