Seminars

UHF and microwave bands have been used in mobile communication systems, but with 5G the use of millimeter wave bands has begun, and studies have begun for the use of terahertz wave bands in Beyond 5G/6G. In terms of wavelength, this means using a range from tens of centimeters to several millimeters, and in terms of frequency, from several hundred MHz to several hundred GHz, a range of about three orders of magnitude. Since the physical properties of electromagnetic waves differ greatly over such a wide range, it is natural to use them in an appropriate manner for each band so that their properties can be maximized. On the other hand, from a system point of view, it is better to use a single system for each frequency band than to develop different systems for each band and operate multiple systems. In addition, from an economic point of view, it is important to reduce the cost of maintaining and operating the equipment.

In the 2030s, when Beyond 5G/6G is introduced, a Cyber-Physical System (CPS) will be formed. Data in physical space will be collected through communication systems and reconstructed, analyzed, and predicted in cyberspace. Based on the predictions made in cyberspace, the physical space is actuated. This cycle is referred to as the CPS loop. The goal is to realize an inclusive, sustainable, human-centered, dependable society by spreading CPS to every corner of social life.

To achieve these goals, next-generation mobile communication systems (Beyond 5G/6G) will play a central role in the CPS loop. It is important to ensure that the various radio bands in Beyond 5G/6G are used in the right places to achieve these goals and objectives.

Dr. Iwao Hosako received his Ph.D. from the University of Tokyo in 1993. After working at the ULSI Research Institute of NKK Corporation, he joined the Communications Research Laboratory (now NICT). He is currently the Executive Director of the Beyond 5G R&D Promotion Unit of the National Institute of Information and Communications Technology (NICT). He is involved in the research and development of terahertz semiconductor devices, cameras, and wireless systems. He is also a lead member of the 6G Working Group of the Terahertz System Application Promotion Council in Japan and vice chair of the IEEE 802.15 TG3mb and the Standing Committee Terahertz (SC-THz). 

Already a couple of years ago THz communications have not only become an attractive new research area on channel modeling but also triggered a couple of projects heading to develop appropriate technological solutions to enable the set-up of hardware demonstrators. In parallel discussions and activities in standardization and regulation already took off. In October 2017, IEEE published Std. IEEE 802.15.3d-2017 the worldwide first wireless communications standard operating in the 300 GHz frequency band. At the World Radio Conference 2019 (WRC-2019) 160 GHz of spectrum has been identified for the use of THz communications and ETSI has recently kicked-off an ETSI ISG THz targeting future standardization in 3GPPP The speaker has been actively involved in all those areas. The talk will provide a brief overview on the current status of the development of THz Communication systems focusing on past and ongoing large research projects in Europe, recent results on advanced channel characterization at 300 GHz, hardware demonstrators operating in this frequency range and at current activities at IEEE 802 and ETSI.

Thomas Kürner (Fellow IEEE) received his Dipl.-Ing. degree in Electrical Engineering in 1990, and his Dr.-Ing. degree in 1993, both from University of Karlsruhe (Germany). From 1990 to 1994 he was with the Institut für Höchstfrequenztechnik und Elektronik (IHE) at the University of Karlsruhe working on wave propagation modelling, radio channel characterization and radio network planning. From 1994 to 2003, he was with the radio network planning department at the headquarters of the GSM 1800 and UMTS operator E-Plus Mobilfunk GmbH & Co KG, Düsseldorf, where he was team manager radio network planning support responsible for radio network planning tools, algorithms, processes and parameters from 1999 to 2003. Since 2003 he is Full University Professor for Mobile Radio Systems at the Technische Universität Braunschweig. In 2012 he was a guest lecturer at Dublin City University within the Telecommunications Graduate Initiative in Ireland. Currently he is chairing the IEEE 802.15 Standing Committee THz and the ETSI ISG THz. He was also the chair of IEEE 802.15.3d TG 100G, which developed the worldwide first wireless communications standard operating at 300 GHz. He was the project coordinator of the H2020-EU-Japan project ThoR (“TeraHertz end-to-end wireless systems supporting ultra-high data Rate applications”) and is Coordinator of the German DFG-Research Unit FOR 2863 Meteracom (“Metrology for THz Communications”). In 2019 and 2022 he received the Neal-Shephard Award of the IEEE Vehicular Technology Society (VTS) and also in 2022 the Best Teacher Award of the European School on Antennas and Propagation (ESoA).

