Implementation and performance study of IEEE 802.21 in integrated IEEE 802.11/802.16e networks

In this paper, we propose a framework for the implementation of the IEEE 802.21 Media Independent Handover (MIH) standard and evaluate its performance through experiments in integrated 802.11/802.16e networks. The IEEE 802.21 standard defines three types of MIH services (event, command, and information) that facilitate the mobility management and handover process in heterogeneous networks. To support MIH services, we develop a MIH-capable mobile node and the MIH information service server. Then, we introduce the Connection Manager (CM) which utilizes MIH services. Two main roles of CM are supporting seamless vertical handovers and efficient access point (AP) discoveries. From the experimental results in the real test-bed, we can know that the MIH services can be used to reduce packet losses during a vertical handover and to reduce the AP discovery time and energy consumption of mobile nodes.     

A survey on applications of IEEE 802.21 Media Independent Handover framework in next generation wireless networks

Integration of various wireless access technologies is one of the major concerns in recent wireless systems in which multi-technology mobile devices are provided to users to roam between different access networks. Being an essential part in heterogeneous wireless systems, vertical handover is more complex than conventional horizontal handover. As IEEE 802.21 Media Independent Handover (MIH) is the standard addressing a uniform and media-independent framework for seamless handover between different access technologies, many works have been carried out in the literature to employ MIH services in handover management This paper presents a comprehensive survey of the proposed mobility management mechanisms that are using this framework. As a comparative view, the paper categorizes the efforts according to the layer of mobility management and evaluates some of the representative methods discussing about their advantages and disadvantages The paper also looks into recent handover decision and interface management methods that are exploiting MIH Moreover, the extensions and the amendments proposed on MIH are overviewed.     

IEEE 802.21-based seamless multicast streaming with dynamic playback control

With the explosion of video streaming available on the Internet, online multimedia applications become more popular in our days and the video quality of the Internet multimedia applications is directly affected by the network transmission state, which will be worse while switching the ongoing network connection from one wireless interface to another heterogeneous wireless technology, such as IEEE 802 families, UMTS (universal mobile telecommunications system) network and 3GPP LTE (3rd generation partnership project-long term evolution). In order to perform seamless handover between heterogeneous wireless networks, IEEE group proposed the “IEEE 802.21 standard” and defined a middleware function called “media independent handover function (MIHF)” to smooth the handover. In this paper, a dynamic playback control for multicasting streaming based on IEEE 802.21 is proposed to reduce the influence of handover between heterogeneous networks. In addition, we evaluate three different rate modes for seamless multicasting streams. The simulation results show that different playback frame rate modes, including the usual, incremental and linear modes, can achieve different video quality and can extend the playing time for handover video playback.     

Call Admission and Handover in Heterogeneous Wireless Networks

Today's mobile communication networks support not just simple mobile voice and data services but also access to mobile Internet-based services with varying bandwidth and quality-of-service requirements. The work presented in this article addresses this issue by proposing a management architecture for mobile user roaming based on efficient call admission and handover control in heterogeneous wireless access networks. Our proposed architecture consists of databases that hold profile and policy information, a roaming controller with two main elements (namely, call admission control for new and handover traffic), and intersystem handover control     

A Secure Correspondent Router Protocol for NEMO Route Optimization

The Network Mobility (NEMO) protocol is needed to support the world-wide mobility of aircraft mobile networks across different access networks in the future IPv6 based aeronautical telecommunications network (ATN). NEMO suffers from the constraint that all traffic has to be routed via the home agent though. The already existing correspondent router (CR) protocol solves this triangular routing problem and permits to route packets on a direct path between the mobile network and the ground based correspondent nodes. We identify security deficiencies of this protocol that make it unsuitable for use within the ATN. We therefore propose a new route optimization procedure based on the CR protocol that provides a higher level of security. We evaluate our new protocol in three ways. We first conduct a simulation based handover performance study using an implementation of a realistic aeronautical access technology. We then investigate the mobility signaling overhead. Finally, we specify a threat model applicable for the aeronautical environment and use it to perform a security analysis of both the old and our new protocol. It is shown that our protocol is not only more secure but also provides better handover latency, smaller overhead in the aeronautical scenario and a higher level of resilience when compared to the original CR protocol.     

