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Novel solutions for mitigating hardware non-idealities in modern communication systems

The doctoral dissertation of M.Sc. (Tech) Adnan Kiayani explores the implementation challenges of radio devices caused by the exponential growth in wireless traffic and the increasing demand for high-speed data transfer.
Adnan Kiayani (29) is originally from Islamabad, Pakistan, and now lives in Tampere, Finland.
Adnan Kiayani (29) is originally from Islamabad, Pakistan, and now lives in Tampere, Finland.

The number of wireless devices is growing rapidly and is estimated to reach 200 billion by 2020. The data rate required for supporting multimedia applications, such as live video broadcast and ultra-high definition (UHD) videos streaming on mobile and portable devices, is also increasing significantly. However, such trends in the wireless industry are placing greater demands on the electronic hardware, where, in addition to the speed of data transfer, the cost, size, power consumption and multi-standard functionality of a device are key considerations.

An effective way to deal with these conflicting requirements is to simplify the radio architecture, i.e., reduce the number of components in the radio equipment. Such a simplification exposes the state-of-the-art electronic systems to new problems that mainly stem from the manufacturing process limitations and the inherently imperfect behaviour of the components. These problems are commonly referred to as radio frequency (RF) impairments in the scientific community, and modern communication signals are extremely sensitive to these impairments. As a result, the signal quality is degraded significantly, which, in turn, limits the capabilities of the devices.

“An interesting alternative that has attracted widespread interest in the research community in the last 10 - 15 years is to improve the signal quality through digital methods. One can think of it as a digitally-enhanced electronic hardware, where more functionality is achieved in the digital domain while using cheaper and non-ideal physical radio components,” says M.Sc. (Tech) Adnan Kiayani.

Kiayani’s doctoral dissertation deals with the radio transmitter’s implementation challenges in the context of future mobile communication systems, in particular, when cost, size, and power efficiency of handsets are important factors. The work broadens the existing understanding of radio impairments by providing complete system models as well as proposes several new digital correction algorithms. The novel impairments correction schemes proposed by Kiayani for Long Term Evolution (LTE) and LTE-Advanced systems ensure reliable communication between the base station (BS) and the user, without complicating the radio transceiver design. Another key contribution of the thesis is to analyse how radio impairments affect the performance of widely-adopted Frequency Division Duplexing (FDD) devices and how to mitigate them in an efficient manner. The outcomes are crucial for the implementation of flexible and efficient FDD transceivers design. Overall, the work in this thesis is not only of high importance for the scientific community but also for the industry.

Public defence of a doctoral dissertation on Tuesday, 27 October

The doctoral dissertation of M. Sc. Adnan Kiayani in the field of communications engineering entitled “Modeling and Digital Mitigation of Transmitter Imperfections in Radio Communication Systems” will be publicly examined at the Faculty of Computing and Electrical Engineering of Tampere University of Technology (TUT) in room TB104 in the Tietotalo building (address: Korkeakoulunkatu 1, Tampere, Finland) at 12:00 on Tuesday, 27 October 2015.

The opponent will be Dr. Ulf Gustavsson (Ericsson Research, Gothenburg, Sweden). Professor Mikko Valkama from the Department of Electronics and Communications Engineering at TUT will act as Chairman.

The dissertation is available online at http://URN.fi/URN:ISBN:978-952-15-3616-8

Further information: Adnan Kiayani, firstname.lastname@tut.fi

News submitted by: Anna Naukkarinen
Keywords: science and research, doctoral dissertation, adnan kiayani