156 research outputs found
Minimization of Handoff Failure Probability for Next-Generation Wireless Systems
During the past few years, advances in mobile communication theory have
enabled the development and deployment of different wireless technologies,
complementary to each other. Hence, their integration can realize a unified
wireless system that has the best features of the individual networks.
Next-Generation Wireless Systems (NGWS) integrate different wireless systems,
each of which is optimized for some specific services and coverage area to
provide ubiquitous communications to the mobile users. In this paper, we
propose to enhance the handoff performance of mobile IP in wireless IP networks
by reducing the false handoff probability in the NGWS handoff management
protocol. Based on the information of false handoff probability, we analyze its
effect on mobile speed and handoff signaling delay.Comment: 16 Page
Mobility and Handoff Management in Wireless Networks
With the increasing demands for new data and real-time services, wireless
networks should support calls with different traffic characteristics and
different Quality of Service (QoS)guarantees. In addition, various wireless
technologies and networks exist currently that can satisfy different needs and
requirements of mobile users. Since these different wireless networks act as
complementary to each other in terms of their capabilities and suitability for
different applications, integration of these networks will enable the mobile
users to be always connected to the best available access network depending on
their requirements. This integration of heterogeneous networks will, however,
lead to heterogeneities in access technologies and network protocols. To meet
the requirements of mobile users under this heterogeneous environment, a common
infrastructure to interconnect multiple access networks will be needed. In this
chapter, the design issues of a number of mobility management schemes have been
presented. Each of these schemes utilizes IP-based technologies to enable
efficient roaming in heterogeneous network. Efficient handoff mechanisms are
essential for ensuring seamless connectivity and uninterrupted service
delivery. A number of handoff schemes in a heterogeneous networking environment
are also presented in this chapter.Comment: 28 pages, 11 figure
A network mobility management architecture for a heteregeneous network environment
Network mobility management enables mobility of personal area networks and vehicular networks across heterogeneous access networks using a Mobile Router. This dissertation presents a network mobility management architecture for minimizing the impact of handoffs on the communications of nodes in the mobile network. The architecture addresses mobility in legacy networks without infrastructure support, but can also exploit infrastructure support for improved handoff performance. Further, the proposed architecture increases the efficiency of communications of nodes in the mobile network with counter parts in the fixed network through the use of caching and route optimization. The performance and costs of the proposed architecture are evaluated through empirical and numerical analysis. The analysis shows the feasibility of the architecture in the networks of today and in those of the near future.Verkkojen liikkuuvudenhallinta mahdollistaa henkilökohtaisten ja ajoneuvoihin asennettujen verkkojen liikkuvuuden heterogeenisessÀ verkkoympÀristössÀ kÀyttÀen liikkuvaa reititintÀ. TÀmÀ vÀitöskirja esittÀÀ uuden arkkitehtuurin verkkojen liikkuvuudenhallintaan, joka minimoi verkonvaihdon vaikutuksen pÀÀtelaitteiden yhteyksiin.
Vanhoissa verkoissa, joiden infrastruktuuri ei tue verkkojen liikkuvuutta, verkonvaihdos tÀytyy hallita liikkuvassa reitittimessa. Standardoitu verkkojen liikkuvuudenhallintaprotokolla NEMO mahdollistaa tÀmÀn kÀyttÀen ankkurisolmua kiinteÀssÀ verkossa pakettien toimittamiseen pÀÀtelaitteiden kommunikaatiokumppaneilta liikkuvalle reitittimelle. NEMO:ssa verkonvaihdos aiheuttaa kÀynnissÀ olevien yhteyksien keskeytymisen yli sekunnin mittaiseksi ajaksi, aiheuttaen merkittÀvÀÀ hÀiriötÀ viestintÀsovelluksille.
