PhD Dissertation Defense

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PhD Defense| Towards Reliable, Scalable, and Energy Efficient Cognitive Radio Systems

Start Date: November 26, 2017
End Date: November 26, 2017

By Lokman Sboui, PhD candidate of Prof. Mohamed-Slim Alouini (KAUST)
The current global data traffic is increasing exponentially. For instance, the global mobile data traffic is expected to increase seven folds between 2016 and 2021 which will cause a scarcity in terms of the frequency spectrum. As a response, telecommunication researchers and industrials are working to define a suitable framework, named the 5G, to handle the expected huge data exchange in the future. One of the concepts aiming to avoid the spectrum shortage is the cognitive radio (CR) in which unlicensed users are introduced in existing networks and are expected to share the spectrum of existent users without harming their Quality of Service (QoS). In this thesis, we present three main directions in which we aim to enhance the CR performances. The first direction is the reliability. We study the achievable rate of a multiple input multiple-output (MIMO) relay-assisted CR under two scenarios; an unmanned aerial vehicle (UAV) one way relaying (OWR) and a fixed two-way relaying (TWR). The second direction is the scalability. We first study a multiple access channel (MAC) with multiple secondary users scenario. Secondly, we expand our scalability study to cognitive cellular networks. We propose a low-complexity algorithm for base station activation/deactivation and dynamic spectrum management maximizing the profits of primary and secondary networks subject to green constraints. The third direction is the energy efficiency (EE). We present a novel power allocation scheme based on maximizing the EE of both single-input and single-output (SISO) and MIMO systems. We solve a non-convex problem and derive explicit expressions of the corresponding optimal power.
BIOGRAPHY: Lokman Sboui is currently a Ph.D. candidate in the Electrical Engineering program at King Abdullah University of Science and Technology (KAUST). He works with Professor Mohamed-Slim Alouini in the Communication Theory Lab (CTL) in KAUST. Lokman received the Diplome d’Ingenieur degree with honors from Ecole Polytechnique de Tunisie (EPT), La Marsa, Tunisia, in 2011. Then, he received the Master’s degree from KAUST in May 2013. His research focuses on cognitive radio systems and green wireless communications.

More Information:

For more info contact: Prof. Mohamed-Slim Alouini: email:
Date: Sunday 26th Nov 2017
Time:05:30 PM - 07:30 PM
Location: Building 1, level 3, room #3119 (Sea side)
Refreshments: Refreshments will be served around 5:15 PM