Oulu is the best choice for a 6G researcher

Having progressed lightning-fast in his career, Onel Alcaraz López is studying wireless power transfer and machine-type communications in the mobile networks of the future.

Onel López sitting outdoor next to the big chessboard.

Postgraduate studies in the 6G research programme

Researcher Onel Alcaraz López shows the way to his office at the Centre for Wireless Communications (CWC) research unit of the University of Oulu. The door has a brand new plaque, Assistant Professor.

The appointment is quite an achievement for a researcher just over 30 who has only recently defended his doctoral dissertation.

“It was definitely flattering”, says López, smiling.

López first arrived in Oulu in March 2017. Academy Professor Matti Latva-aho had heard from his colleague at the University of Parana in Brazil about a talented Cuban master’s degree student who was thinking about postgraduate studies.

“Matti said that Oulu is the best place in the world to do research.”

After four years in Oulu, López can wholeheartedly agree with that claim. The Oulu 6G Flagship is the world’s largest 6G research programme. It employs around 400 researchers representing more than 50 nationalities.

Latva-aho is also happy.

“Onel is a real talent in publishing his results”, Latva-aho says.

Just three years later, López wrapped up his postgraduate studies with about thirty scientific publications under his belt already. The publications present new solutions for data transfer between machines in future 6G networks.

In fact, López’s dissertation, granted the “best doctoral thesis of the year” award by TEK and TFiF (Tekniikan akateemiset and Tekniska Föreningen i Finland) has enough academic merit to cover several dissertations. This is indicated in the statement of the German professor who acted as his opponent in April 2020, who was not being stingy with superlatives when it came to the scientific merits of the dissertation.

Mobile network to meet the needs of machines

Summing up the content of the 12 research papers included in the doctoral dissertation is no easy task.

López brings up a helpful example: the automated systems of future factories. In these factories, the buzzword IoT (Internet of Things) will become everyday reality. In fact, López focused his dissertation on the communication needs of machines – instead of human users – in 6G networks.

“Communication between machines is an integral part of the design of the entire 6G technology.”

When factory sensors and mechanisms are built with wireless technology, data transmission speed is no longer the most important thing, as is the case with all the network generations so far.

“With sensors, what’s more important is reliability and short delays. Data transfers failing is not an option, and if it does happen, the connection has to recover quickly”, López explains.

López’s research papers focused on these types of usage cases. Within a ten-metre radius, there may be a network of up to thousands of sensors that need to communicate effectively and without delay.

“I developed algorithms for efficiently sharing data transfer resources in these kinds of environments. The requirements are completely different from our current mobile networks.”

Wireless power transfer is coming

Some of the research papers in the dissertation aimed even further than that.

In the late 19th century, Nikola Tesla was already envisioning technology for the transfer of wireless electrical power. Wireless charging is already a reality for mobile phones, but López intends to introduce wireless power transfer into future data transfer technology as well.

López’s research papers presented methods for low-power devices to cope in a wireless communication network without their own power supply. Antenna clusters are used to supply electrical energy to devices located in close proximity to enable their wireless communication.

This would completely free sensors and mechanisms, located a few metres apart, from the chains of cabling.

“An operating distance of ten metres is a good goal for us”, says López.

This technology seemed futuristic when López was starting his doctoral dissertation, but now many others are studying wireless power transfer as well.

Even today, keeping all the mobile devices in your home charged is quite a task. As the number of IoT devices around us grows, the problem will only get worse.

“Imagine a factory environment full of wireless sensors and detectors. In the future, IoT batteries can become a huge waste problem.”

A few start-ups are also developing similar technologies, even though no standards exist yet.

López’s doctoral research papers are at the forefront of this technological development.

“So far, the focus has been on wireless charging for a few devices at a time.”

López started with the assumption of having hundreds or thousands of wireless devices in a network. The strategy proposed by the dissertation for wireless power transfer is also simpler than before.

“But this dissertation was only a first step”, the researcher reminds us in his usual modest way.

A great deal of research is still needed, but López intends to soon demonstrate it in practice. If large companies get on board, this technology has a good chance of becoming a part of future 6G standards.

The Oulu 6G Flagship programme produced white papers outlining a future 6G network, and these papers have been downloaded hundreds of thousands of times. Onel López is one of the authors.

Third dissertation award for the research unit

López’s doctoral dissertation was nominated for the award by his supervisor.

“We have great researchers, but I have not encountered talent of this calibre before”, says Matti Latva-aho.

Although López’s dissertation and its publications were exceptionally high in quality, Latva-aho had to work to ensure that there was a professorship waiting for the promising researcher as soon as his dissertation was completed.

“I knew that there was a great deal of interest in his research across Europe. It was great for us that he and his family decided to stay in Oulu.”

The panel of judges of the dissertation award were also convinced of the academic merits as they nominated López the winner of this year’s award from 23 top-quality dissertations.

"This was already the third TEK dissertation award in our research unit”, Latva-aho says.

The first ever such award was granted to Latva-aho himself in 1999, to his doctoral student in 2008 and now to López.

Professor in Oulu from Cuba

Moving all the way from Brazil to Oulu in March 2017 was a real leap into the unknown for Onel López. Images of darkness and cold made him wonder if he could make it.

“But I knew I wanted to continue doing research and that Oulu was a really good university for wireless communications.”

Contrary to expectations, his concerns proved unnecessary.

“I even liked the weather and what people are like here.”

At times, this researcher who found his way to Finland from Cuba via Brazil sounds like a modest Finnish engineer who gets a little flustered when talk turns to his achievements. This interview was still done in English, but López is planning to study Finnish.

López praises his new home town where he has settled with his family. His desk is decorated with a picture of Elli, his two-year-old daughter.

“Research isn’t the be-all and end-all. Family is the most valuable thing”, says López.

Sounds like a very Finnish thing to say.

Text: Petja Partanen. Photography: Teija Soini. This article was previously published in the TEK Magazine.

Onel López’s road to a doctorate

  • 1989. Onel Alcaraz López is born in Sancti Spíritus, Cuba.
  • 2005–2008. López places at the top of Cuban national math competitions on three instances.
  • 2013. Completing his bachelor’s degree in electrical engineering at Las Villas University in Cuba, López begins working at ETECSA, Cuba’s state telephone company.
  • 2015. López gets an opportunity to pursue master’s degree studies in communications technology at the University of Parana in Brazil.
  • 2017. López moves to Oulu with his wife and starts his postgraduate studies.
  • 2020. López’s dissertation “Resource allocation for machine-type communication: from massive connectivity to ultra-reliable low-latency” is approved at the University of Oulu with the grade “excellent”.
  • 2021. López receives the post of assistant professor at the Centre for Wireless Communications (CWC) research unit at the University of Oulu, and TEK grants him the “best doctoral thesis of the year” award.