Seminar on Millimeter Wave Transmission in Cell-less Networking: Opportunities and Challenges by Prof. Claudio Sacchi
Date: 27 August 2019, 09:00-12:00
Location: U02-409, Ehitajate tee 5, Tallinn
The most recent trends in 5G networks are rapidly proceeding toward some key directions:
1) Seamless integration of heterogeneous wireless networks into different tiers;
2) Progressive network densification with a consequential decrease of cell size.
In such a framework, the old paradigm of “cellular networking”, where each terminal is univocally associated to a base station, identifying the “cell” is no longer suitable to afford such kind of evolution. This is the reason why the new concept of “cell-less” network is raising nowadays more and more interest. In cell-less networks, a user terminal is free to access one or more base stations (BSs) and/or access points (Aps) by different uplink and downlink, considering wireless channel status and the rate demand, or, even, not to access to any BS or AP if the terminal is idle.
So, the terminal is not associated to any BS or AP before it transmits. The management of the network switching is completely “soft”, in the sense that an SDN controller, replacing the old Mobile Switching Centers, decides which one of the available BS / AP better performs data transmission for the mobile terminal.
It is clear that such a paradigm is definitely advantageous for a naturally heterogeneous context like the 5G one, where different network technologies will coexist and cooperate together to provide a plethora of services, characterized by very different requirements in terms of throughput and latency.
In the framework of cell-less nets, millimeter wave communications will play a key role. Substantially, the bands above 30 GHz frequencies will provide the “gigahertzes” of bandwidth necessary to support the broadband connectivity in the last short-range tier of the 5G network. In such a tier, no cell will be found, just hotspots providing data rates of the order of Gigabits/sec. in indoor and outdoor small areas large, at most, some tenths of meters. Large bandwidth availability and reduced interference with other tiers make mm-wave transmission very suitable in the context of cell densification, typical of cell-less networks.
However, some key issues inherent to the utilization of mm-wave bands in dense urban environment are still to be solved and are actually matter of intensive research work. The propagation of mm-wave RF signals in urban channels is problematic, as the presence of the Line-of-Sight (LOS) component cannot be guaranteed and the NLOS propagation is usually characterized by huge pathloss and shadowing. Therefore, the power resources are overall scarce and should be exploited in optimized way. In the millimeter wave domain, the spectral efficiency is not a must. On the contrary, the power efficiency is a must. The design of the physical layer should therefore carefully consider this claim.
In the talk, the concept of cell-less nets will be first introduced (Part 1). Then, the role of millimeter wave communications will be considered in the framework of cell-less networking (Part 2). In Part 3, the open issues of millimeter wave communications in dense urban environment will be discussed. In Part 4 of the talk, some possible solutions in terms of waveform design and efficient MIMO processing will be presented. Some conclusion will be drawn, before opening the discussion with the audience.
About the speaker
Claudio Sacchi received the "Laurea" Degree in Electronic Engineering, and the Ph.D. in Space Science and Engineering at the University of Genoa (Italy) in 1992 and 2003, respectively. From 1996 to 2002, he has been research cooperator with the University of Genoa, Dept. of Biophysical and Electronic Engineering (DIBE) and with the National Italian Consortium in Telecommunications (CNIT), managing project activities in the field of multimedia surveillance systems and satellite communications. Since August 2002, Dr. Sacchi is assistant professor at the Department of Information Engineering and Computer Science (DISI) of the University of Trento (Italy).
Claudio Sacchi is author and co-author of more than 100 papers published in international journals and conferences. In 2011, he was guest editor of the special issue of PROCEEDINGS OF THE IEEE: “Aerospace Communications: History, Trends and Future.” Moreover, in 2015, he was guest editor of the featured-topic special issue of IEEE COMMUNICATIONS MAGAZINE: “Toward the Space 2.0 Era.”
Dr. Sacchi has been invited lecturer to international PhD Summer schools. He also held seminars and short courses both for MSc and PhD students in recognized EU and North American Universities and research institutions. The research interests of Dr. Sacchi are mainly focused on wideband mobile and satellite transmission systems based on space, time and frequency diversity; MIMO systems; array processing; multi-rate and multi-access wireless communications; EHF broadband aerospace communications; software radio and cognitive radio; radio communications for emergency recovery applications.
This talk is hosted in the context of the Cognitive Electronics (COEL) ERA-Chair project - European Union’s Horizon 2020 research and innovation programme under grant agreement No 668995. This material reflects only the authors' view and the EC Research Executive Agency is not responsible for any use that may be made of the information it contains.
The visit of Prof. Sacchi is sponsored by a Scholarships for Researchers managed by the Estonian Education Agency/Archimedes.