zigbee相關(guān)外文翻譯---無(wú)線技術(shù)，低功耗傳感器網(wǎng)絡(luò)

1、<p>　　ZigBee: Wireless Technology for Low-Power Sensor Networks</p><p>　　Technologists have never had trouble coming up with potential applications for wireless sensors. In a home security system, for e

2、xample, wireless sensors would be much easier to install than sensors that need wiring. The same is true in industrial environments, where wiring typically accounts for 80% of the cost of sensor installations. And then t

3、here are applications for sensors where wiring isn't practical or even possible.</p><p>　　The problem, though, is that most wireless sensors use too much power, which means that their batteries either ha

4、ve to be very large or get changed far too often. Add to that some skepticism about the reliability of sensor data that's sent through the air, and wireless sensors simply haven't looked very appealing.</p>

5、<p>　　A low-power wireless technology called ZigBee is rewriting the wireless sensor equation, however. A secure network technology that rides on top of the recently ratified IEEE 802.15.4 radio standard (Figure 1

6、), ZigBee promises to put wireless sensors in everything from factory automation systems to home security systems to consumer electronics. In conjunction with 802.15.4, ZigBee offers battery life of up to several years f

7、or common small batteries. ZigBee devices are also expected to be cheap, </p><p>　　Although no formal specification for ZigBee yet exists (approval by the ZigBee Alliance, a trade group, should come late thi

8、s year), the outlook for ZigBee appears bright. Technology research firm In-Stat/MDR, in what it calls a "cautious aggressive" forecast, predicts that sales of 802.15.4 nodes and chipsets will increase from ess

9、entially zero today to 165 million units by 2010. Not all of these units will be coupled with ZigBee, but most probably will be. Research firm ON World predicts shipm</p><p>　　In a sense, ZigBee's bright

10、 future is largely due to its low data rates—20 kbps to 250 kbps, depending on the frequency band used (Figure 2)—compared to a nominal 1 Mbps for Bluetooth and 54 Mbps for Wi-Fi's 802.11g technology. But ZigBee won&

11、#39;t be sending email and large documents, as Wi-Fi does, or documents and audio, as Bluetooth does. For sending sensor readings, which are typically a few tens of bytes, high bandwidth isn't necessary, and ZigBee&#

12、39;s low bandwidth helps it fulfill its goals of </p><p>　　Because of ZigBee applications' low bandwidth requirements, a ZigBee node can sleep most of the time, thus saving battery power, and then wake u

13、p, send data quickly, and go back to sleep. And, because ZigBee can transition from sleep mode to active mode in 15 msec or less, even a sleeping node can achieve suitably low latency. Someone flipping a ZigBee-enabled w

14、ireless light switch, for example, would not be aware of a wake-up delay before the light turns on. In contrast, wake-up delays for Blue</p><p>　　A big part of ZigBee's power savings come from the radio

15、technology of 802.15.4, which itself was designed for low power. 802.15.4 uses DSSS (direct-sequence spread spectrum) technology, for example, because the alternative FHSS (frequency-hopping spread spectrum) would have u

16、sed too much power just in keeping its frequency hops synchronized.</p><p>　　ZigBee nodes, using 802.15.4, can communicate in any of several different ways, however, and some ways use more power than others.

17、 Consequently, ZigBee users can't necessarily implement a sensor network any way they choose and still expect the multiple-year battery life that is ZigBee's hallmark. In fact, some technologists who are planning

18、 very large networks of very small wireless sensors say that even ZigBee is too power hungry for their uses.</p><p>　　A ZigBee network node can consume extra power, for example, if it tries to keep its trans

19、missions from overlapping with other nodes' transmissions or with transmissions from other radio sources. The 802.15.4 radio used by ZigBee implements CSMA/CA (carrier sense multiple access collision avoidance) techn

