VTT explores how to make communications smoother with quantum computing

The growth in the number of information network users frequently leads to congestion, causing delays and disruptions of service for users. At the same time, the increasing complexity of networks and their applications is challenging network control and management. VTT, one of Europe's leading research institutions has launched a project to investigate how quantum computing can be used to solve increasing network problems.

As more people use network resources simultaneously, for example during large events, wireless networks are challenged with congestion and a decline in performance. The problem is not likely to ease in the future as the 6G era will further increase the number of complex applications and users.

These challenges can be defined as combinatorial problems, which refers to determining the order in which different users are served and the routes along which traffic should be transferred to ensure that everyone receives the promised service quality.

"Many are familiar with the so-called travelling salesman problem, which relates to the order in which a salesman should visit different cities to keep his route as short as possible. The complexity of the problem increases exponentially as more options are introduced. Similarly, as telecommunication networks become more complex and the number of applications using them grows, so does the number of combinations of parameters to be optimised. This makes it increasingly challenging to decide in which order and with which resources different users are served," says Kari Seppänen, the Senior Scientist leading the project at VTT.

Combinatorial problems have so far been largely solved using heuristic methods, ie. by simplifying the problem. However, these methods typically yield approximate answers that, in certain situations, may lead to inferior performance. Optimisation methods based on statistics and data, on the other hand, consume a significant amount of energy, and may not be suitable for dynamic situations where quick reactions to changes are necessary, especially when there is no connection to the server.

In VTT's research project, combinatorial problems are addressed through hybrid algorithms that combine quantum and classical computing. Hybrid algorithms enable the optimisation of the strengths of both computing approaches, ultimately leading to an increase in network capacity. Demanding applications can then receive the necessary service quality, even in a busy network, while also saving energy.

"At this stage, quantum computers are already capable of rapidly generating new and more accurate solutions, which can then be evaluated using classical computers. One can also state the opposite: that classical heuristics can be improved by quantum algorithms. In a hybrid approach, algorithms and results are iteratively processed many times on both sides until the optimal result is achieved," says Seppänen.

The aim is to reach a concrete outcome in the near future

VTT's research project engages experts from telecommunications, cryptography and quantum technologies, and will bring a wealth of new knowledge to the design of quantum algorithms.

"It is crucial that Finnish companies are among the first to harness the potential of quantum computing, as we are already pioneers in the development of quantum technologies and future networks. This is a unique project that could open up entirely new possibilities for the application of quantum technologies. The goal is that the research will prove beneficial shortly," Seppänen says.

In addition to VTT, several Finnish companies are involved in the project, including Nokia Bell Labs, Cumucore and Unitary Zero Space. They bring along with them the problems that the project will address.

"Very few technologies have such global impact as wireless communications and quantum. Finland is in a unique position with such a strong foundation in both of these. The intersection of these fields studied in the project is thus ripe for breakthrough innovations," says Topias Uotila Founder and Qubit Zero at Unitary Zero Space Oy.

"Quantum computing can help solve combinatorial problems prevalent in communication networks including resource allocation, routing and scheduling, and network planning. Nokia, currently leading the European flagship projects on 6G – Hexa-X and Hexa-X-II – brings its telecommunication expertise to further advance 6G with hybrid classical-quantum computing,” says Karthik Upadhya, a senior researcher at Nokia Bell Labs.

The research also aims to leverage the LUMI supercomputer. The objective is to combine the computation performed on VTT’s quantum computer and the supercomputer with the VTT 5G and 6G networks and demonstrate their capability to solve concrete practical problems. The research also focuses on lattice problems and quantum-safe encryption methods.

“Quantum computing together with AI are technologies that will bring mobile networks to the next level of speed, security, and automation. Cumucore is proud to be part of this project, bringing 6G expertise to explore the potential of quantum computing to deliver human-centric but ultra-secure communications,” says Jose Costa-Requena, the CEO at Cumucore Oy.

The project, called Combinatorial Optimisation with Hybrid Quantum-Classical Algorithms, started in July 2023 and is scheduled to run until June 2025. Its funding is provided by Business Finland's Quantum Computing Campaign, which aims to establish an ecosystem in Finland that addresses business challenges using quantum computing.

"At this stage, we are still conducting preliminary studies and experiments. We are also planning to use the quantum walk method. Preliminary results have already been very promising," says Kari Seppänen of VTT.