AIDRC Seminar Series - Prof. Petar Popovski

Title:

On Models and Techniques for Massive Access in Wireless Uplink and Downlink

Abstract:

Wireless access from and to a massive number of Internet of Things (IoT) devices is one of the main connectivity modes for the wireless systems in 5G and beyond. The dominant line of research in massive wireless access has built upon the long-established tradition of random access. Within this line, ALOHA-based protocols and their innovative variants have been used to ensure efficient access in the uplink from a large set of devices that are activated in a random, uncoordinated, and uncorrelated manner. This talk will present models and techniques that address three aspects of massive access that have received less attention within the research community. (1) The first aspect is related to the change of the assumption about uncorrelated access. In a number of practical scenarios, the information from IoT devices in a given geographical area is inherently correlated due to a commonly observed physical phenomenon. We introduce models for massive access that accounts for correlation both in device activation and in the message content and show its impact on the access protocol. (2) The second aspect is the one of user identification and authentication. When the number of devices is massive and relatively small packets are transmitted, the overhead of including identification/authentication fields becomes restrictive. This led to schemes based on unsourced random access (U-RA) that completely drop those fields. The talk will present a scheme that builds upon an underlying U-RA protocol and solves the problem of user identification and authentication. (3) Finally, the third aspect is related to the communication with a massive set of devices in the downlink. This is a necessary functionality as reliable communication needs to rely on two-way communication for acknowledgement and retransmission. This talk will introduce the problem massive ARQ (Automatic Retransmission reQuest) protocol and present efficient methods for joint encoding of multiple acknowledgements in the downlink.

Bio:

Petar Popovski is a Professor at Aalborg University, where he heads the section on Connectivity and a Visiting Excellence Chair at the University of Bremen. He received his Dipl.-Ing and M. Sc. degrees in communication engineering from the University of Sts. Cyril and Methodius in Skopje and the Ph.D. degree from Aalborg University in 2005. He is a Fellow of the IEEE. He received an ERC Consolidator Grant (2015), the Danish Elite Researcher award (2016), IEEE Fred W. Ellersick prize (2016), IEEE Stephen O. Rice prize (2018), Technical Achievement Award from the IEEE Technical Committee on Smart Grid Communications (2019), the Danish Telecommunication Prize (2020) and Villum Investigator Grant (2021). He is currently the Editor-in-Chief of IEEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS. Prof. Popovski was the General Chair for IEEE SmartGridComm 2018 and IEEE Communication Theory Workshop 2019. His research interests are in communication theory and wireless connectivity. He authored the book "Wireless Connectivity: An Intuitive and Fundamental Guide'', published by Wiley in 2020.