In this paper, a new receiver structure is described for trellis-encoded signals transmitted over frequency selective channels. This receiver is based on the use of the generalized viterbi algorithm (GVA). Several app...
详细信息
ISBN:
(纸本)0780365070
In this paper, a new receiver structure is described for trellis-encoded signals transmitted over frequency selective channels. This receiver is based on the use of the generalized viterbi algorithm (GVA). Several applications are presented involving convolutional or polynomial block codes. Simulation results show that the proposed receiver structure provides close to optimal performances with reasonable complexity.
An algorithim for finding the optimal sectionalization for sectionalized trellises with respect to distinct optimality criterions was presented by Lafourcade and Vardy. In this paper, for linear block codes, we give a...
详细信息
An algorithim for finding the optimal sectionalization for sectionalized trellises with respect to distinct optimality criterions was presented by Lafourcade and Vardy. In this paper, for linear block codes, we give a direct method for finding the optimal sectionalization when the optimality criterion is chosen as the total number \E\ of the edges, the expansion index \E\ - \V\ + 1, or the quantity 2\E\ - \V\ + 1, only using the dimensions of the past and Future sub-codes. A more concrete method For determining the optimal sectionalization is given for the Reed-Muller codes with the natural lexicographic coordinate ordering.
In this work, we study an EPR-IV system for high density digital recording and compare it to the PRML recording system. A combinatorial optimization technique that uses the simulated annealing algorithm in conjunction...
详细信息
In this work, we study an EPR-IV system for high density digital recording and compare it to the PRML recording system. A combinatorial optimization technique that uses the simulated annealing algorithm in conjunction with a descent method is employed for optimization of partial response (PR) equalizers. The gradient algorithm to track variations of timing phase for the EPR-IV channel is investigated, Also, a generalized viterbi algorithm is used for detecting the EPR-IV system, Simulation results demonstrate that at high recording density, a coding gain over the PRML system can be obtained for the EPR-IV system with a comparable complexity.
In this paper, we propose the building of high rate space-time codes for multiple-input multiple-output (MIMO) block fading multipath additive white Gaussian noise channels by layering small compound space-time trelli...
详细信息
In this paper, we propose the building of high rate space-time codes for multiple-input multiple-output (MIMO) block fading multipath additive white Gaussian noise channels by layering small compound space-time trellis codes. To recover part of the spatial diversity between the different layers, we also study their concatenation with an outer code. Naturally, our space-time coding architecture puts the burden on the receiver complexity. As a main contribution of this paper, a near-optimal soft-input soft-output reduced-complexity trellis search algorithm is suggested for joint MIMO detection and inner decoding.
作者：
Guedon, YannCIRAD
UMR AMAP F-34398 Montpellier 5 France INRIA
F-34398 Montpellier 5 France
The knowledge of the state sequences that explain a given observed sequence for a known hidden Markovian model is the basis of various methods that may be divided into three categories: (i) enumeration of state sequen...
详细信息
The knowledge of the state sequences that explain a given observed sequence for a known hidden Markovian model is the basis of various methods that may be divided into three categories: (i) enumeration of state sequences;(ii) summary of the possible state sequences in state profiles;(iii) computation of a global measure of the state sequence uncertainty. Concerning the first category, the generalized viterbi algorithm for computing the top L most probable state sequences and the forward-backward algorithm for sampling state sequences are derived for hidden semi-Markov chains and hidden hybrid models combining Markovian and semi-Markovian states. Concerning the second category, a new type of state (and state change) profiles is proposed. The viterbi forward-backward algorithm for computing these state profiles is derived for hidden semi-Markov chains and hidden hybrid models combining Markovian and semi-Markovian states. Concerning the third category, an algorithm for computing the entropy of the state sequence that explains an observed sequence is proposed. The complementarity and properties of these methods for exploring the state sequence space (including the classical state profiles computed by the forward-backward algorithm) are investigated and illustrated with examples. (c) 2006 Elsevier B.V. All rights reserved.
The generalized viterbi algorithm, a direct extension of the viterbialgorithm for hidden Markov models (HMMs), has been used to find the most likely state sequence for hierarchical HMMs. However, the generalized Vite...
详细信息
The generalized viterbi algorithm, a direct extension of the viterbialgorithm for hidden Markov models (HMMs), has been used to find the most likely state sequence for hierarchical HMMs. However, the generalized viterbi algorithm finds the most likely whole level state sequence rather than the most likely upper level state sequence. In this paper, we propose a marginalized viterbialgorithm, which finds the most likely upper level state sequence by marginalizing lower level state sequences. We show experimentally that the marginalized viterbialgorithm is more accurate than the generalized viterbi algorithm in terms of upper level state sequence estimation. (C) 2013 Published by Elsevier Ltd.
In this letter, the blind acquisition performance of PSP is discussed. Based on the theory of indistinguishable sequences [4], modifications to conventional PSP are suggested that improve acquisition performance signi...
详细信息
In this letter, the blind acquisition performance of PSP is discussed. Based on the theory of indistinguishable sequences [4], modifications to conventional PSP are suggested that improve acquisition performance significantly. The effects of tree search and list-based algorithms on PSP are also discussed. In blind channel estimation, the performance of list-based algorithms is better than trellis-based algorithms and can be further,enhanced using the proposed techniques. The blind acquisition techniques described here can be used for other applications like multi-user detection or space-time trellis codes.
BackgroundConformational transitions are implicated in the biological function of many proteins. Structural changes in proteins can be described approximately as the relative movement of rigid domains against each oth...
详细信息
BackgroundConformational transitions are implicated in the biological function of many proteins. Structural changes in proteins can be described approximately as the relative movement of rigid domains against each other. Despite previous efforts, there is a need to develop new domain segmentation algorithms that are capable of analysing the entire structure database efficiently and do not require the choice of protein-dependent tuning parameters such as the number of rigid *** develop a graph-based method for detecting rigid domains in proteins. Structural information from multiple conformational states is represented by a graph whose nodes correspond to amino acids. Graph clustering algorithms allow us to reduce the graph and run the viterbialgorithm on the associated line graph to obtain a segmentation of the input structures into rigid domains. In contrast to many alternative methods, our approach does not require knowledge about the number of rigid domains. Moreover, we identified default values for the algorithmic parameters that are suitable for a large number of conformational ensembles. We test our algorithm on examples from the DynDom database and illustrate our method on various challenging systems whose structural transitions have been studied *** results strongly suggest that our graph-based algorithm forms a novel framework to characterize structural transitions in proteins via detecting their rigid domains. The web server is available at http://***/webservice/.
暂无评论