The seminar, that was imparted to IMDEA Networks researchers as well as personnel from the NETCOM research group at University Carlos III, was titled “OTFS: A New Generation of Modulation Addressing the Challenges of 5G”. In it, Dr. Ibars introduced a new two-dimensional modulation technique called Orthogonal Time Frequency Space (OTFS) modulation, designed in the delay-Doppler domain as a waveform ideally suited to new 5G use cases. Through this design, which exploits full diversity over time and frequency, OTFS coupled with equalization, converts the fading, time-varying wireless channel experienced by modulated signals such as OFDM into a time-independent channel with a complex channel gain that is roughly constant for all symbols. Thus, transmitter adaptation is not needed. This extraction of the full channel diversity allows OTFS to greatly simplify system operation and significantly improves performance, particularly in systems with high Doppler, short packets, and large antenna arrays. During the second half of the year, 5TONIC will test OTFS technology in cooperation with Cohere, Telefónica, and IMDEA Networks, focusing on its potential application for fixed wireless access and ultra reliable communications 5G use cases.
Christian Ibars Casas is currently a Principal Engineer at Cohere Technologies, based in Santa Clara, CA, USA. Formerly, he was with the Next Generation Networks group at Intel Corporation, USA (2013-2016), and with the Centre Tecnologic de Telecomunicacions de Catalunya, Spain (2003-2013), as head of the Communications Systems Division and other positions. He has also held external lecturer appointments at Universitat Pompeu Fabra during 2006-2008, and several visiting appointments (visiting student at Stanford University, 2000, visiting scholar at Cisco Research Center, 2010, and Marie Curie Fellow at the University of Padova (2010-2011)). During his career, Christian has specialized in wireless communications systems, with a recent focus on 5fth Generation cellular systems. He participates in the standardization process of 3GPP since Release 13. He also participated in several projects funded by the European Commission, European Space Agency, Spanish Government, and US National Science Foundation, such as Free Bits, IST-Winner, IST-WIP, IST-Coopcom, ICT-Exalted, ICT-Emphatic, and MIMOSat. He has published over 80 international journal and conference papers, and holds over 10 patents. Christian received degrees in electrical engineering from Universitat Politecnica de Catalunya, Spain, and Politecnico di Torino, Italy, in 1999, and a Ph. D. degree in electrical engineering from the New Jersey Institute of Technology, USA, in 2003.