交通信号灯控制电路的设计外文翻译

1、附录4 外文资料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.附录5 外文资料译CDMA2000优点CDMA2000得到了广泛的业务经验,通过几年的cdmaOne系统. 因此,是一个非常有效的、强有力的CDMA2000技术. 它提供了最高的声音和数据能力使用量最少的频谱,它可以提供服务的城市以及偏远地区的成本效益. 独具特色的、效益、业绩优良的CDMA2000技术,使其高表达能力和高速数据包. 由于支持CDMA2000CDMA1X语音和数据服务,无论在同一载体,它使得经营者提供了有效的服务费用. CDMA20001xev,是优化数据,能支持大量数据流量的宽带速度. 1xev,是适合提供高速数据服务的移动用户和/或宽频上网.

37、由于无线电技术的优化,使经营CDMA2000投资少、部署地点细胞更快,最终使服务提供商增加其收入与投资回报快(港澳). CDMA2000的演进道路是为了减少投资和经营的影响,网络服务不中断的用户. 这是通过前后兼容性、硬件使用,波段移民和混合网络结构. 这一特点CDMA2000技术公司提供大量的时间和市场的优势,是其他3G技术. 增加语音能力 频谱效率高CDMA2000CDMA1X许可证部署少量交通(125兆赫频道)的频谱. CDMA2000CDMA1X可以提供语音能力近3倍cdmaOne系统五十九vocoders模式和天线多样性(SMV)技术. CDMA2000提供语音能力比4-8倍式基础技

38、术. CDMA2000支持CDMA1X35元的交通渠道,每部门射频(26erlangs/界/RF)使用EVRCvocoder. 语音能力的提高与发展较快的原因是电力控制,降低税率法(1/4计算),将多样性(单路正在瑞利). 相反的联系,协调能力提高的主要原因是改变联系汇率制度. 更多信息CDMA2000能力 按这里 . 高数据吞吐量 今天的商业CDMA2000CDMA1X网络的数据传输率最高支持153千比特通信(0Rel.Rel.)、307千比特通信(1). CDMA20001xev小康,使最高税率达2.4Mbps(Rev0)或3.1mbps的下行,并在180Mbps上行(RevA). 1xe

39、v小康提供网络数据的速度最高可今天的商业. 平均数据吞吐量 CDMA2000CDMA1X 千比特通信60-100 CDMA20001xev小康 体千比特通信 多信道服务 在引进型小康释放和零点随后发现,做了修改和B公司有能力提供服务的多,"人多"的执行,使传输同一信息,以无限多的用户不必转播信息成倍增长. 多信道功能的用户提供了很大的优势和经营. 经营,让众多的高创收服务网络资源以最低成本低. 为最终用户、多信道提供多媒体服务,如电视、音响MP3档案、电影等,以及较高的服务质量. 为1xev小康Rel0,被称为黄金多信道功能和多信道1xev,难道这就是所谓的白金多信道Rev

40、. 频带弹性 CDMA2000可以部署在移动电话和个人电脑最光谱. CDMA2000网络已经部署在450、800、1700、1900和2100兆赫波段. 移民道路 2000码分多址直接提供的第一代移民之路3G(1G)和第二代(第二代服务)系统. CDMA2000系统已部署了新建、cdmaOne、模拟式和经营. 更多地了解移民CDMA2000 按这里 . 市场多元化服务 CDMA2000技术支持固定(无线本地环路,回路)和流动电话服务,可以用经营者提供语音服务能力和宽带数据存取城市以及偏远地区的成本效益. CDMA2000技术被部署在大多数的流动提供服务的经营者,在许多发展中地区,即非洲、东南亚

41、、CDMA2000技术用于回路语音和数据服务的社区. 支持多种服务平台 CDMA2000可以利用各种操作系统(Palm、袖珍型)、应用平台(爪哇和BREW)、WAP、无线新技术(WiFi推动中讲). 全面兼容 CDMA2000与cdmaOne落后,1xev,是符合落后两cdmaOne和CDMA2000CDMA1X通过多种方式的装置. 为保证兼容最终用户服务的透明度,并顺利地把3G网络的第二代服务营办商. 提高电池的生活 CDMA2000电池性能大大提高. 好处包括: · 传呼业务快速频道 · 提高业绩扭转联系 · 共同经营新格局 · 扭转连接传输设 · 新堡国家普遍闲置和高效运作 同步 CDMA2000与世界同步协调时间(UCT). 远期将传输时间是全世界所有