An intelligent agent-based scheme for vertical handover management across heterogeneous networks

Advances in technology have enabled a proliferation of mobile devices and a broad spectrum of novel and outbreaking solutions for new applications and services. The increasing demand for all time and everywhere services requires the network operators to integrate different kinds of wireless and cellular networks. To enable this integration, it is important that users can roam freely across networks. As different technologies are involved in the current infrastructure, the problem of vertical handover needs to be addressed. To cope with the problem of seamless connectivity, several solutions have been presented. But most of them either lack intelligence or are not adaptable for reducing the packet loss and delay involved in the handover procedure. An intelligent technique is needed in order to perform the service continuity in the heterogeneous environment. This paper presents a cooperative agent based approach for the vertical handover using a knowledge plane. We propose to introduce the agents in the mobile nodes and access points to collect the necessary information from the environment. Based on this information, agents take a handover decision. A selection function is also introduced in this work which helps in choosing a best network from the available ones for handover. Finally, the proposed approach is validated with the help of simulations.     

UMTS-WLAN垂直切换优化策略

随着移动Internet用户对IP业务宽带无线接入需求的急剧增长，通用移动通信系统（UMTS）和无线局域网（WLAN）的融合已成为亟需解决的问题．文章结合移动IPv6快速切换与基于隧道的快速切换技术，提出一种基于双向边隧道的优化策略，来实现UMTS-WLAN两种接入网络之间的无缝垂直切换．利用MN的旧转交地址截获并缓存由CN送往MN的数据分组，然后通过在旧接入路由和目标网络接入路由间预先建立的双向边隧道将分组重定向到新的网络。     

IEEE 802.21: Media independent handover: Features, applicability, and realization

Providing users of multi-interface devices the ability to roam between different access networks is becoming a key requirement for service providers. The availability of multiple mobile broadband access technologies, together with the increasing use of real-time multimedia applications, is creating strong demand for handover solutions that can seamlessly and securely transition user sessions across different access technologies. A key challenge to meeting this growing demand is to ensure handover performance, measured in terms of latency and loss. In addition, handover solutions must allow service providers, application providers, and other entities to implement handover policies based on a variety of operational and business requirements. Therefore, standards are required that can facilitate seamless handover between such heterogeneous access networks and that can work with multiple mobility management mechanisms. The IEEE 802.21 standard addresses this problem space by providing a media-independent framework and associated services to enable seamless handover between heterogeneous access technologies. In this article, we discuss how the IEEE 802.21 standard framework and services are addressing the challenges of seamless mobility for multi-interface devices. In addition, we describe and discuss design considerations for a proof-of-concept IEEE 802.21 implementation and share practical insights into how this standard can optimize handover performance.     

CDMA2000 Ev-Do与WLAN的无缝融合与垂直切换

异构网络无缝融合是未来网络发展的趋势,异构网间的垂直切换则是实现网络无缝融合的关键技术之一。本文针对CDMA2000 Ev-Do网络与WLAN的特点,提出基于移动IP的无缝融合网络结构,并在此基础上提出基于WLAN信号强度的垂直切换方法。     

Vertical Handover Solutions Over LTE-Advanced Wireless Networks: An Overview

The convergence of multitude radio access networks forming a cluster of seamless heterogeneous wireless environment has made the wireless communication industry meet the paradigm of always best connected, where various mobile devices are able to access numerous types of applications and services. However, achieving such landmarks could not be possible without difficulties which this paper tries to highlight some of the technical challenges underlying seamless vertical handover. It provides a general overview of the mobility management process including a brief on multi-homing mobility protocol and focuses on vertical handover decision making techniques, hi ghlighting some radio interface standar and analysed some handover approaches. The paper proposes fast intelligent inter-layer network selection as a new handover approach to select the best network among the candidate networks, where Quality of Service, handover delay and improved data bit rates are set to be achieved.     