An IMS-based integration architecture for WiMax/LTE handover

To enable seamless handovers for broadband networks, many researchers have addressed the integration of heterogeneous access technologies to provide users with always-on connectivity. Currently, there are several researches reported in the literature that discuss the integration of beyond 3G networks such as 3GPP Long Term Evolution LTE and mobile WiMax networks. They mainly focused on providing mobile users with seamless mobility when switching between heterogeneous access networks. In this context, many solutions for integration architecture have been proposed with mobility management considerations such as loose and tight coupling, IP Multimedia Subsystem IMS-based architecture and Evolved Packet Core EPC-based solutions for the purpose of providing mobile users with seamless handovers. In this paper, we present the different integration solutions and propose an integration architecture for WiMax and LTE access technologies with EPC as core network and IMS for service provisioning. A vertical handover VHO scheme is presented based on cross-layer approach that enables vertical handover with less handover latency and signaling cost.     

An enhanced cross-layer fast handover scheme for mobile IPv6 in the IEEE 802.16e networks

The IEEE 802.16e standard enhances the IEEE 802.16 for the mobility support. Mobile stations can move while receiving services, thus ongoing IP sessions may be maintained during a handover in the IEEE 802.16e. To reduce handover latency, the idea of cross-layer handover which incorporates layer 2 handover with IP layer has been devised. Various cross-layer handover schemes supporting fast handover in the IEEE 802.16e networks have been proposed. However, the problem of the conventional cross-layer fast handover schemes is that they are heavily influenced by the new address confirmation latency which is the most time-consuming procedure. In this paper, we propose an enhanced cross-layer fast handover scheme which is not susceptible to the new address confirmation latency. Detailed performance analysis is performed in terms of the signaling costs and the handover latencies to show the effectiveness of the proposed scheme compared with the conventional ones. The results of the performance evaluation confirm the effectiveness of the proposed scheme.     

基于IPv6的城市车载网移动协议

提出了一种基于IPv6的城市车载网移动切换协议。本协议提出了城市车载网络体系结构, 车辆节点在移动过程中由家乡地址唯一标志, 无须转交地址, 因此节省了转交地址配置时间和代价, 从而缩短了移动切换时间, 降低了移动切换代价。车辆节点无须参与移动切换过程, 从而避免了由于车辆节点高速行驶引起丢包而增加移动切换代价和延迟的情况。仿真数据结果表明该方案的性能更好。     

Double-sided auctions applied to vertical handover for mobility management in wireless networks

In the next generation Internet, we have seen the convergence of multimedia services and Internet with the mobility of users. Vertical handover decision (VHD) algorithm are essential components of the mobility management architecture in mobile wireless networks. VHD algorithms help mobile users to choose the best mobile network to connect among available candidates. It also can help the network manager to optimize easily the limited resources shared among the network providers and the users. In this article, we formulate VHD algorithm as a resource allocation problem for down-link transmission power in multiple W-CDMA networks and show how combinatorial double-sided auctions can be applied to this specific problem. The proposed pricing schemes make use of the signal interference to noise ratio, achievable data rates, power allocation at mobile networks, and monetary cost as decision criteria and our model differentiate between new calls and on-going communications to take into account that the last category has somewhat more importance. Several combinatorial double-sided auction are proposed to maximize the social welfare and /or to provide incentives for mobile users and mobile operators to be truth-telling in terms of valuation or cost. Finally, the economic properties of the different proposed pricing schemes are also studied by means of simulations.     

Design,implementation and experimental evaluation of an end-to-end vertical handover scheme on NCTUns simulator

This paper presents the simulation study of “Host based autonomous Mobile Address Translation” using NCTUns simulator. It is a network layer, end-to-end vertical handover solution, based upon modification of “Mobile IP with address Translation”. Vertical handover approaches generally require new network elements, a new layer in TCP/IP stack, or fixing a protocol at a particular layer. To enhance handover experience, recent approaches focus on reducing signalling, localizing the registration, creating hierarchies, using proxy, preparing handover in advance, predicting target network, or exploiting multicasting and path extension techniques. These approaches, however, demand change in the network infrastructure to support mobility and limit the scope of mobility. Despite end-to-end signalling, the Host based autonomous Mobile Address Translation scheme ensures minimum service disruption and distinctly allows global mobility of the mobile node without requiring any modification in the network. We have simulated the mobility of a multi-interface mobile node in a heterogeneous network environment composed of WiFi (IEEE802.11a, IEEE802.11b) and WiMAX (IEEE802.16e) access networks. Performance of the scheme is evaluated taking into account wide range of end-to-end delays between mobile node and the correspondent node, various speeds of the mobile node and different packet loss rates of the network. Based on our detailed simulation study, it has been observed that this scheme offers reduced service disruption time, packet loss and packet latency. The service disruption time is found to be significantly low (typically in the range of 10 ms) compared to that of Mobile IP (which is in the order of 100 ms); this makes this new scheme perfectly suitable for real time applications. Low service disruption time consequently reduces the packet loss by manyfold and the packet latency remains unaffected during and after handover due to translation of address at the source. The results suggest that this protocol is a viable vertical handover solution due to its simplicity, scalability, low overhead and ready deployability.     

