published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

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Kwan Ho-yuet. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 84-[87]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- An Overview on Transmitter Optimization --- p.1 / Chapter 1.1.1 --- Transmitter Precoding Methods --- p.2 / Chapter 1.1.2 --- Chip Waveform Optimization --- p.3 / Chapter 1.1.3 --- Signature Sequence Adaptation --- p.3 / Chapter 1.2 --- Receiver Optimization --- p.5 / Chapter 1.3 --- Nonlinear Optimization with Constraints --- p.6 / Chapter 1.3.1 --- Lagrange Multiplier Methods --- p.6 / Chapter 1.3.2 --- Penalty Function Methods --- p.7 / Chapter 1.4 --- Outline of Thesis --- p.8 / Chapter 2 --- Transmitter Adaptation Scheme for AWGN Channels --- p.10 / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- System Model --- p.12 / Chapter 2.3 --- Adaptation Algorithm --- p.13 / Chapter 2.3.1 --- Receiver optimization --- p.14 / Chapter 2.3.2 --- Single-user transmitter optimization --- p.18 / Chapter 2.3.3 --- Decentralized transmission scheme --- p.20 / Chapter 2.4 --- Modification of the sequence adaptation algorithm --- p.25 / Chapter 2.5 --- Performance Evaluation --- p.28 / Chapter 2.5.1 --- Performance of the decentralized scheme --- p.28 / Chapter 2.5.2 --- System Capacity with Target SNR Constraints --- p.29 / Chapter 2.5.3 --- Performance of modified sequences --- p.31 / Chapter 2.6 --- Summary --- p.33 / Chapter 3 --- Transmitter Adaptation Schemes for Rayleigh Fading Channels --- p.34 / Chapter 3.1 --- Introduction --- p.34 / Chapter 3.2 --- Sequence Adaptation for MC-CDMA Systems --- p.36 / Chapter 3.2.1 --- Multi-sequence MC-CDMA systems --- p.36 / Chapter 3.2.2 --- Single Sequence MC-CDMA systems --- p.41 / Chapter 3.2.3 --- Performance Evaluation --- p.45 / Chapter 3.3 --- Sequence Adaptation for Wideband CDMA System in Fading Channels --- p.50 / Chapter 3.3.1 --- System Model and Algorithm Development --- p.50 / Chapter 3.3.2 --- Performance Evaluation --- p.56 / Chapter 3.4 --- Summary --- p.60 / Chapter 4 --- Practical Issues on Sequence Adaptation --- p.61 / Chapter 4.1 --- Introduction --- p.61 / Chapter 4.2 --- Preliminary --- p.62 / Chapter 4.3 --- Sequence Adaptation Algorithm with Perfect Estimation of SNR --- p.63 / Chapter 4.4 --- Performance Evaluation --- p.68 / Chapter 4.4.1 --- Typical Behaviour Analysis --- p.71 / Chapter 4.4.2 --- Average Performance Analysis --- p.72 / Chapter 4.5 --- Sequence Adaptation Algorithm with imperfect estimation of pre- vious state SNR --- p.75 / Chapter 4.6 --- Performance Evaluation --- p.77 / Chapter 4.7 --- Summary --- p.79 / Chapter 5 --- Conclusions and Future Works --- p.81 / Chapter 5.1 --- Conclusions --- p.81 / Chapter 5.2 --- Future Works --- p.83 / Bibliography --- p.84