Seamless integration of mobile WiMAX in 3GPP networks

As the wireless industry makes its way to the next generation of mobile systems, it is important to engineer solutions that enable seamless integration of emerging 4G access technologies within the currently deployed and/or evolved 2G/3G infrastructures. In this article we address a specific case of such a seamless integration, that of mobile WiMAX in evolved 3GPP networks. In this context we investigate the architecture and the key procedures that enable this integration, and we also introduce a novel handover mechanism that enables seamless mobility between mobile WiMAX and legacy 3GPP access, such as UTRAN or GERAN. The core characteristic of this novel handover mechanism is that mobile terminals do not need to support simultaneous transmission on both WiMAX and 3GPP accesses; therefore, it mitigates the RF coexistence issues that exist otherwise and improves handover performance. In addition, we provide a brief overview of mobile WiMAX and the evolved 3GPP network technologies, and we set the appropriate background material before presenting our proposed handover mechanism. Our main conclusion is that integrating mobile WiMAX in evolved 3GPP networks is a compelling approach for providing wireless broadband services, and mobility across WiMAX and 3GPP access can become seamless and efficient with no need for mobile terminals to support simultaneous transmission on both types of access.     

一种基于SIP与移动IPV6的异构网络切换方法

随着移动通信技术的发展,诞生了各种可供接入的网络,如GPRS,WALN等.它们传输速率和原理各不相同,不同异质接入网络之间的切换已经成为对下一代无线网络的一个基本要求.本文介绍了一种新的切换机制,首先分别介绍了SIP技术与移动IPv6技术的原理,然后结合SIP与移动IPv6技术提出一种全新的无缝切换机制,最后总结并提出了有待进一步研究的相关问题.     

Enabling Heterogeneous Mobility in Android Devices

The fast growing of mobile Internet users with the ability of using a wide diversity of access technologies such as Wi-Fi, WiMAX and UMTS/LTE, and the increasing proliferation of mobile devices with heterogeneous network interfaces, require versatile mobility mechanisms providing seamless roaming across those access technologies. Mobility agents such as Mobile IP and Fast MIPv6 are common, however, these solutions still have limitations when dealing with multiple link-layer technologies. In this context, the emerging standard IEEE 802.21 provides a framework which enables mobile agents and network operators to improve the handover process in heterogeneous networks. In this context, this paper presents and discusses the design and implementation of a mobility-aware solution for an Android device, using the IEEE 802.21 framework. A modified Android user terminal is proposed to improve the handover process, assuming a make-before-break approach. Resorting to an experimental testbed, the obtained results show that the proposed solution is an effective contribution to successfully accomplish seamless mobility of Android-based devices operating in 3G and Wi-Fi networks.     

Optimized Access Network Selection in a Combined WLAN/LTE Environment

Multimode terminals equipped with multiple radio access technologies are becoming increasingly popular. At the same time, network operators and service providers seek opportunities to deliver seamless services cost effectively, leveraging a variety of radio access technologies using both licensed and unlicensed spectrum. In order to standardize the operations of such complex environments 3GPP is currently working on IP flow mobility and mobile data offload solutions. This article proposes and evaluates a new access network selection procedure in such a combined WLAN/LTE environment. The proposed solution takes not only parameters available in the mobile node and its current and candidate access networks into account, but performs an optimization on the heterogeneous wireless network level as well. An optimization model based on an approximate solution to the well-known bin packing problem is presented. Also, there is a signaling scheme for distribution handling presented. Results from simulations performed in OPNET Modeler show improvements compared to basing handover decisions on locally available information only.     

A Robust Seamless Handover Scheme for the Support of Multimedia Services in Heterogeneous Emerging Wireless Networks

With the rapid development of wireless technologies and numerous types of mobile devices, the need to support seamless multimedia services in Mobile and Ubiquitous Computing (MUC) is growing. To support the seamless handover, several mobility protocols such as Mobile IPv6 (MIPv6) (Johnson et al., Mobility Support in IPv6, IETF, RFC 3775, 2004) and fast handover for the MIPv6 (FMIPv6) (Koodli et al. Past handovers for mobile IPv6 (FMIPv6), IETF, RFC 4068, 2005) were developed. However, MIPv6 depreciates the Quality-of-Service (QoS) especially in multimedia service applications because of the long handover latency and packet loss problem. To solve these problems in the MIPv6, FMIPv6 is proposed in the Internet Engineering Task Force (IETF). However, FMIPv6 is not robust for the multimedia services in heterogeneous emerging wireless networks when the MN may move to another visited network in contrast with its anticipation. In MUC, the possibility of service failure is more increased because mobile users can frequently change the access networks according to their mobility in heterogeneous wireless access networks such as 3Generation (3G), Wireless Fidelity (Wi-Fi), Worldwide Interoperability for Microwave Access (WiMax) and Bluetooth co-existed. In this paper, we propose a robust seamless handover scheme for the multimedia services in heterogeneous emerging wireless networks. The proposed scheme reduces the handover latency and handover initiation time when handover may fail through the management of tentative Care-of Addresses (CoAs) that does not require Duplicate Address Detection (DAD). Through performance evaluation, we show that our scheme provides more robust handover mechanism than other scheme such as FMIPv6 for the multimedia services in heterogeneous emerging wireless networks.     

