Theoretische Grundlagen der Kommunikationstechnik

Invitation to a Talk by Prof. Petar Popovski (Universität Aalborg, Dänemark)

Time1 April 2016, 14:00 PM  
LocationHFT - Hochfrequenztechnik building, 6th floor, Room HFT-TA 617, Einsteinufer 25, 10587 Berlin  
TitleMAC layer Perspectives on Massive M2M and Massive MIMO  


Uncertainty is the essential element of communication systems, caused by noise, errors, and random traffic/packet arrivals at users. A canonical example of the latter is seen in random access protocols, used for handling transmissions of users to a common receiver, e.g., a base station, over a shared wireless medium. Random access is necessary when the total number of users associated with the base station is large, but at a given short time interval, the number of active users that have packets to transmit is small and unknown a priori. This talk treats two emerging scenarios that motivate (renewed) interest in random access protocols to deal with uncertainty of user activation. The first is related to the massive Machine-to-Machine (M2M) communication, also called massive Machine Type Communication (mMTC), where a large number of sporadically active devices are connected to the wireless infrastructure. Several methods for massive M2M access will be presented, based on coded random access as well as signature sequences. The second scenario is related to systems based on Massive MIMO that are serving a large crowd of users, each with relatively high speed. One of the central issues in Massive MIMO is the protocol for allocating pilot sequences in order to enable channel estimation and reap the massive MIMO gain. This talk will describe scenarios in which the terminals are intermittently accessing the pilot sequences and show how random access can be used to deal with intra-cell pilot contamination. Specifically, a new protocol termed strongest-user collision resolution (SUCR) will be presented, which exploits the channel hardening feature of Massive MIMO channels in order to enable each user to detect collisions in a distributed way.



Petar Popovski is a Professor in wireless communications at Aalborg University, Denmark. He received Dipl.-Ing. in electrical engineering (1997) and Magister Ing. in communication engineering (2000) from Sts. Cyril and Methodius University, Skopje, Macedonia, and Ph.D. from Aalborg University, Denmark, in 2004. He has more than 250 publications in journals, conference proceedings and books and has more than 25 patents and patent applications. He is a Fellow of IEEE, a holder of a Consolidator Grant from the European Research Council and recipient of the Elite Researcher Award (2016) in Denmark. In the past he served as an Editor in IEEE Trans. Wireless Communications, IEEE JSAC Cognitive Radio Series and Senior Editor in IEEE Communications Letters. He is currently an Editor for IEEE Transactions on Communications. From 2012 to 2014 he served as the Chair of IEEE ComSoc Emerging Technology Committee on Smart Grid Communications. He is a Steering Committee member for IEEE Internet of Things Journal, as well as Steering committee member of IEEE SmartGridComm. His research interests are in the area of wireless communication and networking, and communication/information theory.