Ce projet de recherche doctorale est publié a été réalisé par julien SARRAZIN
Description d'un projet de recherche doctoral
Physical layer-based geocasting using multidimensional modulations and antenna arrays
Résumé du projet de recherche (Langue 1)
Associating wireless information to certain physical locations is an
interesting feature that many applications can benefit from. This capability is
known as geocasting. Just like pictures are tagged with the location where they
have been clicked, geocasting enables to tag a real physical location by
wirelessly transmitting data that are only decodable within desired delimited
areas. Thus, users can receive information related to the place where they are.
This is what is achieved to some extent by applications like Google map where
metadata related to user’s location are sent. To do so, GPS coordinates of
users are required. These systems are limited in terms of spatial resolution,
especially in indoor environments, and necessitate some time to calculate
user’s locations, thereby introducing a delay, which can be a real limitation.
Furthermore, as a general matter, all systems that are based upon user’s
locations lead to privacy issues. The geocasting scheme to be investigated in this
internship is fundamentally different. The idea is to transmit data related to
locations whether a user is present or not. So instead of considering a user
who locates himself with respect to a global reference system and then
correlate his position to some databases to discover surrounding locations of
interest, the user is able to read the data only when he is located at the
right spot. In that case, it is really the location that is tagged, and not the
person. This approach therefore respects users’ privacy and does not introduce
any delay as the data is always sent to the desired location (it is up to the
user to decide whether or not he wants to listen). Furthermore, since this
approach does not require positioning capability, all the classical positioning
system infrastructure (e.g. satellites, multiple base stations…) is not
required anymore. The only added infrastructure is the capability for base
stations to focus data to specific spots. For this scheme to be attractive
enough, this feature has to be performed with minimum complexity, low cost, and
compact size. To date, no existing techniques are capable of realizing the geocasting
scheme without hardware that is too complex, too expensive, too bulky, and too
demanding in terms of energy.
About the PhD
A research group at L2E is currently investigating physical solutions that enable the broadcasting of information to specific spatial locations, using limited infrastructures. From a scientific point of view, the problem is to find a way for a base station to wirelessly transmit data that are decodable only within desired areas. Solutions combining signal processing and Multiple-Input Multiple-Output (MIMO) systems are currently investigated in order to overcome the limitations of classical beamforming techniques. The idea is for an antenna array to exhibit hyper resolution spatial data focusing. The proposed PhD is part of this research and will investigate the benefits of using multidimensional modulations as additional degrees of freedom to enable efficient data focusing. To that aim, the candidate will investigate both time and frequency resources and dedicated transmitter and receiver architectures that could enhance data focusing capabilities in scenarios where the user is cooperative.
This PhD involves multidisciplinary aspects ranging from digital communication to electromagnetic wave propagation. It also deals with MIMO systems and antenna arrays.
The plan for the PhD is the following:
- Development of multidimensional modulations and mapping(s) for geocasting scenarios
- Development of dedicated solutions to recover the carrier at the receiver and to estimate the channel gain
- Experimental assessment of the robustness of the developed techniques using USRP
Informations complémentaires (Langue 1)
- The PhD candidate will work at
the L2E lab (http://www.l2e.upmc.fr/en) of
Sorbonne University (www.sorbonne-universite.fr/en),
located in Paris, France, with co-supervision from Philippe De Doncker from the
Opera lab (http://opera.ulb.ac.be/opera/) of the ULB University (http://www.ulb.ac.be/ulb/presentation/uk.html), located in
Brussels, Belgium, where regular stays will be organized.
- The candidate should hold a Master Degree in Electronics, or equivalent. A high degree of self-motivation and excellent communication skills are expected.
- Duration: 3-year program, starting from September 2018 onwards
- Application deadline: 11th May 2018