20、ology, and a ZigBee node that uses CSMA/CA is essentially taking a listen-before-talk approach to see if any radio traffic is already underway. But, as noted by Venkat Bahl, marketing vice presid</p><p>　　An

21、other ZigBee and 802.15.4 communications option is the beacon mode, in which normally sleeping network slave nodes wake up periodically to receive a synchronizing "beacon" from the network's control node. B

22、ut listening for a beacon wastes power, too, particularly because timing uncertainties force nodes to turn on early to avoid missing a beacon.</p><p>　　In-Your-Face Communication</p><p>　　To sav

23、e as much power as possible, ZigBee employs a talk-when-ready communication strategy, simply sending data when it has data ready to send and then waiting for an automatic acknowledgement. According to Bob Heile, who is c

24、hairman of both the ZigBee Alliance and IEEE 802.15, talk-when-ready is an "in-your-face" scheme, but one that's very power efficient. "We did an extensive analysis that led to the best power-saving st

25、rategy in various kinds of environments from quiet to noisy," Heile says.</p><p>　　Fortunately, this in-your-face strategy leads to very little RF interference. That's largely because ZigBee nodes h

26、ave very low duty cycles, transmitting only occasionally and sending only small amounts of data. Other ZigBee nodes, as well as Wi-Fi and Bluetooth modules, can easily deal with such small, infrequent bursts.</p>

27、<p>　　ZigBee's talk-when-ready scheme doesn't suit all purposes, however. For example, in a network of thousands of tiny sensors dropped into a war zone to monitor enemy troop movements, the power savings pr

28、ovided still might not be enough. With each network node sending data periodically—and with transmissions repeated numerous times through other nearby nodes of a mesh network configuration in order to reach a network con

29、troller—large numbers of packet collisions and retransmissions could waste powe</p><p>　　Although contention for airwave access isn't generally a problem for ZigBee, it can be. Sensor-network company Dus

30、t Networks, in fact, says contention issues are keeping the company from turning to ZigBee—for now, at least—even though Dust remains a member of the ZigBee Alliance. "Each ZigBee device needs to contend for airspac

31、e with its neighbors," says Dust director of product management Robert Shear, "so there's inevitably some contention and some inefficiency." To avoid ZigBee's access conte</p><p>　　Zig

32、Bee has still more power-saving tricks up its sleeve, however. For example, it reduces power consumption in ZigBee components by providing for power-saving reduced-function devices (RFDs) in addition to more capable full

33、-function devices (FFDs). Each ZigBee network needs at least one FFD as a controller, but most network nodes can be RFDs (Figure 3). RFDs can talk only with FFDs, not to other RFDs, but they contain less circuitry than F

34、FDs, and little or no power-consuming memory.</p><p>　　ZigBee conserves still more power by reducing the need for associated processing. Simple 8-bit processors like an 8051 can handle ZigBee chores easily,

35、and ZigBee protocol stacks occupy very little memory. An FFD stack, for example, needs about 32 kbytes, and an RFD stack needs only about 4 kbytes. Those numbers compare with about 250 kbytes for the far more complex Blu

36、etooth technology.</p><p>　　From ZigBee's relatively simple implementations, cost savings naturally accrue. RFDs, of course, reduce ZigBee component costs by omitting memory and other circuitry, and simp

37、le 8-bit processors and small protocol stacks help keep system costs down. Often, an application's main processor can easily bear the small additional load of ZigBee processing, making a separate processor for ZigBee

38、 functions unnecessary.</p><p>　　But the main strategy for keeping ZigBee prices low is to have big markets and high volumes. The ZigBee Alliance, by making ZigBee an open standard and by vigorously promotin

39、g interoperability among ZigBee devices, expects that ZigBee will be very big in applications such as home and building automation. The alliance is currently working on interoperability procedures for those particular ap

40、plications, which it expects to complete later this year along with ZigBee Specification 1.0.</p><p>　　One reason for optimism about ZigBee adoption for home automation and security is its ease of use. ZigBe

