Electrical and Information Technology

Faculty of Engineering, LTH

Denna sida på svenska This page in English

Sara makes communication dependable with Massive MIMO


Portrait. Sara Willhammar.

Sara Willhammar. Photo: Sara Willhammar.

Do you need a reliable connection? Sara Willhammar knows how to do it: by using a lot of antennas, wireless connections can be established even in an industrial environment with much scattering and interference. On December 9 at 9.15 she defends her PhD thesis “Massive MIMO for dependable communication” at LTH, Lund University.

Read more about the dissertation.
Download the thesis.

What is your thesis about?

Wireless communication is constantly evolving, and new applications are being developed. With new applications, come new requirements, and to support this, new technologies are needed. One technology, which has been shown to improve communication, is massive multiple-input multiple-output (MIMO). By increasing the number of antennas at the base station side, the system performance can be improved in several ways. In this thesis, the focus is on how massive MIMO can contribute to dependable communication in industrial automation and Internet-of-Things networks. Investigations concern the channel, i.e., the medium between transmitter and receiver, and how the channel behaves in different environments, frequency bands, and with various antenna array deployments.

As the number of antennas increases, the small-scale fading decreases

Visualization of the channel hardening effect, meaning that the received signal varies less and hence, becomes more stable as the number of antennas increases.

What made you want to pursue a PhD?

I did my master’s thesis as an Erasmus traineeship at KU Leuven on a related topic. During that time, I was a part of the research group there and got first-hand experience with what it is like to research at a university. I liked the process and therefore I applied when a relevant position opened at LU. After getting accepted at LU, I applied to KU Leuven to do a double degree to keep the collaboration with KU Leuven and have internationalization as an integral part of my education.

How does it work to be a part of a double degree collaboration?

Being in this type of collaboration means that you to some extent need to comply with rules and regulations from both universities. For me, this meant that I had the opportunity to do research and work on my thesis for eight months at KU Leuven in Belgium and that I had a supervisor and research group at both universities. In my case, it has been one education and writing one thesis, leading to the two institutions are to reward me with corresponding degrees, in collaboration with the other partner institution.