Arctic 5G Test Network seminar

Researchers from the university of Oulu have studied Internet connectivity problems and their impact to people’s daily life, work and business in the northern Finland and especially its remote areas.  The research is a part of the Arctic 5G Test Network project.

An interview with Emad Farouk Ibrahim, who is doing his licentiate thesis at Luleå University of Technology.

Tell us more about what you researched?
My licentiate thesis is about reconfigurable intelligent surface (RIS) which is a new technology that has gained a lot of attention during the last few years. A RIS is a thin planar array that consists of multiple reflecting elements, each of which is connected to a tunable chip and can induce a controllable reflection coefficient to the incident signal. The RIS is a nearly passive unit as it only leverages the reflection on its elements and it does not consume any power for transmission. The advantage of the RIS arises in creating energy-efficient smart radio environments wherein the wireless channel becomes an optimization variable. In this thesis, we study some of the potential applications and deployments for the RIS in wireless communications.

How did you come to choose this particular area?
It started by investigating a fundamental problem that usually occurs in MIMO communications when it is deployed in line-of-sight environments where spatial multiplexing becomes unattainable. There is a classical solution for this problem by deploying repeaters to enrich the wireless channel with multipath. However, this solution is not energy-efficient due to the power consumption of the repeaters. So, alternatively, we deploy distributed RISs to synthesize a sort of multi-path propagation. From this time, we see the advantages of the RIS as a new player to the whole communication process which may provide several solutions for the limitations that exist in the wireless channel and emerge new applications that have never existed with classical wireless communication systems.

What has been the biggest challenge and discovery?
We faced many challenges during this thesis. However, all of them were pleasant to us as overcoming them makes us one step closer to developing new solutions and applications. Moreover, I believe that our biggest discovery relies on the RIS ability to control the polarization state of the reflected waves. Since we develop a novel application depending on this RIS function. In this application, the RIS acts as an access point for information transfer where it alternates the polarization state of the reflected waves to encode the information data.