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.     

位置相关信息服务移动终端缓存替换研究

随着无线网络的快速发展,相应的无线应用服务越来越多,位置相关信息服务(LDISs)就是其中典型的例子。无线网络受信道带宽以及终端计算能力等因素的限制,缓存技术减少了网络开销并且支持在网络断接下使用数据的优点而成为研究热点。本文根据无线应用环境的特点,结合位置相关信息数据的特征,运用粗糙集(RoughSet,RS)这一强有力的数学工具,给出一种更加准确、实用的移动缓存替换策略。     

无线传感器网络研究现状及应用

作为物联网的重要组成部分,无线传感器网络具有非常广泛的应用领域,因而越来越多的工业界和学术界从 事其开发。本文首先介绍了无线传感器网络的概念和特点,然后分析了无线传感器网络的研究现状和关键技术,最后阐述了 无线传感器网络的应用领域,为相关研究人员提供参考。     

一种无线传感器网络匿名安全路由协议*

为了能在有限资源的无线传感器网络上进行安全的匿名通信,使用双线性函数的双线性对和异或运算提出了一种匿名安全路由协议,与目前现有的无线网络匿名通信方案相比,协议不仅能提供身份的机密性、位置隐私性和路由的匿名性,而且还满足前向和后向安全性,并且大大提高了系统的计算复杂度和带宽消耗,更适合无线传感器网络。     

wmATM enhanced software definable radio system

Driven by the markets and subscribers, broadband telecommunication services are getting more and more significant throughout the world. ATM and Internet technologies are taking the leadership in this storm to bring up the new era of information society. Wireless mobile communication is a very potential system in view of its low cost as well as flexible coverage. Constructing a new broadband, high-speed wireless mobile telecommunications, with full compatibility to existing wireless standards will become an emerging demand in the following years. This kind of system can provide real-time multimedia communications, including voice, data and video to each mobile user or host, and support free roaming and handover any time, anywhere and for anyone. Hence, an intelligent broadband software definable base station is proposed to reflect the advancement of the next generation wireless mobile communications. wmATM (wireless mobile ATM) based software radio will greatly contribute to this technology and enhance the system's performance.     

Beamforming techniques for massive MIMO systems in 5G: overview,classification, and trends for future research

Massive multiple-input multiple-output (MIMO) systems combined with beamforming antenna array technologies are expected to play a key role in next-generation wireless communication systems (5G), which will be deployed in 2020 and beyond. The main objective of this review paper is to discuss the state-of-the-art research on the most favourable types of beamforming techniques that can be deployed in massive MIMO systems and to clarify the importance of beamforming techniques in massive MIMO systems for eliminating and resolving the many technical hitches that massive MIMO system implementation faces. Classifications of optimal beamforming techniques that are used in wireless communication systems are reviewed in detail to determine which techniques are more suitable for deployment in massive MIMO systems to improve system throughput and reduce intra- and inter-cell interference. To overcome the limitations in the literature, we have suggested an optimal beamforming technique that can provide the highest performance in massive MIMO systems, satisfying the requirements of next-generation wireless communication systems.     

一种分布式无线局域网接入系统

随着无线网络的普及,其安全性能也成为关注的焦点.现在无线局域网通常使用802.11b数据传输方式和802.1x无线认证方案,但是它们存在一些安全缺陷.针对现有无线网络的安全缺陷,提出了一种特定应用环境下的解决方案.该方案采用数字证书,实现请求者与认证者之间的双向认证;采用动态密钥产生方式和高级数据加密方法,在加强身份认证的同时提高通信数据的机密性和完整性保护.实际运行情况表明,该系统能有效抵抗多种攻击,安全性能好.     

