The (sub-)THz Horizon

6G Waves sat down with Professor Aarno Pärssinen and Assistant Professor Nuutti Tervo to chart the strides towards radios at new frequency ranges and ultra-high bandwidths, enabling future communications and sensing. 

What is the goal to achieve in the next two years?

For the past few years, one of our main efforts has been to develop a full-scale functional 300 GHz RF receiver and get it measured and tested. This work has progressed steadily with many successes. We have published many world-class publications that push the boundaries of the used integrated circuit technologies beyond traditional limits. 

Now, the final effort is to put together the existing building blocks for a functional receiver and get it measured with real communication signals. While we’ve had good progress, there is still work to finalise this goal. Testing extremely wideband systems in sub-THz frequencies is challenging and requires the efforts of many experts in our team. We have already proven high-quality signal reception capabilities in some of the parts.

In other research topics, we’ll continue our research, focusing on three main themes: materials, key hardware building blocks, and system-level concepts and platforms. To remind you, the 6G is not a system of one-frequency band. We’re actively engaged in research spanning from centimeter-wave frequencies and beyond towards the THz regime. For instance, we continually innovate to challenge conventional notions in transceiver architectures. These groundbreaking ideas will be implemented in current and forthcoming industry-related projects.

What must be done to achieve the goals?

Hard work by innovative minds and a significant team effort! The research requires collaboration from tens of people, especially in areas that aim for real-life demonstrations and physical components and devices. Developing a functional transceiver contains plenty of steps, from early system specifications and novel ideas to remarkable design and circuit innovation efforts, intense collaboration among many people to interface the building blocks, deep knowledge of manufacturing and materials, and finally, plenty of time, hard work, and bright thinking in the laboratory to make everything work smoothly to get something measured. And one must not forget things that we consider routine, like verification. There is no way out from traditional engineering efforts needed to support the novel ideas.

Has your 6G vision remained the same, or has it changed?

We will continue solving the most challenging RF and hardware problems from different perspectives. The focus has been on very high data rates, but that should be achieved with commercially feasible efforts to be able to also enable business in the area. In this phase, we also look beyond 6G systems while the industry is, piece-by-piece, advancing the current technologies. The role of academia should be to look further into the horizon to pave the way for the next technical innovations, which can sometimes go much beyond 6G. Those are valuable parts to carry on when we know better what 6G will eventually be.

What will 6G mean in everyday life in the 2030s?

Great question. It is certain that in 2030, we will have faster communication systems than today. What this means for regular consumers depends on what the industry is putting forward toward feasible products and, on the other hand, what killer applications 6G will generate. For example, sensing solutions using wireless infrastructure or using the same radio hardware is one functionality that has the potential to create applications that have been envisioned and even more applications that we couldn’t imagine but that will be enabled unintentionally.

For whom and for what 6G is being developed?

We want to see 6G developed mostly for people to enhance their lives. Of course, plenty of breakthroughs also happen in sectors that regular consumers may not notice, like in the industry, factory automation, autonomous machines, and so on, where highly reliable and fast wireless systems are needed. 

Success in the wireless industry and related fields relies on high-quality, high-risk research. This truth drives continuous research efforts. The world won’t wait for Finland; complacency is not an option. Active engagement is essential for impact. Long-term research builds expertise vital for short-term industry success.

Why is 6G Flagship among the top 6G research groups in the field?

At the University of Oulu, we have made wireless solutions for decades. That knowledge and expertise is not something one builds in a day. Also, industrial experience in the team broadens the view and provides competencies beyond the traditional academic scope. Competition is getting tougher, however. Hard work, fresh mind and international collaboration are the keys to staying at the crest of innovation.

About the writers

Professor Aarno Pärssinen at the University of Oulu specialises in RF system and circuit design for wireless communications and sensing. With extensive experience in both industry and academia, he has contributed to over 200 publications, holds numerous patents and is the recipient of the EuMC microwave prize. He is one of the original contributors of Bluetooth Low Energy technology.

Nuutti Tervo is an Assistant Professor at the University of Oulu, focusing on RF, signal processing, and wireless communications. Recognised for his contributions, including over 65 publications and several patents, he has been awarded the Young Scientist Award and the EuMC Microwave Prize.