面向隐私保护的无线传感器网络细粒度访问控制协议

针对无线传感器网络访问控制中的用户身份隐私保护和数据安全问题,提出了一种适用于多用户、隐私保护的访问控制协议。该协议采用属性基加密算法和分布式访问控制模式,使用属性证书、数字签名和门限机制,实现了用户的付费访问、细粒度访问控制和匿名访问,并保证了数据传输机密性和查询命令完整性。协议分析和协议比较表明,传感器节点的计算、存储和通信开销较小,方便实现用户和传感器节点动态加入,能更好地适应付费无线传感器网络的访问控制需求。     

宽带无线IP系统移动终端的安全接入技术

针对目前宽带无线IP系统移动终端的接入现状，本文基于公钥密码机制，提出了一种宽带无线IP系统移动终端的安全接入技术。该技术是无线通信技术、网络技术及密码技术相结合的产物，它不仅解决了目前无线IP系统中移动终端没有接入控制与非安全接入问题，而且完成了移动终端的接入控制，实现了其通信保密功能。持有证书的移动终端既可以本地接入，也可以异地登录，从而保障了其通信漫游功能。理论分析与实验结果均表明，该方案不仅切实可行，而且相比目前技术具有无可比拟的安全性。     

具有可扩展性的无线Mesh网络接入方法

分析了无线Mesh网络的特点和安全机制,给出了无线Mesh客户端的接入过程,通过面向方面编程AOP、依赖注入DI和软插件技术实现接入系统的认证协议、密钥协商协议和物理网络适配能力的可扩展性。设计了双向身份认证协议和会话密钥协商协议,能够抵抗反射攻击并保证会话的前向保密性。     

Providing advanced remote medical treatment services through pervasive environments

Advances on sensor technology, wireless environments and data mining introduce new possibilities in the healthcare sector, realizing the anytime-anywhere access to medical information. Towards this direction, integration of packet-switched networks and sensor devices can be effective in deploying assistive environments, such as home monitoring for elderly or patients. In this paper we describe a policy-based architecture that utilizes wireless sensor devices, advanced network topologies and software agents to enable remote monitoring of patients and elderly people; through the aforementioned technologies we achieve continuous monitoring of a patient’s condition and we can proceed when necessary with proper actions. We also present a software framework and network architecture that realizes the provision of remote medical services, in compliance with the imposed security and privacy requirements. A proof of concept prototype is also deployed, along with an evaluation of the overall architecture’s performance.     

How Internet Users' Privacy Concerns Have Evolved since 2002

In 2002, the authors established a baseline for Internet users' online privacy values, finding information transfer, notice/awareness, and information storage were the top online privacy concerns. Since this survey, many privacy-related events have occurred, including changes in online trends and the creation of laws, prompting the authors to rerun the survey in 2008 to examine how these events might have affected users' online privacy concerns. In this article, they discuss the 2008 survey, which revealed that US Internet users' top three privacy concerns didn't change over the course of six years, although their level of concern did. The authors also examine differences in privacy concerns between US and international respondents. The Web extra groups the survey statements according to six dimensions of privacy concerns based on the following classifications—personalization, notice/awareness, information transfer, information collection, information storage, and access/participation.     

TermID: a distributed swarm intelligence-based approach for wireless intrusion detection

With the mushrooming of wireless access infrastructures, the amount of data generated, transferred and consumed by the users of such networks has taken enormous proportions. This fact further complicates the task of network intrusion detection, especially when advanced machine learning (ML) operations are involved in the process. In wireless environments, the monitored data are naturally distributed among the numerous sensor nodes of the system. Therefore, the analysis of data must either happen in a central location after first collecting it from the sensors or locally through collaboration by viewing the problem through a distributed ML perspective. In both cases, concerns are risen regarding the requirements of this demanding task in matters of required network resources and achieved security/privacy. This paper proposes TermID, a distributed network intrusion detection system that is well suited for wireless networks. The system is based on classification rule induction and swarm intelligence principles to achieve efficient model training for intrusion detection purposes, without exchanging sensitive data. An additional achievement is that the produced model is easily readable by humans. While these are the main design principles of our approach, the accuracy of the produced model is not compromised by the distribution of the tasks and remains at competitive levels. Both the aforementioned claims are verified by the results of detailed experiments withheld with the use of a publicly available security-focused wireless dataset.     

