482 research outputs found
On the Experimental Evaluation of Vehicular Networks: Issues, Requirements and Methodology Applied to a Real Use Case
One of the most challenging fields in vehicular communications has been the
experimental assessment of protocols and novel technologies. Researchers
usually tend to simulate vehicular scenarios and/or partially validate new
contributions in the area by using constrained testbeds and carrying out minor
tests. In this line, the present work reviews the issues that pioneers in the
area of vehicular communications and, in general, in telematics, have to deal
with if they want to perform a good evaluation campaign by real testing. The
key needs for a good experimental evaluation is the use of proper software
tools for gathering testing data, post-processing and generating relevant
figures of merit and, finally, properly showing the most important results. For
this reason, a key contribution of this paper is the presentation of an
evaluation environment called AnaVANET, which covers the previous needs. By
using this tool and presenting a reference case of study, a generic testing
methodology is described and applied. This way, the usage of the IPv6 protocol
over a vehicle-to-vehicle routing protocol, and supporting IETF-based network
mobility, is tested at the same time the main features of the AnaVANET system
are presented. This work contributes in laying the foundations for a proper
experimental evaluation of vehicular networks and will be useful for many
researchers in the area.Comment: in EAI Endorsed Transactions on Industrial Networks and Intelligent
Systems, 201
Seamless Infrastructure independent Multi Homed NEMO Handoff Using Effective and Timely IEEE 802.21 MIH triggers
Handoff performance of NEMO BS protocol with existent improvement proposals
is still not sufficient for real time and QoS-sensitive applications and
further optimizations are needed. When dealing with single homed NEMO, handoff
latency and packet loss become irreducible all optimizations included, so that
it is impossible to meet requirements of the above applications. Then, How to
combine the different Fast handoff approaches remains an open research issue
and needs more investigation. In this paper, we propose a new Infrastructure
independent handoff approach combining multihoming and intelligent
Make-Before-Break Handoff. Based on required Handoff time estimation, L2 and L3
handoffs are initiated using effective and timely MIH triggers, reducing so the
anticipation time and increasing the probability of prediction. We extend MIH
services to provide tunnel establishment and switching before link break. Thus,
the handoff is performed in background with no latency and no packet loss while
pingpong scenario is almost avoided. In addition, our proposal saves cost and
power consumption by optimizing the time of simultaneous use of multiple
interfaces. We provide also NS2 simulation experiments identifying suitable
parameter values used for estimation and validating the proposed mode
Deploying ITS Scenarios Providing Security and Mobility Services Based on IEEE 802.11p Technology
Botany & plant science
A Survey on Handover Management in Mobility Architectures
This work presents a comprehensive and structured taxonomy of available
techniques for managing the handover process in mobility architectures.
Representative works from the existing literature have been divided into
appropriate categories, based on their ability to support horizontal handovers,
vertical handovers and multihoming. We describe approaches designed to work on
the current Internet (i.e. IPv4-based networks), as well as those that have
been devised for the "future" Internet (e.g. IPv6-based networks and
extensions). Quantitative measures and qualitative indicators are also
presented and used to evaluate and compare the examined approaches. This
critical review provides some valuable guidelines and suggestions for designing
and developing mobility architectures, including some practical expedients
(e.g. those required in the current Internet environment), aimed to cope with
the presence of NAT/firewalls and to provide support to legacy systems and
several communication protocols working at the application layer
Using Media Independent Handover to Support PMIPv6 Inter-domain Mobility Based Vehicular Networks
Proxy Mobile IPv6 (PMIPv6) was proposed by the Internet Engineering Task Force (IETF) as a new network-based mobility protocol which does not require the involvement of MN’s in any form of mobility management. MN can handover relatively faster in PMIPv6 than in host-based mobility protocols (e.g. Mobile IPv6 (MIPv6)) because it actively uses link-layer attachment information which reduces the movement detection time, and eliminates duplicate address detection procedures. However, the current PMIPv6 cannot provide continuous mobility support for MN when roaming between different PMIPv6 domains; we introduce a novel inter-domain PMIPv6 scheme to support seamless handover for vehicle in motion to support continuous and seamless connection while roaming in the new PMIPv6 domain. In this paper we analytically evaluate our proposed scheme to support inter-domain mobility for vehicle roaming between two PMIPv6 domains by using Media Independent Handover (MIH) and Fully Qualified Domain Name (FQDN) to support the handover in addition to a continuous connection
Advancing the Standards for Unmanned Air System Communications, Navigation and Surveillance
