Zigbee無線傳感器網絡英文文獻與翻譯

1、文檔供參考，可復制、編制，期待您的好評與關注！ Zigbee Wireless Sensor Network in Environmental Monitoring ApplicationsI.ZIGBEE TECHNOLOGY Zigbee is a wireless standard based on IEEE802.15.4 that was developed to address the unique needs of most wireless sensing and control applications. Technology is low cost, low power,

2、a low data rate, highly reliable, highly secure wireless networking protocol targeted towards automation and remote control applications. Its depicts two key performance characteristics wireless radio range and data transmission rate of the wireless spectrum. Comparing to other wireless networking p

3、rotocols such as Bluetooth, Wi-Fi, UWB and so on, shows excellent transmission ability in lower transmission rate and highly capacity of network.A. Zigbee Framework Framework is made up of a set of blocks called layers. Each layer performs a specific set of services for the layer above. As shown in

4、Fig.1. The IEEE 802.15.4 standard defines the two lower layers: the physical (PHY) layer and the medium access control (MAC) layer. The Alliance builds on this foundation by providing the network and security layer and the framework for the application layer.Fig.1 Framework The IEEE 802.15.4 has two

5、 PHY layers that operate in two separate frequency ranges: 868/915 MHz and 2.4GHz. Moreover, MAC sub-layer controls access to the radio channel using a CSMA-CA mechanism. Its responsibilities may also include transmitting beacon frames, synchronization, and providing a reliable transmission mechanis

6、m.B. Zigbees Topology The network layer supports star, tree, and mesh topologies, as shown in Fig.2. In a star topology, the network is controlled by one single device called coordinator. The coordinator is responsible for initiating and maintaining the devices on the network. All other devices, kno

7、wn as end devices, directly communicate with the coordinator. In mesh and tree topologies, the coordinator is responsible for starting the network and for choosing certain key network parameters, but the network may be extended through the use of routers. In tree networks, routers move data and cont

8、rol messages through the network using a hierarchical routing strategy. Mesh networks allow full peer-to-peer communication.Fig.2 Mesh topologies Fig.3 is a network model, it shows that supports both single-hop star topology constructed with one coordinator in the center and the end devices, and mes

9、h topology. In the network, the intelligent nodes are composed by Full Function Device (FFD) and Reduced Function Device (RFD). Only the FFN defines the full functionality and can become a network coordinator. Coordinator manages the network, it is to say that coordinator can start a network and all

10、ow other devices to join or leave it. Moreover, it can provide binding and address-table services, and save messages until they can be delivered.Fig.3 Zigbee network modelII.THE GREENHOUSE ENVIRONMENTAL MONITORINGSYSTEM DESIGN Traditional agriculture only use machinery and equipment which isolating

11、and no communicating ability. And farmers have to monitor crops growth by themselves. Even if some people use electrical devices, but most of them were restricted to simple communication between control computer and end devices like sensors instead of wire connection, which couldnt be strictly defin

12、ed as wireless sensor network. Therefore, by through using sensor networks and, agriculture could become more automation, more networking and smarter. In this project, we should deploy five kinds of sensors in the greenhouse basement. By through these deployed sensors, the parameters such as tempera

13、ture in the greenhouse, soil temperature, dew point, humidity and light intensity can be detected real time. It is key to collect different parameters from all kinds of sensors. And in the greenhouse, monitoring the vegetables growing conditions is the top issue. Therefore, longer battery life and l

14、ower data rate and less complexity are very important. From the introduction about above, we know that meet the requirements for reliability, security, low costs and low power.A. System Overview The overview of Greenhouse environmental monitoring system, which is made up by one sink node (coordinato

15、r), many sensor nodes, workstation and database. Mote node and sensor node together composed of each collecting node. When sensors collect parameters real time, such as temperature in the greenhouse, soil temperature, dew point, humidity and light intensity, these data will be offered to A/D convert

16、er, then by through quantizing and encoding become the digital signal that is able to transmit by wireless sensor communicating node. Each wireless sensor communicating node has ability of transmitting, receiving function. In this WSN, sensor nodes deployed in the greenhouse, which can collect real

17、time data and transmit data to sink node (Coordinator) by the way of multi-hop. Sink node complete the task of data analysis and data storage. Meanwhile, sink node is connected with GPRS/CDMA can provide remote control and data download service. In the monitoring and controlling room, by running gre

