Conversing with the Brain
Jan M. Rabaey
Professor in the Graduate School, University of California at Berkeley
CTO System Technology Co-Optimization, imec, Belgium
Abstract: Over the 30 years of the MobiCom Conference, mobile communication has evolved in ways that were hard to foresee. While we envisioned portable devices (such as the InfoPad) that would become our companion for discourse with our fellow humans, for information access and dissemination, and for many other functions such as wellness. However only science fiction foresaw that the wireless networks would expand around and into the human body, effectively providing a bridge between the cyber and biological worlds. While their primary function is to help detect and address deficiencies, malfunctions, and failures of the biological body, one can easily surmise that a next step would be enhance its operation and/or provide novel functionality. In all of this the brain plays a central role. Hence the title of this talk: how communications technology and technology in general will allow us to effectively communicate and interact with the brain.
BIO: Jan is a Professor in the Graduate School in the EECS Department the University of California at Berkeley, after being the holder of the Donald O. Pederson Distinguished Professorship at the same institute for over 30 years. He is a founding director of the Berkeley Wireless Research Center (BWRC) and the Berkeley Ubiquitous SwarmLab, and has served as the Electrical Engineering Division Chair at Berkeley twice. In 2019, he also became the CTO of the System-Technology Co-Optimization (STCO) Division of IMEC, Belgium.
Prof. Rabaey has made high-impact contributions to a number of fields, including low power integrated circuits, advanced wireless systems, mobile devices, sensor networks, and ubiquitous computing. Some of the systems he helped envision include the infoPad (a forerunner of the iPad), PicoNets and PicoRadios (IoT avant-la-lettre), the Swarm (IoT on steroids), Brain-Machine interfaces and the Human Intranet. His current interests include the conception of the next-generation distributed systems, as well as the exploration of the interaction between the cyber and the biological worlds.
He is the primary author of the influential “Digital Integrated Circuits: A Design Perspective” textbook that has served to educate hundreds of thousands of students all over the world. He is the recipient of numerous awards among which the 2009 EDAA lifetime achievement award, is a Life Fellow of the IEEE, and has been involved in a broad variety of start-up ventures.
Carrier Sense Multiple Access (CSMA)
Fouad A. Tobagi
Professor of Electrical Engineering
Stanford University
Abstract: Carrier Sense Multiple Access (CSMA) is a well-known distributed coordination function for accessing a shared medium (e.g., a wireless channel.) It has its roots in Norman Abramson’s famous random-access ALOHA scheme in which stations can randomly access the medium, and collisions are justifiably acceptable given the benefit of low delay. Considering that knowledge of the state of the medium (busy or idle) is available, CSMA inhibits access to the medium during periods of time that the channel is sensed busy, thus reducing the likelihood of collisions. From this simple viewpoint alone, CSMA achieves considerable improvements in performance (throughput, delay, and stability wise) over the ALOHA scheme. Furthermore, CSMA capitalizes on this knowledge to provide prioritized access to the medium (so as to cater to high priority messages), and to provide differentiated services capabilities (so as to accommodate different traffic types; namely, voice, video, data, and background traffic.)
CSMA’s long-lasting impact rides on the great success of key pervasive networking technologies that use it. The most prominent among them is the IEEE 802.11 standard (commonly known as Wi-Fi) first released in 1997. At present, IEEE 802.11 encompasses a wide range of applications, from Wireless LANs, to Vehicular Ad hoc Networks, Sensors and smart Meters Networks, and more. Historically, early work on CSMA was performed in the early seventies under the auspices of ARPA’s Packet Radio Network Project, the Packet Radio Network being the first wireless (mesh) network to use this scheme. Ethernet, which was also conceived and developed in the early seventies by Robert Metcalfe at XEROX PARC, and which got standardized in the early eighties by then the newly formed IEEE 802 committee as the IEEE 802.3 standard, also uses CSMA (with the added capability of collision detection). It is thus of no surprise that the research community’s interest in CSMA remained strong over the years, producing an abundance of research work on CSMA, both in single-hop environments and multi-hop mesh network environments.
This talk comprises both a historical component and a technical component. On the historical front, the context under which the early work on CSMA took place is revisited. Happenstances in my personal journey that led me to be in the right place at the right time (and be well-equipped to deal with the opportunity at hand) are highlighted. A brief account of the Packet Radio Network Project (goals, working group members, and challenges) is also given.
On the technical front, the early work on CSMA is surveyed, relating it to the IEEE 802.3 and IEEE 802.11 standards. Then, various aspects pertaining to the performance of CSMA in single-hop and multi-hop environments are addressed. With respect to meeting the quality of service required by multimedia traffic, the IEEE 802.11 Enhanced Distributed Channel Access (EDCA) protocol is shown to be perfectly adequate (thus obviating the need for a Point Coordination function based on polling.) The problem of determining the capacity of a wireless mesh network following the IEEE 802.11 standard remains quite complex to tackle. Given a geographical distribution of nodes and a source-destination traffic matrix, the traffic load that can be carried by such a network is determined by: (i) the links’ physical layer parameters (transmission power and data rate), (ii) the selection of links to be used in the paths, and (iii) the Energy Detect threshold used in CSMA, which determines the extent of spatial reuse of the wireless channel and, thus, the extent of interference caused by concurrent transmissions. Key insightful results are summarized. We conclude by citing work in the literature that shows that CSMA, a simple distributed coordination multiple access scheme achieves at least 80% of the capacity achievable with optimum scheduling!
