版權(quán)說明:本文檔由用戶提供并上傳,收益歸屬內(nèi)容提供方,若內(nèi)容存在侵權(quán),請(qǐng)進(jìn)行舉報(bào)或認(rèn)領(lǐng)
文檔簡(jiǎn)介
1、<p> 1700單詞,2950漢字</p><p> Wi-Fi Technology</p><p> Wi-Fi stands for Wireless Fidelity, also known as the 802.11b standard. Its biggest advantage is the high transmission speed can reach
2、 11Mbps, another effective long distance, at the same time compatible with the existing variety of 802.11DSSS equipment. Along with Intel's laptop chipset,"Centrino" is recognized by more and more people, t
3、his technology has become a topic of concern to everyone. However, since the end of 2005, many mobile phone manufacturers, especially the production of smart ph</p><p> With Wi-Fi, no cable can be linked in
4、to the network. More and more devices installed in the factory, Wi-Fi module, but also more and more places to offer Wi-Fi signal coverage. In this way, the Wi-Fi formed from research to equipment production, from networ
5、k access to network services is a huge industrial chain. In 2007, the value of the national the wlan industry, including Wi-Fi industry is expected to exceed 100 million U.S. dollars. For individual users, the popularity
6、 of Wi-Fi, it will be a</p><p> Laptop users will be able to any one with Wi-Fi signal coverage fast access to the Internet without the need to go looking for network cable, a growing number of airports, ho
7、tels, public places, offer Wi-Fi signal coverage. In a timely manner with a laptop computer to meetings, do not worry do not have enough network cable jack in the conference room. At home, you can even in any corner of t
8、he coverage of wireless signals, without having to worry about the alignment of the cable affect the overa</p><p> Wi-Fi in handheld devices are widely used, and smart phones is part of it. Different from t
9、he earlier Bluetooth technology used in mobile phones, Wi-Fi has a greater coverage and higher transmission rates, Wi-Fi phones has become a fashion trend of the mobile communications industry.</p><p> Wi-F
10、i bands in the world without any telecom operator license free band, WLAN wireless devices provides a worldwide can be used, the cost is extremely low and very high data bandwidth wireless air interface. Users can browse
11、 the web quickly in the Wi-Fi coverage area, anytime, anywhere and receive phone calls. Other WLAN-based broadband data applications such as streaming media, online games and other functions more user should expect. With
