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1、英文资料翻译ZigBee/IEEE 802.15.4 Networking Examples ZigBee networking has a diverse range of applications, including but not limited to home automation, inventory tracking, and healthcare. This chapter reviews a number of the application scenarios in which ZigBee devices can increase efficiency and/or re
2、duce cost. Full ZigBee protocol implementation has the advantage of reliable mesh networking capability. However, if the application is simple, it might be possible to implement only IEEE 802.15.4 layers. 2.1 Home Automation Home automation is one of the major application areas for ZigBee wireless n
3、etworking. In this section, a number of these use cases are reviewed. The typical data rate in home automation is only 10Kbps. Figure 2.1 shows some of the possible ZigBee applications in a typical residential building. Most of the applications shown in Figure 2.1 are briefly reviewed in this chapte
4、r. 2.1.1 Security Systems A security system can consist of several sensors, including motion detectors, glass-break sensors, and security cameras. These devices need to communicate with the central security panel through either wire or a wireless network. ZigBee-based security systems simplify insta
5、lling and upgrading security systems. Despite ZigBees low data rate, it is still possible to transfer images wirelessly with acceptable quality. For example, ZigBee has been used in a wireless camera system that records videos of visitors at a homes front door and transmits them to a dedicated monit
6、or inside the house. 2.1.2 Meter-Reading Systems Utility meters need to be read on a regular basis to generate utility bills. One way to do so is to read the meters manually at homeowners premises and enter the values into a database. A ZigBee-based automatic meter-reading (AMR) system can create se
7、lf-forming wireless mesh networks across residential complexes that link meters with utilities corporate offices. AMR provides the opportunity to remotely monitor a residences electric, gas, and water usage and eliminate the need for a human visiting each residential unit on a monthly basis. An AMR
8、can do more than simply deliver the total monthly usage data; it can gather detailed usage information, automatically detect leaks and equipment problems, and help in tamper detection. ZigBee-based wireless devices not only perform monitoring tasks, they can manage the usage peak by communicating wi
9、th the appliances inside the house. For example, when there is a surge in electricity usage, a ZigBee-enabled electric water heater can be turned off for a short period of time to reduce the peak power consumption. 2.1.3 Irrigation Systems A sensor-based irrigation system can result in efficient wat
10、er management. Sensors across the landscaping field can communicate to the irrigation panel the soil moisture level at different depths. The controller determines the watering time based on moisture level, plant type, time of day, and the season. A distributed wireless sensor network eliminates the
11、difficulty of wiring sensor stations across the field and reduces the maintenance cost. 2.1.4 Light Control Systems Light control is one of the classic examples of using ZigBee in a house or commercial building. In traditional light installation, to turn on or off the light it is necessary to bring
12、the wire from the light to a switch. Installation of a new recess light, for example, requires new wiring to a switch. If the recess light and the switch are equipped with ZigBee devices, no wired connection between the light and the switch is necessary. In this way, any switch in the house can be a
13、ssigned to turn on and off a specific light. Figure 2.2 is an example of wireless connections between wall switches and lights. In our example, the lights are located in a residential building entrance, living area, and hallway. The wall switch in the entrance can turn on and off any of the four lig
14、hts. The living area wall switch, in contrast, communicates only with the lights in the living area. Living area lights are in close proximity to each other, and therefore a single ZigBee device can be used for both lights. The concept of using binding tables (see Section 1.12) is applicable in the
15、example of Figure 2.2. Wall switch 1 is logically connected to all four lights. Wall switch 2 is bound only to the lights in the living area. One of the devices in the network has the task of storing and updating the binding table. A ZigBee-enabled recess light can be more expensive than a regular r
16、ecess light, but the installation cost of a ZigBee-enabled light is lower because it requires no additional wiring to a wall switch. Using wireless remotes to control the lights is not a new concept. ZigBee provides the opportunity to implement this concept on a large scale by ensuring long battery
