交通信號燈控制電路的設計外文翻譯

1、附錄4 外文資料Advantages of CDMA2000CDMA2000 benefited from the extensive experience acquired through several years of operation of cdmaOne systems. As a result, CDMA2000 is a very efficient and robust technology. It delivers the highest voice capacity and data throughput using the least amount of spectru

2、m, and it can be used to provide services in urban as well as remote areas cost effectively. The unique features, benefits, and performance of CDMA2000 make it an excellent technology for high-voice capacity and high-speed packet data. Since CDMA2000 1X supports both voice and data services on the s

3、ame carrier, it allows operators to provide both services cost efficiently. CDMA2000 1xEV-DO is optimized for data and is capable to support large volumes of data traffic at broadband speeds. 1xEV-DO is well suited to provide high-speed data services to its mobile subscribers and/or broadband access

4、 to the Internet. Due to its optimized radio technology, CDMA2000 enables operators to invest in fewer cell sites and deploy them faster, ultimately allowing the service providers to increase their revenues with faster Return On Investment (ROI). The CDMA2000 evolutionary path was designed to minimi

5、ze investment and the impact to an operators network without service interruption for the end-user. This has been achieved through backward and forward compatibility, hardware reuse, in-band migration and hybrid network configuration. This unique feature of CDMA2000 technologies has provided operato

6、rs a significant time-to-market advantage over other 3G technologies. Increased Voice Capacity The spectral efficiency of CDMA2000 1X permits high traffic deployments in a small amount (1.25 MHz channel) of spectrum. CDMA2000 1X can provide voice capacity of nearly three times that of cdmaOne system

7、s with Selectable Mode Vocoders (SMV) and antenna diversity techniques. CDMA2000 delivers 4-8 times higher voice capacity than TDMA-based technologies. CDMA2000 1X supports 35 traffic channels per sector per RF (26 Erlangs/sector/RF) using the EVRC vocoder. Voice capacity improvement in the forward

8、link is attributed to faster power control, lower code rates (1/4 rate), and transmit diversity (for single path Rayleigh fading). In the reverse link, capacity improvement is primarily due to coherent reverse link. For more information on CDMA2000 capacity click here.Higher Data Throughput Today

9、9;s commercial CDMA2000 1X networks support a peak data rate of 153 kbps (Rel. 0) or 307 kbps (Rel. 1). CDMA2000 1xEV-DO enables peak rates of up to 2.4 Mbps (Rev. 0) or 3.1 Mbps on the downlink, and 1.8 Mbps on the uplink (Rev A). 1xEV-DO networks deliver the highest data speeds commercially availa

10、ble today. Average Data Throughput CDMA2000 1X 60-100 kbps CDMA2000 1xEV-DO 400-800 kbps Multicast Services With the introduction of EV-DO Release 0 and followed by EV-DO Revisions A and B, operators have the ability to offer multicast services, “one to many” delivery, which allows transmitting the

11、same information to an unlimited number of users without the need to rebroadcast the information multiple times. Multicast functionality offers significant advantages to operators and users. For operators, it allows a vast range of high-revenue generating services with minimum network resources at l

12、ow cost. For the end-user, multicast services provide access to multimedia content, such as TV broadcasts, MP3 audio files, movies, etc., and a higher quality of services. For 1xEV-DO Rel 0, the multicast functionality is referred to as Gold Multicast and for 1xEV-DO Rev A it is called Platinum Mult

13、icast. Frequency Band FlexibilityCDMA2000 can be deployed in most cellular and PCS spectrum. CDMA2000 networks have already been deployed in the 450, 800, 1700, 1900 and 2100 MHz bands. Migration Path CDMA 2000 provides a direct migration path to 3G for first generation (1G) and second generation (2

14、G) systems. CDMA2000 systems have been deployed by Greenfield, cdmaOne, TDMA and analog operators.For more information on migration to CDMA2000 click here. Serves Multiple Markets CDMA2000 technologies support both fixed (Wireless Local Loop WLL) and mobile services and can be used by operators to p

15、rovide affordable voice services and broadband data access in urban, as well as remote areas, cost-effectively. While CDMA2000 technologies are mostly deployed by operators to offer mobile services, in many developing regions, i.e., Africa and South East Asia, CDMA2000 WLL technology is used to prov

16、ide voice and data services to communities. Supports Multiple Service Platforms CDMA2000 can be used with various operating systems (Palm and PocketPC), application platforms (JAVA and BREW), WAP, and emerging wireless technologies (WiFi and Push-to-Talk).Full backward compatibilityCDMA2000 is backw

17、ard compatible with cdmaOne, and 1xEV-DO is backward compatible with both CDMA2000 1X and cdmaOne through multi-mode devices. Backward compatibility assures service transparency for the end user and smooth integration of 2G and 3G networks for the operator. Increased Battery LifeCDMA2000 significant