The recent dramatic growth in interest in the use of high-frequency (millimeter-wave and terahertz) carrier waves for wireless communications has spurred a great deal of research activity. One key topic of current interest is that of the security of such links, and their resilience against malicious attacks such as eavesdropping and jamming. These considerations are quite distinct from those related to security at lower frequencies (below 6 GHz), not only because of the high directionality that such high-frequency links will inevitably require, but also because of numerous other unique characteristics, including the very high free-space path loss, losses due to water vapor absorption lines, and the frequency-dependent radiation patterns that inevitably emerge in the far field of most transmitters. These differences offer new opportunities for eavesdroppers or jammers to implement a successful attack, but also new possibilities for countermeasures that can be implemented at the physical layer of the system. Here, we present a few examples to illustrate the unique security considerations that arise in the context of terahertz wireless links.

Dr. Mittleman received his B.S. in physics from the Massachusetts Institute of Technology in 1988, and his M.S. in 1990 and Ph.D. in 1994, both in physics from the University of California, Berkeley. He then joined AT&T Bell Laboratories as a post-doctoral member of the technical staff, where he built one of the early terahertz time-domain spectrometers for material spectroscopy and imaging. Dr. Mittleman joined the ECE Department at Rice University in September 1996. In 2015, he moved to the School of Engineering at Brown University. His research interests involve the science and technology of terahertz radiation. He is a Fellow of the OSA, the APS, and the IEEE, and a Humboldt Research Award winner, and in 2023 he is a Mercator Fellow of the Deutsche Forschungsgemeinschaft. He has recently completed a three-year term as Chair of the International Society for Infrared Millimeter and Terahertz Waves.

100-300GHz wireless systems can provide very high data rates per signal beam,  and, given the short wavelengths, even compact arrays can contain many elements, permitting massive spatial multiplexing for further increased capacity. After first examining link budgets and the merits and drawbacks of high-frequency systems, we will describe ICs, modules, and system design of 140 GHz massive MIMO wireless hubs and 210 GHz and 280 GHz MIMO backhaul links. 

Mark Rodwell (Ph.D. Stanford University 1988) holds the Doluca Family Endowed Chair in Electrical and  Computer Engineering  at UCSB.  His research group develops nm and THz transistors and high-frequency integrated circuits and systems.  From 2017-23 he directed the SRC/DARPA ComSenTer wireless research center.  From 2007-14 he directed the SRC Nonclassical CMOS Research Center. From 1996-2018, he directed the UCSB Nanofabrication Lab during its growth to a ~500-user facility. The work of  his group and collaborators has been recognized by the 2022 SIA-SRC University Researcher Award, the 2010 IEEE Sarnoff Award,  the 2012 IEEE Marconi Prize Paper Award, the 1997 IEEE Microwave Prize, the 1998 European Microwave Conference Microwave Prize, and the 2009 IEEE IPRM Conference Award. He received the 1994,1997, 1998, 2014, 2019, 2021, and 2022 UCSB Electrical Engineering teaching awards. 

Spectrum above 100 GHz is attractive for applications needing contiguous bandwidths greater than 20 GHz such as alternatives for optical fiber in situations where time urgency or difficult terrain make the low material cost fiber alternative infeasible. But unlike in the lower spectrum, above 100 GHz there is a high density of passive bands due to the presence of many molecular resonances of critical interest to climate scientists and radio astronomers. When the ITU created most of these bands in 2000, at the request of both US and European countries, it also agreed to their requested review of whether carefully controlled sharing of such passive bands was feasible. This webinar will review the technical challenges and potential benefits for sharing such bands subject to ITU quantitative protection goals that are in place. While such sharing is probably not feasible in lower bands, the key differences here are the small wavelengths and resulting small antenna sizes as well as the high atmospheric absorption above 100 GHz and the strong elevation angle dependence that makes terrestrial use with strong control of high elevation angle antenna sidelobes a promising path. The webinar will discuss this and other options as well as the ITU-R for a look at where these discussions are focused now and how one can participate in the deliberations.

