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Full-duplex technology can save mobile network operators billions of euros

The congestion of radio frequencies is one of the greatest challenges in modern wireless communications systems. In his doctoral research, Dani Korpi developed a prototype utilizing full-duplex radio technology that can further enhance the usage of the electromagnetic spectrum.

The explosive growth of wireless communications in recent years has congested the suitable parts of the radio spectrum while also dramatically increasing their prices. Mobile network operators are having to pay billions of euros to gain access to the required spectral resources. Therefore, increasing the spectral efficiency, i.e., the data rate achieved over a given bandwidth, is one of the most important research topics in the field of wireless communications.

“New technologies are desperately needed in order to fulfill the data rate requirements of future 5G mobile networks,” says Dani Korpi who will defend his doctoral dissertation at Tampere University of Technology on 1 December.

The full-duplex radio technology investigated and developed by Korpi in his doctoral research is a promising method for increasing the spectral efficiency, because it can as much as double the data rate of the system without using more valuable frequencies.

“Full-duplex technology allows an individual device to transmit and receive information at the same time on the same frequency band. This means that a mobile network operator does not need to obtain two separate frequency bands for transmission and reception, potentially saving it billions of euros. Alternatively, the technology can also facilitate the doubling of data rates without using more spectral resources,” Korpi says.

In his dissertation, Korpi studied how to implement full-duplex radio transceivers using cheap off-the-shelf components. He developed a prototype that can receive weak radio signals while itself simultaneously transmitting information on the same frequency band.

“The greatest challenge in inband full-duplex communications is that the radio will essentially hear only its own transmission since the transmitter and receiver operate on the same frequency band. In my doctoral research, I developed methods for suppressing the power of the own transmission to less than one billionth of its original power. This facilitates the reception of very weak radio signals, regardless of the simultaneous transmission,” Korpi says.

Full-duplex in future radio networks

Korpi also studied how to best take advantage of full-duplex radio devices in larger networks. Regardless of the promising results, it is unlikely that the technology will be used in the first 5G networks since the practical feasibility of wireless full-duplex communications has been proven only recently. However, the interest shown by various companies indicates that full-duplex technology might at some point be adopted also in 5G systems.

“At the moment it seems likely that the first commercial implementations utilizing full-duplex technology will be inband relays that simply amplify the signals transmitted by the mobile devices and the base stations. Nevertheless, I believe that, after maturing, the full-duplex radio technology will play a large role in enhancing the usage of the electromagnetic spectrum in the frequencies below three gigahertz,” Korpi estimates.

Public defence of a doctoral dissertation on Friday, 1 December 2017

The doctoral dissertation of MSc (Tech) Dani Korpi in the field of communications engineering titled “Full-Duplex Wireless: Self-interference Modeling, Digital Cancellation, and System Studies” will be publicly examined in the Faculty of Computing and Electrical Engineering at Tampere University of Technology (TUT) in room TB109 in the Tietotalo building (address: Korkeakoulunkatu 1, Tampere, Finland) at 12.00 on Friday, 1 December 2017. The opponent will be Professor Daniel W. Bliss from Arizona State University. Professor Mikko Valkama from the Laboratory of Electronics and Communications Engineering at TUT will act as Chairman.

Dani Korpi is 28 years old and comes from Ilmajoki, Finland. He currently works as a researcher in the Laboratory of Electronics and Communications Engineering at TUT.

The dissertation is available online at http://urn.fi/URN:ISBN:978-952-15-4059-2

Further information: Dani Korpi, tel. 044 316 1189, , http://www.tut.fi/full-duplex

News submitted by: Sanna Kähkönen
Keywords: science and research, electronics and communications engineering