588 research outputs found
A Unified Mobility Management Architecture for Interworked Heterogeneous Mobile Networks
The buzzword of this decade has been convergence: the convergence of telecommunications, Internet, entertainment, and information technologies for the seamless provisioning of multimedia services across different network types. Thus the future Next Generation Mobile Network (NGMN) can be envisioned as a group of co-existing heterogeneous mobile data networking technologies sharing a common Internet Protocol (IP) based backbone. In such all-IP based heterogeneous networking environments, ongoing sessions from roaming users are subjected to frequent vertical handoffs across network boundaries. Therefore, ensuring uninterrupted service continuity during session handoffs requires successful mobility and session management mechanisms to be implemented in these participating access networks. Therefore, it is essential for a common interworking framework to be in place for ensuring seamless service continuity over dissimilar networks to enable a potential user to freely roam from one network to another. For the best of our knowledge, the need for a suitable unified mobility and session management framework for the NGMN has not been successfully addressed as yet. This can be seen as the primary motivation of this research. Therefore, the key objectives of this thesis can be stated as: To propose a mobility-aware novel architecture for interworking between heterogeneous mobile data networks To propose a framework for facilitating unified real-time session management (inclusive of session establishment and seamless session handoff) across these different networks. In order to achieve the above goals, an interworking architecture is designed by incorporating the IP Multimedia Subsystem (IMS) as the coupling mediator between dissipate mobile data networking technologies. Subsequently, two different mobility management frameworks are proposed and implemented over the initial interworking architectural design. The first mobility management framework is fully handled by the IMS at the Application Layer. This framework is primarily dependant on the IMS’s default session management protocol, which is the Session Initiation Protocol (SIP). The second framework is a combined method based on SIP and the Mobile IP (MIP) protocols, which is essentially operated at the Network Layer. An analytical model is derived for evaluating the proposed scheme for analyzing the network Quality of Service (QoS) metrics and measures involved in session mobility management for the proposed mobility management frameworks. More precisely, these analyzed QoS metrics include vertical handoff delay, transient packet loss, jitter, and signaling overhead/cost. The results of the QoS analysis indicates that a MIP-SIP based mobility management framework performs better than its predecessor, the Pure-SIP based mobility management method. Also, the analysis results indicate that the QoS performances for the investigated parameters are within acceptable levels for real-time VoIP conversations. An OPNET based simulation platform is also used for modeling the proposed mobility management frameworks. All simulated scenarios prove to be capable of performing successful VoIP session handoffs between dissimilar networks whilst maintaining acceptable QoS levels. Lastly, based on the findings, the contributions made by this thesis can be summarized as: The development of a novel framework for interworked heterogeneous mobile data networks in a NGMN environment. The final design conveniently enables 3G cellular technologies (such as the Universal Mobile Telecommunications Systems (UMTS) or Code Division Multiple Access 2000 (CDMA2000) type systems), Wireless Local Area Networking (WLAN) technologies, and Wireless Metropolitan Area Networking (WMAN) technologies (e.g., Broadband Wireless Access (BWA) systems such as WiMAX) to interwork under a common signaling platform. The introduction of a novel unified/centralized mobility and session management platform by exploiting the IMS as a universal coupling mediator for real-time session negotiation and management. This enables a roaming user to seamlessly handoff sessions between different heterogeneous networks. As secondary outcomes of this thesis, an analytical framework and an OPNET simulation framework are developed for analyzing vertical handoff performance. This OPNET simulation platform is suitable for commercial use
EVM as generic QoS trigger for heterogeneous wieless overlay network
Fourth Generation (4G) Wireless System will integrate heterogeneous wireless
overlay systems i.e. interworking of WLAN/ GSM/ CDMA/ WiMAX/ LTE/ etc with
guaranteed Quality of Service (QoS) and Experience (QoE).QoS(E) vary from
network to network and is application sensitive. User needs an optimal mobility
solution while roaming in Overlaid wireless environment i.e. user could
seamlessly transfer his session/ call to a best available network bearing
guaranteed Quality of Experience. And If this Seamless transfer of session is
executed between two networks having different access standards then it is
called Vertical Handover (VHO). Contemporary VHO decision algorithms are based
on generic QoS metrics viz. SNR, bandwidth, jitter, BER and delay. In this
paper, Error Vector Magnitude (EVM) is proposed to be a generic QoS trigger for
VHO execution. EVM is defined as the deviation of inphase/ quadrature (I/Q)
values from ideal signal states and thus provides a measure of signal quality.
