Head : Jean-Luc SCHARBARG
netwoRks, Mobiles, Embedded, wireleSs, Satellites Team
The convergence of communication networks, especially through the opening of specific systems, requires the control of their performance for sizing and integration purposes. The originality of our approach comes from the exploitation of the specificities of the different types of networks, for example through cross-layer solutions, rather than a standardization that would lead to inefficient solutions. Our activities focus on the architecture and performance of networks with embedded application networks, satellite networks and wireless networks as preferred application areas. The methods used combine mathematical solutions (queues, network computing, …), simulations and experiments.
Modeling and performances (Urtzi Ayesta)
We develop mathematical methods and software tools for the performance evaluation, optimization and control of communication networks and distributed systems. The ultimate goal is to contribute to the enhancement of communication networks (protocols, architectures, applications) with particular emphasis on the Internet, IoT, embedded networks and wireless systems. Our main theoretical tool will be stochastic modelling, analysis and optimization. Stochastic modelling and analysis has been a popular method for analyzing the behavior of algorithms in complex networks. Indeed, randomness is inherent in the network. For example, the behavior of Internet users – when they connect, what they download, when they disconnect – is random. Moreover, changes in topology either due to user mobility or due to faults are random as well. In the context of embedded systems, we resort to deterministic or stochastic worst-case analyses in order to obtain tight bounds on the delay performance. Furthermore, optimization techniques provide the fundamental ideas for efficient resource allocation in such networks.
Wireless Sensor Network & IoT (Adrien van den Bossche)
A powerfull network of connected objects necessarily requires an efficient Data Link layer that is adapted to the characteristics of the underlying immaterial mediums (limited range, high BER, high connectivity variability, complex detection of collision, existence of several channels, more or less important links radio…), and secondly the needs of applications that use this means of communication (guaranteed speed, reduced latency, long life of autonomous nodes and mobile, …). Our experience of more than twenty years in the low layers (1-2-3) of wireless networks has naturally led us to contribute in recent years to the design of new layer #2 protocols responding to many locks related to networks of wireless sensors, for various applications in the fields of monitoring industrial plants, and connected objects for the assistance and assistance. In particular, we have designed MAC layers that meet the two antinomic criteria of low energy consumption and compliance with high time constraints. Combined with these powerful mono or multi-channel access methods, we have also proposed protocols for the localozation of autonomous wireless mobile nodes that can work in indoor environments. The common denominator of our contributions is the adequacy of these protocols to immaterial layers on which we do not contribute directly, but that we apprehend the best possible in a step where the cross-layering 1-2 is advantageously used. We focus on designing Layer #2 least power consuming protocols, thus maximizing the sleep periods of autonomous nodes, which leads us to develop meeting solutions based on strong MAC synchronization of communicating entities. In terms of performance evaluation, there is a lot of room for real prototyping and pragmatic evaluation of protocols through the use of testbeds. The team has been involved in the development of several rapid protocol prototyping tools for wireless sensor networks and is now very more focused on developing the OpenWiNo tool for protocol implementation, then emulation and testing of nodes in controlled and real environments. Work is also carried out on the design of hybrid network architectures of connected objects integrating links and various technologies (satellite, WPAN, WLAN, WMAN, WWAN …).
5G (Gentian Jakllari)
From HD streaming on portable devices to the Internet of Things and smart cities, the global demand for wireless capacity is increasing exponentially, putting a major strain on the wireless networking infrastructure. In the framework of the fifth generation of the cellular network technology (5G), at RMESS we are working on innovative networks and architectures capable of meeting the wireless capacity demands of the next 10 years.
Benefitting from the size of RMESS, we combine stochastic modeling and analysis, optimization, simulation, prototyping, experimentation, with our expertise in diverse networking architectures – cellular, mesh, sensor, satellite networks – and cross-layer design, to deliver solutions that can provide Gbps capacities to people and things. Recent notable results include theoretical models and hardware prototypes for networks incorporating the latest advances at the physical layers, such as cognitive radios and physical-layer network coding, new routing approaches for wireless mesh networks, and new architectures for carrying large amount of data traffic by leveraging V2V communications. Our researched is published in top conferences (IEEE Infocom, ACM MSWiM, IEEE LCN, etc), journals (IEEE/ACM ToN, COMNET, IEEE TWC, etc), and is supported by a mix of ANR financing, industrial as well as regional grants.
Satellite networks (Riadh Dhaou)
In recent years, satellite networks have evolved from the first geostationary satellite networks, used for broadcasting, to future Low Earth Orbit (LEO) constellations or very high-throughput satellites. Through these evolutions, the question of the harmonious operation between satellite and terrestrial components has been posed recurrently. The RMESS team is looking for solutions adapted to the use of satellite links for communications whether in the framework of current (mainly IP based) or future network architectures such as software-defined networks (SDN), content-based networks (CDN, ICN), or the 5th generation of mobile networks (5G) integrating the IoT (Internet of Things) context . Works, carried out through studies and partly through Ph. D. theses, are now moving towards the implementation of network techniques less and less specific to the satellite world. One of the active (and historical) pillars of the team activity in the network domain is unquestionably that of resource management. It is divided into two traditional axes: access methods and scheduling. Thus, work related to the resource management and the quality of service always focus on the access layer according to the evolution of the physical layers. Terrestrial transport protocols are significantly degraded in a satellite environment because of their strong dependence on round-trip time. The RMESS team has been working in this field for several years, and its expertise in this field is strong and covers skills from levels close to the physical layer up to service levels. Besides, the advent of multihoming solutions adapted to terrestrial-satellite hybrid scenarios opens the way to the experimentation of innovative solutions for load-balancing or dynamic routing of content that are placed in a context of network hybridization. The use of several links is indeed a common practice today. The methods used in our research involve stochastic modeling and analysis, optimization, simulation, prototyping, and experimentation. The results of our research are patented or published in high-level conferences and journals and are supported by national and European funding with strong industrial involvement.
Embedded networks and Cyber Physical Systems (Katia Jaffres-Runser)
The team has developed a strong expertise on the design, engineering and performance evaluation of embedded networks and protocols. One of the very specific expertise developed in the team is the design of certifiable embedded networks in the context of real-time systems. Their long-lasting collaboration with the avionics industry of Toulouse made the team develop the algorithms used to certify an AFDX network, the now de-facto networking standard for civil avionics. Certification algorithms together with the specification of AFDX offered the avionics industry a by-design certified embedded network. Mathematical tools such as network calculus, trajectory approach or model checking are leveraged for wired embedded network certification. This research has been driven by several research projects in the last two decades, nurturing a dozen of PhDs. Currently, they are investigating the design of new certifiable protocols for embedded real-time machine-to-machine communications, with a specific focus on the new time sensitive networking technology. Another more recent and core interest of this group is the certifiable design of wireless protocols for cyber physical systems. Machine to machine communications have to ensure reliability but timeliness on top of that in this wireless context. For wireless systems, stochastic bounds on communication delays have to be derived for certification. First results have led to the definition of models and algorithms for distributed medium access protocols and for centralized deterministic medium access protocols. For the latter types of protocols, efforts on time synchronization protocol certification are currently going on. Results on certifiable wireless protocols will serve several operational contexts : embedded networking, cyber-physical systems or industry 4.0.