18、enhouse management software, the sink node can periodically receives the data from the wireless sensor nodes and displays them on monitors.B. Node Hardware Design Sensor nodes are the basic units of WSN. The hardware platform is made up sensor nodes closely related to the specific application requir

19、ements. Therefore, the most important work is the nodes design which can perfect implement the function of detecting and transmission as a WSN node, and perform its technology characteristics. Fig.4 shows the universal structure of the WSN nodes. Power module provides the necessary energy for the se

20、nsor nodes. Data collection module is used to receive and convert signals of sensors. Data processing and control modules functions are node device control, task scheduling, and energy computing and so on. Communication module is used to send data between nodes and frequency chosen and so on.Fig.4 U

21、niversal structure of the wsn nodes In the data transfer unit, the module is embedded to match the MAC layer and the NET layer of the protocol. We choose CC2430 as the protocol chips, which integrated the CPU, RF transceiver, net protocol and the RAM together. CC2430 uses an 8 bit MCU (8051), and ha

22、s 128KB programmable flash memory and 8KB RAM. It also includes A/D converter, some Timers, AES128 Coprocessor, Watchdog Timer, 32K crystal Sleep mode Timer, Power on Reset, Brown out Detection and 21 I/Os. Based on the chips, many modules for the protocol are provided. And the transfer unit could b

23、e easily designed based on the modules. As an example of a sensor end device integrated temperature, humidity and light, the design is shown in Fig. 5. Fig.5 The hardware design of a sensor node The SHT11 is a single chip relative humidity and temperature multi sensor module comprising a calibrated

24、digital output. It can test the soil temperature and humidity. The DS18B20 is a digital temperature sensor, which has 3 pins and data pin can link MSP430 directly. It can detect temperature in greenhouse. The TCS320 is a digital light sensor. SHT11, DS18B20 and TCS320 are both digital sensors with s

25、mall size and low power consumption. Other sensor nodes can be obtained by changing the sensors. The sensor nodes are powered from onboard batteries and the coordinator also allows to be powered from an external power supply determined by a jumper.C. Node Software Design The application system consi

26、sts of a coordinator and several end devices. The general structure of the code in each is the same, with an initialization followed by a main loop. The software flow of coordinator, upon the coordinator being started, the first action of the application is the initialization of the hardware, liquid

27、 crystal, stack and application variables and opening the interrupt. Then a network will be formatted. If this net has been formatted successfully, some network information, such as physical address, net ID, channel number will be shown on the LCD. Then program will step into application layer and m

28、onitor signal. If there is end device or router want to join in this net, LCD will shown this information, and show the physical address of applying node, and the coordinator will allocate a net address to this node. If the node has been joined in this network, the data transmitted by this node will

29、 be received by coordinator and shown in the LCD. The software flow of a sensor node, as each sensor node is switched on, it scans all channels and, after seeing any beacons, checks that the coordinator is the one that it is looking for. It then performs a synchronization and association. Once assoc

30、iation is complete, the sensor node enters a regular loop of reading its sensors and putting out a frame containing the sensor data. If sending successfully, end device will step into idle state; by contrast, it will collect data once again and send to coordinator until sending successfully.D. Green

31、house Monitoring Software DesignWe use VB language to build an interface for the test and this greenhouse sensor network software can be installed and launched on any Windows-based operating system. It has 4 dialog box selections: setting controlling conditions, setting Timer, setting relevant param

32、eters and showing current status. By setting some parameters, it can perform the functions of communicating with port, data collection and data viewing。Zigbee無線傳感器網絡在環(huán)境檢測中的應用1. Zigbee技術Zigbee是一種基于IEEEE802.15.4的無線標準上被開發(fā)用來滿足大多數無線傳感器和控制應用的獨特需求。Zigbee技術是低成本，低功耗，低數據速率，高可靠性，高度安全的無線網絡協(xié)議實現自動化和遠程控制應用的目標。它描述了

33、兩個關鍵的性能特點無線射頻范圍和無線頻譜的數據傳輸速率。相較于其他如藍牙，Wi-Fi技術，超寬帶等無線網絡協(xié)議，Zigbee雖然傳輸速率慢但傳輸容量大的特點向我們展示了他出色的傳輸能力。A. 技術框架Zigbee的框架是有一組層組成的。上訴層中每一層都要執(zhí)行一組特定的服務任務。如圖所示。在IEEE802.15.4標準定義了兩個較低層：物理層（PHY）和媒體接入控制（MAC）層。Zigbee聯(lián)盟建立在網絡層和安全層及應用層框架提供的基礎上。 圖1 技術框架 在IEEE802.15.4有兩個phy層，它們在兩個不同的頻率范圍操作:868/915兆赫和2.4GHz。此外，MAC子層控制訪問無線電頻道