BIO: Fouad A. Tobagi received the Engineering Degree from Ecole Centrale des Arts et Manufactures in Paris, France, in 1970 and the M.S. and Ph.D. degrees in Computer Science from the University of California in Los Angeles, in 1971 and 1974, respectively. From 1974 to 1978 he was a research staff project manager with the ARPA Networking Project in the Computer Science Department at UCLA, and engaged in research into Packet Radio Networks design, performance evaluation, and measurements. In June 1978, Dr. Tobagi joined the faculty of the school of Engineering at Stanford University where he has since been a professor of Electrical Engineering. His research interests spanned local area networks (Ethernet and WiFi), multihop wireless networks, fast packet switch architectures for broadband networks, multimedia communications (voice over IP and video streaming), mobility management, and more recently Internet of Things. He also engaged in various activities outside Stanford working with industry. Among others, he co-founded Starlight Networks, Inc. in 1991, a venture concerned with video streaming and networked multimedia applications, and served as its Chief Technical Officer until 1998.
Prof. Tobagi has published extensively in the field of computer communications. He is a pioneer of the Internet having been directly involved in the earliest development thereof. Notably, he was among the first working group members of the ARPA Packet Radio Network project aimed at developing a wireless multi-hop packet switched network (precursor to what Wi-Fi mesh networks are today). It is in the context of this project that he developed the scheme known as Carrier Sense Multiple Access (CSMA), which constitutes the basis for medium access control in Ethernet (IEEE 802.3), Wi-Fi networks (IEEE 802.11), and other networking technologies. He authored several papers on CSMA providing a comprehensive analysis thereof, as well as extensions thereof to handle different traffic types (voice, video and data traffic) used in Wi-Fi’s enhanced medium access control (IEEE 802.11e).
Dr. Tobagi received the 1981 Leonard G. Abraham Prize Paper Award in the field of Communications Systems for his paper "Multi-access Protocols in Packet Communications Networks," and the IEEE Communications Society 1984 Magazine Prize Paper Award for the paper "Packet Radio and Satellite Networks." He subsequently received several best paper awards for conference papers that he co-authored with his Ph.D. students. In 2016 he received the inaugural Test-of-Time award presented by the ACM SIG-Mobile for his first paper on CSMA, co-authored by Professor Leonard Kleinrock and published in the IEEE Transactions on Communications in December 1975.
Dr. Tobagi served as Associate Editor for Computer Communications for the IEEE Transactions on Communications (1984-1986). He has also served as guest editor for various special issues: namely, (i) the special issue on Local Area Networks in the IEEE Journal on Selected Areas in Communications (November 1983), (ii) the special issue on Packet Radio Networks in the Proceedings of the IEEE (January 1987), and (iii) the special issue on Large Scale ATM Switching Systems for B-ISDN in the IEEE Journal on Selected Areas in Communications (October 1991).
Dr. Tobagi was elected Fellow of the IEEE in 1985 for his contributions in computer communications and local area networks. He received the 1998 Kuwait Prize in Information Sciences, administered by the Kuwait Foundation for the Advancement of Sciences. He recently received the 2024 ACM SIGMOBILE Outstanding Contribution Award for seminal development of Carrier Sense Multiple Access (CSMA) as a widely used fundamental mechanism for efficient wireless transmission.
Wireless is Raw Energy, and so is Wireless Research!
ACM Rockstar Award Keynote
Swarun Kumar
Sathaye Family Foundation Professor
ECE Department
Carnegie Mellon University
Abstract: In this talk, I will walk through my near decade long quest to explore the design space of systems that can make everything around us wireless connected. A key bottleneck in this quest was -- where can we get the energy for connectivity, without having to plug everything around us to the electric grid every once in a while? The answer to this question led to an exciting spectrum of design choices from low-power wide-area networking and long-range RF backscatter to low-power satellite infrastructure. Across the board, a simple observation was key -- wireless is raw energy after all! Efficiently tapping this energy enables not just better connectivity for energy-starved systems but opens up entirely new opportunities. I will walk through how by modeling how devices harvest energy, we enable new sensing paradigms from smart wireless pills that sense inflammation to smart mmWave enabled tires that sense their wear. I will then explore how treating wireless as raw energy took us along a bold (and perhaps crazy) direction -- channeling wireless energy to heat everything from undercooked pizza to soft robots. My talk will conclude with reflection on my own journey, the outstanding inter-disciplinary students and collaborators I've learned from along the way, and what makes wireless truly special -- it's not just a source of energy, it's a source of creative energy!
BIO: Swarun Kumar is the Sathaye Family Foundation Professor at Carnegie Mellon University's ECE department, with an affiliate appointment in the CS department, the HCI Institute and the Cylab Security and Privacy Institute. Swarun heads the laboratory for emerging wireless technologies (WiTech lab). He designs and builds novel systems to enable faster wireless networks and new services. His research has impacted a wide-range of domains ranging from low-power wide-area networking, wireless localization, RFID systems, mmWave sensing and satellite networking. Swarun's research led to several best paper awards in conferences such as ACM SIGCOMM (2016), ACM UbiComp (2020 Best Wearables Paper) and ACM IPSN (2018, 2020, 2021 and 2022) as well as research highlights at the Communications of the ACM (2012, 2021), and GetMobile (2017, 2020, 2021, 2023). Swarun is a recipient of the 2024 ACM SIGMOBILE Rockstar award, the 2021 ACM SIGBED Early Career Researcher Award, the NSF CAREER award and the Google Faculty Research Award. Swarun received the George Sprowls Award for best Ph.D thesis in Computer Science at MIT in 2015 and the President of India gold medal at IIT Madras in 2010.