[en] Consider a function whose set of vector arguments with known distribution is described by a trellis. For a certain class of functions, the distribution of the function values can be calculated in the trellis. The forward/backward recursion known from the BCJR algorithm [2] is generalized to compute the moments of these distributions. In analogy to the symbol probabilities, by introducing a constraint at a certain depth in the trellis we obtain symbol distributions and symbol moments, respectively. These moments are required for an efficient implementation of the discriminated belief propagation algorithm in [8], and can furthermore be utilized to compute conditional entropies in the trellis. The moment computation algorithm has the same asymptotic complexity as the BCJR algorithm. It is applicable to any commutative semi-ring, thus actually providing a generalization of the Viterbi algorithm [10].
Disciplines :
Computer science
Identifiers :
UNILU:UL-ARTICLE-2009-263
Author, co-author :
Heim, Axel
Sidorenko, Vladimir
Sorger, Ulrich ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Computer Science and Communications Research Unit (CSC)
External co-authors :
yes
Language :
English
Title :
Computation of distributions and their moments in the trellis
Publication date :
2008
Journal title :
Advances in Mathematics of Communications
ISSN :
1930-5338
Publisher :
American Institute of Mathematical Sciences, Springfield, United States - Missouri