PhD defense of Mariem BEN YAHIA on May 10th, 2019

The defense of PhD thesis of Mariem Ben Yahia will be held on May 10th at  14:00 at IMT Atlantique, Rennes Campus , Petit Amphi. The thesis is entitled “Low Latency Video Streaming Solutions based on HTTP/2”. It was made in the framework of a CIFRE thesis with Orange Labs (Lannion).

Adaptive video streaming techniques encode the content at different levels of quality and split it into temporal segments. Before downloading a segment, the client runs an adaptation algorithm to determine the best level of quality to consider that matches the network resources. Besides, in the case of immersive video streaming this adaptation mechanism should also consider the head movement of a user watching the 360° video to maximize the quality of the viewed portion of the sphere. However, this adaptation may suffer from errors impacting negatively the end user’s quality of experience. In this case, an HTTP/1 client must wait for the download of the next segment to choose a suitable quality. In this thesis, we propose to use the HTTP/2 protocol instead to address this problem. First, we focus on the live streaming service. We design a strategy to discard video frames when the bandwidth is very variable in order to avoid the rebuffering events and the accumulation of delays. The customer requests each video frame in an HTTP/2 stream which allows to control the delivery of frames by leveraging the HTTP/2 features at the level of the dedicated stream. Second, we use the priority and reset stream features of HTTP/2 to optimize the immersive video streaming service. We propose a strategy to benefit from the improvement overtime of the user’s head movements prediction. The results show that HTTP/2 allows to optimize the use of network resources and to adapt the video delivery to the latencies required by each service.

(Français) Prix de la meilleure thèse “Futur et Rupture” pour Xavier Corbillon

Sorry, this entry is only available in French.

PhD defense of Rabah Guedrez on December 12th, 2018

The defense of PhD thesis of Rabah Guedrez will be held on December 12th at 09:00 at IMT Atlantique, Rennes Campus , Petit Amphi. The thesis is entitled “Enabling Traffic Engineering Over Segment Routing”. It was made in the framework of a CIFRE thesis with Orange Labs (Lannion).

Most major operators use MPLS technology to manage their network via signalling and label distribution protocols. However, these protocols are complex to deploy, maintain and troubleshooting is often very difficult. The IETF has initiated the standardization of a segment routing architecture based on a simple control plane, lightweight, easy-to-manage and instantiated on MPLS or IPv6. This architecture is based on the concept of source routing, in which the packet header carries the indications of the path to follow to reach its destination. Suitable for simple use cases and natively resistant to failure, more complex use cases require the resolution of technological issues for which we offer  several solutions. In this thesis carried out within Orange Labs, we were interested in the instantiation of the Segment Routing architecture on the MPLS transfer plan and more particularly in traffic engineering, particularly with resource reservation. We have proposed solutions to the problems related to the hardware limitation of current routers that do not allow the expression of all constrained paths. This work is divided into two parts: (i) the proposal of algorithms for computing and encoding segment routing paths in order to bypass hardware limitations. (ii) the definition of architectural requirements and the construction of a functional proof of concept. Finally, this thesis proposes new research issues to consolidate traffic engineering tools for segment routing.

Keywords :      Segment Routing, Ingénierie de trafic, Optimisations, IP/MPLS, SDN


PhD defense of Mahdi Ezzaouia on November 8th, 2018

The defense of PhD thesis of Mahdi Ezzaouia will be held on November 8th at 10:00 at IMT Atlantique, Rennes Campus , Petit Amphi. The thesis is entitled “Opportunistic resource allocation in multi-cell wireless networks”. It was made in the framework of a “co-tutelle” with Ecole Nationale d’Ingénieurs de Tunis (ENIT), Tunisia.


PhD defense of Xavier Corbillon on October 30th, 2018

The defense of PhD thesis of Xavier Corbillon will be held on October 30th at 10:15 at IMT Atlantique, Rennes Campus , Petit Amphi. The thesis title is “Enable the next generation of interactive video streaming”.


Omnidirectional videos, also denoted as spherical videos or 360° videos, are videos with pixels recorded from a given viewpoint in every direction of space. A user watching such an omnidirectional content with a Head Mounted Display (HMD) can select the portion of the video to display, usually denoted as viewport, by moving her head. To feel high immersion inside the content a user needs to see viewport with 4K resolution and 90 Hz frame rate. With traditional streaming technologies, providing such quality would require a data rate of more than 100 Mbps , which is far too high compared to the median Internet access bandwidth. In this dissertation, I present my contributions to enable the streaming of highly immersive omnidirectional videos on the Internet. We can distinguish six contributions : a viewport-adaptive streaming architecture proposal reusing a part of existing technologies ; an extension of this architecture for videos with six degrees of freedom ; two theoretical studies of videos with non-homogeneous spatial quality ; an open-source software for handling 360° videos ; and a dataset of recorded users’ trajectories while watching 360° videos. The work done during this thesis was published in eight international conferences and in one journal, and resulted in three “Best Paper Award”s.


Omnidirectional Video, 360°Video, Viewport-Adaptive Streaming, DASH, HEVC

PhD defense of Alassane Samba on October 29th, 2018

The defense of PhD thesis of Alassane Samba will be held on October 29th at 14:00 at IMT Atlantique, Rennes Campus , Petit Amphi. The thesis title is “Data science for services in operated networks”.


Best paper award at IEEE MMSP

Hristina Hristova, Xavier Corbillon, Gwendal Simon, Viswanathan Swaminathan (Adobe), and Alisa Devlic (Huawei) received the best paper award at IEEE MMSP 2017. The paper is entitled “Heterogeneous Spatial Quality for Omnidirectional Video”.


Best paper award at MMSys 2018

Xavier Corbillon, Francesca De Simone, Gwendal Simon and Pascal Frossard received the best student-paper award at ACM MMSys 2018, a top-ranking conference of multimedia. The paper is entitled “Dynamic Adaptive Streaming for Multi-Viewpoint Omnidirectional Videos”.


PhD defense of Farah Slim on March 13th, 2018

The defense of PhD thesis of Farah SLIM will be held on March 13th at 10:00 at IMT Atlantique, Rennes Campus , Petit Amphi. The thesis title is “Design and Implementation of Resource Allocation Algorithms for a Network Operating System”.

PhD defense of Jialong Duan on 27/11/2017

The defense of PhD thesis of Jialong Duan will be held on November 27th at 10:15 at IMT Atlantique, Rennes Campus , Petit Amphi. The thesis title is “Coordination inside Centralized Radio Access Networks with Limited Fronthaul Capacity”.