无线异构网络的关键安全技术

异构网络的融合及协同工作在下一代公众移动网络中将是一个很普遍的问题,无线异构网络融合技术作为改善公众移动网络的覆盖和容量以及提供无处不在的通信能力、接入Internet的能力和无处不在的移动计算能力的有效手段,已引起广泛的关注,有着良好的应用前景。构建无线异构网络的安全防护体系,研究新型的安全模型、关键安全技术和方法,是无线异构网络发展过程中所必须关注的重要问题。无线异构网络中的关键安全技术包括安全路由协议、接入认证技术、入侵检测技术、节点间协作通信等。     

A new 4G architecture providing multimode terminals always best connected services

In recent years, wireless communication technology has undergone a tremendous change. Various radio access technologies have been deployed all over the world. The 4G mobile system was proposed to integrate all of these radio access technologies into a common network called the open wireless architecture (OWA) platform. As one of the main features of a 4G mobile system, always best connected (ABC) services enable users to choose the best available access networks in a way that best suits their needs. A new architecture capable of supporting ABC service is proposed in this study. There are three parts to the proposed architecture. First, a novel access discovery mechanism that integrates service location protocol and location-based service is presented. Second, a new personalized network selection scheme is put forward. Users can select their personalized "best" network by changing weight factors and constraints in a single objective optimization problem. Third, a seamless handover mechanism based on Mobile IPv6 is proposed. The mechanism supports end-to-end quality of service. Through analysis, this architecture demonstrates that it has benefits not only for network operators, but also for users     

Key Technologies of Wireless Heterogeneous Network Security

Convergence and collaboration of heterogeneous networks in the next generation public mobile networks will be a subject of universal significance. Convergence of heterogeneous networks, as an effective approach to improve the coverage and capacity of public mobile network, to enable communication services, to provide Internet access and to enable mobile computing from everywhere, has drawn widespread attention for its good prospects in application. Construction of security system for wireless heterogeneous networks and development of new security models, key security techniques and approaches are critical and mandatory in heterogeneous networks development. Key technology of wireless heterogeneous networks security covers security routing protocol, access authentication, intrusion detection system, cooperative communication between nodes, etc.     

基于媒体独立切换并提供QoS保证的跨UMTS和WiMAX无线异构网络的网络切换方案

The rapid growth and innovation of the various mobile communication technologies have caused a change in the paradigm of internet access. Wireless technologies such as WiMAX, WiFi and UMTS/LTE networks have shown great potential in dominating the wireless access markets. The existence of various access technologies requires a means for seamless internetworking to provide anywhere, anytime services without interruption in the ongoing session, especially in multimedia applications with rigid Quality of Services (QoS) requirements. The IEEE 802.21 Media Independent Handover (MIH) working group was formed to develop a set of mechanisms under a standard framework with the capability to support migration of mobile users across heterogeneous networks. Therefore, the implementation of handover is extremely important in the heterogeneous network environment. In order to guarantee various QoS requirements during handover execution especially in multimedia applications, in this paper we propose a novel MIH-based capacity estimation algorithm to execute handover with QoS provision supporting both horizontal and vertical handovers across UMTS and WiMAX networks. Simulation shows that the proposed mechanism achieves lower call dropping rate (highest approximate 3% ) and higher system throughput (average 92% ) than the basic handover method does.     

