Context of Work:
The PhD falls in the CityLab context of Smart Cities and focuses on the monitoring of the urban infrastructure (such as bridges or building). Indeed, such infrastructure needs to be constantly monitored with regards to vibrations, forces of all kinds (frost, wind, cars, pressures, etc), which is supported by embedded sensors. However, such sensors cannot all be wired because of the related deployment cost, which requires data to be sent wirelessly. This leads to new issues relative to the hardware constraints and the wireless networking:
- First, for some measures, sensors need to be buried while this degrades communications. A technological solution then lies in equipping some sensors with passive RFID tags that have less hardware constraints, and using remote RFID readers. RFID readers then become the communicating nodes in the wireless multihop network that are unfortunately more energy consuming.
- Second, such devices rely on batteries that are not envisaged to be changed and thus requires leveraging energy-harvesting systems (solar cells, vibration-harvested systems, etc).
The purpose of the proposed PhD is to investigate an integrated and complete WSN solution for monitoring urban infrastructures, which leverages the aforementioned technologies, namely RFID and energy harvesting. The resulting collecting mechanism will feature a multi-hop routing protocol that will have to meet the QoS requirements of relevance such as data latency (every data should be received by the server at most t seconds after its production), while accounting for the hardware constraints (storing capacity of readers, current energy levels) and traffic conditions.
The candidate will first define the relevant use case and associated requirements. In particular, the requirements specification will define the kind of sensing devices to be used (based on tradeoff between cost and performance), the density of the network, the frequency at which data should be produced, the delay supported by the application between the production and reception of data, etc.
Following, the candidate will investigate some device deployments strategies to define where to locate devices. The study has to consider the environment constraints (we may not be able to put a sensor everywhere), physical parameters (there is a maximum distance to respect to maintain network connectivity), performance (limit the collisions and interferences) and application requirements. The results should provide the best tradeoff between performances and cost.
The third stage will focus on the communication aspects. Issues to be investigate include: When and where to send the data to fulfill QoS requirements and meet hardware constraints? If nodes are low in energy, they may wait to harvest more but can they afford to wait (regarding delay requirements?) or to store data or ask some neighbors to store them instead? The approach may integrate some energy and traffic prediction models. Several pooling and data collection strategies will be studied. Different aggregation mechanisms could be envisioned.
Finally, some performance evaluation will be performed.
[Cui14] J. Cui, F. Valois, “Data aggregation in Wireless Sensor Networks: Compressing or Forecasting?” In Proceedings of IEEE WCNC, 2014
[Gaillard14] G. Gaillard, D. Barthel, F. Theoleyre and F. Valois, “Service Level Agreements for Wireless Sensor Networks: a WSN Operator’s Point of View”. In Proceedings of IFIP/IEEE NOMS, 2014
[Ghaddar12] A. Ghaddar, T. Razafindralambo, I. Simplot-Ryl, D. Simplot-Ryl, S. Tawbi, A. Hijazi. « Investigating Data Similarity and Estimation Through Spatio-Temporal Correlation to Enhance Energy Efficiency in WSNs ». Adhoc & Sensor Wireless Networks, Old City Publishing, 2012, 16 (4), pp. 273-295
[Jumira12] O. Jumira; R. Wolhuter; N. Mitton « Prediction Model For Solar Energy Harvesting Wireless Sensors » Fourth International IEEE EAI Conference on e‐Infrastructure and e‐Services for Developing Countries (Africomm), Nov 2012, Yaoundé, Cameroon.
[Mitton13] N. Mitton; E. Natalizio; R. Wolhuter « Beacon-less mobility assisted energy efficient georouting in energy harvesting actuator and sensor networks » The 12th International Conference on Ad Hoc Networks and Wireless (ADHOC-NOW), Jul 2013, Wroclaw, Poland.
[Urbanet12] I. Augé-Blum, K. Boussetta, H. Rivano, R. Stanica, and F. Valois, “Capillary Networks: A Novel Networking Paradigm for Urban Environments”. In Proceedings of ACM CoNext workshop, 2012
[Amadou14] Ibrahim Amadou, Abdoul Aziz Mbacké and Nathalie Mitton How to improve CSMA-based MAC protocol for dense RFID reader-to-reader Networks? In the 13th International Conference on Ad-Hoc Networks and Wireless ADHOC-NOW 2014 , Benidorm, Spain on June 22-27, 2014.
[Amadou13] Ibrahim Amadou and Nathalie Mitton Revisiting Backoff algorithms in CSMA/CA based MAC for channel Reservation in RFID reader Networks through broadcasting. In Proc. of the 9th IEEE international Conference On Wireless and Mobile Computing, Networking and Communications – Wimob’2013 , Lyon, France, October 6-9, 2013
Conditions for application:
- You must hold a Master’s in computer science, control engineering, mathematics, scientific computation or an equivalent diploma.
- Candidates who got their Master degree in Lille or Lyon cannot apply for this position, while there is no restriction on the candidates’ nationality.
How to apply:
- Detailed CV including full publication record
- Letter of motivation
- 3 references
- Expected start date (Latest possible date is November 2015)
Application may be submitted till the position is filled.