Zigbee无线解决方案网络层研究

文章介绍了Zigbee网络的组网过程及网络扩展的方法;首先简单介绍了Zigbee协议的网络层,接着给出了建立一个新网络的过程,及加入网络的两种方法;在这里,孩子节点可通过以下两种方式加入到网络中:通过MAC子层连接程序加入或通过先前指派的父节点直接加入网络;最后,文章针对Zigbee网络的现状及发展情况,提出了未来在无线Zigbee网络研究中需要解决的问题.     

LR-WPAN Mesh网络双重能效优化设计

针对IEEE 802.15.5低速无线个域网(LR-WPAN)标准缺乏能效均衡设计的问题,提出LR-WPAN Mesh网络双重能效优化方法.在自适应树建立和拓扑引导分布式链路状态路由环节中引入合理的能效评估要素,优化拓扑结构和路由选择.实验结果表明,双重能效优化方法可使网络寿命延长97％,并使网络的能耗更加均衡.     

一种新的LR—WPAN协议特点及应用分析

本文介绍了最新发展的低速无线个人区域网(LR-W PAN)IEEE 802.15.4协议的产生背景和技术特点,研究了实现802.15.4协议的几项关键技术,并在与蓝牙技术进行比较的基础上,探讨了其网络性能和应用前景。     

一种面向低速无线个域网的AODV改进协议

针对低速无线个域网的特点,在AODV基础上设计并实现了一种考虑节能、对硬件资源要求低、收敛速度快的路由协议,该协议包含"反馈控制标志"、"上游节点寻路"、"只限广播的扩展环搜索"等优化策略。进一步给出路由协议模型、报文格式以及算法实现流程,与同类协议进行了性能比较。实验结果表明,协议在存储资源消耗、链路修复、带宽占用等方面具有很强的优势。     

低速无线个人区域网802．15．4的安全研究

短距离无线通信技术近年来成为通信领域热点,其主要特征是低功耗、低成本和低数据率,可广泛应用于军事、工业控制、精准农业及医学等领域的无线传感器网络构建,将会在未来的后PC即普适计算时代发挥重要作用.同时,由于其开放传输信道和"三低"特性,安全性成为保证短距无线通信网络健壮稳定运行的关键"基石".针对低速无线个人区域网(LR-WPAN)802.15.4,详细分析其安全架构,根据最高安全级别组件AEs-CCM的底层加密算法AES和泛型CCM模式,结合安全帧格式,提出了一种AES-CCM实施的输入分组模型,并进行时间性能对比实验.针对LR-WPAN可能存在的攻击和802.15.4潜在的安全问题,提出相应的改进措施.     

LR-WPAN捷径式能量均衡树路由算法研究

针对LR-WPAN网络中ZigBee树路由算法存在的不足,在综合考虑单个节点的生存周期和整个网络能量消耗的基础上,提出一种捷径式能量均衡树路由算法。通过在节点中使用邻居表以及表中添加动态剩余能量标志位,结合路由跳数、节点和网络的能量状态设计路由算法。运用仿真实验与原始树路由算法进行分析对比,表明改进后的路由算法有效地降低了路由开销和网络节点间的延时,提高了节点存活率和路由效率,达到优化网络能效,延长网络生存周期的目的。     

An optimal GTS scheduling algorithm for time-sensitive transactions in IEEE 802.15.4 networks

IEEE 802.15.4 is a new enabling standard for low-rate wireless personal area networks and has been widely accepted as a de facto standard for wireless sensor networking. While primary motivations behind 802.15.4 are low power and low cost wireless communications, the standard also supports time and rate sensitive applications because of its ability to operate in TDMA access modes. The TDMA mode of operation is supported via the Guaranteed Time Slot (GTS) feature of the standard. In a beacon-enabled network topology, the Personal Area Network (PAN) coordinator reserves and assigns the GTS to applications on a first-come-first-served (FCFS) basis in response to requests from wireless sensor nodes. This fixed FCFS scheduling service offered by the standard may not satisfy the time constraints of time-sensitive transactions with delay deadlines. Such operating scenarios often arise in wireless video surveillance and target detection applications running on sensor networks. In this paper, we design an optimal work-conserving scheduling algorithm for meeting the delay constraints of time-sensitive transactions and show that the proposed algorithm outperforms the existing scheduling model specified in IEEE 802.15.4.     

ZigBee无线传感器网络组网研究

综述了ZigBee网络的组网过程;简单介绍了ZigBee的技术特点,给出了建立一个新网络的过程,及加入网络的两种方法;最后展望了ZigBee技术的发展前景。     

A 2.4 GHz low power CMOS transceiver for LR-WPAN applications

A 2.4 GHz low power transceiver for low-rate wireless personal area network(LR-WPAN)applications is presented.The optimized low-IF receiver consists of a novel current reuse RF front-end with an inductor-less-load balun LNA and quadrature mixer,and an adaptive analog baseband to reduce power and area.It achieves-94 dBm of sensitivity,-9 dBm of IIP3 and 28 dBc of image rejection.The phase-locked loop based direct phase modulated transmitter is proposed to reduce power and deliver a+3 dBm output power.The phase noise of the low power frequency synthesizer with current reuse stacked LC-VCO achieves-107.8 dBc/Hz at 1 MHz offset.An ultra-low power nonvolatile memory is used to store configuration data and save power.The chip is implemented in a 0.18μm CMOS process,and the area is less than 2.8 mm2.The transceiver consumes only 10.98 mW in the receiving mode and 13.32 mW in the transmitting mode.     

Reliable beacon transmission based MAC protocol for LR-WPANs over WLAN interferences

The use of IEEE 802.15.4 standard based application systems has been rapidly increasing, for example, in medical services, sensor networks, public safety systems, and home automation systems. However, issues arise from the fact that IEEE 802.15.4 standard based low rate wireless personal area networks （LR-WPANs） use the same frequency bands as wireless local area networks （WLANs）, and they interfere with each other. Based on past research on this issue, the interference has a more serious impact on LR-WPANs＇ performance than on WLANs＇ performance. In this paper we propose a method to improve LR-WPANs＇ performance while coexisting with WLANs, which is called the reliable beacon transmission based medium access control （MAC） protocol. Since the reliability of a beacon frame is important, in this method, only the beacon frame is transmitted in interference-free channels, and the data packets are transmitted in interfered channels instead of abandoning the channels altogether. This method increases the reliability of beacon frames as well as overall channel utilizations. The effectiveness of the proposed method was evaluated through extensive simulations, and this paper proves that this method improves the performance of IEEE 802.15.4 based wireless sensor networks （WSNs） over WLANs＇ interferences.