5 Sep

TEWI-Kolloquium: Towards power efficient transmitters with multicarrier waveforms: novel PAPR reduction techniques and optimisation of in-band and out-of-band distortions

VeranstaltungsortL4.1.01Veranstalter Fakultät für Technische WissenschaftenBeschreibungOFDM multicarrier techniques are widely deployed in most wireless communication systems, in particular in cellular networks (LTE, LTE Advanced, 5G…), broadcast networks (DVB-T, DVB-T2, ATSC3.0…) and WiFi networks. However, multi-carrier modulations are characterized by a very large dynamic amplitude measured by the Peak to Average Power Ratio (PAPR). This large amplitude prevents radio frequency designers to feed the signal at the optimal point of the non linear High Power Amplifier (HPA) which reduces their energy efficiency and then increases dramatically the overall base station consumption. In literature, the PAPR reduction and the linearization techniques are the main approaches to solve this HPA efficiency problem in cellular and broadcast networksIn recent years, tone reservation (TR) PAPR reduction techniques have been deeply studied and included for example in the DVB-T2 and the new American digital video broadcasting (ATSC 3.0) standards. It is based on a gradient iterative approach where, at each iteration, a predefined kernel is used to reduce one peak in the time domain. During this talk, we will present novel TR PAPR reduction techniques, namely grouped individual carrier allocation for multiple peaks (GICMP) based on a new kernel signal and fully compatible with the new broadcasting DVB-T2 and ATSC3.0 standards. An in-depth performance analysis based on simulation and experimental results demonstrated that the novel proposed PAPR reduction algorithm offers very good performance/complexity/latency trade-off.In the second part of this talk, we will present intelligent solution for future implementations to control the reduction of PAPR and the linearization steps in a flexible way according to some predefined parameters so that they become adaptive and self-configurable. More specifically, our work focused on the analytical analysis of in-band measured by the Error Vector Magnitude (EVM) and out-of-band distortions measured by the Adjacent Chanel Power Ratio (ACPR) for multicarrier signals taking into account the PAPR reduction, the impact of non-linear amplification, the memory effects and the predistortion. Combining those complementary approaches, the power efficiency of the transmitters with OFDM multicarrier waveforms can be highly upgraded and/or the energy consumption reduced by 10 to 15 %Vortragende(r)Prof. Jean-François HélardKontaktKerstin Smounig (kerstin.smounig@aau.at)

5 Sep

TEWI-Kolloquium: MIMO and Massive MIMO schemes: application to time reversal and spatial modulations

VeranstaltungsortL4.1.01Veranstalter Fakultät für Technische WissenschaftenBeschreibungTo meet growing demand for higher throughputs, advanced digital communication techniques based on multicarrier modulations, multiple antenna systems (MIMO) and their extension to massive MIMO (M-MIMO), powerful coding schemes or interference coordination are always under study and could be combined with solutions based on network densification and deployment of heterogeneous infrastructures. For a number of years now, IETR (Institut of Electronics and Telecommunications of Rennes) Labs has being developed strong expertise in communications systems with several experiments associating OFDM and MIMO in some proofs of concept. In the first part of this talk, one of the classical precoding technique, known as Time Reversal applied to digital communications will be presented as well as its easy combination with OFDM. A second part will be dedicated to spatial modulation applied either at transmit or receive side and its possible application to IoT. For both systems, the benefit of using a high number of transmit antenna will be highlighted and a description of the proofs of concept implementation carried out in our labs provided.The talk will then concentrate on the researches carried out with some of our PhD students on hybrid beamforming techniques, mmWave communications and VLC communications.Vortragende(r)Prof. Maryline HélardKontaktKerstin Smounig (kerstin.smounig@aau.at)

16 Sep

Philologie romane et édition des textes

VeranstaltungsortStiftungssaalK.0.01Veranstalter Institut für RomanistikBeschreibungIm Rahmen der Sommerschule ‘Philologie romane et édition des textes’ (16.-21. September 2018) laden das Institut für Romanistik und das Zentrum für romanistische Mediävistik (ZRM) zum öffentlichen Vortrag ein.Vortragende(r)Prof. Dr. Thomas Verjans (Toulouse)Kontakt Univ.-Prof. Dr. Raymund Wilhelm (Raymund.Wilhelm@aau.at)

17 Sep
Recurring

SPU-Infotag

VeranstaltungsortV.1.23Veranstalter E-Learning-ServiceBeschreibungKontakteLearning Service (elearning@aau.at)