MSc Petteri Pöyhönen will defend his doctoral thesis Access Selection Methods in Cooperative Multi-operator Environments to Improve End-user and Operator Satisfaction on Wednesday the 2nd of May, 2012 at noon in theUniversity of Helsinki Main Building, Fabianinkatu 33, Hall 10 (new part), 3rd floor. The defense will be held in Finnish.

Access Selection Methods in Cooperative Multi-operator Environments to Improve End-user and Operator Satisfaction

This dissertation introduces two new access selection strategies called the network-centric and the terminal-centric strategies. These strategies use a distributed access selection algorithm, which is designed to exploit the network cooperation to support both horizontal and vertical handovers. The algorithm development was motivated by the fact that the network cooperation hides the network boundaries and through information dissemination it enables more intelligent decision making practices to ensure better utilization of the access resources resulting in enhanced capabilities serving end-users. Two new performance metrics called the USI (User Satisfaction Index) and the OSI (Operator Satisfaction Indicator) are proposed and used to evaluate the potential performance gains of these access-selection strategies.

A simulation model was developed to model how a distributed access selection algorithm in a multi-radio access technology environment including one or more operators could logically function. The technical metrics for the simulation experiments were selected to measure different aspects of the access network resource usage and end users connectivity, e.g., a number of different types of handovers and network utilization rates. The USI and OSI metrics are used to assess the non-technical performance of these access-selection strategies.

The simulation results and analysis indicate that the cooperation between networks increases the network utilization, coverage and service availability when the access selection is designed to take advantage of it. For the service availability in a single operator environment, the average online time is about 10% higher when the new access selection strategies are used compared to the legacy one. For the network utilization in a multi-operator environment, the network-centric strategy results in about a 20% higher utilization rate over the legacy one when the network is not overloaded. These new strategies are also able to better benefit from the network cooperation when measured using the users disconnectivity. For the end-users, this means that they perceive better connectivity when these strategies are in use compared to the legacy one, while for the operators, this means that their network resources are utilized better. Naturally, these perceived technical benefits translate into greater satisfaction as the analysis clearly shows.

Availability of the dissertation

An electronic version of the doctoral dissertation is available on the e-thesis site at  http://urn.fi/URN:ISBN:978-952-10-7901-6.

Printed copies are available on request from  Petteri Pöyhönen: 050-4837425 or petteri.poyhonen(at)nsn.com.