Séminaire ICI : Rostom Zakaria
Titre du séminaire et orateur
Block filtered multicarrier waveform based on filter-banks.
Rostom ZAKARIA, CNAM, CEDRIC.
Date et lieu
Jeudi 26 avril 2018, 14h.
ENSEA, salle 384.
Future wireless systems will require waveforms which are scalable and spectrally confined in order to benefit more effectively from the available frequency resources without creating interference to neighboring systems. While OFDM is the most widespread multicarrier modulation scheme, it suffers from high sidelobes that result in high undesired out-of-band (OOB) emission. To reduce the out-of-band emission of OFDM, the common technique used is filtering. Nevertheless, in context of non-contiguous spectrum fragments, filters should be dynamically designed for each fragment. That makes the use of filtered OFDM challenging.
On the other hand, filter bank based multicarrier (FBMC) modulation has been considered as an alternative waveform to overcome the drawbacks of limited spectral containment of OFDM. In FBMC, a prototype filter is applied on each subcarrier and carefully designed to minimize ISI and ICI while keeping the side lobes small. However, this modulation fails to guarantee the complex orthogonality and generates an intrinsic interference that corrupts the transmitted data symbols. Therefore despite the fact that FBMC exhibits a better spectral containment, it introduces undesired inherent interference and latency of a few symbol durations due to filtering, and its transmit signal is not compliant with legacy OFDM receivers. In this context, we proposed new schemes (FFT-FBMC, COW-CFMC) based on filter-bank where the available spectrum resources are split into blocks of contiguous subcarriers, namely resource blocks (RB), and the signal transmitted on each RB is generated and filtered individually. This approach has the advantage of being modular and scalable, and addresses most of the weakness of legacy OFDM in terms of spectral containment and performance in asynchronous scenario. Furthermore, the transmitted signal is OFDM-compliant and the receiver could also demodulate legacy OFDM signals.
Rostom ZAKARIA received the engineering degree in electronics from the University of Science and Technology Houari Boumediene, Algiers, Algeria, in 2007, and the M.Sc. degree from the University of Paris-Est de Marne-La-Vallée, France, in 2008, and the Ph.D. degree from the CEDRIC/LAETITIA Research Laboratory, Conservatoire National des Arts et Métiers (CNAM), Paris, in 2012. Since 2012, he has been a temporary Assistant Professor and a Researcher with CNAM. His research interests are interference cancellation techniques in the filter bank-based multicarrier modulations, spatial time and frequency coding in FBMC, and bloc filtered waveform design.