【正文】 ONE(1)The radio age began over a 100 years ago with the invention of the radiotelegraph by Guglielmo Marconi and the wireless industry is now set for rapid growth as we enter a new century and a new millennium. The rapid progress in radio technology is creating new and improved services at lower costs, which results in increases in airtime usage and the number of subscribers. Wireless industry revenues are currently growing between 20% and 30% per year, and these broad trends are likely to continue for several years.馬可尼在100年前無線電報的發(fā)明開啟了無線電時代，現(xiàn)在無線電行業(yè)的快速增長被認(rèn)為我們進(jìn)入了新世紀(jì)和新千年的時代。無線技術(shù)的快速發(fā)展是以較低的成本創(chuàng)造新的和改進(jìn)的服務(wù)，從而增加了在時間上的使用量和用戶使用的數(shù)量。無線電行業(yè)的收入目前每年以20%到30%的速度增長，而這些大的趨勢可能會持續(xù)幾年。(2) Multiple access wireless munications is being deployed for both fixed and mobile applications. In fixed applications, the wireless networks provide voice or data for fixed subscribers. Mobile networks offering voice and data services can be divided into two classes: high mobility, to serve high speed vehicleborne users, and low mobility, to serve pedestrian users.多址無線通信正應(yīng)用于固定和移動設(shè)備。在固定應(yīng)用中，無線網(wǎng)絡(luò)為固定用戶提供了語音、數(shù)據(jù)業(yè)務(wù)。移動網(wǎng)絡(luò)提供的語音、數(shù)據(jù)業(yè)務(wù)被分為兩類：高速移動性，為高速車載用戶服務(wù)；低移動性，為行人用戶服務(wù)。(3) Wireless system designers are faced with a number of challenges. These include the limited availability of the radio frequency spectrum and a plex timevarying wireless environment (fading and multipath). In addition, meeting the increasing demand for higher data rates, better quality of service (QoS), fewer dropped calls, higher network capacity and user coverage calls for innovative techniques that improve spectral efficiency and link reliability.無線系統(tǒng)的設(shè)計人員面臨著一系列挑戰(zhàn)。無線系統(tǒng)的設(shè)計人員面臨著一系列挑戰(zhàn)。此外，滿足更高的數(shù)據(jù)速率的需求日益增加，更好的服務(wù)質(zhì)量（服務(wù)質(zhì)量），更少的掉線問題，以及較高的網(wǎng)絡(luò)容量和用戶覆蓋要求創(chuàng)新的技術(shù)，這些創(chuàng)新技術(shù)能要提高頻譜效率和鏈路可靠性。(4) Wireless system designers are faced with a number of challenges. These include the limited availability of the radio frequency spectrum and a plex timevarying wireless environment (fading and multipath). In addition, meeting the increasing demand for higher data rates, better quality of service (QoS), fewer dropped calls, higher network capacity and user coverage calls for innovative techniques that improve spectral efficiency and link reliability.無線系統(tǒng)設(shè)計人員面臨著許多挑戰(zhàn)，這些挑戰(zhàn)包括無線電頻譜的有限可用性和復(fù)雜的時變無線環(huán)境（衰落及多徑）。此外，需要更好的服務(wù)質(zhì)量，更少的掉線，更高的網(wǎng)絡(luò)容量和改善頻譜效率和鏈路可靠性創(chuàng)新技術(shù)來提升網(wǎng)絡(luò)容量和用戶的覆蓋來滿足越來越高的數(shù)據(jù)速率的需求。(5) The origins of radio date back to 1861 when Maxwell, while at King’s College in London, proposed a mathematical theory of electromagnetic (EM) waves. A practical demonstration of the existence of such waves was performed by Hertz in 1887 at the University of Karlsruhe, using stationary (standing) waves. Following this, improvements in the generation and reception of EM waves were pursued by many researchers in Europe.廣播是一種電磁波的數(shù)學(xué)理論，它的起源可以追溯到麥斯威爾在倫敦國王學(xué)院的1861年。1887年，赫茲使用固定（站立）波在卡爾斯魯厄大學(xué)切實可行的證明了這種波。在此之后，許多歐洲的研究人員繼續(xù)改進(jìn)電磁波的產(chǎn)生和接收。(6) In 1890, Branly in Paris developed a “coherer” that could detect the presence of EM waves using iron filings in a glass bottle. The coherer was further refined by Righi at the University of Bologna and Lodge in England. Other contributions came from Popov in Russia, who is credited with devising the first radio antenna during his attempts to detect EM radiation from lightning.1890年，巴黎的Branly開發(fā)出一種“檢波器”，該檢波器可以通過玻璃瓶中的鐵屑檢測出電磁波的存在。這種檢波器后來被博洛尼亞大學(xué)的Righi和英國的Lodge進(jìn)一步改善。檢波器其他方面的改進(jìn)還源于俄羅斯的Popov，Popov曾在試圖從閃電中檢測電磁輻射的時候發(fā)明了第一個無線電天線。(7) In 1890, Branly in Paris developed a “coherer” that could detect the presence of EM waves using iron filings in a glass bottle. The c