Under NASA program NNA16BD84C, new architectures were identified and developed for supporting reliable and secure Communications, Navigation and Surveillance (CNS) needs for Unmanned Air Systems (UAS) operating in both controlled and uncontrolled airspace. An analysis of architectures for the two categories of airspace and an implementation technology readiness analysis were performed. These studies produced NASA reports that have been made available in the public domain and have been briefed in previous conferences. We now consider how the products of the study are influencing emerging directions in the aviation standards communities. The International Civil Aviation Organization (ICAO) Communications Panel (CP), Working Group I (WG-I) is currently developing a communications network architecture known as the Aeronautical Telecommunications Network with Internet Protocol Services (ATN/IPS). The target use case for this service is secure and reliable Air Traffic Management (ATM) for manned aircraft operating in controlled airspace. However, the work is more and more also considering the emerging class of airspace users known as Remotely Piloted Aircraft Systems (RPAS), which refers to certain UAS classes. In addition, two Special Committees (SCs) in the Radio Technical Commission for Aeronautics (RTCA) are developing Minimum Aviation System Performance Standards (MASPS) and Minimum Operational Performance Standards (MOPS) for UAS. RTCA SC-223 is investigating an Internet Protocol Suite (IPS) and AeroMACS aviation data link for interoperable (INTEROP) UAS communications. Meanwhile, RTCA SC-228 is working to develop Detect And Avoid (DAA) equipment and a Command and Control (C2) Data Link MOPS establishing LBand and C-Band solutions. These RTCA Special Committees along with ICAO CP WG/I are therefore overlapping in terms of the Communication, Navigation and Surveillance (CNS) alternatives they are seeking to provide for an integrated manned- and unmanned air traffic management service as well as remote pilot command and control. This paper presents UAS CNS architecture concepts developed under the NASA program that apply to all three of the aforementioned committees. It discusses the similarities and differences in the problem spaces under consideration in each committee, and considers the application of a common set of CNS alternatives that can be widely applied. As the works of these committees progress, it is clear that the overlap will need to be addressed to ensure a consistent and safe framework for worldwide aviation. In this study, we discuss similarities and differences in the various operational models and show how the CNS architectures developed under the NASA program apply
Mobility management across converged IP-based heterogeneous access networks
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 8/2/2010.In order to satisfy customer demand for a high performance “global” mobility service, network operators (ISPs, carriers, mobile operators, etc.) are facing the need to evolve to a converged “all-IP” centric heterogeneous access infrastructure. However, the integration of such heterogeneous access networks (e.g. 802.11, 802.16e, UMTS etc) brings major mobility issues. This thesis tackles issues plaguing existing mobility management solutions in converged IP-based heterogeneous networks. In order to do so, the thesis firstly proposes a cross-layer mechanism using the upcoming IEEE802.21 MIH services to make intelligent and optimized handovers. In this respect, FMIPv6 is integrated with the IEEE802.21 mechanism to provide seamless mobility during the overall handover process. The proposed solution is then applied in a simulated vehicular environment to optimize the NEMO handover process. It is shown through analysis and simulations of the signalling process that the overall expected handover (both L2 and L3) latency in FMIPv6 can be reduced by the proposed mechanism by 69%. Secondly, it is expected that the operator of a Next Generation Network will provide mobility as a service that will generate significant revenues. As a result, dynamic service bootstrapping and authorization mechanisms must be in place to efficiently deploy a mobility service (without static provisioning), which will allow only legitimate users to access the service. A GNU Linux based test-bed has been implemented to demonstrate this. The experiments presented show the handover performance of the secured FMIPv6 over the implemented test-bed compared to plain FMIPv6 and MIPv6 by providing quantitative measurements and results on the quality of experience perceived by the users of IPv6 multimedia applications. The results show the inclusion of the additional signalling of the proposed architecture for the purpose of authorization and bootstrapping (i.e. key distribution using HOKEY) has no adverse effect on the overall handover process. Also, using a formal security analysis tool, it is shown that the proposed mechanism is safe/secure from the induced security threats. Lastly, a novel IEEE802.21 assisted EAP based re-authentication scheme over a service authorization and bootstrapping framework is presented. AAA based authentication mechanisms like EAP incur signalling overheads due to large RTTs. As a result, overall handover latency also increases. Therefore, a fast re-authentication scheme is presented which utilizes IEEE802.21 MIH services to minimize the EAP authentication process delays and as a result reduce the overall handover latency. Analysis of the signalling process based on analytical results shows that the overall handover latency for mobility protocols will be approximately reduced by 70% by the proposed scheme
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
MP-CFM: MPTCP-Based communication functional module for next generation ERTMS
184 p.
