基于SOA与资源即插即用的RFID中间件

融合各种通信网络异构性的无线泛在网将成为网络发展的必然趋势。为实现无线业务的泛在化,提出一种基于SOA与资源即插即用功能的泛在网RFID中间件架构,使其能在未来的基于Web的无线泛在业务环境体系架构中完成智能感知设备资源的即插即用特性。介绍了该架构逻辑框架中各部分的功能与实现方法,并通过具体应用系统验证了该架构不仅可以解决RFID设备与应用系统之间的紧耦合问题,而且能够实现单一物理设备服务多种业务应用的需求。     

Case study on handoff strategies for wireless overlay networks

One of the most challenging topics for next‐generation wireless networks is the process of vertical handoff since many of wireless technologies overlap each other and build a heterogeneous topology. Several parameters, pertaining to user/application requirements and network conditions, such as data rate, service cost, network latency, speed of mobile, and etc. must be considered in the handoff process of heterogeneous networks along with RSSI information. In this paper, adaptive fuzzy logic‐based vertical handoff decision‐making algorithms are presented for wireless overlay networks which consist of GSM/GPRS/Wi-Fi/UMTS/WiMAX technologies. The parameters data rate, monetary cost, speed of mobile and RSSI information are processed as inputs of the proposed fuzzy‐based systems. According to these parameters, an output value, which varies between 1 and 10, is produced. This output value is utilized to determine whether a handoff process is necessary or not and to select the best candidate access point in the vicinity. The results show that, compared to the traditional RSSI‐based algorithm significantly enhanced outcomes can be achieved for both user and network as a consequence of the proposed fuzzy‐based handoff systems. The simulation results are also compared with those of classical MADM (Multiple Attribute Decision Making) method, i.e. SAW (Simple Additive Weighting). According to the results obtained, the proposed vertical handoff decision algorithms are able to determine whether a handoff is necessary or not, properly, and select the best candidate access network considering the aforementioned parameters. Moreover, fuzzy‐based algorithm noticeably reduces the number of handoffs compared to SAW‐based algorithm.     

Enhancing the performance of futurewireless networks with software-defined networking

To provide ubiquitous Internet access under the explosive increase of applications and data traffic, the current network architecture has become highly heterogeneous and complex, making network management a challenging task. To this end, software-defined networking (SDN) has been proposed as a promising solution. In the SDN architecture, the control plane and the data plane are decoupled, and the network infrastructures are abstracted and managed by a centralized controller. With SDN, efficient and flexible network control can be achieved, which potentially enhances network performance. To harvest the benefits of SDN in wireless networks, the software-defined wireless network (SDWN) architecture has been recently considered. In this paper, we first analyze the applications of SDN to different types of wireless networks. We then discuss several important technical aspects of performance enhancement in SDN-based wireless networks. Finally, we present possible future research directions of SDWN.     

A hybrid intelligent model for network selection in the industrial Internet of Things

Industrial Internet of Things (IIoT) plays an important role in increasing productivity and efficiency in heterogeneous wireless networks. However, different domains such as industrial wireless scenarios, small cell domains and vehicular ad hoc networks (VANET) require an efficient machine learning/intelligent algorithm to process the vertical handover decision that can maintain mobile terminals (MTs) in the preferable networks for a sufficient duration of time. The preferred quality of service parameters can be differentiated from all the other MTs. Hence, in this paper, the problem with the vertical handoff (VHO) decision is articulated as the process of the Markov decision aimed to maximize the anticipated total rewards as well as to minimize the handoffs’ average count. A rewards function is designed to evaluate the QoS at the point of when the connections take place, as that is where the policy decision for a stationary deterministic handoff can be established. The proposed hybrid model merges the biogeography-based optimization (BBO) with the Markov decision process (MDP). The MDP is utilized to establish the radio access technology (RAT) selection’s probability that behaves as an input to the BBO process. Therefore, the BBO determines the best RAT using the described multi-point algorithm in the heterogeneous network. The numerical findings display the superiority of this paper’s proposed schemes in comparison with other available algorithms. The findings shown that the MDP-BBO algorithm is able to outperform other algorithms in terms of number of handoffs, bandwidth availability, and decision delays. Our algorithm displayed better expected total rewards as well as a reduced average account of handoffs compared to current approaches. Simulation results obtained from Monte-Carlo experiments prove validity of the proposed model.     