Michael J. Marcus is a native of Boston and received S.B. and Sc.D. degrees in electrical engineering from MIT. Prior to joining the FCC in 1979, he worked at Bell Labs on the theory of telephone switching, served in the U.S. Air Force where he was involved in underground nuclear test detection research, and analyzed electronic warfare issues at the Institute for Defense Analyses. At FCC his work focused on proposing and developing policies for cutting edge radio technologies such as spread spectrum/CDMA and millimeter waves. Wi-Fi is one outcome of his early leadership. The total amount of spectrum he proposed for unlicensed use and directed the drafting of implementing rules was 8.234 GHz. He also participated in complex spectrum sharing policy formulation involving rulemakings such as ultrawideband and MVDDS. Awarded a Mike Mansfield Fellowship in 1997, he studied the Japanese language and spent a year at the FCC’s Japanese counterpart. He retired from FCC in March 2004 after servicing a senior technical advisor to the Spectrum Policy Task Force and codirecting the preparation of the FCC’s cognitive radio rulemaking. Immediately after retirement he lived in Paris France for 3 years, consulting for US and European clients. In 2006 he was appointed Special Advisor to Mrs. Viviane Reding, European Commissioner for Information Society & Media.He is now Director of Marcus Spectrum Solutions LLC, an independent consulting firm based in the Washington DC area focusing on wireless technology and policy. He is also Adjunct Professor of Electrical and Computer Engineering and a Principal Research Scientist in the Institute for the Wireless Internet of Things at Northeastern University. He was recognized as a Fellow of the IEEE “for leadership in the development of spectrum management policies”, received in 1994 IEEE-USA’s first Electrotechnology Transfer Award, and received in 2013 the IEEE ComSoc Award for Public Service in the Field of Telecommunications “For pioneering spectrum policy initiatives that created modern unlicensed spectrum bands for applications that have changed our world.

Josep M. Jornet is an Associate Professor in the Department of Electrical and Computer Engineering, the Director of the Ultrabroadband Nanonetworking Laboratory and a faculty member of the Institute for the Wireless Internet of Things and the SMART Center at Northeastern University, in Boston, MA. He received the B.S. in Telecommunication Engineering and the M.Sc. in Information and Communication Technologies from the Universitat Politecnica de Catalunya, Barcelona, Spain, in 2008. He received the Ph.D. degree in Electrical and Computer Engineering from the Georgia Institute of Technology, Atlanta, GA, in 2013. Between 2013 and 2019, he was a faculty in the Department of Electrical and Computer Engineering at the University at Buffalo, The State University of New York. His research focus is on terahertz communications, in addition to wireless nano-bio-communication networks and the Internet of Nano-Things. In these areas, he has co-authored more than 220 peer-reviewed scientific publications, one book, and has also been granted six US patents, which accumulate over 13,000 citations (h-index of 52) as of October 2022. He is serving as the lead PI on multiple grants from U.S. federal agencies including the National Science Foundation, the Air Force Office of Scientific Research and the Air Force Research Laboratory as well as industry. He is the recipient of multiple awards, including the 2017 IEEE ComSoc Young Professional Best Innovation Award, the 2017 ACM NanoCom Outstanding Milestone Award, the UB Exceptional Scholar Young Investigator Award in 2018 and Sustained Achievement Award in 2019, the NSF CAREER Award in 2019, the 2022 Martin W. Essigmann Excellence in Teaching Award, 2022 and the 2022 IEEE ComSoc RCC Early Achievement Award, among others. He has received multiple Best Paper Awards in multiple venues, including ACM NanoCom 2017, INFOCOM 2021 and the IEEE WoWMoM Non-Terrestrial Networks Workshop both in 2021 and 2022. He is a senior member of the IEEE and an IEEE Distinguished Lecturer (Class of 2022-2023). He is also the Editor in Chief of the Elsevier Nano Communication Networks journal and Editor for IEEE Transactions on Communications.