El contenido de los capĂtulos 4,5,6,7,8 y 9 está sujeto a confidencialidadEl Sistema Europeo de GestiĂłn del Tráfico Ferroviario (ERTMS, por sus siglasen inglĂ©s), fue originalmente diseñado para los ferrocarriles europeos. Sinembargo, a lo largo de las dos Ăşltimas dĂ©cadas, este sistema se ha convertidoen el estándar de-facto para los servicios de Alta Velocidad en la mayorĂa depaĂses desarrollados.El sistema ERTMS se compone de tres subsistemas principales: 1) el Sistemade Control Ferroviario Europeo (ETCS, por sus siglas en inglĂ©s), que actĂşacomo aplicaciĂłn de señalizaciĂłn; 2) el sistema Euroradio, que a su vez estádividido en dos subsistemas, el MĂłdulo de Seguridad Funcional (SFM, porsus siglas en inglĂ©s), y el MĂłdulo de ComunicaciĂłn Funcional (CFM, porsus siglas en inglĂ©s); y 3) el sistema de comunicaciones subyacente, GSM-R,que transporta la informaciĂłn intercambiada entre el sistema embarcado enel tren (OBU, por sus siglas en inglĂ©s) y el Centro de Bloqueo por Radio(RBC, por sus siglas en inglĂ©s). El sistema de señalizaciĂłn ETCS soporta tresniveles dependiendo del nivel de prestaciones soportadas. En el nivel 3 seintroduce la posibilidad de trabajar con bloques mĂłviles en lugar de bloquesfijos definidos en la vĂa. Esto implica que la distancia de avance entre dos trenesconsecutivos puede ser reducida a una distancia mĂnima en la que se garanticela seguridad del servicio, aumentando por tanto la capacidad del corredorferroviario. Esta distancia de seguridad viene determinada por la combinaciĂłnde la distancia de frenado del tren y el retraso de las comunicaciones deseñalizaciĂłn. Por lo tanto, se puede afirmar que existe una relaciĂłn directaentre los retrasos y la confiabilidad de las transmisiones de las aplicaciones deseñalizaciĂłn y la capacidad operacional de un corredor ferroviario. AsĂ pues,el estudio y mejora de los sistemas de comunicaciones utilizados en ERTMSjuegan un papel clave en la evoluciĂłn del sistema ERTMS. Asimismo, unaoperatividad segura en ERTMS, desde el punto de vista de las comunicacionesimplicadas en la misma, viene determinada por la confiabilidad de lascomunicaciones, la disponibilidad de sus canales de comunicaciĂłn, el retrasode las comunicaciones y la seguridad de sus mensajes.Unido este hecho, la industria ferroviaria ha venido trabajando en ladigitalizaciĂłn y la transiciĂłn al protocolo IP de la mayor parte de los sistemasde señalizaciĂłn. Alineado con esta tendencia, el consorcio industrial UNISIGha publicado recientemente un nuevo modelo de comunicaciones para ERTMSque incluye la posibilidad, no solo de operar con el sistema tradicional,basado en tecnologĂa de conmutaciĂłn de circuitos, sino tambiĂ©n con un nuevosistema basado en IP. Esta tesis está alineada con el contexto de migraciĂłnactual y pretende contribuir a mejorar la disponibilidad, confiabilidad yseguridad de las comunicaciones, tomando como eje fundamental los tiemposde transmisiĂłn de los mensajes, con el horizonte puesto en la definiciĂłn deuna prĂłxima generaciĂłn de ERTMS, definida en esta tesis como NGERTMS.En este contexto, se han detectado tres retos principales para reforzar laresiliencia de la arquitectura de comunicaciones del NGERTMS: 1) mejorarla supervivencia de las comunicaciones ante disrupciones; 2) superar laslimitaciones actuales de ERTMS para enviar mensajes de alta prioridad sobretecnologĂa de conmutaciĂłn de paquetes, dotando a estos mensajes de un mayorgrado de resiliencia y menor latencia respecto a los mensajes ordinarios; y3) el aumento de la seguridad de las comunicaciones y el incremento de ladisponibilidad sin que esto conlleve un incremento en la latencia.Considerando los desafĂos previamente descritos, en esta tesis se proponeuna arquitectura de comunicaciones basada en el protocolo MPTCP, llamadaMP-CFM, que permite superar dichos desafĂos, a la par que mantener laretrocompatibilidad con el sistema de comunicaciones basado en conmutaciĂłnde paquetes recientemente propuesto por UNISIG. Hasta el momento, esta esla primera vez que se propone una arquitectura de comunicaciones completacapaz de abordar los desafĂos mencionados anteriormente. Esta arquitecturaimplementa cuatro tipos de clase de servicio, los cuales son utilizados porlos paquetes ordinarios y de alta prioridad para dos escenarios distintos; unescenario en el que ambos extremos, el sistema embarcado o OBU y el RBC,disponen de mĂşltiples interfaces de red; y otro escenario transicional en el cualel RBC sĂ tiene mĂşltiples interfaces de red pero el OBU solo dispone de unaĂşnica interfaz. La arquitectura de comunicaciones propuesta para el entornoferroviario ha sido validada mediante un entorno de simulaciĂłn desarrolladopara tal efecto. Es más, dichas simulaciones demuestran que la arquitecturapropuesta, ante disrupciones de canal, supera con creces en tĂ©rminos derobustez el sistema diseñado por UNISIG. Como conclusiĂłn, se puede afirmarque en esta tesis se demuestra que una arquitectura de comunicaciones basadade MPTCP cumple con los exigentes requisitos establecidos para el NGERTMSy por tanto dicha propuesta supone un avance en la evoluciĂłn del sistema deseñalizaciĂłn ferroviario europeo
- …