Security context transfer in vertical handover

Wireless channels vary drastically over time and mobility adds further difficulties to the engineering problem of providing stable and robust communication performance. Handovers occur regularly in mobile environments and the increasing heterogeneity of present networks leads to the requirement for seamless vertical handovers. An important practical problem is the lack of a generic interface that enables applications, such as a vertical handover decision engine, to retrieve comparable link-layer information independently of the deployed technology or the used software and hardware platform. In this paper we propose the Unified Link-Layer API (ULLA) as a solution to this problem. We describe its architecture, how it can be utilized for vertical handover scenarios and introduce our Linux prototype. The prototype performance proves that ULLA is appropriate for mobility management.

Continuous striving in the development of wireless mobile networks maximizes the possibility of user services and provides experience context rich and personalized services. In this way, for the development towards fully integrated 4G‐all IP network architecture, the interoperability between future generation wireless networks and seamless vertical handover (VHO) has become a crucially important issue. The proposed work is mainly focusing on exploring interoperability issues in heterogeneous networks considering development towards 4G and emphasizing on emerging IEEE 802.21 standard. Further, Simulation results were presented to showcase vertical handover (VHO) performance using IEEE 802.21. Simulation Analysis is done using Network Simulator (NS-2) with seamless mobility package extension.

Pervasive computing is a vision involving future generation computing environmentsnin which information and communication technologies are seamlessly integrated tonsupport diverse aspects of users' lifestyles. Pervasive computing environments willnsee sophisticated sensors, actuators, and monitoring devices embedded into livingnenvironments and interconnected with a variety of computing devices and networkingntechnologies. In the last decade, significant technological advances have led to thenproliferation of new devices, such as handheld computers (e.g., PDAs and mobilenphones), wearable computers and intelligent home and office appliances. Advances innnetworking technologies have also seen a shift from wired to wireless networks andnincreasing availability of wireless access in businesses and academic institutions, asnwell as in public hot spots located in libraries, coffee shops, and other public places.nAt the same time, developments in wireless technologies have equipped devices withnshort range connection capabilities, allowing computing devices and smart appliancesnlocated within close range of one another to form micro networks without any centralnnetwork infrastructure. Current cellular mobile technology is also providing lownspeed data connections and laying the foundations for future mobile networks thatnwill provide multimedia streaming capabilities to mobile devices.n n Together, these emerging technologies are enabling the vision of pervasive computingnto take shape, so that users are provided with the control and flexibility to performntheir computing tasks in a manner that suits their lifestyles and requirements. Sincenpervasive computing environments combine heterogeneous networking and devicentechnologies, pervasive systems are required to adapt to changes in the context innwhich computational applications operate. This adaptation can take various forms,nsuch as adaptation of applications, communication streams, or underlyingncommunication protocols. One possible type of communication protocol adaptation isnvertical handover between different networks (i.e., redirection of applications'ncommunication streams from one network to another).n n Vertical handover permits users to move freely between heterogeneous networks ornchange computing devices while maintaining application continuity. However, currentnvertical handover solutions are not context-aware and are restricted to reactions tondisconnections as users move out of network coverage. Since the vertical handovernmechanism relies on reactions to disconnections, disruption of the communicationnstream always occurs during the handover process, and the QoS requirements of thenapplication are likely to be violated. This is often inappropriate, especially fornmultimedia applications, which have stringent QoS requirements. A better solution fornpervasive systems is to perform vertical handovers in response to a wider set ofncontext changes, which may include (i) prediction of users moving in or out ofnnetwork coverage, (ii) changes in the network, leading to QoS that is unacceptable fornapplications, (iii) movement of users between different computing devices whilencontinuing their applications, or (iv) users entering preferred networks. This thesisnpresents an innovative solution for vertical handovers in pervasive systems that cannsupport all of these types of context-triggered handover.n n The thesis makes a number of significant research contributions. Firstly, it presents ancontext model that defines types of context information and context changes that arenrelevant to vertical handover in pervasive computing environments. Secondly, itndevelops a set of context evaluation and decision rules for triggering vertical handovernand performing stream adaptations to address QoS requirements. Thirdly, it defines angeneric vertical handover protocol and architecture for handover between networks orndevices. It also presents refinements to the generic solution that take into accountnfeatures of particular networking technologies. Fourthly, the thesis illustratesnmechanisms that can be incorporated into the vertical handover solution to counternand minimise QoS violations during changes between networks, in order to minimisenapplication disruption and maximise handover transparency for the user. Finally, as anproof of concept, the thesis presents a prototype that demonstrates the ability of thenproposed vertical handover architecture to support seamless computing, and alsonenables performance evaluation for various types of networking technology.n