EsitetyssÀ arkkitehtuurissa verkonvaihdon vaikutus minimoidaan varustamalla liikkuva reititin kahdella radiolla. KÀyttÀen kahta radiota liikkuva reititin pystyy suorittamaan verkonvaihdon keskeyttÀmÀttÀ pÀÀtelaitteiden yhteyksiÀ, mikÀli verkonvaihtoon on riittÀvÀsti aikaa. KÀytettÀvissa oleva aika riippuu liikkuvan reitittimen nopeudesta ja radioverkon rakenteesta. Arkkitehtuuri osaa myös hyödyntÀÀ infrastruktuurin tukea saumattomaan verkonvaihtoon. Verkkoinfrastruktuurin tuki nopeuttaa verkonvaihdosprosessia, kasvattaenmaksimaalista verkonvaihdos tahtia. TÀllöin liikkuva reitin voi kÀyttÀÀ lyhyen kantaman radioverkkoja, joiden solun sÀde on yli 80m, ajonopeuksilla 90m/s asti ilman, ettÀ verkonvaihdos keskeyttÀÀ pÀÀtelaitteiden yhteyksiÀ.
LisÀksi ehdotettu arkkitehtuuri tehostaa kommunikaatiota kÀyttÀen cache-palvelimia liikkuvassa ja kiinteÀssÀ verkossa ja optimoitua reititystÀ liikkuvien pÀÀtelaitteiden ja kiinteÀssÀ verkossa olevien kommunikaatiosolmujen vÀlillÀ. Cache-palvelinarkkitehtuuri hyödyntÀÀ vapaita radioresursseja liikkuvan verkon cache-palvelimen vÀlimuistin pÀivittÀmiseen. HeterogeenisessÀ verkkoympÀristossÀ cache-palvelimen pÀivitys suoritetaan lyhyen kantaman laajakaistaisia radioverkkoja kÀyttÀen. Liikkuvan reitittimen siirtyessÀ laajakaistaisen radioverkon peitealueen ulkopuolelle pÀÀtelaitteille palvellaan sisÀltöÀ, kuten www sivuja tai videota cache-palvelimelta, sÀÀstÀen laajemman kantaman radioverkon rajoitetumpia resursseja.
Arkkitehtuurissa kÀytetÀÀn optimoitua reititystÀ pÀÀtelaitteiden ja niiden kommunikaatiokumppaneiden vÀlillÀ. Optimoitu reititysmekanismi vÀhentÀÀ liikkuvuudenhallintaan kÀytettyjen protokollien langattoman verkon resurssien kulutusta. LisÀksi optimoitu reititysmekanismi tehostaa pakettien reititystÀ kÀyttÀen suorinta reittiÀ kommunikaatiosolmujen vÀlillÀ.
Esitetyn arkkitehtuurin suorituskyky arvioidaan empiirisen ja numeerisen analyysin avulla. Analyysi arvioi arkkitehtuurin suorituskykyÀ ja vertaa sitÀ aikaisemmin ehdotettuihin ratkaisuihin ja osoittaa arkkitehtuurin soveltuvan nykyisiin ja lÀhitulevaisuuden langattomiin verkkoihin.reviewe
Handover management in mobile WiMAX using adaptive cross-layer technique
The protocol type and the base station (BS) technology are the main communication media between the Vehicle to Infrastructure (V2I) communication in vehicular networks. During high speed vehicle movement, the best communication would be with a seamless handover (HO) delay in terms of lower packet loss and throughput. Many studies have focused on how to reduce the HO delay during lower speeds of the vehicle with data link (L2) and network (L3) layers protocol. However, this research studied the Transport Layer (L4) protocol mobile Stream Control Transmission Protocol (mSCTP) used as an optimal protocol in collaboration with the Location Manager (LM) and Domain Name Server (DNS). In addition, the BS technology that performs smooth HO employing an adaptive algorithm in L2 to perform the HO according to current vehicle speed was also included in the research. The methods derived from the combination of L4 and the BS technology methods produced an Adaptive Cross-Layer (ACL) design which is a mobility oriented handover management scheme that adapts the HO procedure among the protocol layers. The optimization has a better performance during HO as it is reduces scanning delay and diversity level as well as support transparent mobility among layers in terms of low packet loss and higher throughput. All of these metrics are capable of offering maximum flexibility and efficiency while allowing applications to refine the behaviour of the HO procedure. Besides that, evaluations were performed in various scenarios including different vehicle speeds and background traffic. The performance evaluation of the proposed ACL had approximately 30% improvement making it better than the other handover solutions
Handoff Management: A Critical Function in Mobility Management for Fourth Generation (4G) Wireless Networks
Efficient mobility management techniques are critical to the success of next-generation wireless systems. Handoff management, which is one of the two basic functions of mobility management, has become more critical in fourth generation wireless networks which support multimedia services. The paper treats basic issues involved in handoff management aspect of general mobility management in wireless communication systems. The relevance of mobility management, handoff management, and general mobility management protocols are explained. The taxonomy of handoff mechanisms, causes of delays in handoffs, and security in handoff procedures are elicited. The paper concludes highlighting some open areas of research in providing seamless services