12、 Wi-Fi capability, long-distance calls (including intern</p><p> Wi-Fi flip range more widely in the country, luxury hotels, luxury residential, airports and coffee shops class area has Wi-Fi interface. Whe
13、n we went to the tourist office, you can use our handheld devices in such places and enjoy surfing the web.</p><p> A Wi-Fi connection point network members and structure of the site (Station), the network
14、of basic components. The basic service unit (Basic service the Set, BSS). Network basic service unit. The most simple unit can only be composed by the two sites. The site can be dynamic link (associate) to the basic serv
15、ice unit.</p><p> Distribution System Distribution System (DS). The distribution system used to connect different basic service unit. The media distribution system medium (Medium) logic and the basic servic
16、e unit is completely separate, even though they physically may be the same media, for example, the same radio frequency band.</p><p> Access point (Acess Point, AP). Access point that the identity of the or
17、dinary sites, and access to the distribution function of the system.</p><p> Extended Service Unit (Extended Service Set ESS). A combination of the distribution system and basic services unit. This combinat
18、ion is logical, not physical - the basic service unit of matter may be geographically far removed from. Distribution system can also use a variety of techniques.</p><p> Mark (Portal) is a logical compositi
19、on. For wireless LAN and wired LAN or other network link.</p><p> Here are three kinds of media, the site uses wireless media distribution system to use the media, and other LAN and wireless LAN integration
20、 together media. Physically, they may overlap each other.</p><p> The IEEE802.11 only responsible for addressing (Addressing,) on the site uses the wireless medium. Distribution systems and other LAN addres
21、sing a range of wireless LAN.</p><p> The IEEE802.11 no specific definition of the distribution system, but the definition of the distribution system should provide the services (Service). The entire wirele
22、ss LAN defines nine kinds of service, five kinds of services are part of the task of distribution systems, respectively, joins (Association), the end connection (Diassociation), distribution (Distribution,), integration
23、(Integration), to re-connect.</p><p> Four kinds of services are the tasks of the site, respectively, authentication (Authentication), the end of the authentication (Deauthentication), privacy (Privacy), MA
24、C data transmission (the MSDU delivery).</p><p> The main technical advantage of the Wi-Fi</p><p> First A radio wave coverage, the coverage of radio based on Bluetooth technology is very sma
