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Mojtaba Mahdavi treats need for speed and reliability with hardware friendly algorithms

2021-09-22

Portrait. Mojtaba Mahdavi in a park.

Mojtaba Mahdavi. Photo: Marzieh Majdzadeh

New applications set new demands on the data-rate, reliability, and latency of wireless communication systems in 5G and beyond, pushing forward technology developments. The thesis work of Mojtaba Mahdavi has been oriented towards the domain of hardware-efficient realisation of components in the baseband. The focus has been on the design and implementation of the OFDM* demodulator, massive MIMO detector, and channel decoder.

September 24 at 9.15 he defends his PhD thesis “Baseband Processing for 5G and Beyond: Algorithms, VLSI Architectures, and Co-design” at LTH, Lund University.

Read more about the dissertation.

Download the thesis (PDF)

Applications such as remote surgery and self-driving cars have great demands on the reliability and latency since any failure in such cases would result in a disaster. In these applications, the data transmission should be performed in less than 5 ms with a success rate of 99.999%. Other applications like video streaming and augmented reality rely upon fast and high-volume data transmission. Massive connectivity is another demand, which is required in smart cities and smart homes such that more than 100,000 devices per km2 should be able to communicate. 

“In order to fulfil these requirements, new technologies and sophisticated algorithms are needed. Eventually, these complex algorithms must be implemented in hardware, which is a challenging task”, Mojtaba Mahdavi says. 

“The focus of my dissertation has been on the hardware-efficient realisation of several key components in the baseband processing of wireless communication systems in 5G and beyond. More specifically, we have designed and implemented OFDM demodulator, massive MIMO detector, and channel decoder, which are commonly used in many wireless systems.”

Block diagram. Baseband processing in massive MIMO systems. The highlighted blocks, OFDM demodulator, massive MIMO.

A simplified block diagram of baseband processing in massive MIMO systems. The highlighted blocks, OFDM demodulator, massive MIMO detector, and channel decoder, are targeted in the thesis. Click to enlarge.

Why research wireless systems?
“I did my master thesis in the field of baseband processing for 4G wireless systems in the Sharif University of Technology in Teheran. I found the interdisciplinary research of wireless communication and digital hardware design very interesting, and I wanted to learn more about this field. Thus, I decided to pursue PhD studies at the Department for Electrical and Information Technology at Lund University, which has been one of the main pioneers and contributors in the development of 5G systems.” 

What is the most fascinating or interesting with your thesis subject?
“One of the most fascinating aspects of my thesis work is the realisation of very complex algorithms and mathematical equations in the real hardware using simple circuits. It is interesting to investigate how the system-level features can be utilised to make these algorithms more hardware friendly and develop efficient hardware architectures to perform complicated processing.”

What will happen with the findings?
“An important outcome of my research is to demonstrate how system, algorithm, and architecture levels can be co-optimised to improve the efficiency of the final design. This approach can be employed to design and implement the baseband processor for the current and upcoming wireless communication systems in a more efficient way. In this thesis, we have used this design approach for the key functional blocks in the baseband processing of 5G systems and presented that the hardware cost, latency, reliability, and data rate are significantly improved.”

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* OFDM: Orthogonal frequency-division multiplexing. Get an overview at Wikipedia.org.