异构分层无线网络中基于业务QoS保证的切换策略研究

针对异构分层无线网络提出了一种保证业务QoS的切换策略。该策略在层间呼叫双向溢出基础上,为实时业务切换设置了保护信道,为非实时业务切换设置了缓冲队列。为了进一步降低实时业务切换的掉线率,还使用了信道侵占技术,原理是实时业务切换呼叫可以侵占数据业务正在使用的信道资源。仿真结果表明,提出的切换方法能够显著降低各类切换业务的掉线率,同时整个异构分层系统的信道利用率也略有提高。     

一种基于移动P2P平台的无线传感器网络体系结构

借助P2P思想,构建一个基于移动网络基础设施提供对等服务的无线传感器网络体系结构。移动网络充当移动P2P平台,提供一种普适的传感器组网。代表传感器网络的网关节点隐藏了其实现细节,在P2P模式工作下向用户提供更加优质的个人服务。此外,还讨论了服务平台构建过程中的一般性问题。     

Interference aware vertical handoff decision algorithm for quality of service support in wireless heterogeneous networks

Next generation wireless networks concept aims at collaboration of various radio access technologies in order to provide quality of service (QoS) supported and cost efficient connections at anywhere and anytime. Since the next generation wireless systems are expected to be of heterogeneous topology, traditional handoff (horizontal handoff/handover) mechanisms are not sufficient to meet the requirements of these types of networks. More intelligent vertical handoff algorithms which consider user profiles, application requirements, and network conditions must be employed in order to provide enhanced performance results for both user and network. Moreover, frequency reuse of one (FRO) seems to be the strongest candidate of deployment options for next generation wireless networks; therefore, interference conditions gains a significant attention in vertical handoff decision making process. In this study, a fuzzy logic-based handoff decision algorithm is introduced for wireless heterogeneous networks. The parameters; data rate, received signal strength indicator (RSSI), and mobile speed are considered as inputs of the proposed fuzzy-based system in order to decide handoff initialization process and select the best candidate access point around a smart mobile terminal. Also, in contrast to the traditional fuzzy-based algorithms, the method proposed takes ambient interference power, which is referred to as interference rate, as another input to the decision process. The results show that the performance is significantly enhanced for both user and network by the method proposed.     

PicoRadio supports ad hoc ultra-low power wireless networking

Technology advances have made it conceivable to build and deploy dense wireless networks of heterogeneous nodes collecting and disseminating wide ranges of environmental data. Applications of such sensor and monitoring networks include smart homes equipped with security, identification, and personalization systems; intelligent assembly systems; warehouse inventory control; interactive learning toys; and disaster mitigation. The opportunities emerging from this technology give rise to new definitions of distributed computing and the user interface. Crucial to the success of these ubiquitous networks is the availability of small, lightweight, low-cost network elements, which the authors call PicoNodes. The authors present a configurable architecture that enables these opportunities to be efficiently realized in silicon. They believe that this energy-conscious system design and implementation methodology will lead to radio nodes that are two orders of magnitude more efficient than existing solutions     

可避免数据包乱序的网络层软切换方法及其性能分析

随着异构无线网络的融合和全IP网络的推广,网络层软切换方法不断演进,用以提高垂直切换的性能.但是,现有的软切换方法在下行垂直切换过程中会造成严重的数据包乱序.为此,文中在讨论下行垂直切换时数据包乱序的原因之后,提出了一种新型网络层软切换方法——SHORDER.该方法根据移动终端与其家乡代理之间的交互信令对终端所收数据包进行适当的缓存,能有效避免移动终端因下行垂直切换接收到乱序的数据包.该方法所具有的网络层独立性使其能与各种传输层协议及其改进协议相兼容.此外,文中还从理论上定量地分析了所提方法对TCP应用的切换时延、有效吞吐量及拥塞窗口的影响,并与现有的典型网络层软切换方法进行了比较.通过比较,得出了SHORDER机制的适用条件,并基于此,进一步改进了SHORDER方法.最后,在原型系统上的实验显示出了所提机制便于部署的优点以及该机制在其适用条件下的良好性能.此外,实验结果还显示出与数值分析结果的一致性.     