6G mobile networks consisting of a huge number of base stations and remote antennas will require a variety of transmission media including optical and THz links. This presentation will review device and system technologies for THz seamless networks which can mitigate radio spectrum congestion in conventional radio bands. It will also focus on long-reach THz transmission which can be used for non-terrestrial networks, as well as for short-reach access networks. 

Prof. Tetsuya Kawanishi received the B.E., M.E., and Ph.D. degrees in electronics from Kyoto University, Kyoto, Japan, in 1992, 1994, and 1997, respectively. From 1994 to 1995, he was with the Production Engineering Laboratory, Panasonic. In 1997, he was with the Venture Business Laboratory, Kyoto University, where he was engaged in research on electromagnetic scattering and near-field optics. In 1998, he joined NICT, Tokyo, Japan. In 2004, he was a Visiting Scholar with UCSD. Since April 2015, he has been a Professor with Waseda University, Tokyo. His current research interests include high-speed optical modulators and RF photonics. He also served for international standardization in IEEE 802 and also in non-IEEE standardization bodies, such as International Telecommunication Union (ITU), International Electrotechnical Commission (IEC) and Asia-Pacific Telecommunity (APT). Now, he is the chair of Task Group on Fixed Wireless Systems (TG-FWS) in APT Wireless Group (AWG). From 2017, he is a member of Board of Governors of IEEE Photonics Society. 

Multipath propagation is the reason behind the channel characteristics in a specific scenario. Thus, in the standardization of channel modeling for terahertz (THz) communications, propagation mechanisms and scenarios are two valuable topics. Along with the increase of the frequency (the decrease of the wavelength), the originally smooth surfaces for low frequencies become rough, and therefore, even for the same surface, scattering is more dominant in the THz band compared to sub-6 GHz or millimeter-wave bands. How to model it in a general and concise way is of importance for standard channel modeling of THz communications. Thus, in the first half of this seminar, a stochastic model for the scattering mechanism at the THz band is presented based on the directional scattering model and full-wave simulations. In the second half of the seminar, potential scenarios of THz communications (such as WPAN/WLAN, kiosk downloading, wireless backhaul/front-haul, data center network, and intra-device communications) are defined, and channels are characterized correspondingly with ray-tracing simulations, based on which the first impression of THz channels in these scenarios can be obtained. 

Dr. Ke Guan received B.E. degree and Ph.D. degree from Beijing Jiaotong University in 2006 and 2014, respectively. Since 2019, he is a Full Professor in State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, China. In 2015, he has been awarded a Humboldt Research Fellowship. He has authored/co-authored more than 260 journal and conference papers, receiving ten Best Paper Awards, including IEEE vehicular technology society 2019 and 2022 Neal Shepherd memorial best propagation paper awards. His current research interests include measurement and modeling of wireless propagation channels for various applications in the era of 5G and beyond. He is the pole leader of EURNEX (European Railway Research Network of Excellence), an Editor of the IEEE Vehicular Technology Magazine, the IEEE ACCESS and the IET Microwave, Antenna and Propagation. He is the contact person of BJTU in 3GPP and a member of the COST actions IC1004, CA15104, and CA20120 initiatives. 

Terahertz (THz) can provide hundreds of GHz bandwidth and owns ultra-short wavelength, thus is promising in providing ultra-high-speed wireless data transmission, high-accuracy localization, imaging and environment reconstruction. However, cellular systems will need to be significantly redesigned to fully exploit the potential of the THz bands. This talk will focus on the core challenges of “integration” of sensing and communication at THz frequencies such as contradictory waveform design principles and strong coupling of sub-wavelength scale components in terahertz systems. To that end, potential applications are first reviewed and summarized. Integrated waveform is then designed, to greatly improve the abilities of high-precision sensing and high-capacity data transmission. Thirdly, sensing-aided ultra-reliable THz communications are introduced, with low beam misalignment probability and acceptable beam sweeping cost. Finally, the physical model of common aperture RF front end for sensing and communication is established, to realize organic interconnection and efficient isolation of sensing and communication. It shows that integration of communication and sensing can reduce the hardware cost and benefit from sharing information across communication and sensing modules.

