Talk: Prof. Alexandre Graell i Amat (July 20, 2023 at 11:00 AM, Seminar room N2409)

Prof. Alexandre Graell i Amat

Department of Electrical and Computer Engineering
Chalmers University, Gothenburg, Sweden.

Abstract:

The Internet of Things is characterized by a massive number of low-cost devices with sporadic and time-varying activity transmitting short packets. To effectively accommodate such a massive number of devices, modern random-access protocols have emerged, leveraging packet-based coding at the users and successive interference cancellation decoding at the receiver. Among these protocols, irregular repetition slotted ALOHA (IRSA), a scheme that bears similarities to codes-on-graphs, stands out as a promising low-complexity solution.

In this presentation, we consider massive uncoordinated access over the binary adder channel (BAC). Particularly, we propose an IRSA-based random-access protocol for this scenario. Unlike the commonly-considered collision channel model, the BAC incorporates crucial physical-layer concepts, including packet generation, per-slot decoding, and information rate, making it a more realistic representation of real-world scenarios.

In the regime of practical interest, our scheme resolves more colliding users within a slot, thus achieving higher average sum rate, than a recently-proposed scheme by Paolini et al. (2022).

Biography:

Alexandre Graell i Amat received the M.Sc. degree in electrical engineering from the Politecnico di Torino, Turin, Italy, in 2000, the M.Sc. degree in telecommunications engineering from the Universitat Politècnica de Catalunya, Barcelona, Catalonia, Spain, in 2001, and the Ph.D. degree in electrical engineering from the Politecnico di Torino in 2004. From 2001 to 2002, he was a Visiting Scholar with the University of California at San Diego, La Jolla, CA, USA. From 2002 to 2003, he held a visiting appointment with Universitat Pompeu Fabra, Barcelona, and the Telecommunications Technological Center of Catalonia. From 2001 to 2004, he held a part-time appointment with the STMicroelectronics Data Storage Division, Milan, Italy, as a Consultant on coding for magnetic recording channels. From 2004 to 2005, he was a Visiting Professor with Pompeu Fabra University. From 2006 to 2010, he was with the Department of Electronics, IMT Atlantique (formerly ENST Bretagne), Brest, France. Since 2019, he has been an Adjunct Research Scientist with Simula UiB, Bergen, Norway. He is currently a Professor with the Department of Electrical Engineering, Chalmers University of Technology, Gothenburg, Sweden. His research interests are in the field of coding theory with application to distributed learning and computing, storage, privacy and security, and communications.