Algebraic Space Time Coding (ASTC) for MIMO-OFDM Systems

9 aprile 2015
9 Aprile, 2015

Time: 10 am
Location: Meeting Room Garda, Polo Scientifico e Tecnologico "Fabio Ferrari" (Building Povo 1), via Sommarive 5 - Povo, Trento

Speaker:

  • Dr. Ahmed Bannour

Abstract:
The Seminar will focus on  the use of the Algebraic Space Time Coding (ASTC) technique combined with Orthogonal Frequency Division Multiplexing (OFDM) to overcome the frequency selectivity channel problems. The first part of the presentation analyzed the performance of the ASTC codes under a correlated Rayleigh channel. The Algebraic Space Time Codes (ASTC), based on the cyclic algebras, has shown a good spectral efficiency, a full diversity, and a full rate under non selective channel conditions. However, the radio-mobile channel is a selective channel whose features vary with the time. This selectivity is owed to the multi-path phenomenon and generates interferences between symbols (IES). So, the second part of  the presentation will consider  the  development of  a new technique in order to adapt the ASTC codes to the frequency selective channels. It has been shown that by their construction, the Algebraic Space Time Codes have a reasonable BER when working in a non selective channel thanks to their properties (full rank, full rate, and non-vanishing determinant for increasing rate). We have proved that it is possible to combine MIMO-OFDM systems with a ASTC encoder under a frequency-selective channel. Computer simulations have shown the efficiency of the proposed ASTC encoder either in terms of  BER performance, capacity or in terms of  PAPR reduction. The third part will deal with the sensibility of the ASTC codes to frequency synchronization in selective channels. A new algebraic Carrier Frequency Offset (CFO) estimation technique, for MIMO-OFDM systems with ASTC under quasi-static correlated Rayleigh frequency-selective fading channels, has been developed. The technique uses a preamble and is especially suitable for burst mode communication. The preamble consists of orthogonal training sequences simultaneously transmitted from the various transmit antennas. The proposed system exploits all the subcarriers in frequency domain, which provides a remarkable performance improvement compared to other well known methods and reaches the Cramer-Rao Lower Bound (CRLB).
 
About the Speaker:
Ahmed Bannour received the Engineering degree, the M.Sc degree and the PhD in Telecommunications from the University of ElManar, Tunis, Tunisia, in 2006, 2008 and  2013, respectively. From 2006 to present, he was a Research Associate with the Innovation of Communicant and Cooperative Mobiles Laboratory, Higher School of Communications of Tunis. He is currently an Assistant Professor and at the head of Informatics department   with the High Institute of Computer Science Mahdia, Tunisia. His research interests include multiple input– multiple-output–orthogonal frequency-division multiplexing systems, system identification, space–time coding, array processing, and performance analysis, Cooperative Communication Architecture, Massive MIMO. Two journal papers are published one of them in IEEE Transactions on VTC in 2012, and six international conference papers are also published with one book chapter.  He worked also a  Reviewer in: IEEE transaction on Wireless communication, Wireless  Personnel Communication, IEEETVT and IET Communication.

Contact Person Regarding this Talk: Claudio Sacchi, sacchi [at] disi.unitn.it