Spectrum access in white spaces using spectrum sensing and geolocation databases

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School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2013-12-04
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Author
Date
2013
Department
Tietoliikenne- ja tietoverkkotekniikan laitos
Department of Communications and Networking
Major/Subject
Mcode
Degree programme
Language
en
Pages
128 + app. 83
Series
Aalto University publication series DOCTORAL DISSERTATIONS, 195/2013
Abstract
A spectrum license grants users the right to transmit on a particular piece of spectrum. Historically, a spectrum license has been allocated for a particular technology. While this strategy facilitates interference control, it also results in spectrum scarcity as more spectrum-efficient technologies are invented. In order to meet the increasing data traffic demands in a timely manner, a shared use of the spectrum seems to be the only viable solution. According to this line of thinking, different technologies with possibly different deployment densities can share the same spectrum under certain conditions. While shared spectrum access improves spectral efficiency, it also increases the risk for harmful interference among the different systems. This calls for a change in the traditional way of issuing spectrum licenses: instead of specifying transmit power levels, the spectrum usage rights specify the generated interference that is permitted. Spectrum access to white spaces would enhance spectrum utilisation, while also testing the approach of controlling the interference between different systems directly rather than through the transmission power. The amount of interference generated to the license holder can be controlled by spectrum sensing and/or geolocation database access. Interference control using spectrum sensing usually boils down to a signal detection problem. In this thesis, we show that the traditional signal detection framework is not appropriate for recovering transmission opportunities in the spatial domain and propose an alternative model. Also, sensing strategies for energy efficient wideband spectrum sensing and trade-off analysis between the service requirement and the demand in the measured spectrum are demonstrated. At this moment, spectrum access to white spaces is mostly possible via geolocation databases. The database is responsible for handling spectrum access requests while complying with certain regulatory conditions. In this thesis, we suggest some interference control and power allocation algorithms that may govern the operation of the database. The algorithms have a low complexity to enable a real-time operation in the database. They involve simple models to capture the impact of the non-uniform demand density, terrain-based propagation and fading correlations on the generated interference. Also, we propose a joint rate and power allocation algorithm that protects the license holder in all cases.
Description
Supervising professor
Jäntti, Riku, Prof., Aalto University, Department of Communications and Networking, Finland
Thesis advisor
Ruttik, Kalle, Dr., Aalto University, Department of Communications and Networking, Finland
Keywords
aggregate interference models, flexible spectrum use, spectrum sensing strategy
Other note
Parts
  • [Publication 1]: Konstantinos Koufos, Kalle Ruttik and Riku Jäntti. Controlling the interference from multiple secondary systems at the TV cell border. In Proc. IEEE Personal Indoor and Mobile Radio Communications (PIMRC), Toronto, Canada, pages 645-649, September 2011.
  • [Publication 2]: Konstantinos Koufos and Riku Jäntti. Proportional fair power allocation for secondary transmitters in the TV white space. Journal of Electrical and Computer Engineering, 2013.
  • [Publication 3]: Byungjin Cho, Konstantinos Koufos, Kalle Ruttik and Riku Jäntti. Power allocation in the TV white space under constraint on secondary system self-interference. Journal of Electrical and Computer Engineering, 2012.
  • [Publication 4]: Kalle Ruttik, Konstantinos Koufos and Riku Jäntti. Model for computing aggregate interference from secondary cellular network in presence of correlated shadow fading. In Proc. IEEE Personal Indoor and Mobile Radio Communications (PIMRC), Toronto, Canada, pages 433-437, September 2011.
  • [Publication 5]: Konstantinos Koufos, Kalle Ruttik and Riku Jäntti. Aggregate interference from WLAN in the TVWS by using terrain-based channel model. In Proc. IEEE International Conference on Cognitive Radio OrientedWireless Networks (CROWNCOM), Stockholm, Sweden, pages 185-189, June 2012.
  • [Publication 6]: Konstantinos Koufos, Kalle Ruttik and Riku Jäntti. Signal model for dynamic spectrum allocation close to the cell border of a primary transmitter. In Proc. IEEE International Symposium on New Frontiers in Dynamic Spectrum Access Networks (DySPAN), Chicago, US, pages 1-5, October 2008.
  • [Publication 7]: Konstantinos Koufos, Kalle Ruttik and Riku Jäntti. Distributed Sensing in Multiband Cognitive Networks. IEEE Transactions on Wireless Communications, Volume 10, issue 5, pages 1667-1677, May 2011.
  • [Publication 8]: Konstantinos Koufos, Kalle Ruttik and Riku Jäntti. Voice Service in Cognitive Networks over the TV Spectrum. IET Communications, Volume 6, issue 8, pages 991-1003, May 2012.
Citation
Permanent link to this item
https://urn.fi/URN:ISBN:978-952-60-5455-1
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[diss] Sähkötekniikan korkeakoulu / ELEC