THz communications are a promising candidate for the next wireless frontier in 6G systems. To offer reliable connectivity, they would need to be able to sustain a “virtual fiber” connection quality in a variety of usage scenarios, such as backhaul/fronthaul, multi-user short-range access and adhoc/dynamic topology ultra-reliable connectivity. High propagation losses and high blockage probability in the THz regime indicate the necessity of high-gain directional antennas with strict beam alignment requirements, and Reconfigurable Intelligent Surfaces for non-line-of-sight and blockage avoidance, complemented by appropriate physical layer procedures and suitable medium access and resource allocation schemes.

In this talk, we will first describe some critical usage scenarios and significant technology pillars defining the THz wireless system concept. Then, a quantitative and qualitative assessment of pencil beamforming efficiency and robustness will be presented. Finally, in the presence of blockage and obstructed propagation, the RIS fundamental performance and efficiency and the impact of the usage scenario geometry will be discussed.

A rapid increase in the use of wireless services over the last few decades has led to the problem of radio-frequency (RF) spectrum exhaustion. More specifically, due to this RF spectrum scarcity, additional RF bandwidth allocation, as utilized in the recent past over "traditional bands", is not anymore enough to fulfill the demand for more wireless applications and higher data rates. The talk goes first over the potential offered by extreme band communication (XB-Com) systems to relieve spectrum scarcity.  Indeed, mm-wave, THz, and free space optics broadband wireless systems recently attracted several research interests worldwide due to the progress in electronics and photonics technologies. By utilizing these extreme frequency bands and employing extreme large bandwidths, the 6G target data rates over 100 Gbps could be achieved. The talk then summarizes some of the challenges that need to be surpassed before such kinds of systems can be deployed.  For instance, it explains how the THz transmission band has immunity against the fog compared with the optical one, while being affected by the rain as it is the case for the mm-wave band. In addition, the role of ultra-massive multiple-input multiple-output (UM-MIMO) systems and reconfigurable intelligent surfaces in overcoming the distance problem at very high frequencies will be discussed. Finally, the talk offers an overview of some recent studies illustrating how these different XB-Com technologies can collaborate to increase emerging and future networks' reliability and coverage while maintaining their high capacity. 

In this talk, we present a blueprint of 6G radio access key enabling technologies. In particular, we focus on the research directions of potential RF technologies, and their development roadmap. We discuss the 6G spectrum candidates for lower 15GHz bands, mmWave bands, and Terahertz bands, to realize the diverse KPI for 6G, we analysis the 6G RF technologies to enable (1) Tbps peak rate link, (2)  network-wide sensing capability, (3) the emerging 6G devises for sensing and communications, (4) 6G satellite link. Emphasis is also laid on control of 6G global radio access networks over the greenhouse emission (gCO2/h) target and its design challenges for 6G RF technologies.

