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Design and Implementation Aspects of
Multilevel Codes in Hierarchical
Broadcasting Communications
Der Technischen Fakultät der
Universität Erlangen-Nürnberg
zur Erlangung des Grades
DOKTOR-INGENIEUR
vorgelegt von
Aharón Jesús Vargas Barroso
Erlangen–2011Als Dissertation genehmigt von
der Technischen Fakultät der
Universität Erlangen-Nürnberg
Tag der Einreichnung: 01.07.2011
Tag der Promotion: 29.09.2011
Dekan: Prof. Dr.-Ing. Reinhard German
Berichterstatter: Prof. Dr.-Ing. Wolfgang Gerstacker
Prof. Dr.-Ing. Albert HeubergerAcknowledgement
Especially I thank Prof. Wolfgang Gerstacker for supervising this thesis in an
unique and excellent way, and for all the concise and detailed advises, guidance and
support. Many thanks to Prof. Albert Heuberger for his interest in my work and for
acting as co–referee on my thesis committee.
My best thanks go to M. Breiling for his awesome guidance during the first steps
of my thesis and his continuous ideas and useful discussions. Without him, I would
not have completed this work. Thanks to the colleagues at University of Erlangen,
for their support and the nice common time.
I am indebted to the Fraunhofer Institute for Integrated Circuits in Erlangen for
supporting me during my thesis. In particular, I would like to thank M. Schlicht for
sparing me from project work during the final phase and thereby giving me the time
to finish my thesis.
I would like to thank my parents and family for their continuous encouragement
during my life. Most of all, my warmest thanks I owe to my wife Nayra for her great
support in all the difficult times during my PhD studies.Abstract
Theobjectiveofthisthesisistoprovidedifferentprotectionlevelstoabroadcasting
satellitesystembyemployingamultilevelcoding(MLC)scheme. First,thedesignand
evaluation of an MLC scheme in a broadcasting environment is investigated, defining
some practical rules to help the design of such as scheme. The complexity of an MLC
scheme increases as the modulation order increases because the demapping process
gets more complex as the number of constellation points increase. Low complexity
algorithms for an MLC scheme which uses multi–stage decoding are proposed to
reduce the complexity by keeping the overall performance of the system.
Adifferentapproachisinvestigatedtoincreasethenumberoflevelswithoutincreas-
ing the complexity, that is, the use of multidimensional constellations. An algorithm
to find appropriate partitionings for these constellations is presented, showing the
feasibility of increasing the protection levels by increasing the number of dimensions.
On the other hand, the behavior of the proposed MLC scheme under real impairment
effects associated to satellite communications is investigated, providing some rules to
mitigate the losses introduced by these impairments.vii
Contents
1 Introduction 1
1.1 Satellite Communications . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Hierarchical Channel Coding . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Organization and Contribution . . . . . . . . . . . . . . . . . . . . . . 7
2 Fundamentals 11
2.1 Digital Communication System . . . . . . . . . . . . . . . . . . . . . . 11
2.2 System Model of a Multilevel Coding (MLC) System for Broadcasting
Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.2.1 Transmitter Structure . . . . . . . . . . . . . . . . . . . . . . . 15
2.2.1.1 Forward Error Correction (FEC) . . . . . . . . . . . . 16
2.2.1.2 Partitioning strategy . . . . . . . . . . . . . . . . . . 18
2.2.2 Channel Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.2.3 Receiver Structure . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.3 Channel Capacity and Mutual Information (MI) . . . . . . . . . . . . . 26
2.4 Multidimensional (MD) Constellations . . . . . . . . . . . . . . . . . . 29
2.5 Standards for Satellite Broadcasting Communications . . . . . . . . . 30
2.5.1 The DVB–S2 Standard . . . . . . . . . . . . . . . . . . . . . . 30
2.5.2 The DVB–SH Standard . . . . . . . . . . . . . . . . . . . . . . 31
2.5.3 The ESDR Standard . . . . . . . . . . . . . . . . . . . . . . . . 33