18、ly enhances battery performance. Benefits include:· Quick paging channel operation · Improved reverse link performance · New common channel structure and operation · Reverse link gated transmission · New MAC states for efficient and ubiquitous idle time operation Synchroniza

19、tionCDMA2000 is synchronized with the Universal Coordinated Time (UCT). The forward link transmission timing of all CDMA2000 base stations worldwide is synchronized within a few microseconds. Base station synchronization can be achieved through several techniques including self-synchronization, radi

20、o beep, or through satellite-based systems such as GPS, Galileo, or GLONASS. Reverse link timing is based on the received timing derived from the first multipath component used by the terminal.There are several benefits to having all base stations in a network synchronized:· The common time ref

21、erence improves acquisition of channels and hand-off procedures since there is no time ambiguity when looking for and adding a new cell in the active set. · It also enables the system to operate some of the common channels in soft hand-off, which improves the efficiency of the common channel op

22、eration. · Common network time reference allows implementation of very efficient "position location" techniques. Power ControlThe basic frame length is 20 ms divided into 16 equal power control groups. In addition, CDMA2000 defines a 5 ms frame structure, essentially to support signal

23、ing bursts, as well as 40 and 80 ms frames, which offer additional interleaving depth and diversity gains for data services. Unlike IS-95 where Fast Closed Loop Power Control was applied only to the reverse link, CDMA2000 channels can be power controlled at up to 800 Hz in both the reverse and forwa

24、rd links. The reverse link power control command bits are punctured into the F-FCH or the F-DCCH (explained in later sections) depending on the service configuration. The forward link power control command bits are punctured in the last quarter of the R-PICH power control slot.In the reverse link, d

25、uring gated transmission, the power control rate is reduced to 400 or 200 Hz on both links. The reverse link power control sub-channel may also be divided into two independent power control streams, either both at 400 bps, or one at 200 bps and the other at 600 bps. This allows for independent power

26、 control of forward link channels.In addition to the closed loop power control, the power on the reverse link of CDMA2000 is also controlled through an Open Loop Power Control mechanism. This mechanism inverses the slow fading effect due to path loss and shadowing. It also acts as a safety fuse when

27、 the fast power control fails. When the forward link is lost, the closed loop reverse link power control is "freewheeling" and the terminal disruptively interferes with neighboring. In such a case, the open loop reduces the terminal output power and limits the impact to the system. Finally

28、 the Outer Loop Power drives the closed loop power control to the desired set point based on error statistics that it collects from the forward link or reverse link. Due to the expanded data rate range and various QoS requirements, different users will have different outer loop thresholds; thus, dif

29、ferent users will receive different power levels at the base station. In the reverse link, CDMA2000 defines some nominal gain offsets based on various channel frame format and codingschemes. The remaining differences will be corrected by the outer loop itself.Soft Hand-offEven with dedicated channel

30、 operation, the terminal keeps searching for new cells as it moves across the network. In addition to the active set, neighbor set, and remaining set, the terminal also maintains a candidate set.When a terminal is traveling in a network, the pilot from a new BTS (P2) strength exceeds the minimum thr

31、eshold TADD for addition in the active set. However, initially its relative contribution to the total received signal strength is not sufficient and the terminal moves P2 to the candidate set. The decision threshold for adding a new pilot to the active set is defined by a linear function of signal s

32、trength of the total active set. The network defines the slope and cross point of the function. When strength of P2 is detected to be above the dynamic threshold, the terminal signals this event to the network. The terminal then receives a hand-off direction message from the network requesting the a

33、ddition of P2 in the active set. The terminal now operates in soft hand-off.The strength of serving BTS (P1) drops below the active set threshold, meaning P1 contribution to the total received signal strength does not justify the cost of transmitting P1. The terminal starts a hand-off drop timer. Th

34、e timer expires and the terminal notifies the network that P1 dropped below the threshold. The terminal receives a hand-off message from the network moving P1 from the active set to the candidate set. Then P1 strength drops below TDROP and the terminal starts a hand-off drop timer, which expires aft

35、er a set time. P1 is then moved from candidate set to neighbor set. This step-by-step procedure with multiple thresholds and timers ensures that the resource is only used when beneficial to the link and pilots are not constantly added and removed from the various lists, therefore limiting the associ

36、ated signaling.附錄5 外文資料譯CDMA2000優(yōu)點CDMA2000得到了廣泛的業(yè)務經(jīng)驗,通過幾年的cdmaOne系統(tǒng). 因此,是一個非常有效的、強有力的CDMA2000技術. 它提供了最高的聲音和數(shù)據(jù)能力使用量最少的頻譜,它可以提供服務的城市以及偏遠地區(qū)的成本效益. 獨具特色的、效益、業(yè)績優(yōu)良的CDMA2000技術,使其高表達能力和高速數(shù)據(jù)包. 由于支持CDMA2000CDMA1X語音和數(shù)據(jù)服務,無論在同一載體,它使得經(jīng)營者提供了有效的服務費用. CDMA20001xev,是優(yōu)化數(shù)據(jù),能支持大量數(shù)據(jù)流量的寬帶速度. 1xev,是適合提供高速數(shù)據(jù)服務的移動用戶和/或寬頻上網(wǎng).