41、e networks are self-forming, making it easy even for consumers to set them up. "In the residential space, there's no configuration involved," says the ZigBee Alliance's Heile. "You take something o

42、ut of the box, put the batteries in, and maybe do something as simple as button-press security—bring two devices close together, push the buttons until the green lights come on, and you're done."</p><

43、p>　　ZigBee networks can also self-form in commercial and industrial settings, but professional installers will have tools that provide additional control, particularly for security. ZigBee security is flexible, says H

44、eile, to give both consumer and professional users what they need. "You don't have to have 128-bit public-key encryption for a smoke detector," he says, "but if I'm in a high-rise office complex, t

45、hat's exactly the level of security I'm going to have for my fluorescent light fixtures. I</p><p>　　Proprietary Competition</p><p>　　Competition for ZigBee comes almost entirely from pro

46、prietary technologies. Sensor company Dust, as noted, is sticking with its own technology, and Ember, although pushing strongly into the ZigBee arena, plans to keep offering its proprietary EmberNet as well. In addition,

47、 Zensys is providing its Z-Wave technology to customers. Sylvania, for example, is already using Z-Wave for lighting control, while ZigBee systems remain at least several months away. </p><p>　　By offering i

48、nteroperability, however, ZigBee adds capabilities that proprietary products can't. For example, says Ember's Bahl, interoperability allows the ZigBee nodes of a lighting system to work with the ZigBee network of

49、 an HVAC system, or vice versa. "Philips Lighting is really excited about this," Bahl, says, "because it turns them from a ballast manufacturer into the infrastructure backbone of a building-automation sys

50、tem."</p><p>　　Needless to say, many of the major semiconductor companies, and especially those that are big in embedded systems, are eagerly anticipating ZigBee's entry into mass markets. Freescale

51、 Semiconductor (until recently known as Motorola's Semiconductor Products Sector) is already providing ZigBee-ready technology to select customers. Other semiconductor companies, including AMI, Atmel, Microchip, Phil

52、ips, and Renesas, are members of the ZigBee Alliance.</p><p>　　ZigBee will likely be slow to penetrate the industrial market for wireless sensors, however. According to market research firm ON World, it will

53、 take five to seven years to convince industrial customers of the reliability, robustness, and security of wireless-sensor systems. ON World does predict significant long-term growth of ZigBee in industry, though. By 201

54、0, the company projects, RF modules used in industrial monitoring and control will reach 165 million units, up from 1.9 million in 2004.</p><p>　　Eventually, ZigBee could go into a wide variety of applicatio

55、ns. In household appliances, it could help monitor and control energy consumption. In automotive applications, it could provide tire-pressure monitoring and remote keyless entry. ZigBee could also be used in medical devi

56、ces or even in computer peripherals, such as wireless keyboards or mice.</p><p>　　Concern is increasing, though, that ZigBee could turn into a one-size-fits-all technology that doesn't fit any applicatio

57、n particularly well. Some skeptics, for example, worry that an attempt to make ZigBee all-encompassing could make the ZigBee protocol stack too large for ZigBee's twin goals of very low power consumption and very low

58、 cost. If that happens, then ZigBee's low-power, low-data-rate niche—narrow as it is—will have proven to be too broad. And then, perhaps, we'll need yet another wi</p><p>　　ZigBee：無(wú)線技術(shù)，低功耗傳感器網(wǎng)絡(luò)</p

59、><p>　　技師（工程師）們?cè)诎l(fā)掘無(wú)線傳感器的潛在應(yīng)用方面從未感到任何困難。例如，在家庭安全系統(tǒng)方面，無(wú)線傳感器相對(duì)于有線傳感器更易安裝。而有線傳感器裝置布線的花費(fèi)通常占無(wú)線傳感器安裝費(fèi)用的80%的工業(yè)環(huán)境方面也是同樣適用。而且在有線傳感器的不適合甚至是不能使用的領(lǐng)域，無(wú)線傳感器更具應(yīng)用性。</p><p>　　雖然，無(wú)線傳感器需要消耗更多能量，也就是說(shuō)所需電池的數(shù)量會(huì)隨之增加或充電過(guò)于頻繁

