Blekinge Institute of Technology Licentiate Dissertation Series No. 2006:11 School of Engineering ON APPLICATION-PERCEIVED QUALITY OF SERVICE IN WIRELESS NETWORKS Stefan Chevul Wireless and Mobile Internet have changed the way people and businesses operate. Communica - tion from any Internet access point, including wi - reless networks such as UMTS, GPRS or WLAN has enabled organizations to have a mobile work - force. However, networked applications such as web, email, streaming multimedia etc. rely upon the ability of timely data delivery. The achievable throughput is a quality measure for the very task of a communication system, which is to transport data in time. Throughput is thus one of the most essential enablers for networked applications. While in general, throughput is defined on net - work or transport level, the application-perceived throughput reflects the Quality of Service from the viewpoints of application and user. The focus of the thesis is on the influence of the network on the application-perceived QoS and thus the user perceived experience. An analysis of application based active measurements mimicking the needs of streaming applications is presented. The results reveal clear influence of the network on the application-perceived QoS seen from varia - tions of application-perceived throughput on small time scales. Results also indicate that applications have to cope with considerably large jitter when trying to use the nominal throughputs. It was ob - served that the GPRS network had considerable problems in delivering packets in downstream di - rection even when the nominal capacity of the link was not reached. Finally, the thesis discusses the suitability of wire - less networks for different mobile services, since the influence of the network on the application- perceived Quality of Service is of great significan - ce when it comes to customer satisfaction. The - refore, application-perceived Quality of Service in wireless networks must also be considered by the mobile application programmer during the appli - cation development. ABSTRACT ISSN 1650-2140 ISBN 91-7295-096-X 2006:11 ON APPLICATION-PERCEIVED QUALITY OF SERVICE IN WIRELESS NETWORKS Stefan Chevul 2006:11 On Application-Perceived Quality of Service in Wireless Networks Stefan Chevul On Application-Perceived Quality of Service in Wireless Networks Stefan Chevul Blekinge Institute of Technology Licentiate Dissertation Series No 2006:11 ISSN 1650-2140 ISBN 91-7295-096-X Department of Telecommunication Systems School of Engineering Blekinge Institute of Technology SWEDEN © 2006 Stefan Chevul Department of Telecommunication Systems School of Engineering Publisher: Blekinge Institute of Technology Printed by Kaserntryckeriet, Karlskrona, Sweden 2006 ISBN 91-7295-096-X c � 2006 Stefan Chevul Dissertation Series No. 2006:11 ISSN 1650-2140 ISBN 91-7295-096-X Department of Telecommunication Systems School of Engineering Blekinge Institute of Technology Printed by Kaserntryckeriet AB, Karlskrona, Sweden This publication was typeset using L A T E X. To my family. Abstract Wireless and Mobile Internet have changed the way people and businesses operate. Communication from any Internet access point, including wireless networks such as UMTS, GPRS or WLAN has enabled organizations to have a mobile workforce. However, networked applications such as web, email, streaming multimedia etc. rely upon the ability of timely data delivery. The achievable throughput is a quality measure for the very task of a communi- cation system, which is to transport data in time. Throughput is thus one of the most essential enablers for networked applications. While in general, throughput is defined on network or transport level, the application-perceived throughput reflects the Quality of Service from the viewpoints of the applica- tion and user. The focus of the thesis is on the influence of the network on the application- perceived Quality of Service and thus the user perceived experience. An analysis of application based active measurements mimicking the needs of streaming applications is presented. The results reveal clear influence of the network on the application-perceived Quality of Service seen from variations of application-perceived throughput on small time scales. Results also indi- cate that applications have to cope with considerably large jitter when trying to use the nominal throughputs. It was observed that the GPRS network had considerable problems in delivering packets in the downstream direction even when the nominal capacity of the link was not reached. Finally, the thesis discusses the suitability of wireless networks for different mobile services, since the influence of the network on the application-perceived Quality of Service is of great significance when it comes to customer satisfac- tion. Therefore, application-perceived Quality of Service in wireless networks must also be considered by the mobile application programmer during the application development. vii . 2006:11 ON APPLICATION-PERCEIVED QUALITY OF SERVICE IN WIRELESS NETWORKS Stefan Chevul 2006:11 On Application-Perceived Quality of Service in Wireless Networks. Blekinge Institute of Technology Licentiate Dissertation Series No. 2006:11 School of Engineering ON APPLICATION-PERCEIVED QUALITY OF SERVICE IN WIRELESS NETWORKS