25、ll radius of only about 50 feet, or about 15 meters. Wi-Fi radius of up to about 300 feet, or about 100 meters. A new type of by Vivato company recently launched the switches, which products to current Wi-Fi wireless net
26、work 300 ft, close to 100 m communication distance expanded to four miles, about 6.5 km.</p><p> Second Although the quality of wireless communications transmitted by the Wi-Fi technology is not very good
27、performance of data security than Bluetooth worse, the transmission quality to be improved, but the transfer speed is very fast, you can reach 11Mbps, in line with the needs of personal and social information.</p>
28、<p> Third manufacturers to enter the field is relatively low threshold. Vendors set up "hot spots" in airports, railway stations, coffee shops, libraries and other personnel intensive, and high-speed l
29、ine Internet access to these places. Such "hot spots" to emit radio waves can reach tens of meters to 100 meters away from the radius of the access point, as long as the user will support wireless LAN notebook
30、or PDA to get the region to high-speed Internet access. Means that manufacturers do not have</p><p> Wi-Fi methods of organizing</p><p> Wi-Fi is a wireless network by the AP (Access Point) an
31、d Wireless LAN. Generally set up a wireless network equipped with a wireless card and the AP, so will be able to wireless mode, with both wired architecture to share network resources, erection cost and complexity of the
32、 program is far lower than a traditional wired network. If only a few computers, peer-to-peer network, can also be not to the AP, only require each computer is equipped with a wireless card. AP is generally translated as
33、 "wir</p><p> Wi-Fi is the complement of high-speed wired access technologies</p><p> At present, the wired access technologies including Ethernet, xDSL, etc. Wi-Fi technology as a comple
34、ment of high-speed wired access technology, has the advantage of mobility, inexpensive Wi-Fi technology is widely used in the field of need a wireless extension of wired access, such as the temporary venue. Data rate, co
35、verage and reliability of the difference, Wi-Fi technology in broadband applications will be as a complement of high-speed wired access technologies. The key technology is no doub</p><p> Wi-Fi is the compl
36、ement of cellular mobile communication and 3G</p><p> Secondary positioning of the Wi-Fi technology ---- the complement of cellular mobile communication. Cellular mobile communication can provide a wide cov