60、。再加上對(duì)無(wú)線傳感器經(jīng)空氣傳送數(shù)據(jù)可靠性的懷疑，所以無(wú)線傳感器看起來(lái)并不是那么吸引人。</p><p>　　一個(gè)低功率無(wú)線技術(shù)被稱為ZigBee，它是無(wú)線傳感器技術(shù)的革新。但是，一個(gè)安全的網(wǎng)絡(luò)技術(shù)，對(duì)最近通過(guò)的IEEE 802.15.4無(wú)線標(biāo)準(zhǔn)（圖1）的頂部游戲機(jī)，ZigBee承諾把無(wú)線傳感器應(yīng)用到從工廠自動(dòng)化系統(tǒng)、家庭安全系統(tǒng)到消費(fèi)電子產(chǎn)品的一切領(lǐng)域。與802.15.4的合作下，ZigBee使用的電池壽命可比普

61、通小型電池的長(zhǎng)幾年。 ZigBee設(shè)備的價(jià)格預(yù)計(jì)也比較便宜，有人估計(jì)銷售價(jià)格最終不到3美元每節(jié)點(diǎn)。由于價(jià)格低，他們自然適應(yīng)用在于如無(wú)線光線開(kāi)關(guān)，無(wú)線自動(dòng)調(diào)溫器，煙霧探測(cè)器等家用產(chǎn)品。</p><p>　　圖1 ZigBee在IEEE811.15.4規(guī)范定義的物理層和MAC層的基礎(chǔ)上添加了網(wǎng)絡(luò)/安全層和應(yīng)用服務(wù)層</p><p>　　雖然還沒(méi)有正式的ZigBee規(guī)范存在（由于ZigBee聯(lián)

62、盟是一個(gè)貿(mào)易集團(tuán)，規(guī)范應(yīng)該在年底推出），但ZigBee的前景一片光明。 技術(shù)研究公司In-Stat/MDR在它所謂的“謹(jǐn)慎進(jìn)取”的預(yù)測(cè)中，預(yù)測(cè)802.15.4節(jié)點(diǎn)和芯片的銷售量將從現(xiàn)在基本上為零，增加到2010年的165萬(wàn)個(gè)。 不是所有這些節(jié)點(diǎn)都將與ZigBee結(jié)合，但大多數(shù)可能會(huì)。 世界研究公司預(yù)測(cè)，到2010年射頻模塊無(wú)線傳感器出貨量達(dá)4.65億，其中77％是ZigBee相關(guān)的。</p>

63、<p>　　從某種意義上說(shuō)，ZigBee的光明前途在很大程度上是由于其較低的數(shù)據(jù)速率—20 kbps到250 kbps，取決于使用的頻率 （圖2）， 比1 Mbps的藍(lán)牙和54Mbps的802.11g的Wi-Fi的技術(shù)。 但ZigBee不能像Wi-Fi那樣發(fā)送電子郵件和大型文件，也不能像藍(lán)牙那樣發(fā)送文件和音頻。對(duì)于發(fā)送傳感器的數(shù)據(jù)，它只有幾十字節(jié)數(shù)，高帶寬是沒(méi)有必要的，ZigBee的低帶寬有助于它實(shí)現(xiàn)低功耗

64、，低成本和魯棒性。</p><p>　　圖2 ZigBee的數(shù)據(jù)傳輸速率為20kbps到250kbps，其取決于使用的頻率大小</p><p>　　由于ZigBee應(yīng)用的是低帶寬要求，ZigBee節(jié)點(diǎn)大部分時(shí)間可以采用睡眠模式，從而節(jié)省電池電源，然后醒來(lái)，快速發(fā)送數(shù)據(jù)，回到睡眠模式。而且，由于ZigBee可以用15毫秒或更少的時(shí)間從睡眠模式醒來(lái)，即使是睡眠節(jié)點(diǎn)也可以達(dá)到適當(dāng)?shù)牡脱舆t。&#

