Ultrawideband wireless body-area sensor networks

The operation principles of wireless body-area networks (WBANs) and requirements to their infrastructure are described. The new IEEE 802.15.6 WBAN standard, in which an ultrawideband (UWB) signal is used as an information carrier, is discussed. The general properties of the given standard and its distinctions from the existing wireless personal communications standards are analyzed. It is demonstrated that UWB direct chaotic transceivers are promising for use in the wireless sensor networks based on the new standard.     

Visual node module: An open‐source extension to the ns‐3 network simulator

A wireless visual sensor network is a collective network of directional and battery‐operated sensor nodes equipped with cameras. The field of view of these nodes depends on the camera opening angle, its direction, and its depth of view. Therefore, coverage and object detection in this type of networks are more challenging compared with the traditional wireless sensor networks. Thus, many researchers propose algorithms and solutions in this field that need tests and simulations. In this paper, we focus on network simulator 3 (ns‐3), which is an open‐source and discrete‐event tool suitable for wireless network simulation targeted primarily for research and educational use. The lack of models that can simulate visual sensor nodes in this simulator motivated us to design and develop a new visual node module as an extension of the ns‐3 core libraries and also to adapt the NetAnim tool to present these nodes graphically. This module will help researchers to simulate, test, and visualize their solutions in wireless visual sensor networks field. In this paper, we present the design and implementation of the proposed module. Furthermore, we show how it can be used in ns‐3 to simulate different scenarios of object detection and visualize the results in NetAnim tool.     

A Stochastic Geometry Approach to Coexistence in Heterogeneous Wireless Networks

With the increasing proliferation of different communication devices sharing the same spectrum, it is critical to understand the impact of interference in heterogeneous wireless networks. In this paper, we put forth a mathematical model for coexistence in networks composed of both narrowband (NB) and ultrawideband (UWB) wireless nodes, based on fundamental tools from stochastic geometry. Our model considers that the interferers are spatially scattered according to a Poisson field, and are operating asynchronously in a wireless environment. We first determine the statistical distribution of the aggregate interference for both cases of NB and UWB emitters. We then provide error probability expressions for two dual configurations: 1) a NB victim link subject to the aggregate UWB interference, and 2) a UWB victim link subject to the aggregate NB interference. The results show that while the impact of a single interferer on a link is often negligible due to restrictions on the transmitted power, the aggregate effect of multiple interferers may cause significant degradation. Therefore, aggregate interference must be considered to ensure coexistence in heterogeneous networks. The proposed analytical framework shows good agreement with physical-level simulations of the system.     

基于ZigBee和CDMA的温室远程测控系统的设计

针对农业数据远程测控的实际需求,本文进行了基于ZigBee协议和CDMA通信技术的温室远程测控系统的设计开发。以支持ZigBee协议的芯片CC2520来构建传感器节点和汇聚节点,以CDMA无线通信模块构建能与INTERNET进行数据连接的网关。传感器节点采用星型拓扑结构组成无线传感器网络后,采集数据并将测量数据发送给汇聚节点,再由汇聚节点发送刮网关,最后网关将数据通过互联网远程传输至测控中心。该测控系统能耗少,组网灵活,安装维护便捷,适合大规模温室的远程无线实时测控。     

基于ACP的RPL路由协议设计与实现

有损低功耗网络路由协议(Routing Protocol for Lossy and Low-power Networks,RPL)是为解决在无线传感网中无线传感节点受限而被提出,现有的实现是基于Contiki和Tiny操作系统,并不能应用在基于有线自治网络的自治控制平面(Autonomic Control Plane,ACP)中。为了对ACP提供可靠的通信支撑,设计和实现了基于ACP的RPL路由协议软件。协议软件主要由通信模块、消息处理模块、路由构造模块以及路由维护模块组成。其中,针对协议的实现是基于Linux操作系统根据ACP标准使用C语言进行开发。测试结果表明,实现的RPL协议能够支持ACP中正常的通信功能。     

Integration of Mobile-IP and OLSR for a Universal Mobility

Trends in fourth generation (4G) wireless networks are clearly identified by the full-IP concept where all traffic (data, control, voice and video services, etc.) will be transported in IP packets. Many proposals are being made to enhance IP with the functionalities necessary to manage the mobility of nodes, so that networks can provide global seamless roaming between heterogeneous wireless and wired networks. In this paper, we focus on the management of universal mobility, including both large scale macro-mobility and local scale micro-mobility. We propose a hierachical architecture (i) extending micro-mobility management of a wireless access network to an ad-hoc access network, (ii) connecting this ad-hoc network to the Internet and (iii) integrating Mobile IP and OLSR, a routing protocol for ad-hoc networks, to manage universal mobility. This architecture is validated by an implementation based on DynamicsMobile-IP and OLSR version 7. We show how the brodcast of Mobile-IP Agent Advertisement can be optimized using OLSR MPR-flooding.     

Interference Analysis in a Poisson Field of Nodes of Finite Area

The research for analytical models that are able to estimate the amount of interference, which is the most important cause of performance degradation in wireless networks, has received a lot of attention over the past few years. This interest is expected to increase in the next few years due to the advent of new architectures and communication technologies, such as wireless networks sharing the same (unlicensed) frequency band, infrastructureless wireless networks, and ultrawideband (UWB) systems. In this paper, we try to overcome some of the limitations of the existing interference models and propose an analytical framework for the evaluation of any statistical moment of the interference provided by a Poisson field of nodes located on a given region of limited area. The propagation environment we consider is characterized by a deterministic distance-dependent path-loss model and log-normal shadowing. The present methodology can be used to provide a fast and accurate evaluation of the amount of interference in many practical situations. Exact closed-form expressions are given for some specific cases.     

