Articles

Optimisation of data dissemination

So-called systems of systems are becoming increasingly commonplace today, in a world where objects can all be inter-connected and many already are. Game consoles, satellites, cars … must all be able to forward data as fast as possible. The snag is that communications between the systems are often intermittent. Whenever two elements of a system meet’, they only exchange a part of the data available. Ronan Bocquillon, a PhD student at the UTC-Heudiasyc Lab is working on optimized data transfer protocols in systems of systems.

Optimisation of data dissemination

The objective of his thesis is to obtain better dissemination of data among mobile systems in order to improve of the quality of the exchanges and enable the data to circulate as rapidly as possible between transmitters and receivers. 
We are looking at a general case, to situate our work outside certain practical situations and special cases”, explains Ronan Bocquillon. “This really is basic research”, confirms Antoine Jonglet, research scientist at the UTC-Heudiasyc Laboratory that supervises Ronan’s thesis work. “The model on which we are working has a general scope in order to take the scale of the data into account and also the duration of the contracts”. This research project on “Optimized data dissemination in a collaborative systems of systems”, financially supported by the Picardie Region is also part of the UTC ‘labex’ projects “Control of technological systems”.

Subdividing data into packets

Data exchanged between systems (images, GPS coordinates, satellite photos …) can be of varying formats, but this is not important given that the study concentrates on the theory of data exchange protocols. “In this case, we are looking a huge data, too much to be exchanged in a single transmission between two systems that enter into contact for a relatively short time. We must therefore transit via intermediate messengers who will forward the data in packet to the final addressee”, says Antoine Jouglet. The data must be subdivided into sufficiently small packets to be exchanges in a brief contact between the transmitter and receiver systems. 
For example “data can be divided into 100 separate packets”, says Ronan Bouquillon. “We defined a protocol where a packet could be forward every time the two systems make contact. In order for the information to be transmitted as rapidly as possible, without online losses, we have to decide which packet(s) should be given a priority when transmitted to another system”. There must be relays, who handle and transfer information from the source to the addressee without using the data. It is this collaborative feature is fundamental in the research project, confirms Ronan Bocquillon:

Applications for drone and satellites

We first have to know the order in which the systems ‘make contact’ and the time of the contact. That is what we call the contact sequence. Our data transfer protocol is therefore well adapted to satellite communications or for a squadron of drones, where the precise movements in space and time are well known to the operators.” 
The results of the research could also be used for inter-vehicle communications, which is also a possibility under investigation at the UTC-Heudiasyc Laboratory. “The long term objective is to create a more ‘rugged’ system that is data error resilient and breakdown free”, concludes Ronan Bocquillon.