基于无线TCP的簇生丢失重传协议

为提高TCP在无线网络中的传输性能,提出一种局部数据链路层重传协议,簇生丢失重传协议CLRP(Clustered-Loss Retransmission Protoc01)．针对无线链路上突发丢失性强、分组丢失率高的特点,CLRP协议与移动主机端TCP相结合,一方面为重发提供明确的分组丢失种类和高效的无线多分组丢失信息;另一方面提出了更为完善的无线丢失重发控制机制．此外,本协议无需对固定主机端TCP做任何改动．     

校园无线网络教室设计

当前越来越多的高校实施了校园网无线覆盖工程。该文分析了无线教室建设的意义,介绍了无线教室建设的主要技术,并以某学院软件楼为例介绍了无线教室设计的过程。     

Energy-efficient multipath routing in wireless sensor network considering wireless interference

Due to the energy and resource constraints of a wireless sensor node in a wireless sensor network (WSN), design of energy-efficient multipath routing protocols is a crucial concern for WSN applications. To provide high-quality monitoring information, many WSN applications require high-rate data transmission. Multipath routing protocols are often used to increase the network transmission rate and throughput. Although large-scale WSN can be supported by high bandwidth backbone network, the WSN remains the bottleneck due to resource constraints of wireless sensors and the effects of wireless interference. In this paper, we propose a multipath energy-efficient routing protocol for WSN that considers wireless interference. In the proposed routing protocol, nodes in the interference zone of the discovered path are marked and not allowed to take part in the subsequent routing process. In this way, the quality of wireless communication is improved because the effects of wireless interference can be reduced as much as possible. The network load is distributed on multiple paths instead of concentrating on only one path, and node energy cost is more balanced for the entire wireless network. The routing protocol is simulated in NS2 software. Simulation result shows that the proposed routing protocol achieves lower energy cost and longer network lifetime than that in the literature.     

When networks collide

Convergence, the term used to describe two or more disparate technologies coming together to provide additional functionality or improve efficiency. However, one particular technology convergence often exposes an organisation to potential risks, even if a conscious decision has been made not to integrate it into the business. That is the convergence of wireless and wired IP networks. The aim of this paper is to identify the risks associated with implementing wireless networks, and the risks associated with not implementing sufficient controls in detecting unauthorised wireless networks.     

Reinforcement learning for context awareness and intelligence in wireless networks: Review, new features and open issues

In wireless networks, context awareness and intelligence are capabilities that enable each host to observe, learn, and respond to its complex and dynamic operating environment in an efficient manner. These capabilities contrast with traditional approaches where each host adheres to a predefined set of rules, and responds accordingly. In recent years, context awareness and intelligence have gained tremendous popularity due to the substantial network-wide performance enhancement they have to offer. In this article, we advocate the use of reinforcement learning (RL) to achieve context awareness and intelligence. The RL approach has been applied in a variety of schemes such as routing, resource management and dynamic channel selection in wireless networks. Examples of wireless networks are mobile ad hoc networks, wireless sensor networks, cellular networks and cognitive radio networks. This article presents an overview of classical RL and three extensions, including events, rules and agent interaction and coordination, to wireless networks. We discuss how several wireless network schemes have been approached using RL to provide network performance enhancement, and also open issues associated with this approach. Throughout the paper, discussions are presented in a tutorial manner, and are related to existing work in order to establish a foundation for further research in this field, specifically, for the improvement of the RL approach in the context of wireless networking, for the improvement of the RL approach through the use of the extensions in existing schemes, as well as for the design and implementation of RL in new schemes.     

Cyber Threat Mitigation of Wireless Sensor Nodes for Secured,Trustworthy IoT Services

This article discusses about the potential of the Internet of Things technology (IoT), the IoT-enabled services in smart cities, wireless sensor nodes as key components to deliver the smart services, security threats of wireless sensor nodes and how we can mitigate these threats with assurance to provide secured and trustworthy smart services.     

无线局域网络中跨网络安全认证机制研究

在无线网络体系中,无线传输的品质相对而言也是关键的问题。针对3G/UMTS-WLAN异质网络上进行漫游时,针对快速换手时所要克服的议题,利用W-SKE完成认证程序,达到更安全的新双向完整认证和快速认证,为跨网安全认证提供一套捷径。     

一种安全的无线传感器节点结构设计方案

提出了一种提高无线传感器网络中传感节点安全性的系统结构,通过在传感节点上增加安全存储模块,可靠地保证了传感节点中所存储密钥信息的机密性、完整性,并可有效地对节点上关键应用程序的合法性进行验证,从而保证了传感网络中安全协议、认证方案的有效性、鲁棒性。和传统的传感节点相比,只是增加了节点的少量成本,但传感节点以及传感网络的安全性能得到了大幅度的提升。     

