【正文】
superiority In recent years, the number of WAP at a rapid pace, wireless network convenience and efficient make its rapid popularization. Whether wireless urban construction, or business unit of LAN opening, or mobile phones Wi Fi function, all with Wi Fi technical advantages of itself is not divided: 1) wider LAN coverage Based on bluetooth radio coverage is very small, radius, and only about 15m Wi Fi radius criterion of up to 100 m, can cover whole building office building, 2) transmission speed Wi Fi technology transmission is very fast, can achieve 11Mbps ( b) or 54Mbps ( a), suitable for high speed data transmission business?;跓狳c(diǎn)的接入服務(wù)曾經(jīng)一度被看成是對(duì)3G的巨大沖擊, 但WiFi技術(shù)傳輸距離短和信號(hào)穿透能力差的特點(diǎn)同樣也是不可克服的。 4)頻譜利用率高,系統(tǒng)容量大 因?yàn)椴恍枰a(chǎn)生正弦載波信號(hào),可以直接發(fā)射沖激序列,因而 UWB系統(tǒng)具有很寬的頻譜和很低的平均功率,有利于與其他系統(tǒng)共存,從而提高頻譜利用率,帶來(lái)了極大的系統(tǒng)容量。在短距離(13m 以下)有很大優(yōu)勢(shì),最高傳輸速度可達(dá) 1Gb/S。在 250Kbit/秒的傳輸速度下可確保 30m的通信距離。這在頻率資源日益緊張的今天開(kāi)辟了一種新的時(shí)域無(wú)線電資源。國(guó)內(nèi)的電信、網(wǎng)通、移動(dòng)都非常關(guān)注 WiFi 技術(shù)的發(fā)展和應(yīng)用。 3) without wiring Wi the main advantage lies in the Fi don39?,F(xiàn)在 WiFi 產(chǎn)品利用WED(Wired Equivalent Privacy)技術(shù)作資料加密之用。因此,與 IEEE 、IEEE 和藍(lán)牙相比,在同等碼速條件下,UWB具有更強(qiáng)的抗干擾性。1 超寬帶無(wú)線通信 超寬帶技術(shù)簡(jiǎn)介 UWB(Ultra Wideband,超寬帶)技術(shù)是目前正被廣泛研究的一種新興無(wú)線通信技術(shù),現(xiàn)在已經(jīng)成為高速無(wú)線個(gè)人網(wǎng) (WPAN)的首選技術(shù)。目前超寬帶(UWB)技術(shù)正被整合進(jìn)家庭影院和便攜式產(chǎn)品,主要用于視頻和音頻信號(hào)的無(wú)線發(fā)送。有用信息完全淹沒(méi)在噪聲中,被截獲概率很小,被檢測(cè)的概率也很低,用傳統(tǒng)的接收機(jī)無(wú)法接收。用戶只要將支持無(wú)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); 4)健康安全 100 毫瓦,實(shí)際發(fā)射功率約 60~70毫瓦,而手機(jī)的發(fā)射功率約 200毫瓦~1瓦間,手持式對(duì)講機(jī)高達(dá)5瓦。 3 結(jié)論 每一種無(wú)線通信方式都有其獨(dú)特之處,超寬帶技術(shù)傳輸速率高,WiFi 技術(shù)覆蓋范圍廣。 WiFi 是以太網(wǎng)的一種無(wú)線擴(kuò)展,WiFi 網(wǎng)絡(luò)可以使用來(lái)互連電腦鏈接上互連網(wǎng)。 超寬帶性能特點(diǎn)。新的技術(shù)在 Intel 接入、信息家電、移動(dòng)辦公、工業(yè)化等各個(gè)領(lǐng)域得到了廣泛的運(yùn)用。UWB具有以下特點(diǎn): 1)抗干擾性能強(qiáng) UWB信號(hào),在發(fā)射時(shí)將微弱的無(wú)線電脈沖信號(hào)分散在寬闊的頻帶中,輸出功率甚至低于普通設(shè)備產(chǎn)生的噪聲。但實(shí)際上,如果有多個(gè)用戶同時(shí)通過(guò)一個(gè)點(diǎn)接入,帶寬被多個(gè)用戶分享。s developed a kind of with high potential new wireless munication technology, it was listed as one of the ten future munication technology.1 uwb wireless munication ultrawideband technology introduction UWB (the mkultra Wideband, ultrawideband) technology is currently has been widely studied a new wireless munication technology, it has bee a highspeed wireless personal nets (WPAN first choice of the technology. UWB refers to the signal bandwidth than 500MHz or is the signal bandwidth and center frequency ratio is more than 25% of munications technologies. With the mon use of continuous carrier munication mode is different, use