17、life and interoperability of products from various vendors in a reliable and low-cost network. In addition to potential cost savings, ZigBee-enabled lights can have other benefits in a house. For example, the ZigBee devices embedded in the recess lights can act as routers to relay a message across t
18、he house, or the lights can be programmed to dim whenever the television set is turned on. The ZigBee light control mechanism has been used for street light controls as well. 2.1.5 Multizone HVAC Systems The multizone control system allows a single heating, ventilation, and air-conditioning (HVAC) u
19、nit to have separate temperature zones in the house. Zoning the HVAC system can help save energy by controlling the flow of air to each room and avoiding cooling or heating unnecessary areas. Figure 2.3 is a simplified diagram that shows motors controlling air dampers and regulating the flow of air
20、to different zones. ZigBee devices control these motors based on the commands they receive from the main HVAC zone control panel and temperature sensors. An alternative way of implementing a multizone control system is to connect the zone control panel, motors, and temperature sensors via wires inst
21、ead of a wireless network. A wired system has less flexibility and additional labor cost for wiring, but the cost of the parts might be slightly lower. Total system cost and flexibility for future modifications should be the decision factors in selecting between these two implementation methods. 2.2
22、 Consumer Electronics: Remote Control In consumer electronics, ZigBee can be used in wireless remote controls, game controllers, a wireless mouse for a personal computer, and many other applications. In this section, we briefly review the application of ZigBee in wireless remotes. An infrared (IR) r
23、emote controller communicates with televisions, DVDs, and other entertainment devices via infrared signals. The limitation of IR remotes is that they provide only one-way communication from the remote to the entertainment device. Also, IR signals do not penetrate walls and other objects and therefor
24、e require line of sight to operate properly. Radio frequency (RF) signals, however, easily penetrate walls and most objects. IEEE 802.15.4 is a proper replacement for IR technology in remote controls because of the low cost and long battery life of ZigBee-based wireless communication. IEEE 802.15.4
25、can be used to create two-way communications between the remote control and the entertainment device. For example, song information or on-screen programming options can be downloaded in to the remote itself, even when the remote control is not in the same room as the entertainment device. 2.3 Indust
26、rial Automation At the industrial level, ZigBee mesh networking can help in areas such as energy management, light control, process control, and asset management. In this section, application of ZigBee in asset management and personnel tracking is briefly reviewed. Asset Management and Personnel Tra
27、cking Passive radio frequency identification (RFID) tags have been in use for several years. Although a passive RFID tag does not have any battery, the RFID reader unit can be a battery-powered instrument. A passive RFID tag can transmit only simple information such as an ID number, which is suffici
28、ent for many asset management applications. Active RFIDs, such as ZigBee devices, are battery powered and generally are more expensive than passive RFIDs. ZigBee-based active RFIDs have longer range than passive RFIDs and can provide additional services such as estimating the location of assets or p
29、ersonnel. Chapter 7 covers the details of ZigBee-based location methods. The basic concept of location estimation is shown in Figure 2.4, where location of personnel is tracked inside a typical office building with offices and cubes. There are three fixed ZigBee nodes with known locations. The mobil
30、e ZigBee node, carried by an employee, broadcasts a signal that is received by all three fixed nodes. The signal becomes weaker as it travels longer; therefore, the amplitude of the signal received by each of the fixed nodes can be different. There are several algorithms that can take the received s
31、ignal strength at the three fixed nodes and calculate the approximate location of the mobile node. The signal transmitted from the mobile node is reflected from walls and other objects in the room before it reaches the fixed nodes, which results in reduced accuracy of the location estimation. Chapte
32、r 7 reviews some of the methods developed to improve the location estimation accuracy. 2.3.2 Livestock Tracking Livestock are vulnerable to disease, and it is important to track and identify a diseased animal quickly. Rapid disease response reduces the number of producers impacted by a disease outbr
33、eak or other animal health events 6 . Passive RFID tags have been used as an inexpensive solution for livestock tracking and can be sufficient for some applications. Passive RFID tags have limited range and can only provide previously stored information such as an identification number. IEEE 802.15.