In 4G Interoperable environment, OFDM is the leading Modulation scheme (more
prone to multi-path fading). EVM (modulation error) properly characterises the
wireless link/ channel for accurate VHO decision. EVM depends on the inherent
transmission impairments viz. frequency offset, phase noise,
non-linear-impairment, skewness etc. for a given wireless link. Paper provides
an insight to the analytical aspect of EVM & measures EVM (%) for key
management subframes like association/re-association/disassociation/ probe
request/response frames. EVM relation is explored for different possible
NAV-Network Allocation Vectors (frame duration). Finally EVM is compared with
SNR, BER and investigation concludes EVM as a promising QoS trigger for OFDM
based emerging wireless standards.Comment: 12 pages, 7 figures, IJWMN 2010 august issue vol. 2, no.
Queueing Networks for Vertical Handover
PhDIt is widely expected that next-generation wireless communication systems will be
heterogeneous, integrating a wide variety of wireless access networks. Of particular
interest recently is a mix of cellular networks (GSM/GPRS and WCDMA) and
wireless local area networks (WLANs) to provide complementary features in terms
of coverage, capacity and mobility support. If cellular/ WLAN interworking is to be
the basis for a heterogeneous network then the analysis of complex handover traffic
rates in the system (especially vertical handover) is one of the most essential issues to
be considered.
This thesis describes the application of queueing-network theory to the modelling of
this heterogeneous wireless overlay system. A network of queues (or queueing
network) is a powerful mathematical tool in the performance evaluation of many
large-scale engineering systems. It has been used in the modelling of hierarchically
structured cellular wireless networks with much success, including queueing
network modelling in the study of cellular/ WLAN interworking systems. In the
process of queueing network modelling, obtaining the network topology of a system
is usually the first step in the construction of a good model, but this topology
analysis has never before been used in the handover traffic study in heterogeneous
overlay wireless networks. In this thesis, a new topology scheme to facilitate the
analysis of handover traffic is proposed.
The structural similarity between hierarchical cellular structure and heterogeneous
wireless overlay networks is also compared. By replacing the microcells with
WLANs in a hierarchical structure, the interworking system is modelled as an open
network of Erlang loss systems and with the new topology, the performance
measures of blocking probabilities and dropping probabilities can be determined.
Both homogeneous and non-homogeneous traffic have been considered, circuit
switched and packet-switched. Example scenarios have been used to validate the
models, the numerical results showing clear agreement with the known validation
scenarios
Survey of Vertical Handoff Decision Criteria in LTE Cellular Networks
Vertical handover advantage brilliant importance because of the upgrades in mobility fashions by way of the Fourth era (4G) technology. A handover desire scheme in LTE networks both based totally on unmarried or multiple criteria. The wide variety of standards is right away depending on the overall handover time. In addition, the time required for deciding on a target network at some point of handover is also extended with the growth in a number of parameters. Conventional handover choice Strategies are specifically based at the unmarried parameter. But, with the advent of heterogeneous Wi-Fi networks, the overall performance of those unmarried parameter choice schemes is highly decreased. Consequently, researchers introduce multirequirements handover selection schemes. those enhancements are restricted to specific situations and for this reason do now not offer help for mounted mobility. Further, numerous schemes are proposed
Novel Model of Adaptive Module for Security and QoS Provisioning in Wireless Heterogeneous Networks
Considering the fact that Security and Quality-Of-Service (QoS) provisioning for multimedia traffic in Wireless Heterogeneous Networks are becoming increasingly important objectives, in this paper we are introducing a novel adaptive Security and QoS framework. This framework is planned to be implemented in integrated network architecture (UMTS, WiMAX and WLAN). The aim of our novel framework is presenting a new module that shall provide the best QoS provisioning and secure communication for a given service using one or more wireless technologies in a given time
An analytical approach for performance analysis of handoffs in the next generation integrated cellular networks and WLANs
The main feature of the next generation wireless
communication systems is the ability to establish ubiquitous and seamless access to various radio access technologies (RATs) and standards. For this reason the integration of cellular and wireless local area networks (WLANs) and performance evaluation of the
interaction between these technologies is now an important
research area. Modelling such systems for performance evaluation is essential to improve the architecture according to the quality ofbservice (QoS) requirements and performance characteristics. In this paper, an analytical model for performance evaluation of an integrated cellular network and a WLAN is considered. WLAN is deployed inside of the cellular network to support handoffs between cellular networks with higher bandwidth. Such an
integrated system can be modelled as a two stage open network. An analytical model is proposed together with an exact solution technique in order to evaluate the performance of an integrated system consisting of a cellular network and a WLAN. A two stage
queuing system is considered for this purpose. Numerical results are presented for mean queue length values of cellular system as well as the WLAN
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