37、由于無線電技術的優(yōu)化,使經(jīng)營CDMA2000投資少、部署地點細胞更快,最終使服務提供商增加其收入與投資回報快(港澳). CDMA2000的演進道路是為了減少投資和經(jīng)營的影響,網(wǎng)絡服務不中斷的用戶. 這是通過前后兼容性、硬件使用,波段移民和混合網(wǎng)絡結構. 這一特點CDMA2000技術公司提供大量的時間和市場的優(yōu)勢,是其他3G技術. 增加語音能力 頻譜效率高CDMA2000CDMA1X許可證部署少量交通(125兆赫頻道)的頻譜. CDMA2000CDMA1X可以提供語音能力近3倍cdmaOne系統(tǒng)五十九vocoders模式和天線多樣性(SMV)技術. CDMA2000提供語音能力比4-8倍式基礎技

38、術. CDMA2000支持CDMA1X35元的交通渠道,每部門射頻(26erlangs/界/RF)使用EVRCvocoder. 語音能力的提高與發(fā)展較快的原因是電力控制,降低稅率法(1/4計算),將多樣性(單路正在瑞利). 相反的聯(lián)系,協(xié)調(diào)能力提高的主要原因是改變聯(lián)系匯率制度. 更多信息CDMA2000能力 按這里 . 高數(shù)據(jù)吞吐量 今天的商業(yè)CDMA2000CDMA1X網(wǎng)絡的數(shù)據(jù)傳輸率最高支持153千比特通信(0Rel.Rel.)、307千比特通信(1). CDMA20001xev小康,使最高稅率達2.4Mbps(Rev0)或3.1mbps的下行,并在180Mbps上行(RevA). 1xe

39、v小康提供網(wǎng)絡數(shù)據(jù)的速度最高可今天的商業(yè). 平均數(shù)據(jù)吞吐量 CDMA2000CDMA1X 千比特通信60-100 CDMA20001xev小康 體千比特通信 多信道服務 在引進型小康釋放和零點隨后發(fā)現(xiàn),做了修改和B公司有能力提供服務的多,"人多"的執(zhí)行,使傳輸同一信息,以無限多的用戶不必轉播信息成倍增長. 多信道功能的用戶提供了很大的優(yōu)勢和經(jīng)營. 經(jīng)營,讓眾多的高創(chuàng)收服務網(wǎng)絡資源以最低成本低. 為最終用戶、多信道提供多媒體服務,如電視、音響MP3檔案、電影等,以及較高的服務質量. 為1xev小康Rel0,被稱為黃金多信道功能和多信道1xev,難道這就是所謂的白金多信道Rev

40、. 頻帶彈性 CDMA2000可以部署在移動電話和個人電腦最光譜. CDMA2000網(wǎng)絡已經(jīng)部署在450、800、1700、1900和2100兆赫波段. 移民道路 2000碼分多址直接提供的第一代移民之路3G(1G)和第二代(第二代服務)系統(tǒng). CDMA2000系統(tǒng)已部署了新建、cdmaOne、模擬式和經(jīng)營. 更多地了解移民CDMA2000 按這里 . 市場多元化服務 CDMA2000技術支持固定(無線本地環(huán)路,回路)和流動電話服務,可以用經(jīng)營者提供語音服務能力和寬帶數(shù)據(jù)存取城市以及偏遠地區(qū)的成本效益. CDMA2000技術被部署在大多數(shù)的流動提供服務的經(jīng)營者,在許多發(fā)展中地區(qū),即非洲、東南亞

41、、CDMA2000技術用于回路語音和數(shù)據(jù)服務的社區(qū). 支持多種服務平臺 CDMA2000可以利用各種操作系統(tǒng)(Palm、袖珍型)、應用平臺(爪哇和BREW)、WAP、無線新技術(WiFi推動中講). 全面兼容 CDMA2000與cdmaOne落后,1xev,是符合落后兩cdmaOne和CDMA2000CDMA1X通過多種方式的裝置. 為保證兼容最終用戶服務的透明度,并順利地把3G網(wǎng)絡的第二代服務營辦商. 提高電池的生活 CDMA2000電池性能大大提高. 好處包括: · 傳呼業(yè)務快速頻道 · 提高業(yè)績扭轉聯(lián)系 · 共同經(jīng)營新格局 · 扭轉連接傳輸設 · 新堡國家普遍閑置和高效運作 同步 CDMA2000與世界同步協(xié)調(diào)時間(UCT). 遠期將傳輸時間是全世界所有