基于二分图的两级动态异构网络选择方案

通信技术的发展,使多种接入技术并存的异构网络成为未来通信网络的发展趋势,随着用户业务QoS需求的提高和传输带宽的增加,现有的网络选择算法已经不能满足用户高质量的通信需求。针对异构无线网络频谱资源日益紧缺的问题,提出了由用户端和网络端共同参与的两级动态网络选择方案。该方案包括灰度关联分析法和二分图联合优化匹配算法,通过用户端和网络端的共同决策,算法在有效满足移动用户业务服务质量需求的前提下,优化了系统吞吐量,均衡了网络负载。仿真实验表明,相对传统算法,该方案极大地提高了异构网络频谱资源利用率并降低了用户在无线网络间的切换概率,实现了用户需求和网络资源的合理配置。     

Robust wireless sharing of internet video streams

The gateways are the performance bottleneck of wireless mesh access networks and thus alleviating stress on them is essential to making such wireless networks robust and scalable. Using proxy servers or wireless peer-to-peer streaming techniques can help reduce the gateway load. However, these techniques, because they are data caching methods, do not save wireless resources. We instead consider a communication-sharing approach in this paper. Traditional stream sharing solutions depend on cooperation with the video server. However, in the wireless access network it is difficult to cooperate with online video sites. To address this problem in wireless mesh access networks, we propose a distributed video sharing technique called Dynamic Stream Merging (DSM). DSM is able to improve the robustness of the access network without cooperation from the online video site or the users and has the intelligence to handle sudden spikes in demand for certain videos due to specific events, thereby preventing adverse effects to other daily wireless traffic. The technique can also leverage the 80:20 data access pattern, common for many video applications, to substantially increase the service throughput. We explain the DSM technique, present the system prototype, and discuss the experimental results.     

基于上下文感知的网络选择切换策略

针对异构无线网络环境中如何动态选网的问题,提出了一种基于上下文感知的网络选择切换策略。该策略提出一个动态的网络感知解决方案,引入模糊逻辑切换判决,以某项选择指标为依据过滤掉不满足需求的接入网络,并设计一种网络得分函数对网络进行排名计算。仿真实验表明,所提的切换策略可以为用户选择适合的接入网络,实验资源的有效利用。     

An Efficient Resource Allocation Mechanism for LTE–GEPON Converged Networks

Optical–wireless convergence is becoming popular as one of the most efficient access network designs that provides quality of service (QoS) guaranteed, uninterrupted, and ubiquitous access to end users. The integration of passive optical networks (PONs) with next-generation wireless access networks is not only a promising integration option but also a cost-effective way of backhauling the next generation wireless access networks. The QoS performance of the PON–wireless converged network can be improved by taking the advantages of the features in both network segments for bandwidth resources management. In this paper, we propose a novel resource allocation mechanism for long term evolution–Gigabit Ethernet PON (LTE–GEPON) converged networks that improves the QoS performance of the converged network. The proposed resource allocation mechanism takes the advantage of the ability to forecast near future packet arrivals in the converged networks. Moreover, it also strategically leverages the inherited features and the frame structures of both the LTE network and GEPON, to manage the available bandwidth resources more efficiently. Using extensive simulations, we show that our proposed resource allocation mechanism improves the delay and jitter performance in the converged network while guarantying the QoS for various next generation broadband services provisioned for both wireless and wired end users. Moreover, we also analyze the dependency between different parameters and the performance of our proposed resource allocations scheme.     

