Imperial College London > Talks@ee.imperial > COMMSP Seminar > Novel OFDM Systems based on Layered FFT Structure

Novel OFDM Systems based on Layered FFT Structure

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If you have a question about this talk, please contact Danilo Mandic.

OFDM is very promising for (wireless) broadband communications and is becoming the foundation technique in multiple communication standards. Some well-known inherent problems with OFDM systems include large peak-to-average power ratio (PAPR), high sensitivity to carrier frequency offset (CFO) and low frequency diversity.

In this talk, as an extension of the discrete convolution theory of Digital Fourier Transform, a novel layered Fast Fourier Transform (FFT) structure will be introduced. Based on this structure, two novel OFDM systems will be presented. The first one is named as “Asymmetric OFDM System” which bridges the gap between OFDM and single carrier block systems. Asymmetric OFDM system can mitigate those inherent problems in general OFDM systems, and is particularly promising for distributed networks where transmitters and receivers could adapt system parameters according to their hardware capability and battery status. The second one is named as “Quadrature OFDMA system” which is designed to solve an extra complexity problem in current OFDMA systems. Quadrature OFDMA system can achieve similar performance, same bandwidth efficiency and same overhead ratio with conventional OFDMA systems, while with significantly reduced complexity and power consumption, reduced PAPR , improved CFO sensitivity and improved frequency diversity.


Dr Jian (Andrew) Zhang was awarded a Bachelor of Science degree in telecommunications engineering from Xi’an JiaoTong University, China, in 1996, and a Master of Science degree from Nanjing University of Posts and Telecommunications, China, in 1999. He got his PhD degree in the Department of Telecommunications Engineering, the Australian National University, in 2004. Currently, he is a researcher in National ICT Australia (NICTA) and a conjunct staff in Australian National University.

Dr. Zhang’s research interests are in the areas of adaptive signal processing and broadband wireless communications, with emphasis on multicarrier and Ultra Wideband systems. In NICTA , he was a Multiband OFDM UWB project leader. Now, he is working on the Human performance improvement project to develop advanced techniques for wireless body area networks. Dr. Zhang has won three international prizes for his work. He published more than 40 Journal and conference papers, and delivered six invention disclosures. He is actively involved in the TPC of leading conferences.

During 1999 to 2001, Dr. Zhang worked as a system and hardware engineer in ZTE Corp. in China, being involved in DSLAM and soft switch development.

For more information, please refer to his homepage

This talk is part of the COMMSP Seminar series.

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