New research paves the way for next generation 6G wireless networks with improved signal stability

Wednesday, 15 March 2023

New research has shown wave control is promising technology that could pave the way for future wireless networks that can withstand increasing demand.

Researchers at the University of Nottingham have collaborated with BT, University of Loughborough and Greenerwave, a deeptech French startup based in Paris to develop a mathematical framework to understand the fundamental barriers of interference that reduce signal stability.

The research exploits a new wave technology, grounded on reconfigurable intelligent surfaces, or RIS, to reduce the interference among users while improving the quality of service: an effect predicted theoretically called channel hardening. The findings will lead to providing communication engineers with innovative new antenna design procedures.

Professor Gabriele Gradoni

Professor Gabriele Gradoni, Professor in Applied Mathematics & Electromagnetic Theory at the University of Nottingham has led the study, he explains: “It has been a long time since scientists and engineers have committed to developing the 5th generation of mobile networks. An effort that has led to the improvement of the performance of wireless infrastructures in terms of data-rate boost and coverage improvement. Whilst this is contributing to reducing the digital divide in rural areas and less advantaged regions of the world, the multi antenna and access technologies have effectively enabled a plethora of new added value services from telecom operators, whence subscriptions to 5G networks are increasing exponentially.”

“Users will include not only people's smartphones but also vehicles, e.g., cars and drones, as well as robots, e.g. interconnected smart factories, and much more in the future horizon. This means a massive number of terminals will need to coexist - and maintain the achieved high data-rate! - in the presence of a complex environment where interference will inevitably deteriorate the network performance.”

This research, which is part of the University’s Digital Nottingham programme, examines new ways to prevent deterioration, stabilise and futureproof networks. The team has found that channel hardening could provide a stable network for technologies used now and in the future.

Channel hardening works through tightly packed antenna elements integrated within the RIS receiving and adding multiple waves coming from different directions and carrying the same information signal; different waves have travelled different lengths within the environment, and the RIS is optimized to compensate the length difference among signal replicas so that the signal is routed to terminals in line of sight with the RIS where information is retrieved.

The combined effect of wave compensation and addition results in an average signal that has reduced variability, hence it is more stable and less prone to cause disconnections from the telecom base station. The RIS technology has gathered the attention of industry and academia for a few years, and it is now being considered as a candidate technology for integration in future 6G network development.
Professor Gabriele Gradoni, Professor in Applied Mathematics & Electromagnetic Theory at the University of Nottingham

The research is funded by a Royal Society Industry Fellowship with BT.

Dr Minglei You, Assistant Professor at the Department of Electrical and Electronic Engineering, adds: “This is exciting progress, with a laboratory-based experiment for this novel technology of RIS, which demonstrates its great advantage in enhancing end users’ experiences in both data rate and data link stability. The key feature of RIS is that it can change the propagation of signals in the air, and with our proposed signal processing techniques and optimization algorithms, we are witnessing the great new era of future wireless networks – we are advancing from acknowledge of the wireless channel impairments, to the era of proactively modifying part of it on demand.”

Dr Burton and Dr Zhang from BT add: “As a global telecommunications provider, BT values this research in to future ICT technologies, and we are always keen to identify and support promising scientific concepts and technologies as they emerge. It is a long-standing challenge for mobile network operators to deliver satisfactory services to customers in complex and dynamic environments. The rising paradigm of smart radio environment leads us to new frontiers in both electromagnetics and communications engineering, which truly allow us to rethink the conventions of wireless network architectures and protocols. We are excited to have made such a landmark achievement in our continued collaborations with the University of Nottingham, which leads us a big step forward to the next revolution in wireless communications.”

Dr Geoffroy Lerosey, Greenerwave CEO & CSO, Dr. Jean-Baptiste Gros, Project Manager and Dr. Youssef Nasser, 5G/6G Business Line Tech Lead, are very enthusiastic about the new development on channel hardening. They claimed “As pioneering inventor of RIS and manufacturer of several types of RIS technology covering cross-spectrum, we see that channel hardening techniques add a new capability to our RIS to stabilize the network in general and improve the QoS of the end-user. But we don’t stand there, more development is already foreseen as we believe in new breakthrough that pushes the RIS to be widely adopted in the standards. We are excited to work with world-known Professors such as Prof Gradoni and with BT on this new concept which tackles a tricky problem in wireless communications.”

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More information is available from Prof Gabriele Gradoni on

Jane Icke - Media Relations Manager Science
Phone: 0115 7486462

Notes to editors:

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