January 01, 2018

Optimal VNFs placement in CDN Slicing over Multi-Cloud Environment

This paper introduces a Content Delivery Network as a Service (CDNaaS) platform that allows dynamic deployment and life-cycle management of virtual Content Delivery Network (CDN) slices running across multiple administrative cloud domains. The CDN slice consists of four Virtual Network Function (VNF) types, namely virtual transcoders, virtual streamers, virtual caches, and a CDN-slice-specific Coordinator for the management of the slice resources across the involved cloud domains. To create an efficient CDN slice, the optimal placement of its composing VNFs using adequate amount of virtual resources for each VNF is of vital importance. In this vein, this paper devises mechanisms for allocating an appropriate set of VNFs for each CDN slice to meet its performance requirements and minimize as much as possible the incurred cost in terms of allocated virtual resources. A mathematical model is developed to evaluate the performance of the proposed mechanisms. We first formulate the VNF placement problem as two Linear Integer problem models, aiming at minimizing the cost and maximizing the Quality of Experience (QoE) of the virtual streaming service. By applying the bargaining game theory, we ensure an optimal trade-off solution between the cost efficiency and QoE. Extensive simulations are conducted to evaluate the effectiveness of the proposed models in achieving their design objectives and encouraging results are obtained.

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Recent Publications

January 01, 2018

Fair Dynamic Spectrum Management for QRD-Based Precoding with User Encoding Ordering in Downstream G.fast Transmission

In next generation DSL networks such as G.fast, employing discrete multi-tone transmission in high frequencies up to 212 MHz, the crosstalk among lines reaches very high levels. To precompensate the crosstalk in downstream transmission, QRD-based precoding has been proposed as a near-optimal dynamic spectrum management (DSM) technique. However, the performance ...

January 01, 2018

Practical Mitigation of Passive Intermodulation in Microstrip Circuits

This paper presents new experimental evidence and a novel practical approach for mitigation of passive intermodulation (PIM) in microstrip circuits fabricated on commercial printed circuit board laminates. The mechanisms of distributed PIM in microstrip circuits are reviewed and a phenomenology of PIM generation due to locally enhanced electromagnetic fields at ...

January 01, 2018

Efficient Cooperative HARQ for Multi-Source Multi-Relay Wireless Networks

In this paper, we compare the performance of three different cooperative Hybrid Automatic Repeat reQuest (HARQ) protocols for slow-fading half-duplex orthogonal multiple access multiple relay channel. Channel State Information (CSI) is available at the receiving side of each link only. Time Division Multiplexing is assumed, where each orthogonal transmission occurs ...