Abstract: The ever-increasing requirement on wireless data rates has been motivating technological innovations on wireless communications in both academia and industry. Among emerging research and development trends in wireless communications, Terahertz Band (0.1 – 10 THz) communication has been envisioned as one of the key enabling technologies in the next decade. With the ultra-wide available spectrum resources, THz band can provide terabits per second (Tbps) links for a plethora of applications. With many proposed 6G wireless systems research directions, it is evident that the THz communication is increasingly becoming a major key technology for 6G systems. Recently, many researchers jumped on the bandwagon to make their contributions as if the THz problem just arose couple years ago. This talk will cover all our research activities on THz within the last 15 years. First the theoretical foundations of ultra-broadband communications in the THz band is laid out for wireless environments in order to bring the Tbps links one-step closer to reality. In particular, the channel model is presented along many physical and link layer solutions for THz band. The very large available bandwidth in this ultra-broadband frequency range comes at the cost of a very high propagation loss, which combined with the low power of mm-wave and THz-band transceivers, limits the communication distance. To overcome this distance problem which is the grand challenge in this area, multipath effects, distance adaptive modulation, ultra-massive MIMO communication and reconfigurable intelligent surfaces are introduced. The concept of ultra-massive MIMO (UM MIMO) overcomes the transmission distance limitation, based on the use of the very large antenna arrays with thousands of antenna elements. The dynamic operation modes that include beamforming, spatial multiplexing and a combination of both, as well as the multi-band UM MIMO for THz mobile channels and multi-hop links will be analyzed. The second concept, the intelligent surfaces, yet another worldwide research activity, will be presented, in particular, our own design from VISORSURF project (visorsurf.eu) is introduced as a class of planar meta-materials as well as graphene material that can interact with impinging electromagnetic waves in a controlled manner. They can effectively re-engineer electromagnetic waves, including steering toward any desired direction, full absorption, polarization manipulation, and more. Moreover, the use of THz band in outdoor and mobile environments is discussed and the research challenges are pointed out. The last part of the talk will be based on the CubeSats where inter-satellite links will operate in Thz Bands and the communication between ground and space segments will be realized through integrated ultra-broadband hybrid front-end that is capable of sensing and communication from the RF to the THz bands. Many research directions and challenges will be discussed. 

Biography: Ian F. Akyildiz received his BS, MS, and PhD degrees in Electrical and Computer Engineering from the University of Erlangen-Nürnberg, Germany, in 1978, 1981 and 1984, respectively. He is the Ken Byers Chair Professor Emeritus in Telecommunications, Past Chair of the Telecom group at the ECE and the Director of the Broadband Wireless Networking Laboratory between (1985-2020) at the Georgia Institute of Technology. Since 1989, he is the President and CTO of the Truva Inc.. He also serves on the Advisory Board of the Technology Innovation Institute (TII) in Abu Dhabi, United Arab Emirates since June 1, 2020. Dr. Akyildiz is the Megagrant Research Leader and Advisor to the Director of the Institute for Information Transmission Problems at the Russian Academy of Sciences, in Moscow, Russia, since May 2018. Dr. Akyildiz is an Adjunct Professor with University of Helsinki, Finland since May 2021. He is also a Visiting Professor with Department of Electrical Engineering at University of Iceland since September 2020. Dr. Akyildiz had many international affiliations during his career. He established many research centers in Spain, South Africa, Finland, Saudi Arabia, Germany, Russia, India, Cyprus, etc. He is the Founder and Editor in Chief of the newly established of the ITU (International Telecommunication Union) Journal on Future and Evolving Technologies (ITU-J FET) since August 2020, and is the Editor-in-Chief Emeritus of Computer Networks Journal (Elsevier) (1999- 2019), the founding Editor-in-Chief Emeritus of the Ad Hoc Networks Journal (Elsevier) (2003-2019), the founding Editor-in-Chief Emeritus of the Physical Communication (PHYCOM) Journal (Elsevier) (2008-2017), and the founding Editor-in-Chief Emeritus of the Nano Communication Networks (NANOCOMNET) Journal (Elsevier) (2010-2017). Dr. Akyildiz co-launched many international conferences (ACM MobiCom, ACM SenSys, IEEE BlackSeaCom, ACM NanoCom, BalkanCom conferences the last 3 decades. He is an IEEE Fellow (1996) and ACM Fellow (1997) and received numerous awards from IEEE and ACM and other professional organizations, including Humboldt Award from Germany. His current research interests are in 6G/7G Wireless Systems, THz Communication, Reconfigurable Intelligent Surfaces, Nanonetworks, Internet of Space Things/CUBESATs, Internet of BioNanoThings, Molecular Communication and Underwater Communication. According to Google Scholar as of July 2021, his H-index is 130 and the total number of citations to his papers is 128+K. His worldwide ranking is 51 and the USA ranking is 34.