【正文】 From the perspective of telemunication work, can will be divided into public sites and telemunication users stations s two parts, including local s belongs to all users user, so usually says telemunication work refers to the public telemunications works. The public telemunications works and can be divided into long distance s, relay s and access work of three parts, among them, the long distance s and relay s can merge called core s. Figure 11 access work schemes As shown in figure 11 shows, between the user and the core access work terminal between s. Business phone is concerned, access work is the switch and local connection between users. According to the different methods of transmission, access work can be divided into cable access work and wireless access work two kinds. For wireless access work, user terminal access work core work access work user terminal 13 according to the air interface carrying business of the size of the bandwidth, and can be further divided into the broadband wireless access work and narrowband wireless access work. Broadband wireless access is to show from the exchange node to the user terminals wireless munication, and can realize the broadband access technology, it actually is the core s fall of wireless extension. Broadband wireless access features 1 Coverage Access point coverage from dozens of meters to several thousand metres, can make BWA technology applied flexibly from local area work to the man in the whole area. 2 Frequency application scope From 2 GHz to dozens of GHz, broadband wireless access technology can be applied flexibly in different frequency of the classification of the region. 3 Spectrum efficiency is high Now most of the physical BWA system widely adopted is OFDM/OFMA multiple access technology, modulation, make exchange node to user terminals from the air interface link the utilization rate of the radio spectrum increased significantly. And, because BWA technology monly used to 2 GHz band above, the available channel bandwidth is wide. So can meet high throughput broadband data business needs. 4 The MAC layer have scheduling mechanism Air interface to the MAC layer can through the different business bandwidth for scheduling, make the broadband wireless access technology system endtoend QoS possible, also effective guarantee the broadband wireless access to much of the support system business ability. 5 The dynamic bandwidth ability Broadband wireless access system can support the same in different sectors of the terminal between dynamic bandwidth allocation and the same terminal in different interface between dynamic bandwidth allocation, on the one hand, improved the system frequency use efficiency, improve the spectrum efficiency, on the one hand, cooperate with the MAC layer of scheduling mechanism, so as to better support multiple business concurrent mechanism. 6 High safety coefficient Through the packet encryption packages and key management means such as air interface encrypting of data transmission。 The second part, the WiFi from the concept, characteristics and the development process and so on description, puts forward the WiFi and WiMAX work scheme。 