适于无线传感器网络节点的语音模块设计

传感器节点是构建无线传感器网络的基本硬件单元。为了扩展无线传感器网络的应用范围,本文为MICA2传感器节点设计了具有采集和播放语音能力的扩展模块。文章首先介绍该语音模块的逻辑结构和工作过程,然后给出模块中语音接口部分的FPGA设计。该设计采用了时钟门控和电路资源共享等技术,具有低功耗和高可靠性特点,只需对FPGA作少量修改即可适用于不同类型的传感器节点。     

基于链路预测和网络编码的MAC机制

提出了基于链路预测和网络编码的MAC协议,在EasiLQE的基础上给出了基于窗口自适应的改进EF滤波器的链路质量预测方法,采用自适应周期的主动探测,增加网络环境稳定时的估计准确性,采用了瞬时主动探测模块,在保证估计稳定性的前提下提高了突发状况下的反应速度。在改进链路质量估计方法的基础上,给出了一种新的MAC协议。在协议中合理地利用了无线网络中已经存在的广播特性,在路由算法确定的路由周围增加高阶辅助节点,从而明显增加了网络编码机会,同时又不会引发由流量集中带来的诸多问题。最后讨论了MAC机制中最优的阶数,在编码机会和能量效率上寻求到一个较为合适的平衡点。实验证明,所提MAC协议能够在不集中流量的前提下合理利用节点的过度侦听提高编码机会,增加网络的吞吐量。     

基于ZigBee无线网络的气体监测报警系统设计

利用ZigBee实现短距离无线传输数据的技术,提出一种基于ZigBee无线网络的气体监测报警系统。该系统包括终端节点、协调器、GSM模块、手机4部分,终端节点与协调器通过ZigBee无线网络进行通信,且对系统的硬件和软件设计进行了分析。当有毒气体浓度超过警戒值,则驱动蜂鸣器和LED指示灯进行声光报警。实践证明,利用ZigBee技术传输数据具有功耗低、时延小、体积小、耗资少等优点。     

A Learning Automata Based Area Coverage Algorithm for Wireless Sensor Networks

One way to reduce energy consumption in wireless sensor networks is to reduce the number of active nodes in the network. When sensors are redundantly deployed, a subset of sensors should be selected to actively monitor the field （referred to as a ＂cover＂）, whereas the rest of the sensors should be put to sleep to conserve their batteries. In this paper, a learning automata based algorithm for energy-efficient monitoring in wireless sensor networks （EEMLA） is proposed. Each node in EEMLA algorithm is equipped with a learning automaton which decides for the node to be active or not at any time during the operation of the network. Using feedback received from neighboring nodes, each node gradually learns its proper state during the operation of the network. Experimental results have shown that the proposed monitoring algorithm in comparison to other existing methods such as Tian and LUC can better prolong the network lifetime.     

基于泛搜索路由协议的AdHoc网络设计与实现

在AdHoc网络技术的工程实现中,路由协议的选择以及硬件无线通信系统设计是要解决的两个关键环节。本文针对节点之间无等级结构的AdHoc网络,基于一种泛搜索路由协议进行AdHoc网络系统设计和实现。硬件通信设备采用单片机C8051F920控制无线数传模块的方案进行设计,按照搜索路由协议对单片机编写程序,继而组建AdHoc网络系统。通过对网络测试所得的数据结果进行分析,表明该路由协议能适应网路拓扑结构变化,准确地找到一条适合传输的路由,所设计通信系统满足AdHoc网络的基本特征。     

无线Ad hoc网络中的联合信源信道有效用户安全识别方法

无线Ad hoc网络采用无线信道、有限电源、分布式控制等技术,因此存在信道安全威胁和大量的能量消耗等问题。为了克服以上问题,论文提出了一种基于DS-CDMA的无线Ad hoc联合信源信道有效用户安全识别方法,对已知头标识采用加密保护,在接收机结点处应用基于子空间的多用户检测技术,并通过有效用户识别方法只对头部数据进行有效用户安全识别,。仿真实验表明：本方法改善了漏警概率和活动用户数估计精度,不但减少了丢弃重发,节省无线模组工作时的能量消耗,同时达到了对有效用户安全识别的目的,提高了信道安全性能。     

Wireless ultrawideband communications and sensor networks

An actively advancing branch of wireless ultrawideband communications is considered. Direct chaotic transceivers of two types are described. The transceivers were developed at the Institute of Radio Engineering and Electronics, Russian Academy of Sciences. Application of these transceivers in wireless sensor networks is demonstrated.     

Asymptotic distribution of the number of isolated nodes in wireless ad hoc networks with Bernoulli nodes

Nodes in wireless ad hoc networks may become inactive or unavailable due to, for example, internal breakdown or being in the sleeping state. The inactive nodes cannot take part in routing/relaying, and thus may affect the connectivity. A wireless ad hoc network containing inactive nodes is then said to be connected, if each inactive node is adjacent to at least one active node and all active nodes form a connected network. This paper is the first installment of our probabilistic study of the connectivity of wireless ad hoc networks containing inactive nodes. We assume that the wireless ad hoc network consists of n nodes which are distributed independently and uniformly in a unit-area disk, and are active (or available) independently with probability p for some constant 0

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