Expanding window fountain codes for unequal error protection

A novel approach to provide unequal error protection (UEP) using rateless codes over erasure channels, named Expanding Window Fountain (EWF) codes, is developed and discussed. EWF codes use a windowing technique rather than a weighted (non-uniform) selection of input symbols to achieve UEP property. The windowing approach introduces additional parameters in the UEP rateless code design, making it more general and flexible than the weighted approach. Furthermore, the windowing approach provides better performance of UEP scheme, which is confirmed both theoretically and experimentally

JOURNAL OF AUTOMATIC CONTROL, UNIVERSITY OF BELGRADE, VOL 16:33-36, 2006 © ACE Spectrum of LDPC Codes

Abstract—Construction of short-length LDPC codes with good, both waterfall and error-floor, behavior is still an attractive research problem. Recently proposed construction algorithms in this field are based on remarkably simple ideas, but yet, their effectiveness can still be questioned. In this paper we investigate a novel measure of goodness of a given LDPC code, namely its ACE spectrum, based on a previously introduced ACE metrics associated with each cycle in LDPC code graph. Index Terms—Approximated Cycle EMD (ACE) metric