UWB antenna and MIMO antennas with bandwidth,band‐notched,and isolation properties for high‐speed data rate wireless communication: A review

The prospective of ultrawide band (UWB) technology is enormous due to its remarkable advantages such as the capability of providing high‐speed data rates at short transmission distances with low power dissipation. The swift growth in wireless communication systems has made UWB an exceptional technology to replace the conventional wireless technologies in today's use. UWB bandwidth (3.1‐10.6 GHz) covers most of the communication applications. High frequency of operation with high level of miniaturization has enhanced the interest in designing high performance antennas. There is a growing demand for small and low cost UWB antennas that are able to provide satisfactory performance in both time and frequency domains. The trend in recent wireless systems, including UWB based systems, are to build small, low‐profile integrated circuits so as to be compatible with portable wireless devices. Transformation of UWB in MIMO achieved high data rate and solved the problem of multipath propagation. The main reason for writing this review is to investigate various UWB methods and band rejection approaches on a single platform. Some of the isolation enhancement approaches are also included in article due to the requirement in MIMO antennas.     

基于TIN的无线传感器网络节点调度

针对场监测应用的特点提出了一种基于不规则三角网（TIN）的无线传感器网络节点调度方法。不同于已有的调度方法,此方法综合考虑了感知数据的动态性和空间性,减少了无线传输的电量消耗,同时保证了生成数据场的精度。模拟结果显示,在保证精度要求的前提下,基于TIN的调度方法比传统方法节省10%左右的通信电量消耗,并且具有良好的可扩展性。     

便携式磁弹性传感器检测系统设计

通过对磁弹性传感器检测原理和研究现状分析,设计了一种便携式磁弹性传感器检测系统.采用永磁铁提供静态偏置磁场简化了硬件电路,以STM32嵌入式处理器为控制核心,结合锂电池供电,实现了系统硬件的小型化和低功耗;设计采用了SD卡本地存储和低功耗蓝牙无线传输的数据处理方式,并结合上位机进行命令的控制和数据传输.实验表明,检测系统可使磁弹性传感器在不同环境中完成共振频率的测量,另外,设计系统功耗可低至mW级并且在无线传输条件下实现3天以上的连续工作,而且这部分指标仍然有较大的优化空间.由此可见,该系统具有便携式、低功耗、可用于长期监测等优点,可以更好地发挥磁弹性传感器无线、无源、微型化、高灵敏的特点,使其在各领域内得到更广泛的应用.     

工业无线（无线变送器）在镇海炼化8公里乙烯运输管线项目的应用

这篇论文主要介绍了Honeywell工业无线技术在中石化镇海炼化8公里乙烯运输管线项目上的应用。该项目采用无线温度变送器实时监测管线每隔1公里的温度测点,以确保乙烯管线的正常运行。工业无线方案在管线上的应用,不仅技术先进、应用创新,而且解决了一般有线方案8公里传输的温度信号衰减的问题和安装困难的问题,也节省了大量的安装成本和调试时间,并明显降低后期维护费用,同时确保实时可靠通讯,避免因传统有线方式电缆损坏带来的通讯中断问题。本文详细阐述这个管线项目上的技术实现方案,并进一步探讨工业无线在石油炼化行业中更多的应用场合,并比较了目前无线技术应用于工业控制的2个国际标准,ISA100和WirelessHART。附件也简单介绍了霍尼韦尔公司无线架构,以及一个无线平台支持多种无线应用和多种通讯协议现场仪表的特点等。     

A truthful auction mechanism for channel allocation in multi-radio,multi-channel non-cooperative wireless networks

Due to users’ fast-growing demands, wireless spectrum is becoming a more and more scarce resource. However, the state of spectrum usage shows that while large chunks of spectrum are left idle at many places, many emerging wireless applications cannot get enough spectra to provide their services. In contrast to existing truthful mechanisms for channel redistribution, which achieve strategy-proofness at the price of lowered system performance, we propose SHIELD, which not only guarantees strategy-proofness in the process of channel redistribution, but also achieves high system performance. Our evaluation results show that SHIELD outperforms the existing mechanisms, in terms of spectrum utilization and user satisfaction ratio. Here, channel utilization represents the average number of radios allocated to channels, and buyer satisfaction ratio shows the percentage of buyers who get at least one channel in the auction.