A MIH-based approach for best network selection in heterogeneous wireless networks

In the next generation wireless networks, different technologies belonging to one or more operators should be integrated to form a heterogeneous environment based on an IP core network infrastructure. This ensures user mobility and service continuity by maintaining connections when switching between various technologies and it introduces new resources and possibilities for applications. In this context, an automatic interface selection based on instantaneous and practical constraints and user preferences (Quality of Service (QoS) parameters, available resources, security, power consumption, etc.) is therefore required. The different network selection and handover schemes proposed in the literature can be classified into three approaches according to who is responsible for making the handover decision: the terminal, the network or by a cooperation between both of them. However, these approaches keep presenting some drawbacks; namely the problem of resources management and network load balancing whenever the selection is controlled by the mobile terminal (MT) and the problem of scalability and unknown operator's management policy whenever the selection is rather controlled by the network.In this article, first we propose a MIH based approach for handover initiation and preparation for heterogeneous wireless network. The proposed framework is based on the principals of IEEE 802.21 for context information gathering and optimized handover decision making. Second, we propose a new architecture and new network selection scheme that explicitly take into account the current resource usage and the user preferences. Furthermore, our solution ensures the selection of the most suitable network for each flow while taking into consideration its expectations in terms of QoS. A feasibility study of implementing a new architecture on a single MT is evaluated by using typical scenarios and using various algorithms. Thanks to the introduced function entities and modules in the proposed architecture, network utilization balancing and user and application expectations, which are successfully assured without operator intervention. Performance analysis shows that the proposed algorithm best meets the common quality requirements.     

Enabling inter-PMIPv6-domain handover with traffic distributors

As a network-based localized mobility management protocol, Proxy Mobile IPv6 (PMIPv6) Gundavelli et al. (2008) enables mobile node (MN) to move in a local domain without any involvement in the protocol signaling. In contrast to other mobility protocols (such as cellular IP (CIP) Valkó, 1999, and hierarchical mobile IP (HMIP) Soliman et al., 2005), PMIPv6 does not require any upgrade of MN's protocol stack. Instead, PMIPv6 employs network entities to handle the handover for MN. However, the PMIPv6 can only manage MN's reachability within a local domain. If MN moves beyond the border of PMIPv6 domain, the mobility support will be broken. To provide MN continuous support across domains, we propose a solution to interconnect neighboring PMIPv6 domains. In our proposal, we have introduced a new network entity called traffic distributor (TD). The TD is used to deliver the cross-domain traffic. If MN moves across domain borders, LMA will notify the TD and the TD will redirect MN's traffic to the new domain. To evaluate our proposal, we conduct experiments to compare it with Neumann et al., 2009a, Neumann et al., 2009b proposal which is another proposal to handle inter-PMIPv6-domain issues. Results show that our proposal is a feasible alternative for inter-domain handover, and it outperforms Neumann's proposal in terms of binding cache entry number, transmission delay and handover delay.     

一种基于标地分离的卫星网络移动切换管理技术

移动卫星网络因具有覆盖区域广、通信延时低等优势受到广泛关注,当前有大量研究旨在开发IP协议的组网技术,并将其与地面IP网络融合。融合网络的挑战之一,即为卫星移动性,用户在卫星网络中的接入点频繁切换导致移动管理问题,而现有的移动IP技术不能高效支持卫星网络移动切换。为了高效支持移动切换,在卫星网络中应用标地分离思想,在标地分离的架构下研究切换管理问题;用映射服务系统对终端进行位置管理,在移动切换中由新接入卫星网关和终端的标志为主要信息在原卫星中形成通告转发表。仿真结果表明,相对移动IP技术,该方法有明显优势。将其应用于卫星网络时可以降低切换延时,减少大量的绑定更新开销或是次优路由,提升系统的性能和可扩展性。     

Fuzzy based multi-criteria vertical handover decision modeling in heterogeneous wireless networks