无线医疗传感网数据安全与隐私保护问题研究

本文对无线医疗传感网的数据安全与隐私保护进行了综述,描述了无线医疗传感网的网络结构,着重分析了它的特性及安全需求,并详细讨论了无线医疗传感网所面临的网络攻击.从无线医疗传感网的机密性、访问控制、身份认证、隐私保护等安全需求方面进行了相应的研究,最后指出了对无线医疗传感网安全与隐私可能的未来研究方向.     

Interworking wireless mesh networks: Problems,performance characterization,and perspectives

Wireless broadband networks based on the IEEE 802.11 technology are being increasingly deployed as mesh networks to provide users with extended coverage for wireless Internet access. These wireless mesh networks, however, may be deployed by different authorities without any coordination a priori, and hence it is possible that they overlap partially or even entirely in service area, resulting in contention of radio resources among them. In this paper, we investigate the artifacts that result from the uncoordinated deployment of wireless mesh networks. We use a network optimization approach to model the problem as resource sharing among nodes belonging to one or different networks. Based on the proposed LP formulation, we then conduct simulations to characterize the performance of overlaying wireless mesh networks, with the goal to provide perspectives for addressing the problems. We find that in a system with multiple overlaying wireless mesh networks, if no form of inter-domain coordination is present, individual mesh networks could suffer from capacity degradation due to increased network contention. One solution toward addressing the performance degradation is to “interwork” these wireless mesh networks by allowing inter-domain traffic relay through provisioning of “bridge” nodes. However, if such bridge nodes are chosen arbitrarily, the problems of throughput sub-optimality and unfairness may arise. We profile the impact of bridge node selection and show the importance in controlling network unfairness for wireless mesh network interworking. We conclude that mesh network interworking is a promising direction to address the artifacts due to uncoordinated deployment of wireless mesh networks if it is supplemented with appropriate mechanisms.     

Teaching and learning in the wireless classroom

Wireless networks now support Web browsing, e-mail, real-time chat, and access to remote computing resources. With the increasing use of small portable computers, this emerging communications infrastructure will enable many new Internet applications. Two innovative projects at the University of North Carolina at Wilmington are currently exploring how educators can use portable handheld computers with wireless Internet access to improve teaching and learning in both local and wide area network environments     

基于嵌入式Linux的Ad-Hoc网络视频传输研究

针对目前多数无线网络通信依赖于接入点(AP,access point)的现状,采用ARM9处理器(S3C2440)与嵌入式Linux操作系统相结合的技术,组建了Ad-Hoc无线网络通信系统.重点对无线网卡驱动程序进行了深入分析,实现了无线网卡在Linux环境下的移植,通过移植无线网络配置工具使无线网卡工作于Ad-Hoc...     

面向工业无线网络的动态TDMA系统设计与实现

随着工业4.0的发展, 不同种类的新型工业应用被部署到工厂中, 这对现有工业无线技术提出了实时性和高速率的要求. 为了同时满足这两种需求, 本文在支持高速率的IEEE802.11的基础上, 提出了基于软件定义的动态时分多址(Time division multiple access, TDMA)机制无线接入系统. 首先, 为了提供时延有界的传输服务, 设计并实现了基于MAC (Medium access control)层的动态TDMA接入机制. 然后, 为了满足工业无线网络中的动态变化的带宽需求, 考虑设备数据量的动态变化, 在SDN (Software defined network)控制器上通过基于最小二乘法的线性回归算法预测设备时隙需求, 再将动态时隙分配问题转化为优化问题以最大化网络中所有设备动态时隙需求. 最后, 通过仿真对比TDMA时隙分配算法的性能, 并在实际网络环境中开展系统部署与测试. 结果表明, 相对于其他TDMA接入机制, 动态TDMA机制在保障时延有界的同时能有效提升传输性能.     

High-speed backhaul networks: Myth or reality?

