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Actualités de l'école

11/04/2017

Doctorate thesis defense of Yosra ABBES




Doctorate thesis defense on April 11th 2017 at 09H00 AM ,in Amphi I, Sup’Com.


Entitled :Admission Control and Interference Management for Future Wireless Networks

Presented by : Yosra ABBES 





Committee


President

Mr. Sami Tabbane

Professor at Sup'Com, Tunisia

 

 

 

Examiner

Mr. Sofiane Cherif

Professor at SUP’Com, Tunisia

   

Reviewers

Mrs. Kaouthar Sethom

Associate professor at ENIcarthage, Tunisia

 

Mr. Slimane Ben Slimane

Professeur at KTH, Stockholm, Sweden

 

Supervisor

Mr. Hichem Besbes

Professor at SUP’Com, Tunisia

 

Abstract


Future wireless networks are expected to support high-speed data transmission, efficient wireless access, high-quality services and reliable network coverage while ensuring reduced processing time and power consumption. However, the currently witnessed scarcity of the fundamental radio resources constitutes a significant challenge to satisfy these demands. To overcome this issue, an efficient admission control must be applied to maximize the overall system utility while respecting the resource availability constraint and providing user's Quality of Service (QoS) expectation. We aim in this dissertation to propose different admission control strategies to simultaneously improve the efficiency utilization of network resources and guarantee the QoS for the admitted users.


In this thesis, we investigate resource allocation policy for a QoS-aware Orthogonal Frequency Division Multiple Access (OFDMA) wireless network. The objective is to minimize the power consumption while maintaining buffer's stability. Numerical studies evaluating the performance of the proposed admission control, power adjustment and PRB assignment algorithms in terms of the number of served user, power consumption and packet transmission delay are derived.


The Superposition Coding (SC)concept can be used in the multiuser communication network to improve the system capacity by enhancing the user's throughput. In order to optimize the available resource by applying the SC concept, a joint admission control and superposition coding scheme allowing the improvement of the system capacity is derived. Hence, we reformulate the previous proposed optimization problem of resource management while including the specification brought up by superposition coding. Since the complexity of the reformulated optimization problem, we suggest a novel suboptimal algorithm through which power allocation and PRB assignment are achieved.


Inter-Cell Interference (ICI) caused by the simultaneous usage of the same spectrum in different cells, creates severe problems for both homogeneous and Heterogeneous Networks (HetNet). In order to address the problem of Intercell Interference Coordination (ICIC) in homogeneous networks, we design a novel Coordinated Multi-Point (CoMP) transmission scheme supporting user's simultaneous transmission via the SC concept. Thus, we formulate a resource allocation problem aiming to enhance the overall user throughput and guarantee the desired QoS for all Granted Bit Rate (GBR) users given the required throughput. To reduce the complexity of the optimization problem, a simplified scheduling scheme is then suggested to determine the set of cooperating Base Station (BS)s and the set of scheduled users over each PRB.


In the HetNet context, we design a novel cross-tier and co-tier cooperation scheme based on the Joint Transmission (JT) CoMP transmission and the enhanced Intercell Interference Coordination (eICIC) technology to strengthen the signals of users located in the Cell Range Expansion (CRE) zone, suffering from high level of interference. Using stochastic geometry, Signal to Interference Noise Ratio (SINR) analysis of the proposed transmission scheme is conducted which permitting to provide a complete analysis of the outage probability and the ergodic rate.


Keywords


Admission Control, Resource allocation, power minimization, buffer’s stability, QoS, ICI, CoMP, JT, Using stochastic geometry