37、erage, high mobility and the low data transfer rate, it can use the Wi-Fi high-speed data transmission characteristics to compensate for the deficiencies of their own data transfer rate is limited. Wi-Fi not only the use
38、 of cellular mobile communication network authentication and billing mechanisms, and characteristics of multi-access switching f</p><p><b> Wi-Fi技術(shù)</b></p><p> Wi-Fi的全稱是Wireless Fi
39、delity,又叫802.11b標(biāo)準(zhǔn)。它的最大優(yōu)點(diǎn)就是傳輸速度較高,可以達(dá)到11Mbps,另外它的有效距離也很長(zhǎng),同時(shí)與已有的各種802.11DSSS設(shè)備兼容。伴隨著Intel公司提出的筆記本電腦芯片組。“迅馳”被越來越多的人認(rèn)可,這一技術(shù)也逐漸成為了大家關(guān)注的話題。不過自2005年底開始,很多手機(jī)廠商,特別是以生產(chǎn)智能手機(jī)為主的品牌便開始將Wi-Fi引入自己的產(chǎn)品當(dāng)中。簡(jiǎn)而言之:Wi-Fi就是無線網(wǎng)絡(luò)Wi-Fi已經(jīng)廣泛的應(yīng)用在了筆記本
40、電腦,手機(jī)掌上電腦,數(shù)碼相機(jī)等移動(dòng)終端上。</p><p> 有了Wi-Fi之后,不需要網(wǎng)線即可聯(lián)入網(wǎng)絡(luò)。越來越多的設(shè)備在出廠前安裝了Wi-Fi模塊,也有越來越多的場(chǎng)所提供了Wi-Fi信號(hào)覆蓋。這樣,Wi-Fi形成了一個(gè)從科研到設(shè)備生產(chǎn)、從網(wǎng)絡(luò)接入到網(wǎng)絡(luò)內(nèi)容服務(wù)等一個(gè)龐大的產(chǎn)業(yè)鏈。2007年,全國(guó)包括Wi-Fi在內(nèi)的wlan行業(yè)產(chǎn)業(yè)價(jià)值有望超億美元。對(duì)于個(gè)人用戶來說,Wi-Fi的普及,將是用戶體驗(yàn)的一次飛躍。&
41、lt;/p><p> 筆記本電腦用戶將可以任意一個(gè)具備Wi-Fi信號(hào)覆蓋的地方快速接入Internet而不需要再去尋找網(wǎng)線,越來越多的機(jī)場(chǎng)、酒店、公共場(chǎng)所都提供了Wi-Fi信號(hào)覆蓋。及時(shí)帶筆記本電腦開會(huì),也不用擔(dān)心會(huì)議室沒有足夠的網(wǎng)線插口。而在家中,您更可以在任何一個(gè)角落都覆蓋無線信號(hào),而不需要擔(dān)心網(wǎng)線的走線影響整體室內(nèi)美觀。</p><p> Wi-Fi在掌上設(shè)備上應(yīng)用越來越廣泛,而智能
42、手機(jī)就是其中一份子。與早前應(yīng)用 于手機(jī)上的藍(lán)牙技術(shù)不同,Wi-Fi具有更大的覆蓋范圍和更高的傳輸速率,因此Wi-Fi手機(jī)成為了目前移動(dòng)通信業(yè)界的時(shí)尚潮流。</p><p> 由于Wi-Fi的頻段在世界范圍內(nèi)是無需任何電信運(yùn)營(yíng)執(zhí)照的免費(fèi)頻段,因此WLAN無線設(shè)備提供了一個(gè)世界范圍內(nèi)可以使用的,費(fèi)用極其低廉且數(shù)據(jù)帶寬極高的無線空中接口。用戶可以在Wi-Fi覆蓋區(qū)域內(nèi)快速瀏覽網(wǎng)頁,隨時(shí)隨地接聽撥打電話。而其它一些基于
43、WLAN的寬帶數(shù)據(jù)應(yīng)用,如流媒體、網(wǎng)絡(luò)游戲等功能更是值得用戶期待。有了Wi-Fi功能我們打長(zhǎng)途電話(包括國(guó)際長(zhǎng)途哦),瀏覽網(wǎng)頁、收發(fā)電子郵件、音樂下載、數(shù)碼照片傳遞等,再無需擔(dān)心速度慢和花費(fèi)高的問題。</p><p> 現(xiàn)在Wi-Fi翻蓋范圍在國(guó)內(nèi)越來越廣泛了,高級(jí)賓館,豪華住宅區(qū),飛機(jī)場(chǎng)以及咖啡廳之類的區(qū)域都有Wi-Fi接口。當(dāng)我們?nèi)ヂ糜危k公時(shí),就可以在這些場(chǎng)所使用我們的掌上設(shè)備盡情網(wǎng)上沖浪了。</p
44、><p> 一個(gè)Wi-Fi聯(lián)接點(diǎn)網(wǎng)絡(luò)成員和結(jié)構(gòu)站點(diǎn)(Station) ,網(wǎng)絡(luò)最基本的組成部分?;痉?wù)單元(Basic Service Set, BSS) 。網(wǎng)絡(luò)最基本的服務(wù)單元。最簡(jiǎn)單的服務(wù)單元可以只由兩個(gè)站點(diǎn)組成。站點(diǎn)可以動(dòng)態(tài)的聯(lián)結(jié)(associate)到基本服務(wù)單元中。</p><p> 分配系統(tǒng)(Distribution System, DS) 分配系統(tǒng)用于連接不同的基本服務(wù)單元