65、160;有人反對(duì)基于ZigBee的無(wú)線光開(kāi)關(guān)，例如，將不會(huì)在燈亮起前知道喚醒延遲。與此相反，藍(lán)牙喚醒延遲通常大約三秒鐘。</p><p>　　ZigBee的功耗節(jié)省中的很大一部分來(lái)自802.15.4無(wú)線電技術(shù)，它本身是為低功耗設(shè)計(jì)的。 802.15.4采用DSSS（直接序列擴(kuò)頻）技術(shù)，例如，因?yàn)镕HSS（跳頻擴(kuò)頻）會(huì)消耗很多能量用于保持它的頻率跳變同步。</p><p>　　使用

66、802.15.4的ZigBee節(jié)點(diǎn)，可以用幾種不同的方式通信，然而，某些方式比其他的消耗更多的電能。 因此，ZigBee的用戶不一定能夠?qū)崿F(xiàn)他們想要的任何傳感器網(wǎng)絡(luò)，他們?nèi)匀黄谕鸝igBee的特點(diǎn)—多年的電池壽命。事實(shí)上，一些技術(shù)專家打算用小型無(wú)線傳感器創(chuàng)建大的網(wǎng)絡(luò)，即使ZigBee的電池滿足不了他們的需求。</p><p>　　一個(gè)ZigBee網(wǎng)絡(luò)節(jié)點(diǎn)可以消耗額外的功率，例如，如果它試圖避免與其他節(jié)點(diǎn)

67、的傳輸或與其他無(wú)線電的傳輸產(chǎn)生沖突。 那么采用802.15.4標(biāo)準(zhǔn)的ZigBee使用CSMA / CA（載波偵聽(tīng)多址接入沖突避免）技術(shù)，ZigBee節(jié)點(diǎn)使用CSMA / CA本質(zhì)上采取的是監(jiān)聽(tīng)先于通話的方式，看是否有無(wú)線電通信已經(jīng)進(jìn)行。 但是，正如傳感器營(yíng)銷公司恩貝爾公司副總裁兼ZigBee聯(lián)盟的副主席Venkat Bahl所指出的，這不是一個(gè)首選的方法?！氨O(jiān)聽(tīng)消耗更多的電能”，Bahl說(shuō)，“我們不喜歡這樣做。”&l

68、t;/p><p><b>　　當(dāng)面通信</b></p><p>　　ZigBee和802.15.4通訊的另一個(gè)選擇是同步模式，通常從睡眠模式醒來(lái)的網(wǎng)絡(luò)從節(jié)點(diǎn)定期從網(wǎng)絡(luò)的控制節(jié)點(diǎn)接收同步幀。 但是，監(jiān)聽(tīng)同步幀信號(hào)浪費(fèi)電能，同時(shí)也因?yàn)闀r(shí)間的不確定性，強(qiáng)制節(jié)點(diǎn)提前打開(kāi)，以免錯(cuò)過(guò)同步幀信號(hào)。</p><p>　　為了盡可能節(jié)省電力，ZigBee采

69、用一種“就緒時(shí)通話”的通信策略，當(dāng)數(shù)據(jù)準(zhǔn)備好后發(fā)送數(shù)據(jù)，然后等待自動(dòng)確認(rèn)。根據(jù)ZigBee聯(lián)盟兼802.15協(xié)會(huì)主席Bob Heile說(shuō)，“就緒時(shí)通話”是一種“當(dāng)面通信”的計(jì)劃，但電力效率很高?！拔覀儚V泛地分析了在各種從安靜到嘈雜的環(huán)境下最省電的策略，”Heile說(shuō)，“我們發(fā)現(xiàn)，我們?nèi)菀讓?shí)現(xiàn)在發(fā)送數(shù)據(jù)包和承認(rèn)它。如果你沒(méi)收到確認(rèn)信息，表示你發(fā)送失敗了，所以進(jìn)行重發(fā)。這種方式比監(jiān)聽(tīng)并確認(rèn)通話前是否安靜的方式具有更好的電源管理性能?！?lt

