Bluetooth and ZigBee have much in common. Both are types of IEEE 802.15 “wireless personal-area networks,” or WPANs. Both run in the 2.4-GHz unlicensed frequency band, and both use small form factors and low power.

At the Wireless Communications Alliance's recent meeting in Silicon Valley, Bhupender Virk, president and CEO of WPAN components maker CompXs, sorted out the application and technical differences between Bluetooth (IEEE 802.15.1) and the ZigBee specification (based on IEEE 802.15.4), which was ratified in December.

ZigBee protocols define a type of sensor network for residential and commercial applications such as heating, air conditioning and lighting control. It combines IEEE 802.15.4, which defines the physical and MAC protocol layers, with network, security and application software layers as specified by the ZigBee Alliance, a consortium of technology companies.

Imagine the freedom if light switches were to become wireless, eliminating the electrical cabling through your walls, for example.

Bluetooth, as you likely know, eliminates cabling between electronic products and accessories, such as between computers and printers or between phones and headsets. Bluetooth users with handhelds or laptops can exchange files, business cards and calendar appointments. Bluetooth is more oriented toward user mobility and eliminating short-distance cabling; ZigBee aims more for grand-scale automation and remote control.

The first ZigBee products are now in interoperability testing through April, says Virk, who expects alliance-certified products to be available in the third quarter (when he says CompXs will ship a ZigBee protocol analyzer). Industry reports imply that, eventually, ZigBee might be built into mobile phones via dual-function ZigBee-Bluetooth chips for remote control of nearly anything you can think of and for buying items from vending machines.

Finally, for the geeks among us, Virk pointed out some technical differences between the two protocols:

● Modulation technique

Bluetooth: Frequency Hopping Spread Spectrum (FHSS)

ZigBee: Direct Sequence Spread Spectrum (DSSS)

● Protocol stack size

Bluetooth: 250K bytes

ZigBee: 28K bytes

● Battery

Bluetooth: Intended for frequent recharging

ZigBee: Not rechargeable (one reason batteries will last for up to 10 years)

● Maximum network speed:

Bluetooth: 1M bit/sec

ZigBee:? 250K bit/sec

● Network range:

Bluetooth: 1 or 100 meters, depending on radio class

ZigBee: Up to 70 meters

● Typical network join time

Bluetooth: 3 seconds

ZigBee: 30 milliseconds

時(shí)文選讀

Bluetooth與ZigBee的異同

Bluetooth(藍(lán)牙)與ZigBee有很多相同之處。兩者都屬于IEEE 802.15“無線個(gè)人局域網(wǎng)”(WPAN)類型，都運(yùn)行在無需許可證的2.4GHz頻段，都只有很小的外形尺寸和消耗很低的電力。

最近在硅谷召開的無線通信聯(lián)盟會(huì)議上，WPAN部件制造商CompXs公司的總裁兼CEO Bhupender Virk指出了藍(lán)牙 (IEEE 802.15.1) 和今年(2004年)12月被批準(zhǔn)的ZigBee 規(guī)范(基于IEEE 802.15.4)之間在應(yīng)用和技術(shù)上的不同點(diǎn)。

ZigBee協(xié)議定義了家居和商業(yè)應(yīng)用(如供熱、空調(diào)以及燈光控制)的傳感器網(wǎng)絡(luò)的類型。它將定義物理和MAC協(xié)議層的IEEE 802.15.4與網(wǎng)絡(luò)、安全和應(yīng)用軟件層結(jié)合在起來，這是由ZigBee聯(lián)盟(一個(gè)由技術(shù)公司組成的團(tuán)體)制定的。

想象一下，如果電燈開關(guān)變成無線的，消除了墻內(nèi)的連接電線，將帶來多大的自由度。

Bluetooth如同你可能了解的那樣，消除了電子產(chǎn)品與附件之間的連線，如計(jì)算機(jī)與打印機(jī)或者電話機(jī)與話筒之間的連線。擁有手持式或便攜式計(jì)算機(jī)的藍(lán)牙用戶就能交換文件、名片和約會(huì)時(shí)間。Bluetooth更多地面向用戶的移動(dòng)性和消除短距離的連線，而ZigBee更多地瞄準(zhǔn)大范圍的自動(dòng)化和遠(yuǎn)程控制。

Virk稱，第一批ZigBee產(chǎn)品現(xiàn)正在進(jìn)行互用性測(cè)試，他預(yù)計(jì)獲得聯(lián)盟鑒定的展品將于今年第三季度問世(屆時(shí)，CompXs將交付ZigBee協(xié)議分析儀)。業(yè)界的報(bào)告暗示，最終 ZigBee將通過雙功能的ZigBee-Bluetooth芯片做進(jìn)移動(dòng)電話，用于你能想象出的任何設(shè)備的遙控以及從售貨機(jī)買東西等等。

最后，Virk為我們中間的極客(技術(shù)迷)們指出了這兩個(gè)協(xié)議之間的技術(shù)差異:

● 調(diào)制技術(shù)

Bluetooth：調(diào)頻擴(kuò)頻

ZigBee：直接序列擴(kuò)頻

● 協(xié)議堆棧大小

Bluetooth:：250K字節(jié)

ZigBee：28K字節(jié)

● 電池

Bluetooth：需要經(jīng)常充電

ZigBee：不能充電(原因之一，電池壽命高達(dá)10年之久)

● 最大網(wǎng)絡(luò)速度

Bluetooth: 1M bit/sec

ZigBee: 250K bit/sec

● 網(wǎng)絡(luò)范圍

Bluetooth： 1米或100米，視無線電的級(jí)別而定

ZigBee：較高達(dá)70米

● 典型的網(wǎng)絡(luò)連接時(shí)間

Bluetooth: 3 秒

ZigBee: 30 毫秒