Wireless technology promises a realization of the long-standing vision of ubiquitous high-speed Internet access. WiFi-based wireless mesh networks that provide user access and wireless data transport over a multi-hop backhaul network are a promising incarnation of the above vision. However, while WiFi is successfully used to provide user connectivity via access points, we note that currently deployed wireless mesh networks show a dismal performance and lack mechanisms in the backhaul to provide an efficient and fair data transport over multiple hops. To assess the capabilities and the limitations of wireless backhaul networks, we are currently building MagNets, a next-generation wireless mesh network in the city of Berlin. Using MagNets, this paper provides insight on how to plan and design efficient wireless backhaul networks by describing the work breakdown and the lessons learned from the design and deployment process. Then, we perform a comprehensive performance evaluation to investigate the impact of a wide range of parameters to shed light on the potential and limitations of wireless backhaul networks.     

Energy-efficient dynamic resource allocation with opportunistic network coding in OFDMA relay networks

Network coding is significantly able to save system resources for wireless networks, and has been widely studied for the 802.11 wireless local area network and traditional cellular networks. The relay technology was introduced in 802.16j, 802.16m, and Long Term Evolution-Advanced (LTE-A) standards. Recently, the application of network coding to multi-hop wireless relay networks has been taken into consideration. Although the introduction of relay stations (RSs) may bring more energy consumption, it provides opportunities for network coding to save spectrum resources. Nevertheless, the benefits of network coding are diminished by high multiuser diversity based on orthogonal frequency division multiple access (OFDMA). For ensuring the superiority, network coding is performed opportunistically according to the channel state. Hence dynamic resource allocation (DRA) subject to rate constraints is combined with the idea of opportunistic network coding to minimize the total transmission power in a frame. A fixed set of discrete modulation levels in an OFDMA relay system is also considered. By taking the characteristic of a half-duplex decode-and-forward (DF) mode relay, a solution is proposed for the optimal problem of each subframe after separating power-aware relay selection. Simulation results show that DRA with opportunistic network coding can improve system energy efficiency. Further, it is more efficient for saving energy than DRA with static network coding compared solely to DRA.     

Medium access control in wireless sensor networks

Limited energy, computational, and communication resources complicate protocol design within sensor networks and prevent the application of many techniques used within other networks. Constraints on sensor node cost further restrict which technologies sensor networks may utilize. Despite much attention in recent years, researchers have yet to achieve the goal of long term, independent operation of sensor network deployments under these constraints. One research direction considers the energy expended performing communication functionality. Medium access protocols provide the greatest influence over communication mechanisms and provide the most direct influence over the utilization of the transceiver, the largest energy consumer in most sensor nodes. We present a discussion of medium access control concepts in relation to sensor networks and examine previous wireless medium access control protocols to illustrate how they do not match the requirements and characteristics of sensor networks. We then present several protocols recently proposed in the literature specifically for sensor networks.     

UMA方式实现固网与蜂窝网络融合的研究

UMA(Unlicensed Mobile Access)是一种使用ISM(Industrial,Scientific,Medical)频段的无线接入技术。文中分析了目前固网和移动网络存在的问题,并介绍了UMA技术实现固网与蜂窝网络融合的方式。介绍UMA方式是如何融入GSM/GPRS系统中(通过重新定义空中接口以及相关协议),使得固网资源得到充分利用,并且保证互连互通。     

Reuse efficiency of wireless access networks under physical carrier sense: A Markovian analysis

The setting of the physical carrier sense is critical in wireless networks, since it often has to account for contrasting objectives like limiting the overall interference while ensuring high concurrency among wireless transmissions. This paper proposes an analytical approach for evaluating the impact of carrier sense setting on the throughput efficiency of wireless access networks. A time continuous Markov chain is used to describe the system, and to further gathering performance measures in terms of throughput and collision probability. Numerical results obtained through the model and further validated against simulations are used to derive qualitative dimensioning criteria for the carrier sense under different network conditions.