70、;/p><p>　　幸運(yùn)的是，這種當(dāng)面策略導(dǎo)致的RF干擾非常小。 這主要是因?yàn)閆igBee節(jié)點(diǎn)具有非常低的占空比，只是偶爾傳輸并且每次發(fā)送少量的數(shù)據(jù)。 其他ZigBee節(jié)點(diǎn)，以及Wi-Fi和藍(lán)牙模塊，可以輕松應(yīng)付這么小，不頻繁的數(shù)據(jù)量。</p><p>　　但是，ZigBee的就緒時(shí)通話計(jì)劃并不適合所有的目的。例如，在戰(zhàn)區(qū)中部署由成千上萬(wàn)的微型傳感器組成的傳感器網(wǎng)絡(luò)用于監(jiān)視

71、敵方部隊(duì)的調(diào)動(dòng)，提供的電能儲(chǔ)備仍可能是不夠的。每個(gè)網(wǎng)絡(luò)節(jié)點(diǎn)周期性地發(fā)送，并通過(guò)網(wǎng)狀網(wǎng)絡(luò)中的其他鄰近節(jié)點(diǎn)多次重發(fā)以使數(shù)據(jù)包到達(dá)網(wǎng)絡(luò)控制器，大量的數(shù)據(jù)包碰撞和重發(fā)數(shù)據(jù)包會(huì)浪費(fèi)電能，并顯著縮短傳感器節(jié)點(diǎn)的電池壽命。 如果傳感器電池量非常小并且功率有限，這特別成問(wèn)題。</p><p>　　雖然電波信道競(jìng)爭(zhēng)對(duì)于ZigBee不是一個(gè)普遍的問(wèn)題，但它有成為問(wèn)題的可能。 傳感器網(wǎng)絡(luò)公司Dust網(wǎng)絡(luò)表示，競(jìng)爭(zhēng)問(wèn)

72、題使該公司轉(zhuǎn)向ZigBee，至少在現(xiàn)在，即使Dust公司仍是ZigBee聯(lián)盟的成員。 “每個(gè)ZigBee設(shè)備需要與相關(guān)領(lǐng)域爭(zhēng)奪信道，” Dust公司產(chǎn)品管理總監(jiān)Robert Shear 說(shuō)，“所以有一些不可避免的競(jìng)爭(zhēng)和低效率?！睘榱吮苊鈀igBee信道的爭(zhēng)奪，Dust公司使用免競(jìng)爭(zhēng)的TDMA（時(shí)分多址）技術(shù)。 ZigBee通過(guò)802.15.4的MAC層提保證時(shí)隙，有點(diǎn)類似于TDMA的時(shí)隙，但只是作為一個(gè)可選的“超幀”

73、，比TDMA更復(fù)雜，更省電。</p><p>　　但是ZigBee仍然有更省電的方式。 例如，它在除了性能更好的全功能設(shè)備(FFDs)之外還提供了更省電的半功能設(shè)備(RFDs)。 每個(gè)ZigBee網(wǎng)絡(luò)至少需要一個(gè)全功能設(shè)備FFDs作為一個(gè)控制器，但大多數(shù)網(wǎng)絡(luò)節(jié)點(diǎn)可以是半功能設(shè)備RFDs。 RFDs只能和FFDs通信，而不能和其他RFDs通信，它們比FFDs電路簡(jiǎn)單，很少或沒(méi)有功率消耗