34、4-based active tags can cost more than passive ones, but the IEEE 802.15.4 tags have extended range and can provide additional information such as animal heartbeat and the animals approximate location. 2.4 Healthcare One of the applications of IEEE 802.15.4 in the healthcare industry is monitoring a
35、 patients vital information remotely. Consider a patient who is staying at his home but for whom it is important that his physician monitor his heart rate and blood pressure continuously. In this system, an IEEE 802.15.4 network can be used to collect data from various sensors connected to the patie
36、nt. The 802.15.4 standard uses 128-bit Advanced Encryption Standard (AES) technology to securely transfer data between ZigBee devices and other networks. Figure 2.5 is a simplified diagram of a remote monitoring system. A patient wears a ZigBee device that interfaces with a sensor, such as a blood p
37、ressure sensor, that gathers the information on a periodic basis. Then this information is transmitted to a ZigBee gateway. A ZigBee gateway provides the interface between a ZigBee network and other networks, such as an Internet Protocol (IP) network. The patient information is then transmitted over
38、 the Internet to a personal computer that the physician or nurse uses to monitor the patient. This system could help hospitals improve patient care and relieve hospital overcrowding by enabling them to monitor patients at home. 2.5 Other Applications 2.5.1 Hotel Guest Room Access ZigBee-based system
39、s can replace the magnetic key card systems used in hotels to access guest rooms. The traditional room access plastic cards have a magnetic strip on their back; the card reader installed on the guest door reads the information encoded into the magnetic strip to allow or deny access to the room. Inst
40、alling this reader for each door requires wiring through the door. Alternatively, a ZigBee- based room access system includes a portable ZigBee device that acts as the key and a battery-powered ZigBee device inside the door that locks and unlocks it. Unlike the traditional method, the ZigBee-based r
41、oom access system does not require wiring each door, which reduces the installation cost. 2.5.2 Fire Extinguishers Fire extinguishers should be checked every 30 days to make sure all the canisters are charged and pressures are correct. Instead of checking the extinguishers manually, in a ZigBee-base