Handover approaches for seamless mobility management in next generation wireless networks

Next generation wireless networks (NGWN) will be an integration of heterogeneous wireless access networks that will interwork over an IP‐based infrastructure. This all‐IP vision has led to the development of handover mechanisms to support seamless mobility for active network services among the different interworking wireless networks in order to ensure network access ubiquity in NGWN. These handover mechanisms need to ensure that mobile devices continue to receive ongoing communication without any noticeable disruption during handover events among the heterogeneous networks. This paper gives a qualitative and quantitative review of current handover approaches of IP mobility management protocols for NGWN with an objective to introduce a new way of further optimizing the handover performance. In particular, the paper focuses on handover approaches of mobile IPv6 (MIPv6) based mobility management protocols. Thus, the need, benefits, and limitations of these handover approaches are explored. Thereafter, dynamic handover coordination is introduced as a new viable solution that exploits the benefits and mitigates the limitations of these handover approaches hence improving handover performance in terms of handover delay, packet loss, and signaling overhead. Copyright © 2011 John Wiley & Sons, Ltd.     

Seamless proactive handover across heterogeneous access networks

Dual-mode handsets and multimode terminals are generating demand for solutions that enable convergence and seamless handover across heterogeneous access networks. The IEEE 802.21 working group is creating a framework that defines a Media Independent Handover Function (MIHF), facilitates handover across heterogeneous access networks, and helps mobile users experience better performance during mobility events. In this paper, we describe this 802.21 framework and also summarize a Media-independent Pre-Authentication (MPA) mechanism currently under discussion within the IRTF that can further optimize handover performance. We discuss how the 802.21 framework and the MPA technique can be integrated to improve handover performance. Finally, we describe a test-bed implementation and validate experimental performance results of the combined mobility technique.     

Quality-of-service signaling for next-generation IP-based mobile networks

We present a novel end-to-end QoS architecture that enables seamless services over heterogeneous wireless access networks. We discuss the main architectural approaches and design issues of mobility-aware QoS signaling in IP networks. Then we introduce a QoS signaling architecture that integrates resource management with mobility management. It is based on a domain resource manager concept and nicely supports various handover types in an integrated approach. In particular, we support anticipated handover with pre-reservation of resources over the old network before the mobile node is attached to the new access point.     

异构无线网络垂直切换技术综述

垂直切换是多网融合的基础,是实现异构网络互通、支持不同接入方式无缝衔接的核心技术,目前正在受到业界的重点关注,并成为学术界研究的热点问题。随着无线移动通信技术向接入多元化、网络一体化和应用综合化的方向发展,各种蜂窝移动接入、宽带无线接入和固定接入将共同接入基于IP的统一核心网络,通过网络间的垂直切换,支持用户的移动性和移动过程中业务的连续性。首先给出了垂直切换的定义和基本概念,介绍了垂直切换的分类和基本流程,随后详细论述垂直切换的切换判决和切换执行2个环节。针对切换判决,总结了现有判决算法,重点评述各代表算法工作原理并剖析论其特点和存在的不足。针对切换执行,详述了现有垂直切换执行机制的工作原理和适用场景,并分析其优缺点。最后,对未来垂直切换技术的研究方向进行了展望。     

Terminal-Controlled Mobility Management in Heterogeneous Wireless Networks

The coexistence of multiple access technologies deployed by different operators is fundamental for future fourth-generation mobile networks. In spite of this heterogeneity, seamless interoperator/intersystem mobility is a mandatory requirement. In this article we present a seamless mobility management approach that does not require changes to existing network infrastructure. The novelty of the proposed approach is that mobility management is fully controlled by the terminal, and network selection is user-centric, power-saving, cost-aware, and performance-aware. Total mobility management, including interface management, handover decision, and execution, is also detailed     

Dynamic inter-domain MDS approach with secure seamless handover based on IEEE 802.21 MIH

The accessibility of available wireless access technologies with increasing demand for real time multimedia application becomes an essential part for mobile communication. Mobile users resourcefully utilize the heterogeneous environment for best quality of service (Qos) anywhere and anytime. Efficient handover optimization and intelligent mobility management is a key requirement for designing next generation wireless networks. Therefore, a novel IEEE 802.21 media independent handover (MIH) standard is adopted to provide an associated service for intelligent handover procedures. In addition, dynamic mobility management decision server (MDS) and IEEE 802.21a security extension for MIH services are also integrated in the proposed architectures to support fast, seamless and secure handover optimization in inter-domain mobility. Simulation results prove that the presented work resourcefully minimizes the packet loss, unnecessary handover probability and vertical handover delay by avoiding time consuming scanning process for target network discovery. The system thus achieves Qos guarantee by balancing the network load and throughput improvement for different applications with Proxy MIPv6 mobility management protocol.