45、。分配系統(tǒng)使用的媒介(Medium) 邏輯上和基本服務(wù)單元使用的媒介是截然分開的,盡管它們物理上可能會(huì)是同一個(gè)媒介,例如同一個(gè)無線頻段。</p><p> 接入點(diǎn)(Acess Point, AP) 接入點(diǎn)即有普通站點(diǎn)的身份,又有接入到分配系統(tǒng)的功能。</p><p> 擴(kuò)展服務(wù)單元(Extended Service Set, ESS) 由分配系統(tǒng)和基本服務(wù)單元組合而成。這種組合是邏
46、輯上,并非物理上的--不同的基本服務(wù)單元物有可能在地理位置相去甚遠(yuǎn)。分配系統(tǒng)也可以使用各種各樣的技術(shù)。</p><p> 關(guān)口(Portal) 也是一個(gè)邏輯成分。用于將無線局域網(wǎng)和有線局域網(wǎng)或其它網(wǎng)絡(luò)聯(lián)系起來。</p><p> 這兒有3種媒介,站點(diǎn)使用的無線的媒介,分配系統(tǒng)使用的媒介,以及和無線局域網(wǎng)集成一起的其它局域網(wǎng)使用的媒介。物理上它們可能互相重迭。</p>&
47、lt;p> IEEE802.11只負(fù)責(zé)在站點(diǎn)使用的無線的媒介上的尋址(Addressing)。分配系統(tǒng)和其它局域網(wǎng)的尋址不屬無線局域網(wǎng)的范圍。</p><p> IEEE802.11沒有具體定義分配系統(tǒng),只是定義了分配系統(tǒng)應(yīng)該提供的服務(wù)(Service) 。整個(gè)無線局域網(wǎng)定義了9種服務(wù),5種服務(wù)屬于分配系統(tǒng)的任務(wù),分別為,聯(lián)接(Association), 結(jié)束聯(lián)接(Diassociation), 分配(
48、Distribution), 集成(Integration), 再聯(lián)接(Reassociation) 。</p><p> 4種服務(wù)屬于站點(diǎn)的任務(wù),分別為,鑒權(quán)(Authentication), 結(jié)束鑒權(quán)(Deauthentication), 隱私(Privacy), MAC數(shù)據(jù)傳輸(MSDU delivery) 。</p><p> Wi-Fi的主要技術(shù)優(yōu)勢(shì)</p>&
49、lt;p> 1、無線電波的覆蓋范圍廣,基于藍(lán)牙技術(shù)的電波覆蓋范圍非常小,半徑大約只有50英尺左右,約合15米。而Wi-Fi的半徑則可達(dá)300英尺左右,約合100米。最近由Vivato公司推出的一款新型交換機(jī),該款產(chǎn)品能夠把目前Wi-Fi無線網(wǎng)絡(luò)300英尺,接近100米的通信距離擴(kuò)大到4英里,約6.5公里。</p><p> 2、雖然由Wi-Fi技術(shù)傳輸?shù)臒o線通信質(zhì)量不是很好,數(shù)據(jù)安全性能比藍(lán)牙差一些,傳
50、輸質(zhì)量也有待改進(jìn),但傳輸速度非???,可以達(dá)到11Mbps,符合個(gè)人和社會(huì)信息化的需求。 </p><p> 3、廠商進(jìn)入該領(lǐng)域的門檻比較低。廠商只要在機(jī)場(chǎng)、車站、咖啡店、圖書館等人員較密集的地方設(shè)置“熱點(diǎn)”,并通過高速線路將因特網(wǎng)接入上述場(chǎng)所。這樣由于“熱點(diǎn)”所發(fā)射出的電波可以達(dá)到距接入點(diǎn)半徑數(shù)十米至100米的地方,用戶只要將支持無線LAN的筆記本電腦或PDA拿到該區(qū)域內(nèi),即可高速接入因特網(wǎng)。也就是說廠商不用耗
51、費(fèi)資金來進(jìn)行網(wǎng)絡(luò)布線接入,從而節(jié)省了大量的成本。</p><p><b> Wi-Fi組建方法</b></p><p> Wi-Fi是由AP(Access Point)和無線網(wǎng)卡組成的無線網(wǎng)絡(luò)。一般架設(shè)無線網(wǎng)絡(luò)的基本配備就是無線網(wǎng)卡及一臺(tái)AP,如此便能以無線的模式,配合既有的有線架構(gòu)來分享網(wǎng)絡(luò)資源,架設(shè)費(fèi)用和復(fù)雜程序遠(yuǎn)遠(yuǎn)低于傳統(tǒng)的有線網(wǎng)絡(luò)。如果只是幾臺(tái)電腦的對(duì)等網(wǎng)
52、,也可不要AP,只需要每臺(tái)電腦配備無線網(wǎng)卡。AP一般翻譯為“無線訪問節(jié)點(diǎn)”,或“橋接器”。它主要當(dāng)作傳統(tǒng)的有線局域網(wǎng)絡(luò)與無線局域網(wǎng)絡(luò)之間的橋梁,因此任何一臺(tái)裝有無線網(wǎng)卡的PC均可透過AP去分享有線局域網(wǎng)絡(luò)甚至廣域網(wǎng)絡(luò)的資源,其工作原理相當(dāng)于一個(gè)內(nèi)置無線發(fā)射器的HUB或者是路由,而無線網(wǎng)卡則是負(fù)責(zé)接收由AP所發(fā)射信號(hào)的CLIENT端設(shè)備。有了AP就像一般有線網(wǎng)絡(luò)的Hub一般,無線工作站可以快速且輕易地與網(wǎng)絡(luò)相連。特別是對(duì)于寬帶的使用,Wi
53、-Fi更顯優(yōu)勢(shì),有線寬帶網(wǎng)絡(luò)(ADSL、小區(qū)LAN等)到戶后,連接到一個(gè)AP,然后在電腦中安裝一塊無線網(wǎng)卡即可。普通的家庭有一個(gè)AP已經(jīng)足夠,甚至用戶的鄰里得到授權(quán)后,則無需增加端口,也能以共享的方式上網(wǎng)。 </p><p> Wi-Fi是高速有線接入技術(shù)的補(bǔ)充</p><p> 目前,有線接入技術(shù)主要包括以太網(wǎng)、xDSL等。Wi-Fi技術(shù)作為高速有線接入技術(shù)的補(bǔ)充,具有為可移動(dòng)性、價(jià)
