328 research outputs found
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
MIPv6 Experimental Evaluation using Overlay Networks
The commercial deployment of Mobile IPv6 has been hastened by the concepts of Integrated
Wireless Networks and Overlay Networks, which are present in the notion of the
forthcoming generation of wireless communications. Individual wireless access networks
show limitations that can be overcome through the integration of different technologies
into a single unified platform (i.e., 4G systems). This paper summarises practical experiments
performed to evaluate the impact of inter-networking (i.e. vertical handovers) on
the Network and Transport layers. Based on our observations, we propose and evaluate a
number of inter-technology handover optimisation techniques, e.g., Router Advertisements
frequency values, Binding Update simulcasting, Router Advertisement caching, and Soft
Handovers. The paper concludes with the description of a policy-based mobility support
middleware (PROTON) that hides 4G networking complexities from mobile users, provides
informed handover-related decisions, and enables the application of different vertical
handover methods and optimisations according to context.Publicad
A QoS Aware Vertical Handover In Mobile Network
The convergence of heterogeneous wireless access technologies characterizes the 4G wireless networks. In such converged systems, the seamless and efficient handoff between different access technologies (vertical handoff) is essential and remains a challenging problem. The heterogeneous co-existence of access technologies with largely different characteristics creates a decision problem of determining the âbestâ available network at âbestâ time to reduce the unnecessary handoffs. This project proposes a dynamic decision model to decide the âbestâ network at âbestâ time moment to handoffs. The proposed dynamic decision model make the right vertical handoff decisions by determining the âbestâ network at âbestâ time among available networks based on, dynamic factors such as âReceived Signal Strength(RSS)â of network and SNR(Signal-to-Noise Ratio), Link capacity(offered bandwidth) and power consumption. This model not only meets the individual user needs but also improves the whole system performance by reducing the unnecessary handoffs
A Genetic Algorithm-based Framework for Soft Handoff Optimization in Wireless Networks
In this paper, a genetic algorithm (GA)-based approach is used to evaluate the probability of successful handoff in heterogeneous wireless networks (HWNs) so as to increase capacity and network performance. The traditional handoff schemes are prone to ping pong and corner effects and developing an optimized handoff scheme for seamless, faster, and less power consuming handoff decision is challenging. The GA scheme can effectively optimize soft handoff decision by selecting the best fit network for the mobile terminal (MT) considering quality of service (QoS) requirements, network parameters and userâs preference in terms of cost of different attachment points for the MT. The robustness and ability to determine global optima for any function using crossover and mutation operations makes GA a promising solution. The developed optimization framework was simulated in Matrix Laboratory (MATLAB) software using MATLABâs optima tool and results show that an optimal MT attachment point is the one with the highest handoff success probability value which determines direction for successful handoff in HWN environment. The system maintained a 90% Â with 4 channels and more while a 75% was obtained even at high traffic intensity
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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
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
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