Client-based and Cross-layer Optimized Flow Mobility for Android Devices in Heterogeneous Femtocell/Wi-Fi Networks*

AbstractThe number of subscribers accessing Internet resources from mobile and wireless devices has been increasing continually since i-mode, the first mobile Internet service launched in 1999. The handling and support of dramatic growth of mobile data traffic create serious challenges for the network operators. Due to the spreading of WLAN networks and the proliferation of multi-access devices, offloading from 3G to Wi-Fi seems to be a promising step towards the solution. To solve the bandwidth limitation and coverage issues in 3G/4G environments, femtocells became key players. These facts motivate the design and development of femtocell/Wi-Fi offloading schemes. Aiming to support advanced offloading in heterogeneous networks, in this paper we propose a client-based, cross-layer optimized flow mobility architecture for Android devices in femtocell/Wi-Fi access environments. The paper presents the design, implementation and evaluation details of the aforementioned mechanisms

Towards seamless inter-technology handovers in vehicular IPv6 communications

Network mobility plays an important role in communications when using different access networks while maintaining application sessions. This is the case of vehicular networks used by the emerging Cooperative Intelligent Transport System (C-ITS), where vehicles are constantly moving, changing their access network. Standardization bodies like IETF, and particular proposals in the literature, have already defined mobility mechanisms by using widely used Internet technologies. The usefulness of these mechanisms in vehicular networks is clear when using IPv6, however, its performance suffer from the high mobility of nodes, the fluctuating performance of communication technologies, and the need for a decision mechanism to choose a proper attachment point among the available access networks on roads. For this reason, here we propose an instantiation of the ISO/ETSI reference architecture for vehicular cooperative systems, by deploying a real vehicular network based on IPv6, as well as a mobility service provided by Network Mobility Basic Support (NEMO) and the Multiple Care of Addresses Registration (MCoA) extension. This mobility solution is embedded into a framework that integrates the IEEE 802.21 technology, which provides a greater control over the handover process. The resulting architecture not only provides a seamless handover but also supports the decision making when searching for the most suitable target network. Our experiments reveal that our combined NEMO/MCoA/802.21 system within a vehicular communication stack is able to provide uninterrupted communications during handovers with a dramatic reduction in the time needed by this process.This work has been sponsored by the Spanish Ministry of Economy and Competitiveness through the EDISON project (contract TIN2014-52099-R) and the Spanish Department of Transport (DGT) through the S-CICLO project (contract SPIP2015-01757)

A framework for supporting network continuity in vehicular IPv6 communications

The appearance of recent standards about cooperative ITS architectures towards a reference communication stack has been an inflection point in the research about vehicular networks. The ISO Communication Access for Land Mobiles (CALM) and the ETSI European ITS communication architecture have paved the way towards real and interoperable vehicular cooperative systems. Within these convergent proposals, IPv6 communications are recognized as a key component to enable traffic efficiency and infotainment applications. The proper operation of these applications and the achievement of value-added ITS services require an uninterrupted network connectivity. This paper addresses this problem by proposing a novel communication stack to support the provision of continuous and secure IPv6 vehicular communications. The solution follows the ISO/ETSI guidelines for the development of cooperative ITS systems and is based on standardized technologies such as Network Mobility (NEMO) protocol to provide an integral management of IPv6mobility. The solution integrates IEEE 802.21 media independent handover services for optimizing the handover process. While the support to the handover optimization offered by the proposed ITS communication stack is demonstrated through a mobility use case, a real testbed supporting most of the communications features is developed to validate and assess the real performance of the stack design.This work has been sponsored by the European Seventh Framework Program, through the ITSSv6 (contract 270519) and FOTsis (contract 270447) projects; the Ministry of Science and Innovation, through the Walkie-Talkie project (TIN2011-27543-C03); and the Seneca Foundation, by means of the GERM program (04552/GERM/06)