74、內(nèi)存。</p><p>　　圖3 ZigBee網(wǎng)絡(luò)可在多種配置中包含多達(dá)65536個(gè)節(jié)點(diǎn)</p><p>　　ZigBee還通過(guò)減少相關(guān)處理能力來(lái)節(jié)省電能。 簡(jiǎn)單的8位處理器像8051可以容易地處理ZigBee的任務(wù)，并且ZigBee協(xié)議棧占用很少的內(nèi)存。 例如，一個(gè)全功能設(shè)備的協(xié)議棧，大概需要32字節(jié)，而一個(gè)半功能設(shè)備的協(xié)議棧只需要4字節(jié)。 耗費(fèi)250字節(jié)

75、內(nèi)存空間藍(lán)牙技術(shù)與之相比顯得復(fù)雜的多。</p><p>　　由于ZigBee實(shí)現(xiàn)簡(jiǎn)單，自然節(jié)約了成本。 RFDs，通過(guò)減少內(nèi)存空間和電路成本降低了ZigBee的元件花費(fèi)，同時(shí)簡(jiǎn)單的8位處理器和小型的協(xié)議棧幫助保持了系統(tǒng)的低成本。 通常，ZigBee處理器能夠很輕松的勝任一個(gè)應(yīng)用程序的處理要求，使得ZigBee不需要額外的處理器。</p><p>　　但是，保持ZigBe

76、e低價(jià)格的主要策略是為了擁有很大的市場(chǎng)空間和高占有率。ZigBee聯(lián)盟，通過(guò)開(kāi)放ZigBee標(biāo)準(zhǔn)和推進(jìn)ZigBee設(shè)備之間的互操作性，期待ZigBee在家庭與樓宇自動(dòng)化領(lǐng)域產(chǎn)生巨大作用。 該聯(lián)盟目前正在致力于為這些特殊應(yīng)用制定規(guī)范，它預(yù)計(jì)將在今年較遲推出ZigBee規(guī)范1.0。</p><p>　　一個(gè)ZigBee能勝任家庭自動(dòng)化與安全應(yīng)用的原因就是它的易用性。ZigBee網(wǎng)絡(luò)的自組織，使消費(fèi)者更容易對(duì)

77、它們進(jìn)行設(shè)置?！霸诰幼】臻g，沒(méi)有相關(guān)的配置條件，” ZigBee聯(lián)盟的Heile說(shuō)，“只需你從箱子拿出一些東西，放電池進(jìn)去，可能做一些簡(jiǎn)單的操作，如按下安全按鈕使兩個(gè)設(shè)備并攏，直到亮起綠色燈光，你就完成操作了。”</p><p>　　ZigBee網(wǎng)絡(luò)還可以在商業(yè)和工業(yè)環(huán)境自我形成，但專業(yè)安裝人員將有特別的工具，提供額外的控制功能。 ZigBee的安全功能是靈活的，Heile說(shuō)，分別給消費(fèi)者和專業(yè)用戶提供

78、他們各自需要的?！澳悴槐貫闊熿F探測(cè)器設(shè)置128位公共密鑰的加密，”他說(shuō)，“但如果我在一幢復(fù)雜的高層辦公樓，這就需要增加熒光燈的安全級(jí)別。如果你在第五大道上的高層建筑里，你不想有人在街上把你的燈關(guān)調(diào)?！?lt;/p><p><b>　　專利競(jìng)爭(zhēng)</b></p><p>　　ZigBee的競(jìng)爭(zhēng)幾乎完全來(lái)自專利技術(shù)。 傳感器公司Dust，如上所述，堅(jiān)持使用自己的技術(shù)，

