Voice over IP Capacity of IEEE 802.11 WLAN and IEEE 802.21 based Interworking Performance of WLAN and Mobile LTE Networks
Author(s): Jennen,R.
Communication Networks (ComNets) Research Group @ RWTH Aachen University
Contact: publications@comnets.rwth-aachen.de
Ph. D. Dissertation
, ABMT
70
,
p.
256
, ISBN: 978-3-86130-959-8
Wissenschaftsverlag Mainz,
Year: 2012
On page(s):256
ISBN: 978-3-86130-959-8
Abstract During recent years mobile service usage has been continuously growing as more and more mobile Internet capable devices appeared, services became sophisticated, and mobile network operatorsÂ’ pricing policies changed from data volume to flat rate based charging. That is why today operatorsÂ’ customers expect to have ubiquitous access to their services, independent from access technologies being either wired or wireless. Furthermore, users do not want to be bothered with details of network selection or connection set-up and service interruptions have to be avoided where applicable. In the best case for users there is no difference between fixed and mobile access. This is supported by so called fixed, mobile convergence. Nowadays convergence of voice and data services is achieved by forming packet switched networks using the Internet Protocol (IP) and introduction of IP Multimedia Subsystem (IMS) for session related signaling and multimedia delivery. However, to deal with increasing amounts of data traffic mobile network operators have to increase their capacity. Even the introduction of Long-Term Evolution (LTE), which has been explicitly designed for data traffic, is insufficient as traffic forecasts indicate. Therefore multiple access technologies are combined, e.g. Long-Term Evolution (LTE), Second Generation (2G), Third Generation (3G), and Wireless Local Area Network (WLAN), to form a heterogeneous network. But these access technologies have inhomogeneous characteristics with respect to Quality of Service (QoS) provisioning. This results in a network selection procedure where the QoS requirement of an application is a criteria for the Access Technology (AT) chosen. There is a paradigm shift from always on to always best connected, which means that the best AT is selected depending on the need of an application, e.g. voice or web browsing. This thesis presents interworking functions, such as path selection, vertical handover, access selection, and frameworks which allow the distribution of traffic to several access technologies. Multiple interworking schemes are investigated with respect to overhead and delay. Achievable performance for different degrees of interworking depends on many factors, such as network topology, number of users, and traffic type. To investigate performance a tool for estimation of time and effort needed for interworking is required. Within this thesis an analytical tool is created that is useful to check if QoS demands can be fulfilled. As an example of an AT a precise analytical Distributed Coordination Function (DCF) WLAN Signal Flow Graph (SFG) model is derived which is used in the analysis of a Media Independent Handover (MIH) based interworking framework. This thesis applies analytical methods like Markov Chain, Queuing Network, and SFG to calculate Cumulative Distribution Functions of data link layer frame delay under non-saturated network conditions where delay includes service and waiting time. As a side effect, showing the strengths of the model, the Voice over Internet Protocol (VoIP) capacity in WLANs is obtained analytically taking into account satisfied user criteria and realistic network conditions. Mathematical analysis results are validated for typical WLAN application scenarios by simulation results gained from the openWNS system level simulator. LTE WLAN interworking is one focus of this thesis. The interworking model is based on the developed link layer models, the previously mentioned model for WLANs and a simple LTE model. The model is applied to investigate handover signaling following the MIH specification and to calculate the achievable performance. Shown results aim at providing an example for the applicability of the model. Possible model extensions are outlined throughout the thesis, easing future heterogeneous network research.
Author Keywords
Internettelefonie; Heterogenes Netzwerk; Drahtloses lokales Netz; Long Term Evolution; IEEE 802.11; IEEE 802.21; Dienstgüte; Zugangsverfahren; OSI-Modell; Traffic Engineering
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Bibtex
@PHDTHESIS{Diss_RalfJennen_2012
AUTHOR = {Jennen,R.} ,
TITLE = {Voice over IP Capacity of IEEE 802.11 WLAN and IEEE 802.21 based Interworking Performance of WLAN and Mobile LTE Networks} ,
YEAR = {2012} ,
VOLUME = {70},
PAGES = {256},
PUBLISHER = {Wissenschaftsverlag Mainz},
ADDRESS = {Communication Networks (ComNets) Research Group @ RWTH Aachen University},
SERIES = {ABMT},
AFFILIATION = {Communication Networks (ComNets) Research Group @ RWTH Aachen University},
ISBN = {978-3-86130-959-8 },
KEYWORDS = {Internettelefonie; Heterogenes Netzwerk; Drahtloses lokales Netz; Long Term Evolution; IEEE 802.11; IEEE 802.21; Dienstgüte; Zugangsverfahren; OSI-Modell; Traffic Engineering},
URL = {https://www.comnets.rwth-aachen.de}