罗强通信专业英语大作业.doc

通信专业英语大作业姓 名： 罗强 学 号： 201230105089 序 号： 01号 系 别： 中兴通信工程学院 班 级： 12级通信六班 完成时间： 2014、12、26 一、 翻译4G Mobile:4G MobileVoice was the driver for second-generation mobile and has been a considerable success.Today,video and TV services are driving forward third generation (3G) deployment. And in the future, low cost, high speed will drive forward the fourth generation (4G) as short-range communication emerges. Service and a plication ubiquity,with a high degree personalization and synchronization between various user appliances, will be another driver. At the same time, it is probable that the radio access network will evolve from a centralized architecture to a distributed one.声音是第二代移动驱动，并得到了相当大的成功。今天，视频和TV服务正在向第三代（3G）发展。并且在以后，低成本和高速的特点将带动它们进入第四代（4G）即短距离通信，随着服务和折叠技术的普及，各种用户设备之间的个性化和同步化程度越高，将成为另一个驱动器。在同一时间，该无线电接入网络有可能将来自集中式架构演进到一个分布式之一。1 .Service EvolutionThe evolution from 3G to 4G will be driven by services that offer better quality(e.g.,video and sound) thanks to greater bandwidth, more sophistication in the association of a large quantity of information, and improved personalization. Convergence with other network (enterprise,fixed) services will come about through the high session data rate. It will require an always-on connection and a revenue model based on a fixed monthly fee. The impact on network capacity is expected to be significant. Machine-to-machine transmission will involve two basic equipment types: sensor (which measure parameters)and tags (which are generally read/write equipment).It is expected that users will require high data rates,similar to those on fixed networks,for data and streaming applications. Mobile terminal usage (laptops, personal digital assistants, handhelds) is expected to grow rapidly as they become more user friendly. Fluid high quality video and network reactivity are important user requirements. Key infrastructure design requirements include: fast response, high session rate, high capacity, low user charges, rapid return on investment for operators, investment that is line with the growth in demand, and simple autonomous terminals.The infrastructure will be much more distributed than in current deployments, facilitating the introduction of a new source of local traffic: machine-to-machine.1服务革命从3G到4G演进将由更高质的服务（例如，视频和声音）推动，更大的带宽使得大量信息的关联显得更加复杂，个人化也得到了提高。要想融合了其他网络（企业，固定的）服务的出现得通过高会话的数据速率。这将需要一个永远在线的连接，并收取固定的月租费。预计这对网络容量的影响是显著。机器间的传输将涉及两个基本类型的设备：传感器（用来测量参数）和标签（通常用来读/写设备）。据估计，用户会需要高数据速率，类似于那些在固定网络提供数据和数据流的应用程序。移动终端的使用（笔记本电脑，个人数字助理，掌上电脑）有望迅速增长，因为它们变得更加方便用户。流畅高质的的视频和网络的反应性是重要的用户需求。关键基础设施的设计要求包括：快速响应，高会话率，高容量，低使用费，运营商投资的快速回报。投资能够按照需求的增长，以及简单的自发终端。基础设施将比目前的部署更加分散，这样便于引进本地通话的新来源：机器对机器。2 .Multi-technology Approach Many technologies are competing on the road to 4Q,as can be seen in Figure 1.Three paths are possible, even if they are more or less specialized. The first is the 3G-centric path, in which Code Division Multiple Access (CDMA) will be progressively pushed to the point at which terminal manufacturers will give up. When this point is reached, another technology will be needed to realize the required increases in capacity and data rates. The second path is the radio LAN one. Widespread deployment of WiFi is expected to start in 2005 for PCs, laptops and PDAs. In enterprises, voice may start to be carried by Voice over Wireless LAN (VoWLAN). However, it is not clear what the next successful technology will be. Reaching a consensus on a 200 Mbit/s (and more) technology will be a lengthy task, with too many proprietary solutions on offer. A third path is IEEE 802.16e and 802.20, which are simpler than 3G for the equivalentperformance. A core network evolution towards a broadband Next Generation Network (NGN) will facilitate the introduction of new access network technologies through standard access gateways,based on ETSI-TISPAN, ITU-T, 3GPP, China Communication Standards Association (CCSA) and other standards. How can an operator provide a large number of users with high session data rates using itsexisting infrastructure? At least two technologies are needed. The first (called parent coverage) is dedicated to large coverage and real-time services. Legacy technologies, such as 2G/3G and their evolutions will be complemented by WiFi and WiMAX. A second set of technologies is needed to increase capacity, and can be designed without any constraint on coverage continuity. This is known as pico-cell coverage. Only the use of both technologies can achieve both targets.Handover between parent coverage and pico cell coverage is different from a classical roaming process, but similar to coverage handover.Parent cover can also be used as a back-up when service delivery in the pico cell become too difficult.2多技术方法如在图1可以看出，许多技术都在4Q的道路上争夺着，.