42、d monitoring system a sensor is attached to each extinguisher to monitor its status and wirelessly communicate with the coordinator when maintenance is needed. A ZigBee-based monitoring system not only saves time and labor cost, it also helps improve fire safety by immediately alerting authorities i
43、f a fire extinguisher is not working properly. ZigBee/IEEE 802.15.4 网络应用实例ZigBee非常广泛的应用，包括智能家居、库存跟踪和医疗保健，但又不仅限于此。本章回顾了许多可以运用ZigBee设备提高效率和降低成本的应用实例。完整的ZigBee协议具备可靠的网状网络性能的优点。然而，如果应用很简单，也可能仅使用IEEE 802.15.4层。1.1 智能家居智能家居是ZigBee无线网络的一个主要应用领域。在本节中，回顾了大量这样的用例。在智能家居中典型的数据率只有10 Kbps。图1.1展示了在一个典型的住宅建筑中的一些可行的
44、ZigBee应用。在本章中对图1.1中展示的大多数应用作了简要介绍。1.1.1 安全系统 一个安全系统可以由多个传感器组成，包括运动探测器、玻璃破碎传感器和安全摄像头。这些设备需要通过有线或无线网络与中央安全面板通讯。基于ZigBee的安全系统简化了安全系统的安装和更新过程。尽管ZigBee的数据率很低，但它仍然可以无线传输质量可接受的图像。例如，ZigBee已被应用于一个录制门外访客视频传送到住宅里一个专用监控器的无线摄像系统。图1.1 可能启用ZigBee设备的典型居住建筑1.1.2 抄表系统电表需要定期读取数据生成水电费账单。一种方法是手动读取房主房屋前的电表数值，然后输入到一个数据库。
45、 一个基于ZigBee的自动抄表系统（AMR）可以自发创建一个连接住宅区电表与电表公司办公室的无线网状网络。AMR通过远程监控住宅的电力、煤气和水的使用的机会，并且淘汰了人力每月挨家挨户去查电表的方式。AMR的作用不仅仅是传输每月水电使用量数据；它还可以收集详细的使用信息，自动检测泄漏和设备问题，协助入侵检测。基于ZigBee的无线设备不仅执行监控任务，他们还可以通过和室内的装置通信来管理使用高峰期。例如，当用电量激增时，可以关闭ZigBee电热水器一段时间来降低高峰期用电量。1.1.3 灌溉系统一个基于传感器的灌溉系统能使水资源管理更有效率。田野里的传感器能够把不同深度土壤的湿润程度传给灌溉
46、面板。控制器根据土壤的湿度，植物种类，一天中的时间和季节等情况来确定灌溉时间。分布式无线传感器网络消除了在田野中建立有线传感器基站的困难，降低了维修成本。1.1.4 灯控系统灯光控制是在室内或商业建筑中使用ZigBee的一个典型例子。在传统的照明装置中，必须从电灯到开关扯一根电线来开启或关闭电灯。例如，安装一个新壁灯的时候，需要一条新的到开关的电线。如果壁灯和开关都配备了ZigBee设备的话，那么电灯和开关之间将不再需要电线连接。这样，室内的任何开关都可以被指派来打开和关闭一盏特定的电灯。图1.2是一个墙上开关和电灯间无线连接的例子。在我们的示例中, 电灯位于居民建筑的入口处，居住区和走廊。在
47、入口处的墙壁开关可以打开或关闭任何四个灯。相反, 居住区墙上的开关仅与位于居住区的电灯进行通信。居住区的电灯彼此挨得很近，因此一个ZigBee设备就能够控制这两个灯。使用绑定表的概念也适应于图1.2的例子。墙上开关1逻辑上与所有的4盏灯相连，开关2只与居住区的电灯绑定，网络的其中一个设备负责存储和更新绑定表。一个支持ZigBee的壁灯要比常规的壁灯更贵，但是它的安装费用却较低，因为它不需要额外的电线连接到墙上的开关。使用无线来遥控电灯已经不是一个新的概念，通过确保较长的电池寿命和来自不同经销商的产品的互操作性，ZigBee提供了在可靠的，低成本的网络中大范围实现这个概念的机会。除了潜在的成本节
48、省外，在室内，ZigBee电灯还有其他的好处。例如，嵌入到壁灯内的ZigBee设备可以充当路由器，在房间内转发信息，或者，壁灯可以被编程设计为当电视打开时变暗。ZigBee灯控机制同样也已经被用于路灯控制。图1.2 住宅建筑中的ZigBee无线网络光控系统1.1.5 多层供暖系统在多层的控制系统允许单个的供暖，通风和空调单元在室内有各自的温度区域。HVAC分区系统通过控制每个房间的空气流动可以帮助节省能源，避免对不必要的区域进行冷却或加热。图1.3是一个简化的图表，它显示了发动机控制空气湿度和管理不同房间的空气流动。ZigBee设备根据它们从主HVAC区域控制面板和温度传感器接收到的命令来控制这些发动机。另一种使用多区域控制系统的方法是通过有线而非无线网络的方式来连接区域控制面板，发动机和温度传感器。无线系统有较低的复杂度和额外的布线成本，但是这部分的成本可能会稍微低一些。总共的系统花费和将来的更新复杂度是在这两种应用方法间进行选择的决定因素。. 图1.3 采用ZigBee空气阻尼器的多层空调1.21.31.4 待添加的隐藏文字内容2 消费电子：远程控制在消费电子中，ZigBee可以被用在远程无线控制，游戏控制器，个人电脑的无线鼠标和许多其他应用中。在这部分中，我们简单的介绍了ZigBee在远程无线控制中的应用。红外（IR）远程控制器通过红