Pun Siu Yi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 126-128). / Abstracts in English and Chinese. / List of Figure / List of Table / Chapter 1 --- Introduction --- p.11 / Chapter 2 --- Capacity of Single-Cell S-CDMA System --- p.15 / Chapter 2.1 --- Preliminary --- p.16 / Chapter 2.1.1 --- Information measure --- p.16 / Chapter 2.1.2 --- Capacity of a channel --- p.20 / Chapter 2.1.3 --- Capacity of multiple access Gaussian DS-CDMA channel --- p.22 / Chapter 2.2 --- Evaluation of the sum capacity for selected sequence sets --- p.26 / Chapter 2.2.1 --- Walsh Code --- p.28 / Chapter 2.2.2 --- M-Sequence --- p.34 / Chapter 2.2.3 --- Binary Almost Perfect Sequence --- p.42 / Chapter 2.3 --- Asymptotic Upper Bound of the sum capacity for 2 sequence sets --- p.50 / Chapter 2.3.1 --- Upper Bound of the sum capacity for selected sequence sets --- p.50 / Chapter 2.3.2 --- Asymptotic Upper Bound --- p.52 / Chapter 2.4 --- Optimal dynamic code allocation scheme for ad-hoc S-CDMA System --- p.62 / Chapter 2.4.1 --- Ad-hoc S-CDMA System --- p.62 / Chapter 2.4.2 --- Code Allocation Scheme --- p.63 / Chapter 2.4.3 --- Proof of Optimality --- p.66 / Chapter 3 --- Simulation of code adaptation schemes for mobile CDMA System --- p.72 / Chapter 3.1 --- Introduction of mobile CDMA System --- p.72 / Chapter 3.2 --- Simulation of code adaptation scheme --- p.77 / Chapter 3.2.1 --- System Model --- p.77 / Chapter 3.2.2 --- Description of 3 schemes --- p.78 / Chapter 3.2.3 --- Simulation Results --- p.96 / Conclusion and Future Work --- p.108 / Appendix --- p.110 / Bibliography --- p.126

Turbo codes have been used successfully for error correction in digital communications, however, their application to wireless mobile communications is still a fresh research topic. The objective of this thesis is to present a new solution that involves the usage of turbo codes, spatial diversity, and orthogonal complementary codes in a CDMA spread spectrum system in order to deliver good performance in a fading environment at low signal-to-noise ratios. The results of the research that was performed to write this thesis are presented in a modular and progressive fashion. That is, the design of a basic turbo-coded system in additive white Gaussian noise (AWGN) is developed first in order to get a good understanding of its potential in a wireless communication environment. Then the basic system design is expanded to include fading channel characteristics and multiple access spread spectrum capabilities using classical code division multiple access (CDMA) techniques. Finally, orthogonal complementary codes are used in lieu of traditional spreading codes and spatial diversity is introduced to maximize system performance. / Graduation date: 2003

This dissertation presents the continued study of a non-iterative decision feedback (DF) receiver/decoder design and its application to cellular communications or wireless local loop systems based on the IS-95(-A) standard of the Telecommunications Industry Association and also Personal Communications Services systems based on the American National Standards Institute standard J-STD- 008-1996, which use code-division multiple access (CDMA) spread spectrum technology. Specifically, the DF decoder presented herein can be used in the uplink of these systems, which simultaneously uses a concatenation of convolutional coding, interleaving, and orthogonal Walsh modulation. The main contributions of this dissertation are the demonstration that the DF concept works well in multipath fading environments, the design of a new time-efficient decoding algorithm, and a new interleaver design. Initially, the performance of the DF decoder is assessed in unfaded as well as Rayleigh fading multipath propagation in additive white Gaussian noise interference. Simulation results using coherent and noncoherent detection are presented for both independent Rayleigh fading and Rayleigh fading with a commonly used Doppler spectrum. The results show improved performance compared to conventional non-DF receivers using the same decoding metric. This is a prerequisite for application of the DF decoder in an actual mobile communications environment. The effectiveness of the initial DF decoder design, as it is applied to IS-95 based systems, is studied. It is found that the effectiveness of the DF decoder is determined by the decoding delay of the convolutional decoder and the interleaver specification. Based on these findings, two methodologies to improve the effectiveness of the DF decoder are investigated. First, the average decoding delay is reduced using sub-optimal convolutional decoding. Second, the combination of a new block interleaver design and the DF decoder is considered. Simulation results of average decoding delay, bit error rate and frame error rate are presented for coherent and noncoherent detection of unfaded and Rayleigh fading multipath signals. It is shown that both approaches result in better system performance, which can further improve the quality of service and/or capacity of an IS-95 based system. Finally, a simplified analysis of the DF decoder performance is presented. / Graduation date: 1999

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Tri T. Ha, Jan E. Tighe, David C. Jenn, Jovan Libaric. Includes bibliographical references (p. 133). Also available online.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Tri T. Ha, Jan E. Tighe, David C. Jenn. Includes bibliographical references (p. 97). Also available online.

Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 102-103).

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy