Framelet-based of DM system

Dissertant

Abd al-Karim, Ziyad Qays

Thesis advisor

Sabri, Athir A.

University

University of Technology

Faculty

-

Department

Department of Electrical Engineering

University Country

Iraq

Degree

Master

Degree Date

2011

English Abstract

-As demand for higher data rates is continuously rising, there is always a need to develop more efficient wireless communication systems.

The work described in this thesis is an effort in this direction, Orthogonal Frequency Division Multiplexing (OFDM) is one of these systems.

The conventional Cyclic Prefixed OFDM system (CP-OFDM) exhibits high resistance to multipath effect as the channel delay spread being less than the cyclic prefix length that had been inserted between the transmitted OFDM symbols.

Furthermore, the addition of CP reduces the spectral efficiency and transmission bandwidth of the OFDM system since it contains no useful data.

In this work, Framelet based OFDM has been proposed, in which the Framelet Transform (FT) to be used as a modulator instead of the conventional Fast Fourier Transform (FFT).

Through this work, it is found that using Framelet Transform adds significant improvement on the performance of the proposed system.

Furthermore, because of the cyclic repetition nature of the Framelet reconstruction matrix, there is no need for the addition of the CP extension to the proposed system, which makes it use the transmission bandwidth efficiently and provides it with high spectral efficiency.

In Addition, because of the Framelet properties regarding linearity, orthogonality and symmetry, it provides the system with the ability to reconstruct the original data as it was before modulation even after the addition of the channel effects with very small errors.

MATLAB7.9 (R2009b) is used to simulate the proposed system and compare it with four other systems that have been proposed by other researchers, that include Packet Wavelet Transform based OFDM (PWT-OFDM), Discrete Multi-Wavelet Transform based OFDM (DMWT-OFDM), Discrete Wavelet Transform based OFDM (DWT-OFDM) and the conventional FFT-OFDM.

All of these systems are tested under the same conditions and by using three signal mapping schemes, Quadrature Amplitude Modulation (QAM), Phase Shift Keying (PSK), and Differential Phase Shift Keying (DPSK), and tested through Additive White Gaussian Noise (AWGN) and multipath fading channel.

The simulation is performed for both flat and frequency selective fading channel, Rician fading channel with different k-factor, and the effect of Co-Channel Interference (CCI).

The results show that the proposed system exhibits better performance as compared with other systems under all channel types.

The results show that at BER of 10-5, and when PSK is used as a mapping scheme, the minimum Eb/N0 gain achieved by FT-OFDM is about 0.2dB, and a maximum of 3dB, when DPSK is used as a mapping technique, the minimum Eb/N0 gain achieved by FT-OFDM is about zero, i.e., it is better than three of the four compared systems and equal to one of them, and a maximum of 4dB, finally, based on QAM mapping scheme, the minimum Eb/N0 gain achieved by FT-OFDM is about 0.5dB, and a maximum of 2.5dB.

Main Subjects

Information Technology and Computer Science

Topics

• Telecommunications

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305131