LP Decoding meets LP Decoding: A Connection between Channel Coding and Compressed Sensing (2009)
Dimakis, Alexandros G., Vontobel, Pascal O.
This is a tale of two linear programming decoders, namely channel coding linear programming decoding (CC-LPD) and compressed sensing linear programming decoding (CS-LPD). So far, they have evolved...
Absdet-Pseudo-Codewords and Perm-Pseudo-Codewords: Definitions and Properties (2009)
Smarandache, Roxana, Vontobel, Pascal O.
The linear-programming decoding performance of a binary linear code crucially depends on the structure of the fundamental cone of the parity-check matrix that describes the code. Towards a better...
A Factor-Graph Approach to the Context-Tree Weighting Method (2008)
Factor graphs [1, 2] (FGs) are graphical models with origins in coding theory. The sum-product and the max-product algorithms (SPA/MPA), which operate by message passing in an FG, subsume a great...
for Channels With Memory (2008)
Dieter M. Arnold, Hans-andrea Loeliger, Pascal O. Vontobel, Ar Kavčić, Senior Member, Wei Zeng, ...
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Lower Bounds, Dieter Arnold, Ar Kavčić, Hans-andrea Loeliger, Pascal O. Vontobel, Wei Zeng
It has recently become feasible to compute information rates of finite-state source/channel models with not too many states. Such methods can also be used to compute upper and lower bounds on the...
Extended Summary Background (2007)
Pascal O. Vontobel, Hans-andrea Loeliger
Factor graphs are graphical models with origins in coding theory. It is well known that Kalman filtering is an instance of the generic sum(mary)-product algorithm on the corresponding factor graph....
Kavcic proposed in [1] an algorithm that optimizes the parameters of a Markov source at the input to a finite-state machine channel in order to maximize the mutual information rate. Numerical results...
Characterizations of pseudo-codewords of LDPC codes (2006)
Ralf Koetter, Pascal O. Vontobel, L. Walker
Abstract. An important property of high-performance, low complexity codes is the existence of highly efficient algorithms for their decoding. Many of the most efficient, recent graph-based...
Lower Bounds on the Minimum Pseudo-weight of Linear Codes (2004)
Pascal O. Vontobel, Ralf Koetter, X ||x
Abstract — We discuss two techniques for obtaining lower bounds on the (AWGN channel) pseudo-weight of binary linear codes. Whereas the first bound is based on the largest and second-largest...
Simulation-Based Computation of Information Rates for Channels with Memory (2004)
Dieter Arnold, Hans-Andrea Loeliger, For Channels Memory, Aleksandar Kavcic, Pascal O. Vontobel, Ar Kavcic, ...
The information rate of finite-state source/channel models can be accurately estimated by sampling both a long channel input sequence and the corresponding channel output sequence, followed by a...
Graph-Covers and Iterative Decoding of Finite Length Codes (2003)
Ralf Koetter, Pascal O. Vontobel
Codewords in finite covers of a Tanner graph G are characterized. Since iterative, locally operating decoding algorithms cannot distinguish the underlying graph G from any covering graph, these...
Pascal Vontobel Coordinated, Pascal O. Vontobel
Factor graphs are graphical models with origins in coding theory. The sum-product and the maxproduct algorithms, which operate by message passing on a factor graph, subsume a great variety of...
Algebraic coding for iterative decoding / (2003)
Zugl.: Zürich, Eidgenössische Techn. Hochsch., Diss., 2003.
On the Construction of Turbo Code Interleavers Based on Graphs with Large Girth Pa (2002)
We discuss how interleavers for parallel concatenated turbo codes with good minimum distance can be derived from graphs having large girth, i.e. graphs whose length of the shortest cycle is large.
On Factor Graphs And Electrical Networks (2002)
Pascal O . Vontobel, Hans-andrea Loeliger
Factor graphs are graphical models with origins in coding theory. The sum-product and the max-product algorithms, which operate by message passing in a factor graph, subsume a great variety of...
Constructions of LDPC codes using Ramanujan graphs and ideas from Margulis (2000)
Joachim Rosenthal, Pascal O. Vontobel
Some twenty years ago G.A. Margulis [8] proposed an algebraic construction of LDPC codes. In this paper we analyze the performance of the codes proposed by Margulis. Mimicking the construction of...