Year

2011

Degree Name

Master of Engineering - Research

Department

School of Electrical, Computer and Telecommunications Engineering

Abstract

The fourth generation (4G) mobile communications technology and beyond are widely in development nowadays. Among all the technologies, Orthogonal Frequency Division Multiplexing (OFDM) is the most potential candidate of the 4G system, due to the advantages it can offer in wideband wireless communications. However, it also has some disadvantages. Researchers are trying to find methods to make this scheme perform better. In other words, they are trying to overcome the disadvantages, while keeping the advantages.

In my project, a new scheme based on OFDM called Block Transform OFDM (BTOFDM) is introduced. In this scheme, data symbols are grouped into blocks. Thus, a reduced size Inverse Fast Fourier Transform (IFFT) will be used for block transformation compared to the conventional OFDM. This scheme takes the advantages of the singlecarrier system to solve some well-known problems such as high Peak-to-Average Power Ratio (PAPR), Inter-Channel Interference (ICI) caused by the frequency offset. At the same time, it still has the advantages from the OFDM compared to the single carrier systems. Hence, it is more power and bandwidth efficient and achieves higher degree frequency diversity than the conventional OFDM. Also, the BT-OFDM is robust against carrier frequency offset and timing errors, and achieves significant performance improvement over frequency-selective fading channels.

The system architecture and properties are introduced and analyzed in detail. Monte Carlo simulations on system performances such as transmit signal PAPR, bit error rate (BER) under different parameters are presented to verify the improvement of the new system compared with the conventional OFDM system. The first step of Universal Software Radio Peripheral (USRP) hardware implementations will be performed as well.

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