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Title: Novel DWT-DAPSK based transceivers for DVB-T transmission and next generation mobile networks
Author: Al-hussiany, Yahya Ali Lafta
Awarding Body: Liverpool John Moores University
Current Institution: Liverpool John Moores University
Date of Award: 2012
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Digital wireless communication has become one of the most exciting research topics in the electronic engineering field due to the explosive demands for high-speed wireless services, such as cellular video conferencing. The second generation Terrestrial Digital Video Broadcasting (DVB- T2) has been demonstrated to provide digital communication services with very high spectral efficiency and significantly improved performance. Orthogonal Frequency Division Multiplexing (OFDM) systems have been increasingly deployed in mobile networks for their spectral efficiency and optimum bit error rate. An OFDM system is a multi-carrier system which transmits signals from a single source at different frequencies simultaneously as parallel components. A distinguishing feature of the OFDM system is its ability to preserve high bandwidth efficiency in high speed data streams. Among the different types of OFDM systems, wavelet based systems have been demonstrated to have much better bandwidth and channel performance compared to the Discrete Fourier transform (DFT) and Discrete Cosine Transform (DCT) based systems. The DFT and DCT systems suffer from several disadvantages including less bandwidth efficiency due 'to the need for guard interval and highly complex system design. Discrete Wavelet transform (DWT) based OFDM systems naturally overcome these disadvantages by their design methodology and the technique of transmitting concentrated energy over small spectral coefficients. Several types of modulation schemes such as DPSK, QAM are employed in OFDM systems, which introduce certain penalties such as increased bandwidth and complexity of the system design. So a multilevel differential modulation technique namely Differential Amplitude and Phase Shift Keying (64 DAPSK) has been proposed as an alternative solution. DAPSK-OFDM is very suitable for high date-rate digital mobile radio channel with additive white Gaussian noise (A WGN). In this research work it has been f demonstrated that a combination of DWT -OFDM with DAPSK modulation can be employed to achieve very low peak-to-average power ratio (PAPR), improved bit error ratio (BER), and much reduced inter symbol interference (ISI) & inter-carrier interference (IeI) in wireless mobile network applications. A mathematical model has been proposed for the DWT-OFDM system with DAPSK modulation scheme in this work. The system performance has been evaluated via simulation using Matlab Simulink package and also verified using Matlab programming. This proposed DWT-OFDM with 64DAPSK hybrid system is demonstrated to have better BER (by an order of magnitude for an SNR of 25dB) performance and improved P APR (by 7.2dB) and interference values. It is also demonstrated that including companding with this system results in further reduction of PAPR. Finally, the simulation results also demonstrate that DWT-DAPSK scheme can be successfully employed in DVTB-T2 systems due to its very high spectral efficiency, much improved BER and significantly reduced PAPR performance.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TK Electrical engineering. Electronics. Nuclear engineering