34、使用的CSMA-CA的機制。它的功能還可以包括信標幀傳輸，同步，并開發(fā)一個可靠的傳輸機制。B.Zigbee技術的拓撲 Zigbee網絡層支持星形，樹形和網狀拓撲結構，如圖2所示。在星型拓撲結構中，網絡是由一個叫做Zigbee協(xié)議器的單一設備控制的。Zigbee協(xié)議器負責發(fā)起和維護網絡上面的設備。所有其他設備，稱為終端設備，直接與Zigbee協(xié)議器連接。在網狀和樹狀拓撲結構中，Zigbee協(xié)議器的作用是啟動網絡，并選擇一些重要的網絡參數，但是網絡可以通過Zigbee路由器擴展。在樹狀網絡中，路由器將通過使用分層路由策略移動數據和控制消息。網狀網絡允許完全對等的對等通信。圖2 技術的拓撲 圖3是一

35、個Zigbee網絡模型，它表明Zigbee支持協(xié)議器中心的單挑星型拓撲結構和終端設備，以及網狀拓撲構造。在Zigbee網絡中，智能節(jié)電有全功能設備（FFD）和精簡功能設備（RFD)組成。只有FFN定義了完整的Zigbee功能，并且可稱為網絡協(xié)議器。協(xié)議器管理網絡，也就是說，協(xié)議器可以啟動網絡，并允許其他設備加入或離開它，此外，它還可以提供綁定和地址表服務，并保存，直到它們能傳遞信息。圖3 Zigbee網絡模型 2. 溫室環(huán)境監(jiān)測的系統(tǒng)設計 傳統(tǒng)農業(yè)只使用孤立的和沒有溝通能力的機器和設備。農民們必須自己親自監(jiān)控顧作物的生長。及時有些人用電氣設備，但他們中的大多數只限于控制計算機和終端設備的簡單通

36、信，此終端設備像傳感器而不是像線相連接的傳感器，嚴格意義上來說，不能被定義為無線傳感器網絡，因此，通過使用傳感器網絡和Zigbee，農業(yè)可能變得更加自動化，更加的網絡化和智能化。 在這個項目中，我們要在溫室的地下室部署5種傳感器。通過這些部署的傳感器，如溫室的溫度，土壤溫度，露點，濕度和光照強度的參數可以實時監(jiān)測。他的關鍵是從各種不同的傳感器來收集不同的參數。而在溫室，檢測蔬菜的長勢是首要問題。因此，延長電池的壽命，減少數據數率和降低復雜度是非常重要的。從上述關于Zigbee的介紹，我們知道Zigbee滿足了可靠性，安全性，低成本，低功耗的要求。A、 系統(tǒng)概述溫度環(huán)境監(jiān)測系統(tǒng)是由一個接收器節(jié)點

37、（協(xié)議器）。許多傳感器節(jié)點，工作點和數據庫采集組成的。模特節(jié)點和傳感器節(jié)點共同組成了每個收集節(jié)點。當傳感器參數進行實時采集，如溫室溫度，土壤溫度，露點，濕度，光照強度，這些數據將提供給A/D轉換器，然后透過量化和編碼稱為數字信號，它能通過無線傳感器通信節(jié)點傳送。每一個無線傳感器通信節(jié)點有傳輸和接收的能力。在這種傳感器網絡中，傳感器節(jié)點部署在溫室，它可以采集實時數據和通過多條方式傳輸數據到接收器節(jié)點（協(xié)議器）。接收器節(jié)點完成另外數據分析和存儲的任務。同時，接收器節(jié)點與GPRS/CDMA連接可以提供遠程控制和數據下載服務。在監(jiān)控室通過運行溫室管理軟件，接收器節(jié)點可以定期收到來自無線傳感器節(jié)點和在監(jiān)視器上顯示這些數據。B、節(jié)點的硬件設計在傳感器節(jié)點是無線傳感器網絡的基本單元。硬件平臺是由密切相關的具體應用要求的傳感區(qū)節(jié)點組成的。因此，最重要的工作是節(jié)點設計，可以完美執(zhí)行無線傳感器網絡的傳送和檢測功能，并體現Zigbee的技術特