Networking Solutions for Integrated Heterogeneous Wireless Ecosystem

This work targets at applying computer networking techniques to address challenges in modern wireless networks and in various environments built around these networks. The main focus of the work is on designing and implementing prototypes and demonstrators to support research in domains of heterogeneous networks (HetNets). These research domains include centralized radio resource management in emerging cellular network architectures, network assistance role in device-to-device (D2D) communications, and studying prospective services in these networks. Within the research group the author was tasked with designing network architectures and demonstrating certain connectivity and functionality interesting for the research. The author was responsible for modifying commercial off-the-shelf equipment to become suitable for target research scenarios, selecting network technologies to achieve connectivity requirements, deploying network architecture entities within the research group's cloud platform. For HetNet track, the primary goal was to design a platform that would mimic a device connected through a heterogeneous network, allowing researchers to experiment with traffic flow optimization in an environment close to the envisioned next-generation network architecture. Prototype solution and testbed were designed building on software defined network principles of automation, abstraction and software based flow switching, and were implemented using overlay networks and virtual network functions. Within D2D communications research, the task was to design architecture demonstrating feasibility of traffic offloading from infrastructure network to direct links. Prototype was implemented with automated routing control in overlay network. To demonstrate novel services enabled by advanced security frameworks, D2D platform was augmented and a new network application has been implemented, also suitable for wearable electronics

Inter-domain mobility with LISP-MN:a performance comparison with MIPv6

In this work, we aim to evaluate Locator Identifier Separation Protocol-Mobile Node (LISP-MN) performance in an inter-domain mobility scenario for both multi-interface and single interface MN with focus on throughput, handover delay, service disruption time and packet loss. To serve as the benchmark for performance, we compare LISP-MN with the IETF standardised MIPv6. We implement the 2 protocols on a laboratory testbed comprising all the nodes necessary for their operation. For multi-interface MNs, LISP-MN shows a better response in soft handover scenarios in terms of throughput and packet loss. MIPv6 on the other hand shows shorter handover delay with lower service disruption time in a hard handover scenario. Both protocols demonstrate poor performance for a single interface MN due to the long handover delay experienced. Although LISP-MN’s handover control messages doubled that of MIPv6, our experiments show that it takes a similar time as MIPv6 to complete the handover message exchange

Design of interface selection protocols for multi-homed wireless networks

This thesis was submitted for the degree of Doctor of Philosophy and was awarded by Brunel University on 10 December 2010.The IEEE 802.11/802.16 standards conformant wireless communication stations have multi-homing transmission capability. To achieve greater communication efficiency, multi-homing capable stations use handover mechanism to select appropriate transmission channel according to variations in the channel quality. This thesis presents three internal-linked handover schemes, (1) Interface Selection Protocol (ISP), belonging to Wireless Local Area Network (WLAN)- Worldwide Interoperability for Microwave Access (WiMAX) environment (2) Fast Channel Scanning (FCS) and (3) Traffic Manager (TM), (2) and (3) belonging to WiMAX Environment. The proposed schemes in this thesis use a novel mechanism of providing a reliable communication route. This solution is based on a cross-layer communication framework, where the interface selection module uses various network related parameters from Medium Access Control (MAC) sub-layer/Physical Layer (PHY) across the protocol suite for decision making at the Network layer. The proposed solutions are highly responsive when compared with existing multi-homed schemes; responsiveness is one of the key factors in the design of such protocols. Selected route under these schemes is based on the most up to date link-layer information. Therefore, such a route is not only reliable in terms of route optimization but it also fulfils the application demands in terms of throughput and delay. Design of ISP protocol use probing frames during the route discovery process. The 802.11 mandates the use of different rates for data transmission frames. The ISP-metric can be incorporated into various routing aspects and its applicability is determined by the possibility of provision of MAC dependent parameters that are used to determine the best path metric values. In many cases, higher device density, interference and mobility cause variable medium access delays. It causes creation of ‘unreachable zones’, where destination is marked as unreachable. However, by use of the best path metric, the destination has been made reachable, anytime and anywhere, because of the intelligent use of the probing frames and interface selection algorithm implemented. The IEEE 802.16e introduces several MAC level queues for different access categories, maintaining service requirement within these queues; which imply that frames from a higher priority queue, i.e. video frames, are serviced more frequently than those belonging to lower priority queues. Such an enhancement at the MAC sub-layer introduces uneven queuing delays. Conventional routing protocols are unaware of such MAC specific constraints and as a result, these factors are not considered which result in channel performance degradation. To meet such challenges, the thesis presents FCS and TM schemes for WiMAX. For FCS, Its solution is to improve the mobile WiMAX handover and address the scanning latency. Since minimum scanning time is the most important issue in the handover process. This handover scheme aims to utilize the channel efficiently and apply such a procedure to reduce the time it takes to scan the neighboring access stations. TM uses MAC and physical layer (PHY) specific information in the interface metric and maintains a separate path to destination by applying an alternative interface operation. Simulation tests and comparisons with existing multi-homed protocols and handover schemes demonstrate the effectiveness of incorporating the medium dependent parameters. Moreover, show that suggested schemes, have shown better performance in terms of end-to-end delay and throughput, with efficiency up to 40% in specific test scenarios