79、而Ember公司，雖然已經(jīng)進(jìn)入了ZigBee領(lǐng)域，但仍計(jì)劃繼續(xù)提供其專有的Ember Net設(shè)備。 此外，Zensys公司向客戶提供Z-Wave技術(shù)。 例如，西爾韋尼亞，已經(jīng)使用Z – Wave進(jìn)行照明控制，而ZigBee系統(tǒng)至少在數(shù)個(gè)月后才能使用。</p><p>　　但是，通過(guò)提供互操作性， ZigBee擁有兼容能力，而專利產(chǎn)品則沒(méi)有。 比如，Ember的Bahl說(shuō)，互操作性允許

80、照明系統(tǒng)的ZigBee節(jié)點(diǎn)和一個(gè)空調(diào)系統(tǒng)的ZigBee網(wǎng)絡(luò)一同工作，反之亦然?！帮w利浦照明對(duì)此很興奮，” Bahl說(shuō)，“因?yàn)檫@使他們從原來(lái)從一個(gè)鎮(zhèn)流器生產(chǎn)廠家進(jìn)入到樓宇自動(dòng)化系統(tǒng)的基礎(chǔ)設(shè)施主力廠家?！?lt;/p><p>　　不用說(shuō)，許多主流的半導(dǎo)體公司，尤其是那些在嵌入式系統(tǒng)中的大公司都熱切期待ZigBee大規(guī)模投入市場(chǎng)。飛思卡爾半導(dǎo)體（直到最近，摩托羅拉半導(dǎo)體產(chǎn)品部稱）已經(jīng)提供ZigBee - ready技術(shù)來(lái)選

81、擇客戶。其他半導(dǎo)體公司，包括AMI，愛(ài)特梅爾，微芯，飛利浦，瑞薩，都是ZigBee聯(lián)盟的成員。 </p><p>　　ZigBee可能是緩慢滲透到無(wú)線傳感器的工業(yè)市場(chǎng)。但是，據(jù)市場(chǎng)研究公司ON World表示，它會(huì)需要五至七年來(lái)說(shuō)服工業(yè)客戶相信其在工業(yè)上的可靠性，耐用性，以及無(wú)線傳感器系統(tǒng)的安全性。但是，ON World公司預(yù)測(cè)ZigBee將長(zhǎng)期在工業(yè)制造上保持增長(zhǎng)。到2010年，應(yīng)用于工業(yè)監(jiān)測(cè)和控制領(lǐng)域的公司

82、項(xiàng)目、射頻模塊將從2004年的190萬(wàn)臺(tái)增長(zhǎng)到1.65億臺(tái)。ON World公司預(yù)測(cè)這些模塊中有大約75％將基于ZigBee和802.15.4。</p><p>　　最終，ZigBee可進(jìn)入各種廣泛的應(yīng)用。在家用電器應(yīng)用中，它可以幫助監(jiān)測(cè)和控制能源消耗。在汽車應(yīng)用中，它可以提供輪胎壓力監(jiān)測(cè)和遠(yuǎn)程無(wú)鑰匙準(zhǔn)入系統(tǒng)。ZigBee也可用于醫(yī)療設(shè)備中，甚至用于在計(jì)算機(jī)外圍設(shè)備，如無(wú)線鍵盤(pán)或鼠標(biāo)。</p>&l

83、t;p>　　雖然關(guān)注ZigBee的人越來(lái)越多，ZigBee可能變成一種適用性極強(qiáng)的技術(shù)，但它不可能適合任何的應(yīng)用。例如，一些懷疑者擔(dān)心，如果使ZigBee技術(shù)無(wú)所不包，可能會(huì)導(dǎo)致ZigBee協(xié)議棧太大，則無(wú)法實(shí)現(xiàn)ZigBee的最重要的兩個(gè)目標(biāo)即低功耗和低成本。如果出現(xiàn)這種情況，那么ZigBee的低功耗、低數(shù)據(jù)速率、基帶窄的特點(diǎn)將不復(fù)存在。然后，也許我們會(huì)需要另一種無(wú)線標(biāo)準(zhǔn)，以配合我們已經(jīng)有的蓬勃發(fā)展的新技術(shù)。</p>