Description
Date depot: 9 mars 2021
Titre: Wireless geocasting based on OFDM spatial data focusing
Directeur de thèse:
Julien SARRAZIN (GeePs (EDITE))
Encadrant :
Philippe DE DONCKER (Université Libre de Bruxelles)
Domaine scientifique: Sciences et technologies de l'information et de la communication
Thématique CNRS : Signal et communications
Resumé: Geocasting refers to the transmission of information towards specific geographical areas. Transmission is performed without cooperation of the receiver, i.e. without channel state information at the transmitter and without user localization, avoiding potential privacy issues. Geocasting has numerous potential applications: connected transportation systems, mobile marketing, tourism,… all applications where information related or contextualized to the receiver position is important. In a wireless scenario, geocasting accuracy is fully determined by the base station coverage. Increasing this accuracy requires base stations to exhibit spatial focusing capabilities.
Geocasting in urban environments is challenging to achieve with classical macro-cellular network infrastructures since a clear Line-of-Sight (LOS) is required to focus the signal towards a given area. 5G small cells at street level will offer new perspectives: each small cell will be dedicated to communications towards nearby users, so that a dominant LOS component can be assumed. Those small cells will be equipped with antenna arrays, in order to use beamforming. Beamforming, however, only focuses power in the angular domain and not according to range, so that no real geocasting is possible. Additionally, it requires large arrays to be selective in the angular domain, which jeopardizes this approach for base stations located at street level, except in the mm-wave band.
The general objective of this PhD is to develop a wireless geocasting system dedicated to small cells. The proposed method focuses the transmitted data rather than the transmitted power, by using an OFDM-based technique that relies on multi-subcarrier multi-antenna transmission. In this scheme, a desired focusing area in both angles and range can be obtained with small antenna arrays. A proof-of-concept of the system will be built, based on Software Defined Radios (SDR).
Doctorant.e: Molineaux Guylian