Cooperative resource pooling in multihomed mobile networks

The ubiquity of multihoming amongst mobile devices presents a unique opportunity for users to co-operate, sharing their available Internet connectivity, forming multihomed mobile networks on demand. This model provides users with vast potential to increase the quality of service they receive. Despite this, such mobile networks are typically underutilized and overly restrictive, as additional Internet connectivity options are predominantly ignored and selected gateways are both immutable and incapable of meeting the demand of the mobile network. This presents a number of research challenges, as users look to maximize their quality of experience, while balancing both the financial cost and power consumption associated with utilizing a diverse set of heterogeneous Internet connectivity options. In this thesis we present a novel architecture for mobile networks, the contribution of which is threefold. Firstly, we ensure the available Internet connectivity is appropriately advertised, building a routing overlay which allows mobile devices to access any available network resource. Secondly, we leverage the benefits of multipath communications, providing the mobile device with increased throughput, additional resilience and seamless mobility. Finally, we provide a multihomed framework, enabling policy driven network resource management and path selection on a per application basis. Policy driven resource management provides a rich and descriptive approach, allowing the context of the network and the device to be taken into account when making routing decisions at the edge of the Internet. The aim of this framework, is to provide an efficient and flexible approach to the allocation of applications to the optimal network resource, no matter where it resides in a mobile network. Furthermore, we investigate the benefits of path selection, facilitating the policy framework to choose the optimal network resource for specific applications. Through our evaluation, we prove that our approach to advertising Internet connectivity in a mobile network is both efficient and capable of increasing the utilization of the available network capacity. We then demonstrate that our policy driven approach to resource management and path selection can further improve the user’s quality of experience, by tailoring network resource usage to meet their specific needs

The Design and Implementation of an Over-the-top Cloud-based Vertical Handover Decision Service for Heterogeneous Wireless Networks

The widespread availability of heterogeneous wireless networks (hetnets) presents a resource allocation challenge to network operators and administrators. Overlapping network coverage should be utilized to its fullest extent, providing users with a fair share of bandwidth while maximizing the efficient use of the operator\u27s resources. Currently, network selection occurs locally at the mobile device and does not take into account factors such as the state of other networks that might be available in the device\u27s location. The local decision made by the device can often result in underutilization of network resources and a degraded user experience. This type of selfish network selection might not result in optimal bandwidth allocation when compared to approaches that make use of a centralized resource controller \cite{gpf}. The decision making process behind the selection of these networks continues to be an open area of research, and a variety of algorithms have been proposed to solve this problem. An over-the-top handover decision service treats each wireless access network in a hetnet as a black box, assuming detailed network topology and state information is unavailable to the handover decision algorithm. The algorithm then uses network data gathered empirically from users to provide them with a network selection service that considers the current conditions of available networks in a given location. This is a departure from past designs of vertical handover decision algorithms, which tend to approach the problem from the perspective of individual network operators. The wide range of radio access technologies operated by different network operators that are available to a device within a hetnet, coupled with the mobile data offload effort, is the primary motivator behind our novel choice in direction. This thesis documents the design and implementation of such an over-the-top vertical handover decision service

SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS

A finales de los años noventa, y al comienzo del nuevo milenio, las redes inalámbricas han evolucionado bastante, pasando de ser sólo una tecnología prometedora para convertirse en un requisito para las actividades cotidianas en las sociedades desarrolladas. La infraestructura de transporte también ha evolucionado, ofreciendo comunicación a bordo para mejorar la seguridad vial y el acceso a contenidos de información y entretenimiento. Los requisitos de los usuarios finales se han hecho dependientes de la tecnología, lo que significa que sus necesidades de conectividad han aumentado debido a los diversos requisitos de las aplicaciones que se ejecutan en sus dispositivos móviles, tales como tabletas, teléfonos inteligentes, ordenadores portátiles o incluso ordenadores de abordo (On-Board Units (OBUs)) dentro de los vehículos. Para cumplir con dichos requisitos de conectividad, y teniendo en cuenta las diferentes redes inalámbricas disponibles, es necesario adoptar técnicas de Vertical Handover (VHO) para cambiar de red de forma transparente y sin necesidad de intervención del usuario. El objetivo de esta tesis es desarrollar algoritmos de decisión (Vertical Handover Decision Algorithms (VHDAs)) eficientes y escalables, optimizados para el contexto de las redes vehiculares. En ese sentido se ha propuesto, desarrollado y probado diferentes algoritmos de decisión basados en la infraestructura disponible en las actuales, y probablemente en las futuras, redes inalámbricas y redes vehiculares. Para ello se han combinado diferentes técnicas, métodos computacionales y modelos matemáticos, con el fin de garantizar una conectividad apropiada, y realizando el handover hacia las redes más adecuadas de manera a cumplir tanto con los requisitos de los usuarios como los requisitos de las aplicaciones. Con el fin de evaluar el contexto, se han utilizado diferentes herramientas para obtener información variada, como la disponibilidad de la red, el estado de la red, la geolocalizaciónMárquez Barja, JM. (2012). SCALABLE AND EFFICIENT VERTICAL HANDOVER DECISION ALGORITHMS IN VEHICULAR NETWORK CONTEXTS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17869Palanci

Design of interface selection protocols for multi-homed wireless networks

The IEEE 802.11/802.16 standards conformant wireless communication stations have multi-homing transmission capability. To achieve greater communication efficiency, multi-homing capable stations use handover mechanism to select appropriate transmission channel according to variations in the channel quality. This thesis presents three internal-linked handover schemes, (1) Interface Selection Protocol (ISP), belonging to Wireless Local Area Network (WLAN)- Worldwide Interoperability for Microwave Access (WiMAX) environment (2) Fast Channel Scanning (FCS) and (3) Traffic Manager (TM), (2) and (3) belonging to WiMAX Environment. The proposed schemes in this thesis use a novel mechanism of providing a reliable communication route. This solution is based on a cross-layer communication framework, where the interface selection module uses various network related parameters from Medium Access Control (MAC) sub-layer/Physical Layer (PHY) across the protocol suite for decision making at the Network layer. The proposed solutions are highly responsive when compared with existing multi-homed schemes; responsiveness is one of the key factors in the design of such protocols. Selected route under these schemes is based on the most up to date link-layer information. Therefore, such a route is not only reliable in terms of route optimization but it also fulfils the application demands in terms of throughput and delay. Design of ISP protocol use probing frames during the route discovery process. The 802.11 mandates the use of different rates for data transmission frames. The ISP-metric can be incorporated into various routing aspects and its applicability is determined by the possibility of provision of MAC dependent parameters that are used to determine the best path metric values. In many cases, higher device density, interference and mobility cause variable medium access delays. It causes creation of ‘unreachable zones’, where destination is marked as unreachable. However, by use of the best path metric, the destination has been made reachable, anytime and anywhere, because of the intelligent use of the probing frames and interface selection algorithm implemented. The IEEE 802.16e introduces several MAC level queues for different access categories, maintaining service requirement within these queues; which imply that frames from a higher priority queue, i.e. video frames, are serviced more frequently than those belonging to lower priority queues. Such an enhancement at the MAC sub-layer introduces uneven queuing delays. Conventional routing protocols are unaware of such MAC specific constraints and as a result, these factors are not considered which result in channel performance degradation. To meet such challenges, the thesis presents FCS and TM schemes for WiMAX. For FCS, Its solution is to improve the mobile WiMAX handover and address the scanning latency. Since minimum scanning time is the most important issue in the handover process. This handover scheme aims to utilize the channel efficiently and apply such a procedure to reduce the time it takes to scan the neighboring access stations. TM uses MAC and physical layer (PHY) specific information in the interface metric and maintains a separate path to destination by applying an alternative interface operation. Simulation tests and comparisons with existing multi-homed protocols and handover schemes demonstrate the effectiveness of incorporating the medium dependent parameters. Moreover, show that suggested schemes, have shown better performance in terms of end-to-end delay and throughput, with efficiency up to 40% in specific test scenarios.EThOS - Electronic Theses Online ServiceGBUnited Kingdo