Delivered by: Prof. Oualid Hammi, American University of Sharjah, UAE.
Date, time, and venue: 30th April 2025, 12:15 PM, Earl Mountbatten Building – EM2.33 – In-Person Event (Edinburgh Campus) [External attendees please email: G.Goussetis@hw.ac.uk]
Abstract: Power amplifiers (PAs) are critical components in wireless communication systems, responsible for boosting signal power prior to transmission. However, their inherent non-linearity introduces distortions, including static non-linearities and memory effects, which degrade signal quality, increase out-of-band emissions, and limit overall system performance.
Traditional digital predistortion (DPD) techniques often struggle with wideband signals and the increasing complexity of modern communication standards. These advanced standards demand significantly higher signal bandwidths, which in turn requires proportional increases in the sampling rates of digital-to-analog converters (DACs) in the transmit path and analog-to-digital converters (ADCs) in the observation path. This leads to increased hardware costs, higher power consumption, and more complex system design.
This talk addresses the challenges of mitigating these distortions, focusing on advanced techniques to overcome sampling rate limitations in the transmit and observation paths, which are crucial for cost-effective and efficient implementation in modern communication systems. The presentation will then explore neural network-based structures for accurate behavioral modeling and predistortion of PAs. These models have recently drawn increasing interest due to their ability to capture the complex non-linear characteristics of PAs, including dynamic behavior and long-term memory effects, enabling the design of effective predistortion techniques. The use of neural networks in predistortion systems can lead to numerous advantages, but is often accompanied by significant computational complexity. We will discuss techniques for complexity reduction in neural network models, making them more suitable for real-time implementation in resource-constrained wireless systems.
Finally, the talk will discuss future research directions, including the extension of these techniques to dual-band signals for 5G and beyond, to meet the increasing demands of modern wireless communication systems. This extension is essential for supporting the wide range of frequencies and bandwidths employed in next-generation communication.
Speaker bio: Oualid Hammi received a B.Eng. degree from the École Nationale d’Ingénieurs de Tunis, Tunis, Tunisia, in 2001, an M.Sc. degree from the École Polytechnique de Montréal, Montréal, QC, Canada, in 2004, and a Ph.D. degree from the University of Calgary, Calgary, AB, Canada, in 2008, all in electrical engineering.
From 2010 to 2015, he was a faculty member with Department of Electrical Engineering at King Fahd University of Petroleum and Minerals, Dhahran, KSA. In 2015, he joined the Electrical Engineering Department of the American University of Sharjah, Sharjah, United Arab Emirates. Prof. Oualid Hammi where he was promoted to a Full Professor in 2020. He is the founder of the Advanced Radio Technology (ART) laboratory.
His research interests include the design of energy-efficient linear transmitters for wireless communication and satellite systems, and the characterization, behavioral modeling, and linearization of radiofrequency power amplifiers and transmitters. He is the co-author of two books: “Behavioral Modeling and Predistortion of Wideband Wireless Transmitters” by Wiley, and “Design and Applications of Active Integrated Antennas” by Artech House. His publications include more than 100 articles, and 13 US patents.