Research Internship: Advanced Radio Technologies for Energy-Efficient RAN Pruning in Mobile Networks F/H

Publication date : Sep 21, 2026, 11:15AM

Context

Mobile networks are traditionally dimensioned to satisfy coverage, capacity and Quality of Service (QoS) requirements. However, in the context of energy reduction, carbon-footprint mitigation and cost control, network design must also account for broader impact indicators.

Within the Network Design-to-Impact (D2I) framework, an ongoing PhD work studies RAN pruning, i.e., reducing the number of active, deployed or renewed radio sites while preserving controlled QoS constraints [1]. When deciding which sites may be pruned, the technical limits of the network should first be evaluated by exploiting the available radio-access diversity: frequency diversity, angular diversity, spatial/user diversity and cooperation between transmission points. This internship focuses on the following question: How much further can RAN pruning go when advanced radio technologies are jointly exploited?

Main Objective

The objective is to extend an existing RAN pruning simulation framework in order to evaluate advanced radio-access technology levers for deeper pruning. The internship will focus on the technical layer: improving coverage, load distribution and cell-edge performance before deciding which sites can be pruned.
The main technology levers considered are:

• Multi-User Multiple-Input Multiple-Output (MU-MIMO), exploiting spatial and user diversity;
• multi-band operation, exploiting frequency diversity;
• beamforming, antenna tilt and power optimization, exploiting angular and power-domain degrees of freedom;
• multiple Transmission and Reception Point (multi-TRP) / Coordinated Multi-Point (CoMP)-like cooperation, exploiting cooperation diversity.

A MU-MIMO analytical and simulation framework has already been developed in previous works [2].

The internship will focus on implementing, integrating and evaluating this model within the RAN pruning framework. The multi-band part will be considered at the modelling level.

The intern is not expected to implement a full standardized Carrier Aggregation (CA) mechanism, but CA will be used as a practical reference technology showing how several component carriers can be jointly exploited in cellular systems [6].

The broader multi-band modelling perspective will be inspired by recent multi-band network architectures [5].

The multi-TRP part will be considered as a cooperation layer for cell-edge areas.

The objective is not to reproduce the full standardization complexity of multi-TRP, but to evaluate whether neighbouring transmission points can jointly improve coverage and throughput after pruning.

This direction will also benefit from recent works conducted within the team on 3GPP multi-TRP coherent joint transmission [10].

The internship is suitable for a final-year engineering student, Master 2 student, or gap-year engineering student with a background in wireless communications, mobile networks, signal processing, applied mathematics, scientific computing or optimization.

Expected skills:

• strong programming skills in MATLAB and/or Python/C/C++;

• good understanding of wireless communications and mobile networks;

• basic knowledge of probability, queuing theory and optimization;

• interest in 5G/6G radio-access technologies;

• ability to work with an existing research codebase.

Knowledge of MU-MIMO, CoMP, stochastic geometry or queueing models is appreciated, but not mandatory if the candidate has strong technical and programming skills. The modelling background will rely on stochastic-geometry and flow-level queueing tools inspired by [3, 4]. The sustainability motivation is aligned with green cellular network design [9].

References

[1] I. Merah, M. Kieffer, S.-E. Elayoubi, T. Clessienne, and B. Sayrac, “Towards Network Design-to-Impact: RAN Pruning for Sustainability,” in Proc. IEEE International Conference on Communications (ICC), 2026.
[2] I. Merah, M. Kieffer, S.-E. Elayoubi, T. Clessienne, and B. Sayrac, “A Unified PHY–MAC Queuing Theoretical Framework for MU-MIMO Optimization,” submitted to IEEE Global Communications Conference (GLOBECOM), 2026.
[3] J. G. Andrews, F. Baccelli, and R. K. Ganti, “A Tractable Approach to Coverage and Rate in Cellular Networks,” IEEE Transactions on Communications, Nov. 2011.
[4] T. Bonald and A. Proutiere, “Wireless Downlink Data Channels: User Performance and Cell Dimensioning,” in Proc. ACM MobiCom, 2003.
[5] M. A. Saeidi, H. Tabassum, and M.-S. Alouini, “Multi-band Wireless Networks: Architectures, Challenges, and Comparative Analysis,” IEEE Communications Magazine, Jan. 2024.
[6] G. Yuan, X. Zhang, W. Wang, and Y. Yang, “Carrier Aggregation for LTE-Advanced Mobile Communication Systems,” IEEE Communications Magazine, Feb. 2010.
[7] D. Gesbert, S. Hanly, H. Huang, S. Shamai, O. Simeone, and W. Yu, “Multi-Cell MIMO Cooperative Networks: A New Look at Interference,” IEEE Journal on Selected Areas in Communications, Dec. 2010.
[8] H. Eckhardt, S. Klein, and M. Gruber, “Vertical Antenna Tilt Optimization for LTE Base Stations,” in Proc. IEEE 73rd Vehicular Technology Conference (VTC Spring), 2011.
[9] Z. Hasan, H. Boostanimehr, and V. K. Bhargava, “Green Cellular Networks: A Survey, Some Research Issues and Challenges,” IEEE Communications Surveys & Tutorials, 2011.
[10] L. Berrah, R. Visoz, and D. Le Ruyet, “Precoding and Delay Offset Selection Strategies for 3GPP Multi-TRP Coherent Joint Transmission,” in Proc. IEEE International Conference on Communications (ICC) Workshops, 2026.

[11] E. Björnson, J. Hoydis, and L. Sanguinetti,“Massive MIMO Networks: Spectral, Energy, and Hardware Efficiency,” Foundations and Trends in Signal Processing, 2017.

• A practical, meaningful internship with strong technical content;
• A topic at the intersection of physical layer, Medium Access layer, and energy optimization;
• A rewarding assignment with genuine autonomy;
• An applied innovation environment;
• The opportunity to contribute to a project with significant societal impact;
• Guidance grounded in strong sustainability principles.

Within Orange Research, the Networks and Infrastructures Research domain designs and experiments the networks and infrastructures of the future with our ecosystems, to provide ambient connectivity and distributed computing capabilities that deliver value, are sustainable and trustworthy.

Desired start date : Feb 01, 2027, 12:00AM

At Orange, only your skills matter.

Regardless of your age, gender, background, origin, religion, sexual orientation, disability, neurodiversity, or appearance, we actively encourage diversity within our teams, as it is a collective strength and a driver of innovation.
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