PhD proposition M/F : Low energy precoding for centralized and distributed multi-user massive MIMO systems

5 Mar 2024
Job Information

Organisation/Company

CNRS

Department

Equipes Traitement de l'Information et Systèmes

Research Field

Physics

Researcher Profile

First Stage Researcher (R1)

Country

France

Application Deadline

25 Mar 2024 - 23:59 (UTC)

Type of Contract

Temporary

Job Status

Full-time

Hours Per Week

35

Offer Starting Date

1 Oct 2024

Is the job funded through the EU Research Framework Programme?

Not funded by an EU programme

Is the Job related to staff position within a Research Infrastructure?

No

Offer Description

This position is a 3-year PhD contract in the context of PEPR 5G réseaux du futur, PC3 PERSEUS investigating the design of power amplifiers for multi-user massive MIMO with low energy consumption. This thesis is thus part of a larger scientific project including internal and external
collaborations from which the candidate will be able to benefit. The PhD project will be carried out in the ICI (Information, Communication, Imagerie) team of ETIS (UMR8051), under Prof. Inbar Fijalkow's primary supervision and Prof Myriam Ariaudo's co-supervision. The successful candidate will be enrolled at CY's EM2PSI (Economics, Management, Mathematics, Physics, Computer Science) doctoral school.
ETIS is a joint lab between CY Cergy Paris Université, ENSEA and CNRS, and a prominent
research unit in computer science and information technologies in France. ICI is one of ETIS's
four multi-PI groups and is specialized in signal processing, information theory and wireless communications. The group's research areas include optimization of resource allocation for wireless communication systems, massive MIMO, NOMA systems, physical layer security, etc. ICI has built a world-class reputation and has become a major actor in these research
areas in France with multiple national and international collaborations.

Context :
Multi-user wireless communications using multiple and a massive number of inputs and outputs (MU-mMIMO), are among the enablers of beyond-5G wireless communication systems that drives to allow wideband wireless communication systems in very dense areas.

Objectives :
In this PhD, we will search for new wideband precoding methods designed for their reobustness to the power amplifier effect. The impairments due to RF frontal, in particular the non-linearity of the power amplifier, will be taken into account [1]. In this study, we will consider in particular the low energy consumption and the reduction of the amount of interferences outside of the band of interest.

Research program :
On the contrary to what was expected (see [2], [3]), the mean power emitted by each component of the massive antenna descreases with its size as well as the crest power. Therefore, we will question the analyses of the Peak to Average Power ratio (PAPR) and of the adjacent bands power ratio (ACLR) that are performed by analogy with Fourier transform based precoding.
We will revisit these analyses in the MU-mMIMO context and use a local linearization thanks to the Busssgang decomposition (see [3]) in order to optimize in a second time the precoder so to be best adapted to improve the energy efficiency in the band of interest and outside the band of interest. We will in particular consider the active constellation approach as in [4].
The optimization will be performed in both centralized and distributed (cell free access) context.

[1] Sparse Linear Precoders for Mitigating Nonlinearities in Massive MIMO, A Mezghani, D Plabst, LA Swindlehurst, I Fijalkow, JA Nossek, IEEE SSP 2021.

[2] Spatial characteristics of distortion radiated from antenna arrays with transceiver nonlinearities, C Mollén, U Gustavsson, T Eriksson, EG Larsson, IEEE transactions on wireless communications 17 (10), 6663-6679, 2018.

[3] Analysis of One-Bit Quantized Precoding for the Multiuser Massive MIMO Downlink, AK Saxena, I Fijalkow, AL Swindlehurst, IEEE Transactions on Signal Processing, 65 (17), 4624 - 4634, 2017.

[4] Massive MIMO precoding and spectral shaping with low resolution phase-only DACs and active constellation extension, A Mezghani, RW Heath, IEEE Transactions on Wireless Communications 21 (7), 5265-5278, 2022.

Requirements

Research Field

Physics

Education Level

PhD or equivalent

Languages

FRENCH

Level

Basic

Research Field

Physics

Years of Research Experience

None

Additional Information

Website for additional job details

https://emploi.cnrs.fr/Offres/Doctorant/UMR8051-VIRLAI-004/Default.aspx

Work Location(s)

Number of offers available

1

Company/Institute

Equipes Traitement de l'Information et Systèmes

Country

France

City

CERGY

Geofield

Where to apply

Website

https://emploi.cnrs.fr/Candidat/Offre/UMR8051-VIRLAI-004/Candidater.aspx

Contact

City

CERGY

Website

https://www.etis-lab.fr

STATUS: EXPIRED