Today, wireless network devices are equipped with multiple access technologies like UMTS andWireless LAN. The handover between the technologies has been widely studied in literature. Several of these research papers build their handover mechanisms on top of existing protocols like Mobile IP. These protocols operate on the network layer and recognize link layer changes only by timeouts. Consequently, if no cross layer approach is implemented, a seamless vertical handover between Wireless LAN and UMTS cannot be provided.In this paper, we introduce a vertical handover protocol based on a tightlycoupled network architecture. With this architecture, it is possible to perform the handover on the link layer and thus, reducing the handover delays. The protocol is implemented in a simulation environment and the results reveal that a seamless vertical handover can be performed with blackout times of only a few milliseconds.

Regarding of the problem of visible light communication (VLC) and WiFi heterogeneous network handover, most of the existing work focuses on the research of the vertical handover algorithm of heterogeneous networks, and the coordinated handover of horizontal handover (HHO) and vertical handover (VHO) of heterogeneous networks Strategies are rarely studied. Based on this, this paper proposes a new coordinated vertical handover (CVHO)scheme for heterogeneous networks. This scheme simplifies the motion model of the mobile terminal (MT), and proposes a handover algorithm to realize the coordinated handover of HHO and VHO of the network. The simulation results show that, compared with the traditional immediate vertical handover (IVHO)and dwell vertical handover (DVHO), this handover strategy can better meet the actual movement demands.

The pouring of more and more attractive radio access technologies (RATs) with complementary characteristics has inspired the trends of interworking and convergence in future wireless systems. End-to-end reconfigurability (E2R) is an approach toward the convergence of diverse RATs. This paper aims at investigating an effective seamless vertical handover (VHO) scheme for E2R systems. The system model supporting the VHO scheme is brought forward. A network sort algorithm is developed enabling terminals to select the most appropriate network to handover. Particularly, we propose a novel handover trigger algorithm based on quality of service (QoS) evaluation allowing terminals to initiate a handover when the QoS is lower than their expected value. Simulation results reveal that the proposed VHO scheme enhances the user satisfaction as well as optimizes the overall network performance.

Nowadays, the current trend is to integrate mobile WiMAX with 3G networks to meet the growing demand for high-speed connectivity and ubiquitous coverage. The design and implementation of seamless integration architecture for heterogeneous networks is a challenging task, as it requires comprehensive effort to provide mobile user with seamless experience while switching between access networks. In order to realize seamless vertical handover (VHO) with QoS support, an IMS-based integration architecture for mobile WiMAX and UMTS is proposed with a VHO mechanism using integrated MIP-SIP protocols to provide transparent mobility and QoS at minimum signaling cost on both user terminal and IMS network.

An important and modern trend in wireless network is managing and accessing in heterogeneous wireless networks structures effectively. Vertical handover or handoff technology is major and acting vital role in wireless communication, it has key challenging issues in wireless network, while handover gets call drop kind of latency and call quality minimization. So the communication networks needs an efficient and dynamic services and knowledge monitoring management to select network for handover of different network environments (example: WiMAX, WiFi, WLAN, etc.). In this paper we proposed the concepts of knowledgeable monitoring (KM-method), cognitive advisor (CA) and Advanced Handover Optimization (AHO) technique to improve effective network selection for seamless communication, while travels over heterogeneous wireless networks (HWN). KM-method monitoring and manage effective network selection and holding connected mobile nodes inform header files also maintaining re-initiate to next network information (network IP address, user ID, new path, etc.). CAVHO-Cognitive Advisor based Vertical Handover (VSH and V2H) and KM-methods perform and measures velocity and direction of mobility nodes through SRSS sequential Received Strength Signal. Also CA receives the nearest networks details of each another using nearest neighbouring concept with SDT ratio Algorithm. Optimization technique (AHO) performs dynamically balancing the threshold level of speed, load and quality based on Receiving signal strength and user preference. Simulation results of CAVHO Shows it secure and increases the handover probability of access also proposed system reduce delay and improve quality of services and throughput.