Vertical handover gain significant importance due to the enhancements in mobility models by the Fourth Generation (4G) technologies. However, these enhancements are limited to specific scenarios and hence do not provide support for generic mobility. Similarly, various schemes are proposed based on these mobility models but most of them are suffered from the high packet loss, frequent handovers, too early and late handovers, inappropriate network selection, etc. To address these challenges, a generic vertical handover management scheme for heterogeneous wireless networks is proposed in this article. The proposed scheme works in three phases. In the first phase, a handover triggering approach is designed to identify the appropriate place for initiating handover based on the estimated coverage area of a WLAN access point or cellular base station. In the second phase, fuzzy rule based system is designed to eliminate the inappropriate networks before deciding an optimal network for handover. In the third phase, a network selection scheme is developed based on the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) decision mechanism. Various parameters such as delay, jitter, Bit Error Rate (BER), packet loss, communication cost, response time, and network load are considered for selecting an optimal network. The proposed scheme is tested in a mobility scenario with different speeds of a mobile node ranging from very low to very high. The simulation results are compared with the existing decision models used for network selection and handover triggering approaches. The proposed scheme outperforms these schemes in terms of energy consumption, handover delay and time, packet loss, good put, etc.     

Handoff performance analysis of PMIPv6-based distributed mobility management protocol-urban scenario

Mobility management allows the networks to track down a mobile user's location for sending datagrams and to retain the connection when the user changes its location points repeatedly. Whenever a node switches between one base station and another, the connectivity is maintained through a process called handoff management. For real-time traffic implementations in wireless network communications, handover performance is essential. A mobile node is blocked from transmitting and receiving a datagram for a longer time as the handover delay increases. Unacceptable handover delays are common in real-time communication services. To guarantee smooth connectivity and continuous provision of services, effective handoff methods are required. The handoff efficiency of network-based distributed mobility management (DMM) is studied extensively in this article, along with a comparison to PMIPv6. We specifically investigate how handover delay, session recovery, and packet loss are influenced by cell radius. From the analytical and simulation findings this paper concludes that network-based DMM performs better than PMIPv6.     

关于切换技术解决3G网络融合问题的综述

通过对无线通信网络的体系结构,运营方式,切换技术实现细节等方面的分析和研究,研究和探讨异构网络之间的切换技术,最终提出一个面向下一代无线通信网络的新型的基于IP的综合切换(Integrated Handover,IH)框架。IH技术的最终目标就是要解决移动通信网络中因网络异构、资源开销瓶颈等影响,成功地实现全球无线网络覆盖范围的低时延、高带宽、宽切换域、开销低和QoS保证的不同网络间顺畅的无缝切换。     

Mobility management solution for IPv6-based vehicular networks

This paper proposes a mobility management solution for IPv6-based vehicular networks. First, the architecture based on vehicle domains is proposed in order to reduce the mobility handover frequency and delay. Based on the architecture, a distributed address configuration algorithm is proposed. Based on the address configuration algorithm, a vehicle can establish a routing path reaching the nearest AP (Access point) and achieve the multi-hop communication with the Internet through the routing path. Finally, based on the routing algorithm, the mobility management solution is proposed. The data results show that the solution shortens the mobility handover delay and lowers the packet loss.     

A predictive handover scheme to improve service quality in the IEEE 802.21 network

The Media Independent Handover (MIH) standard defined in the IEEE 802.21 specification supports vertical handovers across heterogeneous networks. A cross-layer scheduling scheme is proposed to exploit Link Going Down information from MIH to predict handover requirements, and then improve the performance of Quality of Service (QoS) enabled transport services given the limited radio spectrum available for handovers in a heterogeneous network environment. According to simulation results, the proposed scheme can effectively increase the effective range of QoS sensitive services at the cell border while executing the handover procedure.     

Optimization for adaptive bandwidth reservation in wireless multimedia networks

In future wireless multimedia networks, user mobility management for seamless connection regarding realtime multimedia applications is one of the most important problems. In this paper we propose an opportunity-cost concept-based approach for adaptive bandwidth reservation with admission control for handover calls utilizing network traffic information. Excessive reservation guarantees low blocking probability of handover calls at the cost of high blocking probability of new calls. According to our survey, however, it may degrade bandwidth utilization while no prioritization for handover admissions degrades quality of service (QoS) for ongoing calls. We consider both QoS assurance and bandwidth utilization in order to optimize the amount of bandwidth to reserve for handover admissions. We believe that our scheme could be utilized as a guideline for cost-effective radio resource allocation in mobile multimedia networks.