54、格低廉的優(yōu)點(diǎn),Wi-Fi技術(shù)廣泛應(yīng)用于有線接入需無線延伸的領(lǐng)域,如臨時(shí)會(huì)場(chǎng)等。由于數(shù)據(jù)速率、覆蓋范圍和可靠性的差異,Wi-Fi技術(shù)在寬帶應(yīng)用上將作為高速有線接入技術(shù)的補(bǔ)充。而關(guān)鍵技術(shù)無疑決定著Wi-Fi的補(bǔ)充力度。現(xiàn)在OFDM、MIMO(多入多出)、智能天線和軟件無線電等,都開始應(yīng)用到無線局域網(wǎng)中以提升Wi-Fi性能,比如說802.11n計(jì)劃采用MIMO與OFDM相結(jié)合,使數(shù)據(jù)速率成倍提高。另外,天線及傳輸技術(shù)的改進(jìn)使得無線局域網(wǎng)的傳輸
55、距離大大增加,可以達(dá)到幾公里。</p><p> Wi-Fi是蜂窩移動(dòng)通信與3G的補(bǔ)充</p><p> Wi-Fi技術(shù)的次要定位----蜂窩移動(dòng)通信的補(bǔ)充。蜂窩移動(dòng)通信可以提供廣覆蓋、高移動(dòng)性和中低等數(shù)據(jù)傳輸速率,它可以利用Wi-Fi高速數(shù)據(jù)傳輸?shù)奶攸c(diǎn)彌補(bǔ)自己數(shù)據(jù)傳輸速率受限的不足。而Wi-Fi不僅可利用蜂窩移動(dòng)通信網(wǎng)絡(luò)完善的鑒權(quán)與計(jì)費(fèi)機(jī)制,而且可結(jié)合蜂窩移動(dòng)通信網(wǎng)絡(luò)廣覆蓋的特點(diǎn)進(jìn)行
56、多接入切換功能。這樣就可實(shí)現(xiàn)Wi-Fi與蜂窩移動(dòng)通信的融合,使蜂窩移動(dòng)通信的運(yùn)營(yíng)錦上添花,進(jìn)一步擴(kuò)大其業(yè)務(wù)量。對(duì)于電信運(yùn)營(yíng)商來說,Wi-Fi技術(shù)的定位主要是作為高速有線接入技術(shù)的補(bǔ)充,逐漸也會(huì)成為蜂窩移動(dòng)通信的補(bǔ)充。當(dāng)然Wi-Fi與蜂窩移動(dòng)通信也存在少量競(jìng)爭(zhēng)。一方面,用于Wi-Fi的IP話音終端已經(jīng)進(jìn)入市場(chǎng),這對(duì)蜂窩移動(dòng)通信有一部分替代作用。另一方面,隨著蜂窩移動(dòng)通信技術(shù)的發(fā)展,熱點(diǎn)地區(qū)的Wi-Fi公共應(yīng)用也可能被蜂窩移動(dòng)通信系統(tǒng)部分取
溫馨提示
- 1. 本站所有資源如無特殊說明,都需要本地電腦安裝OFFICE2007和PDF閱讀器。圖紙軟件為CAD,CAXA,PROE,UG,SolidWorks等.壓縮文件請(qǐng)下載最新的WinRAR軟件解壓。
- 2. 本站的文檔不包含任何第三方提供的附件圖紙等,如果需要附件,請(qǐng)聯(lián)系上傳者。文件的所有權(quán)益歸上傳用戶所有。
- 3. 本站RAR壓縮包中若帶圖紙,網(wǎng)頁內(nèi)容里面會(huì)有圖紙預(yù)覽,若沒有圖紙預(yù)覽就沒有圖紙。
- 4. 未經(jīng)權(quán)益所有人同意不得將文件中的內(nèi)容挪作商業(yè)或盈利用途。
- 5. 眾賞文庫僅提供信息存儲(chǔ)空間,僅對(duì)用戶上傳內(nèi)容的表現(xiàn)方式做保護(hù)處理,對(duì)用戶上傳分享的文檔內(nèi)容本身不做任何修改或編輯,并不能對(duì)任何下載內(nèi)容負(fù)責(zé)。
- 6. 下載文件中如有侵權(quán)或不適當(dāng)內(nèi)容,請(qǐng)與我們聯(lián)系,我們立即糾正。
- 7. 本站不保證下載資源的準(zhǔn)確性、安全性和完整性, 同時(shí)也不承擔(dān)用戶因使用這些下載資源對(duì)自己和他人造成任何形式的傷害或損失。
最新文檔
- wi-fi技術(shù)原理以及應(yīng)用
- 對(duì)wi-fi技術(shù)與覆蓋的研究
- Wi-Fi數(shù)字全息成像.pdf
- wi-fi移動(dòng)安全報(bào)告2017
- 到機(jī)場(chǎng)盡情蒲免費(fèi)wi-fi
- 淺談樓宇wi-fi網(wǎng)絡(luò)的設(shè)計(jì)
- 基于開源硬件的 wi-fi四
- 基于Wi-Fi室內(nèi)無線定位技術(shù)的研究.pdf
- Wi-Fi無線傳輸視頻混沌保密通信技術(shù).pdf
- 嵌入式Wi-Fi技術(shù)研究與應(yīng)用.pdf
- 基于Wi-Fi技術(shù)的災(zāi)后通信基站設(shè)計(jì).pdf
- 基于Wi-Fi的室內(nèi)定位技術(shù)研究.pdf
- 校園大規(guī)模Wi-Fi網(wǎng)絡(luò)建設(shè).pdf
- 密集WI-Fi網(wǎng)絡(luò)集中控制技術(shù)研究.pdf
- 基于情景感知的Wi-Fi節(jié)能技術(shù)研究.pdf
- 基于Wi-Fi的室內(nèi)外定位技術(shù)研究.pdf
- 基于Wi-Fi技術(shù)的心音無線傳輸系統(tǒng)設(shè)計(jì).pdf
- 電信級(jí)Wi-Fi網(wǎng)絡(luò)優(yōu)化的研究.pdf
- 基于Wi-Fi的點(diǎn)餐系統(tǒng)設(shè)計(jì).pdf
- TD-SCDMA與Wi-Fi網(wǎng)絡(luò)融合技術(shù)的研究.pdf
評(píng)論
0/150
提交評(píng)論