In wireless heterogeneous environment, the integration of wireless access network will be accomplished by seamless handover which contains many challenges i.e. service mobility, vertical handover, common authentication, unified accounting/billing, security mechanisms, QoS and service provisioning, etc. Toward this direction, our research aims to provide a complete integration of heterogeneous network architecture and support a fit mobility management for network to seamless handover. This paper offers an HIP-based vertical handover idea in heterogeneous wireless network. We propose a mobile integrated architecture in personal communication system. Moreover, we hope to contribute our research to beyond 4G (B4G) wireless networks.

SummaryIn view of the handover problem of visible light communication (VLC) and WiFi, most of existing works focus on optimization of vertical handover algorithm of heterogeneous network. However, cooperative handover strategy of horizontal handover (HHO) and vertical handover (VHO) was rarely studied. In the situation, this paper proposes a cooperative horizontal VHO (CHVHO) strategy for heterogeneous network based on quality of experience (QoE). This strategy mainly coordinates the HHO and VHO of the network from the aspects of building servers and the simplification of indoor movement model, which improves the QoE allocated to users. Simulation results demonstrate that, compared with traditional immediate VHO (IVHO) and dwell VHO (DVHO), this strategy can be adaptive to user movement and get higher average QoE.

At present, none of the wireless access or mobile cellular network technologies provides ubiquitous coverage and the complete set of services required by the users. Therefore, the next generation of wireless networks i.e. 4th Generation (4G) network aims at the integration of these distinct yet complementary networks to satisfy user requirements and to provide ubiquitous coverage, anywhere and anytime. This integration of heterogeneous networks requires efficient and fast switching from one network to another, which is possible through seamless vertical handover. This paper presents a proactive, seamless vertical handover algorithm that caters for user preferences, mobile station velocity, network conditions and application requirements. It selects a candidate network for handover which is stable and can provide necessary services required by the applications. The proposed algorithm improves handover performance by minimizing signaling overhead and delay.

One of the major design issues in heterogeneous wireless networks is the support of seamless vertical handover for mobile users. The cognitive capability for mobile terminal enables the functionalities of system parameter estimation and learning. By utilizing these parameters, cognitive users make a

With financial, business and personal transactions shifting to the mobile domain, Mobile Computing and Wireless Communication technologies are on focus. One of the major challenge is to provide best connectivity across heterogeneous networks, in fast moving vehicles, without knowledge and disturbance to the user. An Intelligent system is required for seamless vertical handover, with less battery consumption and with best connectivity. The Vertical Handover process can be optimized for different criteria like cost, bandwidth, signal strength etc. This paper aims to develop a best solution framework for VHO in vehicular networks where OMNeT++ (Objective Modular Network Testbed in C++) can be used for evaluating and testing along with Veins (Vehicles in Network Simulation) software for the simulation of Inter-Vehicular Communication (IVC) framework, which is composed of an event-based network simulator and a road traffic micro simulation model.

One of the major challenges posed by 4th generation (4G) network concept is that of integrating heterogeneous wireless networks technologies to build a globally interoperable system. In this context, issues like mobility management and session management have been widely addressed by researchers. In this paper we attempt to design effective vertical handover schemes applied to mobile users roaming across heterogeneous wireless access domains. The focus is put on how the performance of the Internet applications are affected by vertical handovers. We modeled a scenario of two interworking (WLAN and GPRS) access systems and run, by simulation, an analyses of how the connection discontinuity provoked by frequent vertical handovers between the two heterogeneous networks impacts on the performance of the application's sessions.

Vertical handover supporting pervasive computing in future wireless networks