Advanced constellation and demapper schemes for next generation digital terrestrial television broadcasting systems

206 p.Esta tesis presenta un nuevo tipo de constelaciones llamadas no uniformes. Estos esquemas presentan una eficacia de hasta 1,8 dB superior a las utilizadas en los últimos sistemas de comunicaciones de televisión digital terrestre y son extrapolables a cualquier otro sistema de comunicaciones (satélite, móvil, cable¿). Además, este trabajo contribuye al diseño de constelaciones con una nueva metodología que reduce el tiempo de optimización de días/horas (metodologías actuales) a horas/minutos con la misma eficiencia. Todas las constelaciones diseñadas se testean bajo una plataforma creada en esta tesis que simula el estándar de radiodifusión terrestre más avanzado hasta la fecha (ATSC 3.0) bajo condiciones reales de funcionamiento.Por otro lado, para disminuir la latencia de decodificación de estas constelaciones esta tesis propone dos técnicas de detección/demapeo. Una es para constelaciones no uniformes de dos dimensiones la cual disminuye hasta en un 99,7% la complejidad del demapeo sin empeorar el funcionamiento del sistema. La segunda técnica de detección se centra en las constelaciones no uniformes de una dimensión y presenta hasta un 87,5% de reducción de la complejidad del receptor sin pérdidas en el rendimiento.Por último, este trabajo expone un completo estado del arte sobre tipos de constelaciones, modelos de sistema, y diseño/demapeo de constelaciones. Este estudio es el primero realizado en este campo

On Construction of Bit-Interleaved Coded Modulation Systems with Iterative Decoding

A new construction of Bit-Interleaved Coded Modulation systems with Iterative Decoding (BICM-ID) is proposed to achieve the best performance over white additive Gaussian noise (AWGN) channels, assuming that the ideal feedback (IF) holds for iterative decoding. For a class of so-called regular IF mappings, new upper bounds for error probabilities are presented for both cases of BICM-ID systems using overall and in-line interleaving. Search results for component Recursive Systematic Convolutional (RSC) codes with and without puncturing are reported for 4-PSK and 8-PSK signal sets

High Speed Turbo Tcm Ofdm For Uwb And Powerline System

Turbo Trellis-Coded Modulation (TTCM) is an attractive scheme for higher data rate transmission, since it combines the impressive near Shannon limit error correcting ability of turbo codes with the high spectral efficiency property of TCM codes. We build a punctured parity-concatenated trellis codes in which a TCM code is used as the inner code and a simple parity-check code is used as the outer code. It can be constructed by simple repetition, interleavers, and TCM and functions as standard TTCM but with much lower complexity regarding real world implementation. An iterative bit MAP decoding algorithm is associated with the coding scheme. Orthogonal Frequency Division Multiplexing (OFDM) modulation has been a promising solution for efficiently capturing multipath energy in highly dispersive channels and delivering high data rate transmission. One of UWB proposals in IEEE P802.15 WPAN project is to use multi-band OFDM system and punctured convolutional codes for UWB channels supporting data rate up to 480Mb/s. The HomePlug Networking system using the medium of power line wiring also selects OFDM as the modulation scheme due to its inherent adaptability in the presence of frequency selective channels, its resilience to jammer signals, and its robustness to impulsive noise in power line channel. The main idea behind OFDM is to split the transmitted data sequence into N parallel sequences of symbols and transmit on different frequencies. This structure has the particularity to enable a simple equalization scheme and to resist to multipath propagation channel. However, some carriers can be strongly attenuated. It is then necessary to incorporate a powerful channel encoder, combined with frequency and time interleaving. We examine the possibility of improving the proposed OFDM system over UWB channel and HomePlug powerline channel by using our Turbo TCM with QAM constellation for higher data rate transmission. The study shows that the system can offer much higher spectral efficiency, for example, 1.2 Gbps for OFDM/UWB which is 2.5 times higher than the current standard, and 39 Mbps for OFDM/HomePlug1.0 which is 3 times higher than current standard. We show several essential requirements to achieve high rate such as frequency and time diversifications, multi-level error protection. Results have been confirmed by density evolution. The effect of impulsive noise on TTCM coded OFDM system is also evaluated. A modified iterative bit MAP decoder is provided for channels with impulsive noise with different impulsivity

Mitigation of impulsive noise for SISO and MIMO G.fast system

To address the demand for high bandwidth data transmission over telephone transmission lines, International Telecommunication Union (ITU) has recently completed the fourth generation broadband (4GBB) copper access network technology, known as G.fast. Throughout this thesis, extensively investigates the wired broadband G.fast coding system and the novel impulsive noise reduction technique has been proposed to improve the performance of wired communications network in three different scenarios: single-line Discrete Multiple Tone (DMT)- G.fast system; a multiple input multiple-output (MIMO) DMTG.fast system, and MIMO G.fast system with different crosstalk cancellation methods. For each of these scenarios, however, Impulsive Noise (IN) is considered as the main limiting factor of performance system. In order to improve the performance of such systems, which use higher order QAM constellation such as G.fast system, this thesis examines the performance of DMT G.fast system over copper channel for six different higher signal constellations of M = 32, 128, 512, 2048, 8192 and 32768 in presence of IN modelled as the Middleton Class A (MCA) noise source. In contrast to existing work, this thesis presents and derives a novel equation of Optimal Threshold (OT) to improve the IN frequency domain mitigation methods applied to the G.fast standard over copper channel with higher QAM signal constellations. The second scenario, Multi-Line Copper Wire (MLCW) G.fast is adopted utilizing the proposed MLCW Chen model and is compared to a single line G-fast system by a comparative analysis in terms of Bit-Error-Rate(BER) performance of implementation of MLCW-DMT G.fast system. The third scenario, linear and non-linear crosstalk crosstalk interference cancellation methods are applied to MLCW G.fas and compared by a comparative analysis in terms of BER performance and the complexity of implementation.University of Technology for choosing me for their PhD scholarship and The Higher Committee For Education Development in Iraq(HCED