无线异构网络环境下的MIPv6集成切换框架*

针对多接口移动节点在无线异构网络环境下的切换问题,将移动IPv6水平切换与垂直切换相结合,提出了一个无线异构网络环境下的移动IPv6集成切换框架,使移动节点在网络侧实体的支持下能够自主选择切换目标网络并进行水平或垂直切换。为改进移动IPv6的切换性能,为该框架设计了水平及垂直切换协议,并进行了实验验证。     

Ubiquitous system software

We're physically deploying a network of thousands of sensor nodes across the campus. Recent advances in wireless communication and sensor and actuator technologies have given rise to new genre of ubiquitous systems. We design middleware that can provide network connectivity in a decentralized fashion and use of a decentralized self-organizing infrastructure to improve the availability of today's ubiquitous networks.     

一种无线异构网络的自适应垂直切换算法

针对移动节点在异构网络间切换性能不理想的问题,提出了一种自适应主动预测的垂直切换算法。采用一种面向当前应用程序的代价函数对可接入网络进行评估与选择;根据稳定周期、移动节点的运动速度及所处位置来自动调整切换执行时间,使移动节点能自适应地进行切换判决。仿真结果表明,该算法可以有效地减少切换延迟、分组丢失及切换次数,提高系统的切换性能,改善业务的QoS。     

Cross-layer radio resource management in integrated WWAN and WLAN networks

This paper proposes a mobility adaptive network selection scheme in the context of wireless wide area network (WWAN) and wireless local area network (WLAN) radio access technologies (RATs) that supports both real-time (RT) and non-real-time (NRT) service classes. Physical layer information based call admission control (CAC) is considered for the two RATs to enforce service specific QoS requirements. The effectiveness of the cross-protocol-layer information for radio resource management (RRM) in integrated WWAN and WLAN networks is assessed analytically for individual service classes in a multi-service environment using the theory of Markov chains. The impact of non-uniform user and mobility distributions due to the existence of hotspot in the macro-cell area and the effect of network selection parameter measurement errors on the RRM performance are also evaluated. Numerical results show that the proposed network selection scheme minimizes the rate of unnecessary vertical handoffs, thereby providing stable communication without degrading the call blocking probability and call outage probability performance metrics.     

Implementation of call admission control scheme in next generation mobile communication networks using particle swarm optimization and fuzzy logic systems

In the present and next generation wireless networks, cellular system remains the major method of telecommunication infrastructure. Since the characteristic of the resource constraint, call admission control is required to address the limited resource problem in wireless network. The call dropping probability and call blocking probability are the major performance metrics for quality of service (QoS) in wireless network. Many call admission control mechanisms have been proposed in the literature to decrease connection dropping probability for handoffs and new call blocking probability in cellular communications. In this paper, we proposed an adaptive call admission control and bandwidth reservation scheme using fuzzy logic control concept to reduce the forced termination probability of multimedia handoffs. Meanwhile, we adopt particle swarm optimization (PSO) technique to adjust the parameters of the membership functions in the proposed fuzzy logic systems. The simulation results show that the proposed scheme can achieve satisfactory performance when performance metrics are measured in terms of the forced termination probability for the handoffs, the call blocking probability for the new connections and bandwidth utilization.     

一种无线传感器网络与Internet的集成方案

目前对传感网的研究主要解决如何在满足特定应用要求的网络指标下,尽可能节约能耗从而延长网络生存期。这些研究假设WSN为一个能够感知真实物理环境的孤立网。然而,实际客户通常处在远离WSN的Internet上,需要一种有效的方式使客户能驱动WSN收集数据并将其快速地传输给客户,因此该文基于对现有研究进行分析总结,提出了一种能够面对多种挑战的传感网与IP网集成方案,采用用户代理、应用代理、注册代理、资源管理器架设WSN与Internet之间的桥梁。通过组件描述和查询操作流程分析,说明了该集成方案较已有框架更加灵活、可靠、能量有效,从而使Internet不同种类的应用能够尽可能快速地获得低成本的WSN查询服务。     

An AAA scheme using ID-based ticket with anonymity in future mobile communication

An AAA protocol is an information protection technology that systematically provides authentication, authorization and accounting functions not only in existing wired networks, but also in rapidly developing wireless networks. Currently, standardization of various applied services is in progress and involves AAA standardization for a mobile user in a wireless network. Various studies have considered using AAA with a roaming service in a mobile IPv6 network, between heterogeneous networks. In this paper, we proposed an ID-based ticket for user authentication with a mobile device in a ubiquitous environment. Service is seamless, even when a mobile device moves from the home network to a foreign network. In addition, since the ticket is renewed from the foreign network, the overhead of the home authentication server is reduced, and the anonymity ID guarantees anonymity during service.     

