AAU logo

PhD defence by Renato Barbosa Abreu


04.09.2019 kl. 12.30 - 16.00


“Uplink Grant-free Access for Ultra-Reliable Low-Latency Communications in 5G - Radio Access and Resource Management Solutions”

5G cellular networks should enable Ultra-Reliable Low-Latency Communications (URLLC) for supporting mission-critical applications. URLLC impose strict requirements for a data packet transmission over the radio interface, such as 99.999% success probability within 1ms. Grant-free access is placed as a technical solution for satisfying the latency requirement. However, many challenges arise for meeting the reliability target with efficient usage of the radio resource. The first part of the thesis addresses channel access solutions, with emphasis on the transmission and retransmission procedures for grant-free URLLC. Different schemes are studied and the conditions for efficiently employing the proposed approaches are identified. Then, radio resource management solutions are in depth analyzed through detailed system level simulations. Insights regarding power control, resource allocation and receive strategy are provided for improving the supported URLLC load in the system. Finally, the multiplexing of grant-free URLLC with broadband traffic is studied. The trade-offs of multiplexing both traffic in shared resources are revealed for different operation conditions. Recommendations for 5G radio networks implementation are provided based on the presented results.

Assessment Committee
Associate Professor, Gerhard Wunder, Freie Universität Berlin, Germany
Master Researcher, Imadur Rahman, ERICSSON, Sweden
Professor, Hans-Peter Schwefel, Aalborg University (Chairman)

Professor, Preben E. Mogensen, Aalborg University
Associate Professor, Gilberto Berardinelli, Aalborg University
Professor, Klaus Pedersen, Aalborg University

Professor MSO, Elisabeth de Carvalho, Aalborg University

After the defence there will be a reception at Fredrik Bajers Vej 7, room A1-112 Please feel welcome to join


Free of Charge


Wireless Communication Networks Section Department of Electronic Systems


Fredrik Bajers Vej 7, room B3-104