12 外文 原文 之一 Broadband wireless WiFi applied research In recent years, the wireless local area work technology are used widely, especially in home and abroad can say is limelight is healthy. And in many of the wireless local area work, the most by the people of attention is WiFi technology, WiFi technology of the birth of the cable work from the bondage of anywhere at any time the user access to the Inter. And, WiFi prospective high and so many hardware manufacturers to provide all the support, WiFi field research and development and the market will continue to expand. Along with the development of wireless work, WiFi quickly swept through the laptop market, has been to mobile phones, such as game embedded field development, constructing di gital home and bee digital enterprise39。這有很多原因： 第一， WiFi 的傳輸距離有限，受干擾的可能性較大，沒有有線網(wǎng)穩(wěn)定可靠； 第二， WiFi 設(shè)備的傳輸速率可達(dá)到 11Mbps，雖然這個(gè)速率對(duì)于瀏覽普通網(wǎng)頁足夠了，但對(duì)于一些應(yīng)用還是不足。企業(yè)級(jí)的 AP 還支持漫游、負(fù)載均衡以及無限路由等多種高級(jí)功能 四、 對(duì)于小型公司來說，可供選擇的產(chǎn)品很多，一般的 AP 都能夠滿足。 三、 對(duì)于大型企業(yè)來說，一般都使用企業(yè)級(jí)的產(chǎn)品，比如 Intel 的PRO/Wireless2021LAN AP 或者思科公司的類似產(chǎn)品。 二、 對(duì)家庭應(yīng)用市場(chǎng)來說，現(xiàn)在適用的產(chǎn)品有 KOWAWL1100BAR。正是由于 WiFi 的便攜性能，如今國(guó)內(nèi)越來越多的小型公司也開始在公司內(nèi)進(jìn)行 WiFi 的使用。只要在辦公室內(nèi)安裝一個(gè)無線局域網(wǎng)的接入點(diǎn)，同時(shí)在每臺(tái)電腦上安裝一個(gè)無線網(wǎng)卡，就可以建立起公司自己的內(nèi)部網(wǎng)絡(luò)，快速的進(jìn)入工作狀態(tài)。一部分大型企業(yè)，他們的員工大多數(shù)都使用筆記本電腦，而且工作的流動(dòng)性很強(qiáng)，在這種情況下，使用 WiFi 技術(shù)覆蓋，可以為這些用戶提供無所不在的網(wǎng)絡(luò)連接。 三、大型企業(yè)應(yīng)用 一般來說每個(gè)大 型企業(yè)都已經(jīng)有了一個(gè)成熟的有線網(wǎng)絡(luò)，在這種情況下，無線局域 11 網(wǎng)就可以成為大型企業(yè)內(nèi)部網(wǎng)絡(luò)的一個(gè)延伸和補(bǔ)充。這樣一來，家里的網(wǎng)絡(luò)就變得非常的簡(jiǎn)單方便：臺(tái)式機(jī)安裝 USB接口的網(wǎng)卡，可以不受拘束的移動(dòng)到任何地方使用。最優(yōu)的解決方案是選擇一臺(tái) WiFi 網(wǎng)關(guān)設(shè)備，覆蓋到家庭的全部范圍。目前，國(guó)內(nèi)已經(jīng)有不少的咖啡屋、茶吧、機(jī)場(chǎng)以及許多酒店等公共場(chǎng)所，都進(jìn)行了WiFi 的覆蓋，用戶只要攜帶配有無線網(wǎng)卡的筆記本電腦或 PDA，就可以在這些地方上網(wǎng)了。還有，在咖啡屋和茶吧等休閑場(chǎng)所，也有不少客人希望能夠提供上網(wǎng)服務(wù)。在美國(guó)，這叫做“ Hotspot”服務(wù)，即熱點(diǎn)服務(wù)，也就是說在熱點(diǎn)地區(qū)，比如酒店、機(jī)場(chǎng)、休閑場(chǎng)所等地方，利用 WiFi技術(shù)進(jìn)行覆蓋，為用戶提供高速的寬帶無線連接。其中城市寬帶接入業(yè)務(wù)普及率較高，但是偏遠(yuǎn)的農(nóng)村地區(qū)則落后很多。運(yùn)營(yíng)商們開始積極關(guān)注寬帶接入市場(chǎng)： 2021年的價(jià)格戰(zhàn)顯示了運(yùn)營(yíng)商占據(jù)市場(chǎng)的決心；從 2021年 6月開始，中國(guó)電信和中國(guó)網(wǎng)通開始推進(jìn)全國(guó)范圍內(nèi)的寬帶接入服務(wù)。運(yùn)營(yíng)商普遍認(rèn)識(shí)到 寬帶市場(chǎng)在未來很長(zhǎng)的一段時(shí)期內(nèi)，是業(yè)務(wù)收入很重要的一項(xiàng)來源。 在中國(guó)的應(yīng)用和發(fā)展 中國(guó)寬帶接入市場(chǎng)的趨勢(shì) 寬帶接入業(yè)務(wù)市場(chǎng)對(duì)運(yùn)營(yíng)商來說非常重要。到 2021年底，德國(guó)共建設(shè)了 6000多個(gè)熱點(diǎn)，其中商用接入點(diǎn)站 90%，非商用的占 10%， 2021年底熱點(diǎn)數(shù)增加到 8579個(gè)。目前在法國(guó)提供 WiFi 業(yè)務(wù)的主要有 Orange、 SFR和 VG 電信等。法國(guó)也從 2021年開始使用 WiFi，隨后隨著 WiFi 覆蓋面積不斷擴(kuò)大，用戶數(shù)迅速增加，目前法國(guó)已經(jīng)有 169加運(yùn)營(yíng)商提供 WiFi 業(yè)務(wù)。目前 WiFi 網(wǎng)絡(luò)的覆蓋率已占到美國(guó)家庭總數(shù)的 12%左右，因頻率使用無須申請(qǐng)，不要授權(quán)，加之地方政府又作為大力扶植居民無線上網(wǎng)的重要舉措，又因可與移動(dòng)網(wǎng)結(jié)合達(dá)到互補(bǔ)，資費(fèi)又比較低，有些地方由地方政府興建的 WiFi 網(wǎng)絡(luò)無線上網(wǎng)甚至免費(fèi)，而且技術(shù)已逐漸成熟，安全性也得到提高，所以 WiFi 網(wǎng)絡(luò)在美國(guó)發(fā)展的很快，電信公司和電視電纜公司由起初的抵制地方政府組建 WiFi 網(wǎng)絡(luò)到合作，而且自 己也在大力興建WiFi 網(wǎng)絡(luò)。隨著 正式推向市場(chǎng)，以及 的不斷完善和成熟，市場(chǎng)研究公司 TeleView 統(tǒng)計(jì)，全球?qū)拵o線接入市場(chǎng)在 2021年的規(guī)模將超過 150億人民幣。工程師和技術(shù)員在進(jìn)行檢修、更新 產(chǎn)品設(shè)計(jì)、討論工程方案以及其他技術(shù)處理時(shí)，可以利用無線網(wǎng)在工廠車間或其他任何地方查閱技術(shù)檔案、工程工藝和過程圖，發(fā)出技術(shù)指令，請(qǐng)求技術(shù)救援，甚至還可以和廠外的專家進(jìn)行技術(shù)討論。 制造業(yè) 制造工廠往往不能鋪設(shè)連接到計(jì)算機(jī)的電纜，在加固混凝土的地板下面也沒有辦法鋪設(shè)計(jì)算機(jī)電纜，零配件及貨物運(yùn)輸通道也不方便在地面鋪線，空中起重機(jī)也很難布線。鋪設(shè)光纜費(fèi)用太高，施工難度也很大。而無網(wǎng)絡(luò)鏈接可以提供從 鉆井到壓縮機(jī)房的數(shù)據(jù)鏈接，以便顯示和輸入由礦井獲取的重要數(shù)據(jù)。這種情況下，無線計(jì)算機(jī)網(wǎng)絡(luò)可以把貨物的基本資料和情況直接輸入到