3 Design of MLC/Multi–Stage Decoding (MSD) Systems for Broadcasting
Communications 35
3.1 Motivation of the use of MLC . . . . . . . . . . . . . . . . . . . . . . . 35
3.2 Design of an Ideal MLC Scheme . . . . . . . . . . . . . . . . . . . . . . 38
3.2.1 Comments on the Partitioning Strategy . . . . . . . . . . . . . . 40
3.3 MSD Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.3.1 Characterizing the FEC Block . . . . . . . . . . . . . . . . . . . 42
3.3.2 Designing the Levels . . . . . . . . . . . . . . . . . . . . . . . . 44
3.3.3 MSD Chart applications . . . . . . . . . . . . . . . . . . . . . . 46
3.4 MLC under Land–Mobile–Satellite (LMS) Channels . . . . . . . . . . . 48
3.4.1 Outage Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4 Low Complexity Demapping Algorithms for MLC/MSD Systems 57
4.1 Log Separation Algorithm (LSA) . . . . . . . . . . . . . . . . . . . . . 58
4.2 Jacobian Maximum Algorithm (JMA) . . . . . . . . . . . . . . . . . . 61
4.3 Jacobian Refined Algorithm (JRA) . . . . . . . . . . . . . . . . . . . . 65
4.4 Mixed Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.5 Comments on the Complexity . . . . . . . . . . . . . . . . . . . . . . . 704.6 Evaluation of Low Complexity Demapping Algorithms . . . . . . . . . 71
4.6.1 Quality of Generated Log–Likelihood Ratios (LLRs) . . . . . . . 71
4.6.1.1 LLR Consistency Check . . . . . . . . . . . . . . . . . 72
4.6.1.2 Error Variance Analysis . . . . . . . . . . . . . . . . . 76
4.6.2 Coded Transmission . . . . . . . . . . . . . . . . . . . . . . . . 78
4.6.2.1 TransmissionoverAdditiveWhiteGaussianNoise(AWGN)
Channel . . . . . . . . . . . . . . . . . . . . . . . . . 79
4.6.2.2 Transmission over Rayleigh Fading Channel . . . . . . 83
5 Use of MD Constellations in MLC/MSD Systems 89
5.1 Design of MD Constellations for MLC/MSD Schemes with Block La-
beling (BL) Partitioning . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.2 Evaluation of MD Constellations for MLC Schemes with BL Partition-
ing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.2.1 Uniform MD Constellations . . . . . . . . . . . . . . . . . . . . 93
5.2.2 Non–Uniform MD Constellations . . . . . . . . . . . . . . . . . 97
5.2.3 General MD Constellations . . . . . . . . . . . . . . . . . . . . 99
5.2.4 Analysis and Comparison . . . . . . . . . . . . . . . . . . . . . 100
5.3 EvaluationofLowComplexityDemappingAlgorithmsforMDMLC/MSD
Schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
6 Satellite System Impairments in MLC/MSD Systems 105
6.1 Introduction to Satellite System Impairments . . . . . . . . . . . . . . 105
6.2 Modeling the Satellite System Impairments . . . . . . . . . . . . . . . 106
6.2.1 Channel Estimation Errors . . . . . . . . . . . . . . . . . . . . 108
6.2.2 Phase Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
6.2.3 Non–Linearity of High Power Transmitters . . . . . . . . . . . 111
6.3 Evaluation of the Satellite System Impairments . . . . . . . . . . . . . 112
6.3.1 Channel Estimation Errors . . . . . . . . . . . . . . . . . . . . . 113
6.3.2 Phase Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
6.3.3 Non–Linearity of Power Transmitters . . . . . . . . . . . . . . . 116
7 The DVB–SH Standard. Practical Case 121
7.1 The DVB–SH interleaver . . . . . . . . . . . . . . . . . . . . . . . . . . 122
7.2 Adding Different Levels of Quality of Service (QoS) to the DVB–SH
Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
7.2.1 Early–Uniform Interleaver . . . . . . . . . . . . . . . . . . . . . 123
7.2.2 Molded Interleaver . . . . . . . . . . . . . . . . . . . . . . . . . 125
7.2.2.1 Analysis and Evaluation of the Molded Interleaver . . 127
7.2.3 Hierarchical Modulation . . . . . . . . . . . . . . . . . . . . . . 131
8 Conclusions 135
A LLR soft output calculation 139
B Binary Switching Algorithm. Pseudo Code 143ix
C German translations 145
C.1 Titel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
C.2 Zusammenfassung . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Glossary 147
Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Mathematical Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
Bibliography 153x

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