130 research outputs found
Bounds on the Error Probability of Raptor Codes under Maximum Likelihood Decoding
In this paper upper and lower bounds on the probability of decoding failure
under maximum likelihood decoding are derived for different (nonbinary) Raptor
code constructions. In particular four different constructions are considered;
(i) the standard Raptor code construction, (ii) a multi-edge type construction,
(iii) a construction where the Raptor code is nonbinary but the generator
matrix of the LT code has only binary entries, (iv) a combination of (ii) and
(iii). The latter construction resembles the one employed by RaptorQ codes,
which at the time of writing this article represents the state of the art in
fountain codes. The bounds are shown to be tight, and provide an important aid
for the design of Raptor codes.Comment: Submitted for revie
Erasure Codes with a Banded Structure for Hybrid Iterative-ML Decoding
This paper presents new FEC codes for the erasure channel, LDPC-Band, that
have been designed so as to optimize a hybrid iterative-Maximum Likelihood (ML)
decoding. Indeed, these codes feature simultaneously a sparse parity check
matrix, which allows an efficient use of iterative LDPC decoding, and a
generator matrix with a band structure, which allows fast ML decoding on the
erasure channel. The combination of these two decoding algorithms leads to
erasure codes achieving a very good trade-off between complexity and erasure
correction capability.Comment: 5 page
LT Code Design for Inactivation Decoding
We present a simple model of inactivation decoding for LT codes which can be
used to estimate the decoding complexity as a function of the LT code degree
distribution. The model is shown to be accurate in variety of settings of
practical importance. The proposed method allows to perform a numerical
optimization on the degree distribution of a LT code aiming at minimizing the
number of inactivations required for decoding.Comment: 6 pages, 7 figure
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
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. © 2009 IEEE
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