Inter-Domain Authentication for Seamless Roaming in Heterogeneous Wireless Networks
The convergence of diverse but complementary wireless access technologies and inter-operation among administrative domains have been envisioned as crucial for the next generation wireless networks that will provide support for end-user devices to seamlessly roam across domain boundaries. The integration of existing and emerging heterogeneous wireless networks to provide such seamless roaming requires the design of a handover scheme that provides uninterrupted service continuity while facilitating the establishment of authenticity of the entities involved. The existing protocols for supporting re-authentication of a mobile node during a handover across administrative domains typically involve several round trips to the home domain, and hence introduce long latencies. Furthermore, the existing methods for negotiating roaming agreements to establish inter-domain trust rely on a lengthy manual process, thus, impeding seamless roaming across multiple domains in a truly heterogeneous wireless network. In this thesis, we present a new proof-token based authentication protocol that supports quick re-authentication of a mobile node as it moves to a new foreign domain without involving communication with the home domain. The proposed proof-token based protocol can also support establishment of spontaneous roaming agreements between a pair of domains that do not already have a direct roaming agreement, thus allowing flexible business models to be supported. We describe details of the new authentication architecture, the proposed protocol, which is based on EAP-TLS and compare the proposed protocol with existing protocols
Fast and seamless mobility management in IPV6-based next-generation wireless networks
Introduction -- Access router tunnelling protocol (ARTP) -- Proposed integrated architecture for next generation wireless networks -- Proposed seamless handoff schemes in next generation wireless networks -- Proposed fast mac layer handoff scheme for MIPV6/WLANs
QoS provisioning and mobility management for IP-based wireless LAN
Today two major technological forces drive the telecommunication era: the wireless cellular systems and the Internet. As these forces converge, the demand for new services, increasing bandwidth and ubiquitous connectivity continuously grows. The next-generation mobile systems will be based solely or in a large extent, on the Internet Protocol (IP). This thesis begins by addressing the problems and challenges faced in a multimedia, IP-based Wireless LAN environment. The ETSI HiperLAN/2 system has been mainly selected as the test wireless network for our theoretical and simulation experiments. Apart from the simulations, measurements have been taken from real life test scenarios, where the IEEE 802.11 system was used (UniS Test-bed). Furthermore, a brief overview of the All-IP network infrastructure is presented. An extension to the conventional wireless (cellular) architecture, which takes advantage of the IP network characteristics, is considered. Some of the trends driving the 3G and WLANs developments are explored, while the provision of quality of service on the latter for real-time and non-real-time multimedia services is investigated, simulated and evaluated. Finally, an efficient and catholic Q0S framework is proposed. At the same time, the multimedia services should be offered in a seamless and uninterrupted manner to users who access the all-IP infrastructure via a WLAN, meeting the demands of both enterprise and public environments anywhere and anytime. Thus providing support for mobile communications not only in terms of terminal mobility, as is currently the case, but also for session, service and personal mobility. Furthermore, this mobility should be available over heterogeneous networks, such as WLANs, IJMTS, as well as fixed networks. Therefore, this work investigates issues such as, multilayer and multi-protocol (SIP-Mobile IP-Cellular IP) mobility management in wireless LAN and 3G domains. Several local and global mobility protocols and architectures have been tested and evaluated and a complete mobility management framework is proposed. Moreover, integration of simple yet efficient authentication, accounting and authorisation mechanisms with the multimedia service architecture is an important issue of IP-based WLANs. Without such integration providers will not have the necessary means to control their provided services and make revenue from the users. The proposed AAA architecture should support a robust AAA infrastructure providing secure, fast and seamless access granting to multimedia services. On the other hand, a user wishing a service from the All-IP WLAN infrastructure needs to be authenticated twice, once to get access to the network and the other one should be granted for the required service. Hence, we provide insights into these issues by simulating and evaluating pre-authentication techniques and other network authentication scenarios based on the wellknown IEEE 802.lx protocol for multimedia IP-based WLANs.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Quality of Service Oriented Access Point Selection Framework for Large Wi-Fi Networks
