March 10th 2022, 2 pm
Hybrid event (online and in lecture hall: Amphi 2 in Telecom Paris)

Contention-based channel access is the oldest wireless data communications technology, where transmitters send packets on a shared medium in a completely non-coordinated way. For a long time, Aloha seemed surpassed by protocols that ensure a certain level of coordination, such as TDMA centralized scheduling or CSMA-like communications. However, with the integration of Industrial Internet of Things (IIoT) services within the wireless networks, Aloha protocols are becoming popular again, as stringent delay constraints make coordination and scheduling almost impossible. We explore the Aloha-like protocols for critical services, where transmitters are completely blind (do not receive any feedback about their actions) or far-sighted (receive a delayed feedback). Repetitions are key in this context, hoping that the repetition rate ensures reliability without much aggressively. We derive the optimal repetition rates for different scenarios and apply them to the main 5G radio configurations.

Salah Eddine Elayoubi received the M.S. degree from the National Polytechnic Institute of Toulouse, France, in 2001, and the Ph.D. and Habilitation degrees in computer science from the University of Paris VI, Paris (now Sorbonne University) , in 2004 and 2009, respectively. From 2004 to 2017 he was with Orange Labs in France as a principal researcher. In 2018, he joined CentraleSupelec, France, where he is now a full professor and head of the Optimization and Mathematical Tools for Networks (OOMR) Team at L2S laboratory. In the past years, he coordinated several EU and French collaborative projects on 4G and 5G system design. His research interests include radio resource management, modeling, and performance evaluation of wireless networks.