Optimization in Self-Organizing Cellular Networks

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Volume Title

School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2018-12-14

Date

2018

Major/Subject

Mcode

Degree programme

Language

en

Pages

110 + app. 90

Series

Aalto University publication series DOCTORAL DISSERTATIONS, 240/2018

Abstract

Radio Access Technologies (RATs) continuously evolve as a response to the ever-growing demand for various services ranging from mobile broadband to machine-type communications. On the other hand, the evolution of RATs as in Long Term Evolution (LTE), is not sufficient alone to guarantee the coverage and capacity needs in cellular networks. This is because the overall Radio Access Network (RAN) performance does not only depend on the RAT capabilities but also the RAN parameters adjusted according to the network planning assumptions. Yet these assumptions may change in time, especially due to deployment densification, resulting in suboptimal RAN performance. Furthermore, base station outage or structural changes in the deployment area could impact the RAN performance. Since reacting on these inherent scenarios manually is very expensive and time consuming, automated recovery and optimization of cellular networks, i.e., Self-Organizing Networks (SON), was addressed as an essential technology component within the evolution of LTE standards. The work presented in this doctoral dissertation contributed to the development of the SON framework by analyzing the potential impact of adaptable RAN parameters on the system performance, designing practical SON algorithms and providing guidelines for SON architecture evolution toward the 5th Generation (5G). To assess the network performance, both analytical and experimental frameworks were developed based on the 3rd Generation Partnership Project (3GPP) guidelines. Whilst the analytical framework simplifies the link-level modeling, the system-level modeling enables the evaluation of overall network performance with a large number of RAN parameters. In the system-level simulations, the recommended 3GPP urban and suburban scenarios (with regular cell layouts) are assumed for the performance evaluations. In addition, the downtown Helsinki scenario is adopted for the SON performance analysis in a deployment model with an irregular cell layout. Performance evaluations reveal that antenna configuration impacts the coverage and capacity performance significantly. Furthermore, the results obtained for a realistic urban deployment verify that antenna optimization processes can be managed by both centralized and distributed SON architecture options. In addition, the studies demonstrate that cross-channel resource optimization could improve the network capacity in uplink by means of the localized SON architecture. Toward 5G, context-aware SON solutions were also considered. The long-term scheduling of delay-tolerant services in heterogeneous networks was selected as an example. The study assumes a novel SON architecture that is of User Equipment (UE) extension to involve UE context in decision-making. Approximate gains are revealed to address the potential of SON architecture evolution in 5G.

Description

Supervising professor

Hämäläinen, Jyri, Prof., Aalto University, Department of Communications and Networking, Finland

Thesis advisor

Hämäläinen, Seppo, Dr., Nokia, Finland

Keywords

optimization, self-organizing networks, cellular networks, SON, LTE, 4G, 5G

Other note

Parts

  • [Publication 1]: Osman N.C. Yilmaz, Seppo Hämäläinen, Jyri Hämäläinen. Analysis of antenna parameter optimization space for 3GPP LTE. In IEEE Vehicular Technology Conference (VTC Autumn), Anchorage-Alaska, USA, pp. 1-5, September 2009.
    DOI: 10.1109/VETECF.2009.5379077 View at publisher
  • [Publication 2]: Osman N.C. Yilmaz, Seppo Hämäläinen, Jyri Hämäläinen. Comparison of remote electrical and mechanical antenna downtilt performance for 3GPP LTE. In IEEE Vehicular Technology Conference (VTC Autumn), Anchorage-Alaska, USA, pp. 1-5, September 2009.
    DOI: 10.1109/VETECF.2009.5379074 View at publisher
  • [Publication 3]: Osman N.C. Yilmaz, Seppo Hämäläinen, Jyri Hämäläinen. System level analysis of vertical sectorization for 3GPP LTE. In International Symposium on Wireless Communication Systems (ISWCS), Siena, Italy, pp. 453-457, September 2009.
    DOI: 10.1109/ISWCS.2009.5285317 View at publisher
  • [Publication 4]: Osman N.C. Yilmaz, Seppo Hämäläinen, Jyri Hämäläinen. Self-optimization of remote electrical tilt. In IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), Istanbul, Turkey, pp. 1128-1132, September 2010.
    DOI: 10.1109/PIMRC.2010.5672065 View at publisher
  • [Publication 5]: Osman N.C. Yilmaz, Jyri Hämäläinen, Seppo Hämäläinen. Optimization of adaptive antenna system parameters in self-organizing LTE networks. Wireless Networks, Volume 19, Issue 6, pp. 1251-1267, August 2013.
    DOI: 10.1007/s11276-012-0531-3 View at publisher
  • [Publication 6]: Osman N.C. Yilmaz, Jyri Hämäläinen, Seppo Hämäläinen. Vertical sectorization in self-organizing LTE-advanced networks. Wireless Networks, Volume 22, Issue 5, pp. 1685-1698, July 2016.
    DOI: 10.1007/s11276-015-1057-2 View at publisher
  • [Publication 7]: Osman N.C. Yilmaz, Jyri Hämäläinen, Seppo Hämäläinen. Self-optimization of random access channel in 3rd Generation Partnership Project Long Term Evolution [Invited Paper]. Wireless Communications and Mobile Computing, Volume 11, Issue 12, pp. 1507-1517, December 2011.
    DOI: 10.1002/wcm.1217 View at publisher
  • [Publication 8]: Osman N.C. Yilmaz, CarlWijting, Petteri Lundén, Jyri Hämäläinen. Optimized mobile connectivity for bandwidth-hungry, delay-tolerant cloud services toward 5G. In International Symposium on Wireless Communication Systems (ISWCS), Barcelona, Spain, pp. 6-10, August 2014.
    DOI: 10.1109/ISWCS.2014.6933310 View at publisher

Citation