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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Coded modulation techniques with bit interleaving and iterative processing for impulsive noise channels

Bui, Trung Quang 22 August 2006
Power line communications (PLC) surfers performance degradation due mainly to impulsive noise interference generated by electrical appliances. This thesis studies coded modulation techniques to improve the spectral efficiency and error performance of PLC. Considered in the first part is the application of bit-interleaved coded modulation with iterative decoding (BICM-ID) in class-A impulsive noise environment. In particular, the optimal soft-output demodulator and its suboptimal version are presented for an additive class-A noise (AWAN) channel so that iterative demodulation and decoding can be performed at the receiver. The effect of signal mapping on the error performance of BICM-ID systems in impulsive noise is then investigated, with both computer simulations and a tight error bound on the asymptotic performance. Extrinsic information transfer (EXIT) chart analysis is performed to illustrate the convergence properties of different mappings. The superior performance of BICMID compared to orthogonal frequency-division multiplexing (OFDM) is also clearly demonstrated.<p>Motivated by the successes of both BICM-ID and OFDM in improving the error performance of communications systems in impulsive noise environment, the second part of this thesis introduces a novel scheme of bit-interleaved coded OFDM with iterative decoding (BI-COFDM-ID) over the class-A impulsive noise channel. Here, an iterative receiver composed of outer and inner iteration loops is first described in detail. Error performance improvements of the proposed iterative receiver with different iteration strategies are presented and discussed. Performance comparisons of BI-COFDM-ID, BICM-ID and iteratively decoded OFDM are made to illustrate the superiority of BI-COFDM-ID. The effect of signal mapping on the error performance of BI-COFDM-ID is also studied.
2

Coded modulation techniques with bit interleaving and iterative processing for impulsive noise channels

Bui, Trung Quang 22 August 2006 (has links)
Power line communications (PLC) surfers performance degradation due mainly to impulsive noise interference generated by electrical appliances. This thesis studies coded modulation techniques to improve the spectral efficiency and error performance of PLC. Considered in the first part is the application of bit-interleaved coded modulation with iterative decoding (BICM-ID) in class-A impulsive noise environment. In particular, the optimal soft-output demodulator and its suboptimal version are presented for an additive class-A noise (AWAN) channel so that iterative demodulation and decoding can be performed at the receiver. The effect of signal mapping on the error performance of BICM-ID systems in impulsive noise is then investigated, with both computer simulations and a tight error bound on the asymptotic performance. Extrinsic information transfer (EXIT) chart analysis is performed to illustrate the convergence properties of different mappings. The superior performance of BICMID compared to orthogonal frequency-division multiplexing (OFDM) is also clearly demonstrated.<p>Motivated by the successes of both BICM-ID and OFDM in improving the error performance of communications systems in impulsive noise environment, the second part of this thesis introduces a novel scheme of bit-interleaved coded OFDM with iterative decoding (BI-COFDM-ID) over the class-A impulsive noise channel. Here, an iterative receiver composed of outer and inner iteration loops is first described in detail. Error performance improvements of the proposed iterative receiver with different iteration strategies are presented and discussed. Performance comparisons of BI-COFDM-ID, BICM-ID and iteratively decoded OFDM are made to illustrate the superiority of BI-COFDM-ID. The effect of signal mapping on the error performance of BI-COFDM-ID is also studied.
3

[pt] MULTIPLEXAÇÃO ÓPTICA NO DOMÍNIO DO TEMPO EM SISTEMA STM-16, STM-64, STM-256 / [en] TIME-DOMAIN OPTICAL MULTIPLEXING IN STM-16, STM-64 AND STM-256 SYSTEMS

28 February 2002 (has links)
[pt] Este trabalho tem como foco o up-grade da taxa de bits em enlaces ópticos através da tecnologia OTDM. Os sistemas analisados contemplam os up-grades das taxas de 2,48 Gbps para 10 Gbps e também da taxa de 10 Gbps para 40 Gbps. Para tal, foram introduzidos módulos de transmissão e recepção, capazes de utilizar arquiteturas quase totalmente ópticas. É avaliado então, através de simulações, o comportamento da arquitetura proposta em infra-estruturas de enlaces já instalados no Brasil, destacando os pontos mais críticos. No que se refere ao up-grade de 10 Gbps para 40 Gbps, foi dado enfoque especial para as penalidades relativas à PMD (Polarization Mode Dispersion). / [en] This work aims at up grading the bit rate of optical links through the OTDM technology. The analyzed up-grades change the bit rate of 2,48 Gbps up to 10 Gbps and also from the bit rate of 10 Gbps up to 40 Gbps. To reach these objectives, transmission and reception modules were introduced, using all optical networks topologies. The performance of the proposed architecture was simulated using a infrastructure of links already installed in Brazil. The most critical issues were pointed out. Concerning the up-grade from 10 Gbps to 40 Gbps, a special focus was given to the penalties due to PMD (Polarization Mode Dispersion).

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