Network selection in a WiMAX–WiFi environment

The tremendous growth of wireless technologies has introduced the potential of continuous service adaptation to the users’ needs by giving them the ability to be able to select and access the proper network based on different criteria. Moreover, next generation wireless networks have been designed to provide support for multimedia services, with different traffic characteristics and different Quality of Service (QoS) guarantees. However, the expansion of Wireless Local Area Networks (WLANs) and Worldwide Interoperability for Microwave Access (WiMAX) networks poses new research era in the decision of the access network selection. In this paper, the existing access network selection schemes are classified into three categories: the network-centric, the user-centric and the collaborative schemes, and are analyzed respectively. Moreover, we propose a multicriteria access network selection algorithm applied in a WiMAX–WLAN environment, in order to facilitate the provision of high quality services and at the same time to satisfy different types of user Service Level Agreements (SLAs).     

Intra domain route optimization for ubiquitous network

The main advantage of a wireless network is user mobility, which calls for efficient routing support at the network layer. An architecture combines hierarchical mobile IPv6 and network mobility for a network mobile and mobile nodes move in tandem and make a hierarchy in the wireless network to management of micro-mobility and seamless handoff. But the capability of the architecture for intra domain route optimization is impaired. So we propose functionality in domain nodes to enable intra domain path optimization for ubiquitous network. It is shown that intra domain cost effect is beneficial in every hierarchical domain that spans mesh network topology. We address the key function for our proposed scheme and analyze the usefulness of our proposed method using mathematically. We show that our proposed scheme performs much better than Network Mobility protocol, especially when the number of mobile nodes or mobile routers or correspondent nodes increases in hierarchically nested in ubiquitous networks.     

基于无线体域网的在线人体活动识别

基于智能手机传感器的人体活动识别是普适计算领域的研究热点.为扩展可识别的活动种类,并提高准确率和实时性,提出了由智能手环和智能手机组建无线体域网通过深度神经网络在线识别人体活动的方法.首先,设计由智能手环和智能手机组成的无线体域网的总体框架;然后,对预处理后的传感信号,构造带有Inception结构的卷积神经网络和长短时记忆递归神经网络来分别提取时空域特征,并结合两类网络结构来融合多模态传感数据,离线进行神经网络模型训练;最后,对训练好的神经网络模型进行优化,并部署到智能手机上,在线实时识别人体活动.实验结果表明,本文方法无需手工设计特征,可自动融合各类异构传感数据,更加准确、高效地识别了更多种类的活动.     

System supports for protocol and application adaptation in vertical handoffs

In overlay networks, the network characteristics before and after a vertical handoff would be drastically different. Consequently, in this paper, we propose an end‐to‐end based scheme to support protocol and application adaptation in vertical handoffs. First, we proposed a Vertical‐handoff Aware TCP, called VA‐TCP. VA‐TCP can identify the packet losses caused by vertical handoffs. If segments losses are due to vertical handoffs, VA‐TCP only retransmits the missing segments but does not invoke the congestion control procedure. Moreover, VA‐TCP dynamically estimates the bandwidth and round‐trip time in a new network. Based on the estimated bandwidth and round‐trip time, VA‐TCP adjusts its parameters to respond to the new network environment. Second, during a vertical handoff, applications also need to be adapted accordingly. Therefore, we design a programming interface that allows applications to be notified upon and adapt to changing network environments. To support our interface, we utilize the signal mechanism to achieve kernel‐to‐user notification. Nevertheless, signals cannot carry information. Thus, we implement the shared memory mechanism between applications and the kernel to facilitate parameters exchange. Finally, we also provide a handoff‐aware CPU scheduler so that tasks that are interested in the vertical‐handoff event are given preference over other processes to attain a prompt response for new network conditions. We have implemented a prototype system on the Linux kernel 2.6. From the experimental results, our proposed protocol and application adaptation mechanisms are shown to effectively improve the performance of TCP and applications during vertical handoffs. Copyright © 2008 John Wiley & Sons, Ltd.