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Sudharsan Srinivasan: Managing radio interference can increase the capacity of wireless communication networks

Tampere University
LocationHervanta Campus, Tietotalo, auditorium TB209 (Korkeakoulunkatu 1, Tampere)
11.11.2022 12.00–16.00
Entrance feeFree of charge
In his doctoral dissertation MSc (Tech) Sudharsan Srinivasan developed novel and practical signal processing methods for radio interference cancellation and radio resource allocation in digital communications. These techniques help improve the performance and spectral efficiency of current and future radio systems.

The use of world’s scarce resources must be sustainable and efficient. In wireless communication engineering the most precious natural resource is the radio frequency spectrum. Judicious use of the frequency spectra is essential for the current and next generation internet and data communication.

In his doctoral dissertation Sudharsan Srinivasan introduces in a pragmatic way technical solutions to using radio spectrum more efficiently. For example, cognitive radios and dynamic spectrum sharing are disruptive technologies that help to attain spectrum efficiency through spectrum reuse.

New methods proposed to improve spectral efficiency

One of the enabling technologies for spectrally efficient wireless system is interference management and cancellation. Cancelling interference from other radio signals makes it possible to use the radio spectrum more efficiently, by utilizing spectral gaps which are left unused in traditional radio systems.

“Interference rejection combining is one of the widely used signal processing techniques in the previous and current generation of radio systems. Developing and enhancing this signal processing method and making it future-ready is one of the primary motivations for my research," Srinivasan says.

As another element, effective radio resource allocation is essential for optimal usage of the spectrum and reducing the interference to other users of the spectrum. Improved methods of using resource allocation are also reported in his thesis. 

While developing theoretical understanding of the problem is crucial, understanding its implications in practical implementation is a necessary condition for its useful application. Important parts of radio transmitters and receivers are RF front-ends, which help in converting radio signals to digital form.

“Due to inevitable imperfections in analog electronics, there are many challenges in designing these systems. In my thesis I have also studied and reported the issues related to the radio front-end imperfections, especially the RF non-linearity and its effects on interference cancellation,” he adds.

Sudharsan Srinivasan proposed several methods and algorithms which can be used to improve the spectral efficiency by better handling of radio interference.  These algorithms are comprised of various techniques like multi-antenna combining, sample covariance-based techniques, silent gap interpolation, resource allocation methods, and RF nonlinearity compensation which enhance the receiver’s performance and its spectral efficiency under interference.      

The doctoral dissertation of MSc (Tech) Sudharsan Srinivasan in the field of Communications Engineering titled Multiantenna Interference Mitigation Schemes and Resource Allocation for Cognitive Radio will be publicly examined in the in the Faculty of Information Technology and Communications Sciences of Tampere University at Hervanta Campus in the auditorium TB109 of Tietotalo at 12 o’clock on Friday, 11 November 2022..  The Opponent will be Dr. Kalle Ruttik from Aalto University. The Custos will be Professor Emeritus Markku Renfors from Tampere University.  The work is co-supervised by Dr. Sener Dikmese from Ericsson Sweden.

The dissertation is available online.

Photo: Sindhuja Ranganathan