Disputerer på økt effektivisering i mobil kommunikasjon

For fremtidens trådløse kommunikasjonssystemer er det helt nødvendig å finne metoder for å utnytte den begrensede plassen bedre – uten å overkjøre eksisterende brukere.

Lei Jiao disputerer på ph.d.-programmet i Informasjons- og kommunikasjonsteknologi ved Institutt for IKT ved UiAs Fakultet for teknologi og realfag med avhandlingen "Medium Access in Cognitive Radio Networks: from Single Hop to Multiple Hops".

Doktorgradsarbeidet har resultert i 12 publikasjoner - tre tidsskriftartikler og ni konferanseartikler. Blant de tre tidsskriftartiklene er to nivå 2 artikler, hvor en allerede er publisert og en annen er under runde-2-vurdering med status som ‘minor revison’.

Slik beskriver kandidaten selv essensen i avhandlingen:

With the growing ubiquity of wireless communications and the pervasiveness of the Internet in our daily life, wireless devices as well as mobile applications have experienced an explosive growth in the past two decades.

On the one hand, as limited natural resource, most spectrum bands that can be utilized for wireless communications have been allocated to different existing systems, leaving little room for emerging wireless systems and services.

On the other hand, studies on spectrum utilization have revealed that most of the allocated spectrum is not utilized efficiently.

Therefore, how to make an efficient use of the spectrum becomes an important and imperative question for the design of future wireless communication systems. Cognitive radio networks (CRNs), which target at enhancing spectrum utilization by re-utilizing already allocated spectrum without affecting licensed users, have been proposed and regarded as the most promising technology to answer this question.

In the initial stage of the research on CRNs, the main focus has been on the physical layer design. However, physical layer techniques alone do not suffice cognitive radios (CRs) for opportunistic spectrum access and communications among multiple users, neither within single hop nor over multiple hops.

Therefore, based on the advanced underlying physical layer technologies developed for CRs, higher layer issues, i.e., medium access control and routing, become essential topics for CR networking.

In this dissertation, we enhance the state-of-the-art technologies for CRNs considering various single-hop and multiple-hop scenarios.

The results of this work have been published in various conference proceedings and journals.

Kandidaten: Lei Jiao was born in Jinan, China in 1982. He received the B. E. degree in telecommunications engineering from Hunan University, Changsha, China (2005), and the M. E. degree in communications and information system from Shandong University, Jinan, China (2008). He joined the Department of Information and Communication Technology, University of Agder, in August 2008 as a PhD candidate. His research interests include cognitive radio networks, wireless sensor networks, localization algorithms, and intelligent transportation systems.

Prøveforelesning og disputas finner sted i Rom C5 040, UiA Campus Grimstad. Dekan ved Fakultet for teknologi og realfag, professor Frank Reichert, leder disputasen

Tid for prøveforelesning: Onsdag 12. september 2012 kl 10:00

Oppgitt emne for prøveforelesning: «Wireless LAN 802.11 MAC performance models»

Tid for disputas: Onsdag 12. september 2012 kl 12:30

Tittel på avhandling: “Medium Access in Cognitive Radio Networks: from Single Hop to Multiple Hops”

Les avhandlingen i AURA - Agder University Research Archive, som er et digitalt arkiv for vitenskapelige artikler, avhandlinger og masteroppgaver fra ansatte og studenter ved Universitetet i Agder.

Førsteopponent professor Ulf Körner, Lund Universitet

Annenopponent associate professor Hans-Peter Schwefel, Aalborg Universitet

Bedømmelseskomitéen har vært ledet av professor Andreas Prinz, Institutt for IKT, UiA

Veiledere i doktorgradsarbeidet var professor Frank Li, UiA og professor Vicent Pla, Universitat Politecnica de Valencia