This paper addresses the problem of Access Point (AP) selection in large Wi-Fi networks. Unlike current solutions that rely on Received Signal Strength (RSS) to determine the best AP that could serve a wireless userâs request, we propose a novel framework that considers the Quality of Service (QoS) requirements of the userâs data flow. The proposed framework relies on a function reflecting the suitability of a Wi-Fi AP to satisfy the QoS requirements of the data flow. The framework takes advantage of the flexibility and centralised nature of Software Defined Networking (SDN). A performance comparison of this algorithm developed through an SDN-based simulator shows significant achievements against other state of the art solutions in terms of provided QoS and improved wireless network capacity
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Game theory for dynamic spectrum sharing cognitive radio
This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University on 21 June 2010.âGame Theoryâ is the formal study of conflict and cooperation. The theory is based on a set of tools that have been developed in order to assist with the modelling and analysis of individual, independent decision makers. These actions potentially affect any decisions, which are made by other competitors. Therefore, it is well suited and capable of addressing the various issues linked to wireless communications. This work presents a Green Game-Based Hybrid Vertical Handover Model. The model is used for heterogeneous wireless networks, which combines both dynamic (Received Signal Strength and Node Mobility) and static (Cost, Power Consumption and Bandwidth) factors. These factors control the handover decision process; whereby the mechanism successfully eliminates any unnecessary handovers, reduces delay and overall number of handovers to 50% less and 70% less dropped packets and saves 50% more energy in comparison to other mechanisms. A novel Game-Based Multi-Interface Fast-Handover MIPv6 protocol is introduced in this thesis as an extension to the Multi-Interface Fast-handover MIPv6 protocol. The protocol works when the mobile node has more than one wireless interface. The protocol controls the handover decision process by deciding whether a handover is necessary and helps the node to choose the right access point at the right time. In addition, the protocol switches the mobile nodes interfaces âONâ and âOFFâ when needed to control the mobile nodeâs energy consumption and eliminate power lost of adding another interface. The protocol successfully reduces the number of handovers to 70%, 90% less dropped packets, 40% more received packets and acknowledgments and 85% less end-to-end delay in comparison to other Protocols. Furthermore, the thesis adapts a novel combination of both game and auction theory in dynamic resource allocation and price-power-based routing in wireless Ad-Hoc networks. Under auction schemes, destinations nodes bid the information data to access to the data stored in the server node. The server will allocate the data to the winner who values it most. Once the data has been allocated to the winner, another mechanism for dynamic routing is adopted. The routing mechanism is based on the source-destination cooperation, power consumption and source-compensation to the intermediate nodes. The mechanism dramatically increases the sellerâs revenue to 50% more when compared to random allocation scheme and briefly evaluates the reliability of predefined route with respect to data prices, source and destination cooperation for different network settings. Last but not least, this thesis adjusts an adaptive competitive second-price pay-to-bid sealed auction game and a reputation-based game. This solves the fairness problems associated with spectrum sharing amongst one primary user and a large number of secondary users in a cognitive radio environment. The proposed games create a competition between the bidders and offers better revenue to the players in terms of fairness to more than 60% in certain scenarios. The proposed game could reach the maximum total profit for both primary and secondary users with better fairness; this is illustrated through numerical results
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