Phones ”dying” because the battery is drained is a common nuisance for all mobile phone users. There are many things that can be done to extend battery life. One of them is to make the modem – a piece of hardware that handles the signals in the phone – adaptive to signal quality, so that it always delivers a good enough performance without wasting energy. In addition to phones, the energy waste of base stations is also of importance, due to environmental but also economic reasons. One way to deal with this problem is choosing the hardware that will deliver the right performance with minimal energy consumption.

Hardware limitations on the operation of wireless systems can sometimes be fundamental and no flexible solution is available. In this case, the system needs to be designed “around” the limitation. Muris Sarajlić’s PhD thesis analyses both the systems using flexible hardware – and how much can be gained by being flexible – and finds efficient workarounds for situations when hardware generates a fundamental limitation to system operation. 

What made you want to pursue a PhD?
– After my Master studies, I felt that I only scratched the surface of the big and exciting field that is wireless communications, and I wanted to learn more. Doing a PhD offered a chance of learning more, in a structured way, says Muris Sarajlić.

– The idea of making my own original contribution that would improve the way wireless systems are built also appealed to me. And the PhD was the way to make this come true. In particular, it was the practical aspects of making my own contribution that were attractive: the PhD would give me a chance to come up with a method or a design that would maybe one day be used by many people, and make their user experience much better, he continues.

Why wireless communication?
– When it comes to wireless communications in general, what’s most fascinating is the transfer of information over distances without any need for physical connection. Wireless enabled us to get photos of distant worlds on the edge of the Solar system. It also enables us to read news, chat and talk with our friends who might be on the other side of the world, while taking the bus to work. We take all of this for granted, but it’s truly amazing, says Muris Sarajlić.

– When it comes to what I researched in particular, it’s the potential for improved user experience and improved system efficiency that is the most exciting aspect of it. Smaller, cheaper wireless units that don’t waste energy and money would definitely make both users and service providers happier. And on top of everything, it’s good for the environment.

Will your solutions be implemented in the real world?
– I truly believe it, and I hope they will! All of the things I did have a strong practical side and are meant as solutions to real-life problems. I would say that pretty much everything I did, if some additional testing in real-life use-cases is done, is readily implementable, either as algorithms or system design solutions. And my solutions go well together, or are explicitly part of, other proposed technologies for 5G, so maybe I will not wait long to see some of it actually implemented.

What are your plans?
– Since everything I did during the PhD had a pronounced practical side, a natural next step for me was to continue with wireless research but in an industrial setting. I will be joining Ericsson Research in Lund in April. I am really excited about continuing to develop and learn in this environment that will be new for me, Muris Sarajlić concludes.

Muris Sarajlić will defend his thesis “Hardware-Conscious Wireless Communication System Design” the 25 February 9.15 in E:1406, Ole Römers Väg 3, Lund University, Faculty of Engineering, LTH.

Download the thesis here.