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

A likelihood ratio analysis of digital phase modulation

Bibliography: p. 180-188.Although the likelihood ratio forms the theoretical basis for maximum likelihood (ML) detection in coherent digital communication systems, it has not been applied directly to the problem of designing good trellis-coded modulation (TOM) schemes. The remarkably simple optimal receiver of minimum shift keying (MSK) has been shown to result from the mathematical simplification of its likelihood ratio into a single term. The log-likelihood ratio then becomes a linear sum of metrics which can be implemented as a so-called simplified receiver, comprising only a few adders and delay elements. This thesis project investigated the possible existence of coded modulation schemes with similarly simplifying likelihood ratios, which would have almost trivially simple receivers compared to the Viterbi decoders which are typically required for maximum likelihood sequence estimation (MLSE). A useful notation, called the likelihood transform, was presented to aid the analysis of likelihood ratios. The work concentrated initially on computer-aided searches, first for trellis codes which may give rise to simplifying likelihood ratios for continuous phase modulation (CPM), and then for mathematical identities which may aid in the simplification of generic likelihood ratios for equal-energy modulation. The first search yielded no simplified receivers, and all the identities produced by the second search had structures similar to the likelihood ratio of MSK. These observations prompted a formal proof of the non-existence of simplified receivers which use information from more than two symbols in their observation period. This result strictly bounds the error performance that is possible with a simplified receiver. It was also proved that simplified receivers are only optimal for modulation schemes which use no more than two pairs of antipodal signals, and that only binary modulation schemes can have simplified receivers which use information from all the symbols in their observation period

Investigation of coding and equalization for the digital HDTV terrestrial broadcast channel

Includes bibliographical references (p. 241-248).Supported by the Advanced Telecommunications Research Program.Julien J. Nicolas

Técnicas de codificação para sistemas sem fios por infravermelhos

Doutoramento em Engenharia ElectrotécnicaEste trabalho insere-se na área de comunicações sem fios por infravermelhos. Os elevados níveis de ruído presente nos ambientes de trabalho e a grande variação espacio-temporal do canal de comunicação, bem como as limitações de potência de sinal por motivos de segurança, condicionam o desempenho deste tipo de comunicações. Existe desta forma uma notória necessidade de investigar técnicas de processamento que combatam as adversidades dos canais de comunicação e permitam obter melhores desempenhos. A escolha da técnica de modulação a usar é determinante no desempenho do sistema. Tendo como base a elevada eficiência de potência do esquema de modulação da posição de um pulso (PPM), foram estudadas outras modulações baseadas em PPM, tais como APPM e OPPM. A avaliação comparativa das várias propostas de modulação incluem parâmetros como eficiência de potência, eficiência espectral e complexidade de implementação. Uma das técnicas de processamento de sinal passíveis de incrementar o desempenho das comunicações é a introdução de codificação utilizando códigos correctores de erros. Para as várias modulações em estudo é feita uma avaliação do seu desempenho com codificação calculando a capacidade de canal para cada modulação. São analisadas as técnicas mais convencionais de codificação como os códigos de blocos e os códigos convolucionais. Por forma a tentar aumentar os ganhos de codificação são estudadas técnicas conjuntas de modulação e codificação recorrendo a códigos TCM, fazendo uma pesquisa computacional dos melhores códigos TCM para algumas das modulações propostas. Uma vez mais é efectuado um estudo comparativo dos desempenhos alcançados com sistemas sem codificação usando PPM e os sistemas com codificação TCM usando as modulações baseadas em PPM, ou seja as modulações APPM e OPPM. Os desempenho dos esquemas TCM propostos são avaliados em cenários próximos de uma implementação prática, nomeadamente, na avaliação de alguns sistemas de comunicação com adaptação das taxas de transmissão e em ambientes com dispersão multipercurso estudando o efeito da interferência entre-símbolos induzida. Este estudo integrou-se no projecto de investigação IRWLAN e apresenta parte do trabalho de dimensionamento e projecto do mecanismo de adaptação de taxas de transmissão.This work approaches the area of infrared wireless communications. Once the indoor office environment is populated with unregulated sources of light, creating a variable and noisy environment, the power consumption and eye safety concerns limit the average transmitter power. These conditions govern the optical link design making it a demanding task. Thus, there is a necessity on the processing techniques research able to fight the communication channel adversities and allow getting better performances. An accurate choice of the modulation technique to use is determinative in the system performance. The high average-power efficiency of pulse position modulation (PPM) schemes, motivated the study of other modulations based on PPM, such as APPM and OPPM. The comparative evaluation of these modulation proposals includes parameters as power efficiency, spectral efficiency and implementation complexity. One possible signal processing technique to improve the wireless infrared communications performance is the appliance of error correction codes. The performance capabilities, when coding is used with the modulations in study, are evaluated resorting to the channel capacity calculations. The use of conventional coding techniques, like convolucional and block codes, is analysed. But the classical separation of coding and modulation requires some bandwidth expansion, what may be unacceptable when the channel is bandwidth constrained. In these cases, one should combine the modulation and coding schemes accordingly TCM. In order to access the coding profits of APPM and OPPM schemes with TCM codes, relatively uncoded PPM systems, computational research of best codes are made. The performance for the proposed TCM codes is evaluated in near reality cenaries, namely, evaluating some multirate adaptive systems and considering the effects of inter-symbol interference induced by dispersion in multipath channels. The definition and design work for the transmission rate adaptation mechanism done as part of IRWLAN project is reported