What: PhD position on information and communication theory - Fundamental bounds for communications with reconfigurable intelligent surfaces.
Where: INSA Rennes and IETR Laboratory (SIGNAL Team)
When: starting at October, 1st 2024.
With: Philippe Mary and Luc Le Magoarou
Laboratory:
IETR: Institut d’électronique et des technologies du numérique (https://www.ietr.fr) (https://www.ietr.fr/equipe-signal-signal-processing-and-algorithm)
Starting date: October 1st, 2024 – duration: 36 months
Topic
This thesis work will be carried out as part of the "Sustainable, Secured, Sovereign and Intelligent Networks (RIS3)" project, at the IETR laboratory on the INSA Rennes campus.
The ever-increasing demand for bandwidth to satisfy ever more sophisticated applications continues to grow in the telecoms sector, leading to exponential data consumption and rising energy bills. Ericsson estimates the average worldwide consumption per smart phone at 21 GB/month in 2023 (with considerable geographical disparities), rising to 56 GB/month by 2029 [1]. The Shift Project, based on a Cisco study, estimated in 2018 a +26% / year growth in network traffic, notably due to more and more connected devices and high-definition video consumption [2]. To support this increase in data and energy consumption, a regular transition of technology is necessary, and takes place every 10 years on average. Each transition is accompanied by technological innovations, such as waveform changes for radio transmission.
The integration of reconfigurable smart surfaces into future wireless communication networks has attracted a great deal of academic and industrial interest in recent years [3]. These devices, incorporating small elementary radiative circuits, can be controlled to modify the phase of the incident wave in order to focus it towards the end-user. This technology allows to control the propagation environment in the sense that multi-paths are no longer undergone but exploited. Numerous works in the literature demonstrate the potential benefits of this technology in terms of achievable throughput, user coverage and energy efficiency [4,5]. On the other hand, the control of wavefronts impacting the smart surface requires information from the end-user, in order to agilely change the properties of the radiating surface. The amount of data to be transmitted back to the transmitter and the reconfigurable surface will depend on the time and coherence bandwidth of the channel, as well as the number of users to be served. Few studies have addressed the information overhead involved in controlling these surfaces, except in [6,7]. The authors consider only a single Tx-surface-Rx link, and in [6], the amount of information required to operate the smart surface is not studied. The authors in [7] adopt an information-theoretic approach to propose joint "data-control" encoding to maximize end-to-end throughput. The authors show that joint encoding maximizes the achievable throughput of the system, compared to the case where control is done separately. However, the return link required to encode the information is not considered. Furthermore, the imperfect knowledge of the channel state and the consideration of multiple users are not taken into account.
This thesis aims at studying the fundamental limits of communication with a reconfigurable surface and to quantify the amount of information needed to optimally operate these devices. This work has the potential to fully understand how to design the future networks with these devices. More precisely, we propose to tackle the following research questions:
Q1: What is the capacity region of a communication with reconfigurable intelligent surfaces? The analysis will be carried out in the asymptotic regime, and its extension to finite block length will be carried out according to the candidate progresses.
Q2: Is there a tradeoff between the data rate to be granted to control signals and that for encoding user information?
Q3: If time allows, writing and solve the extension to the multi-user cases, i.e. multiple access channel and broadcast channel.
References
[1] Ericsson, « Ericsson Mobility Report: Resilient 5G uptake – global mobile data traffic set to triple in six years »,https://mb.cision.com/Main/15448/3884810/2463363.pdf.
[2] The Shift Project, “ Impact environmental du numérique : tendance à 5 ans et gouvernance de la 5G », https://theshiftproject.org/wp-content/uploads/2021/03/Note-danalyse_Numerique-et-5G_30-mars-2021.pdf
[3] M. Di Renzo et al., "Smart Radio Environments Empowered by Reconfigurable Intelligent Surfaces: How It Works, State of Research, and The Road Ahead," IEEE Journal on Selected Areas in Communications, vol. 38, no. 11, pp. 2450-2525, Nov. 2020.
[4] N. Shlezinger, et al., "Dynamic Metasurface Antennas for Uplink Massive MIMO Systems," IEEE Transactions on Communications, vol. 67, no. 10, pp. 6829-6843, Oct. 2019.
[5] Z. Yang et al., "Energy-Efficient Wireless Communications with Distributed Reconfigurable Intelligent Surfaces," IEEE Transactions on Wireless Communications, vol. 21, no. 1, pp. 665-679, Jan. 2022.
[6] A. Zappone, et al., "Overhead-Aware Design of Reconfigurable Intelligent Surfaces in Smart Radio Environments," IEEE Transactions on Wireless Communications, vol. 20, no. 1, pp. 126-141.
[7] R. Karasik, et al. "Beyond max-SNR: Joint encoding for reconfigurable intelligent surfaces", In Proc. IEEE Int. Symp. Inf. Theory, 2020.
Key skills
The candidate must have earned a Master 2 or an engineering degree of a Grande Ecole in one of the following fields: information and communication theory, signal processing, applied mathematics. He or she should be comfortable with one or more of the following programming languages: Matlab, Python or C/C++. A strong spirit of curiosity and strong interest in mathematical developments are expected.
Keywords
Asymptotic and non-asymptotic information theory, control theory, probability, convex and non-convex optimization, intelligent reconfigurable surfaces.
How to apply
No need to send a separate motivation letter but an email to the people listed below, explaining your interest to the topic and why you think you have the background to address it. Please, attach the following documents:
- A CV with a complete list of projects / internships / courses related to the topic.
- Academic records from Bachelor to MSc.
- The contact of one or two referees (internship or project supervisor, teacher, etc.)
Applications will be evaluated as they are received until one candidate is selected. Only short-listed candidates will be contacted.
Environment and added-values of the offer
The PhD student will be part of the RIS3 project team, which includes researchers from IETR and IRISA. He or she will benefit from a national network of experts in information and communication theory. In addition, the position includes
- A 3-year full-time funded contract.
- National health coverage.
- Employer's contribution to transport costs and accommodation at competitive rates.
- Funding of missions to present results at major international conferences in the field.
- Possibility of teaching assignments.
Contacts:
Philippe Mary, philippe.mary@insa-rennes.fr, website: http://pmary.perso.insa-rennes.fr
Luc Le Magoarou, luc.le-magoarou@insa-rennes.fr, website: https://https://luclemagoarou.netlify.app
INSA de Rennes / IETR UMR CNRS – 6164
(c) GdR IASIS - CNRS - 2024.