有三种路径是可能的，即使它们或多或少专门化。第一种路径是3G中心，其中码分多址（CDMA）将逐步被推到终端制造商放弃的状态下。当达到这一状态，另一种技术，将需要实现所需容量的增加和数据传输速率。第二种路径是无线局域网之一。广泛部署的WiFi，预计从2005年开始使用在个人电脑，笔记本电脑和PDA。在企业中，语音可能会开始通过无线局域网语音（VoWLAN）进行。然而，下一种成功的技术是不明确的。提供太多专有的解决方案，达到200 Mbit / s（以上）的技术达成共识将是一个漫长的任务。第三种路径是IEEE802.16e和802.20，在相同性能下比3G技术更简单了。对宽带的下一代网络（NGN）核心网络演进将有利于通过标准的接入网关推出新的接入网技术，这是基于ETSI-TISPAN，ITU-T，3GPP，中国通信标准化协会（CCSA）等标准。可使用操作者提供大量使用着现有的基础设施有着高速度会话数据传输速率的用户呢？至少需要两种技术。第一种（称为“父覆盖”）是专用于大覆盖范围和实时服务。传统技术，比如2G / 3G和它们的演进将由WiFi和WiMAX来补充。第二种技术是用来增加容量，并且可以被设计成没有覆盖连续性的任何约束。这就是所谓的皮蜂窝区覆盖。只有采用这两种技术才可实现目标。交接技术在父覆盖和皮蜂窝区上，与传统的漫游过程中不同，但在交接覆盖相似。当皮蜂窝区服务提供变得过于困难时，父覆盖还起到一种后备作用。3 .Key 4G TechnologiesSome of the key technologies required for 4G are briefly described below:一些4G所需的关键技术简述如下：3.1 OFDMAOrthogonal Frequency Division Multiplexing (OFDM) not only provides clear advantages for physical layer performance, but also a framework for improving layer 2 performance by proposing an additional degree of free-dom. Using ODFM, it is possible to exploit the time domain, the space domain, the frequency domain and even the code domain to optimize radio channel usage. It ensures very robust transmission in multi-path environments with reduced receiver complexity. As shown in Figure 2, the signal is split into orthogonal subcarriers, on each of which the signal is narrowband (a few kHz) and therefore immune to multi-path effects, provided a guard interval is inserted between each OFDM symbol. OFDM also provides a frequency diversity gain, improving the physical layer performance. It is also compatible with other enhancement technologies, such as smart antennas and MIMO. OFDM modulation can also be employed as a multiple access technology (Orthogonal Frequency Division Multiple Access; OFDMA). In this case, each OFDM symbol can transmit information to/from several users using a different set of subcarriers (sub-channels). This not only provides additional flexibility for resource allocation (increasing the capacity), but also enables cross-layer optimization of radio link usage. 3.1正交频分多址正交频分复用（OFDM）不仅拥有针对物理层性能的明显优势，同时拥有通过附加的自由程度来提高2层性能的这样一个框架。使用ODFM，能够利用时域，空间域，频域和代码域来优化无线电信道的使用情况。它确保了在多径环境下通过降低接收器的复杂性来进行有效的传输。如图2，该信号被分成正交子载波，对每一个所述信号是“窄带”（几kHz），因此不受多路径的影响，OFDM提供插入每个OFDM符号之间一个保护间隔以及频率分集增益用来提高物理层性能。OFDM也与其他增强技术兼容，例如智能天线和MIMO。也可以把OFDM调制作为一种多址技术（正交频分多址; OFDMA）。在这种情况下，每个OFDM符号可以传输由多个用户所使用的不同的子载波集合（子信道）的信息。这不仅提供了对资源分配（增加容量）的更多的灵活性，而且还优化无线电链路的跨层使用。 3.2 Software Defined Radio Software Defined Radio (SDR) benefits from todays high processing power to develop multi-band, multi-standard base stations and terminals. Although in future the terminals will adaptthe air interface to the available radio access technology, at present this is done by the infrastructure. Several infrastructure gains are expected from SDR. For example, to increase network capacity at a specific time (e.g.，during a sports event), an operator will reconfigure its network adding several modems at a given Base Transceiver Station (BTS). SDR makes this reconfiguration easy. In the context of 4G systems, SDR will become an enabler for the aggregation of multi-standard pico/micro cells. For a manufacturer, this can be a powerful aid to providing multi-standard, multi-band equipment with reduced development effort and costs through simultaneous multi-channel processing.3.2软件无线电软件无线电（SDR）受益于当今的高处理能力所带来的多频段，多标准基站和终端的发展。虽然在未来该终端将适应可用无线接入的空中接口技术，但是目前这项技术只在基础设施实现。一些基础设施预计会从SDR技术获益。例如，为了在特定的时间提高网络容量，（例如体育赛事期间）操作员将重新配置其网络，在一个给定的基站收发台（BTS）加入几个调制解调器。SDR简化了这个的重新配置。在4G系统的背景下，SDR将推动多标准微蜂窝的聚集。对于制造商，这可能是一个有力的援助，以提供多标准，多频段设备，降低了开发难度，同时通过多频道的处理减少费用。3.3 Multiple-Input Multiple-Output(MIMO)MIMO uses signal multiplexing between multiple transmitting antennas (space multiplex) and time or frequency. It is well suited to OFDM, as it is possible to process independent time symbols as soon as the OFDM waveform is correctly designed for the channel. This aspect of OFDM greatly simplifies processing. The signal transmitted by mantennas is received by nantennas. Processing of the received signals may deliver several performance improvements: range, quality of received signal and spectrum efficiency. In principle, MIMO is more efficient when many multiple path signals are received. The performance in cellular deployments is still subject to research and simulations. However, it is generally admitted that the gain in spectrum efficiency is directly related to the minimum number of antennas in the link.3.3多输入多输出（MIMO）MIMO使用多个发送天线（空间复用）和时间或频率之间的信号多路复用。它非常适合于OFDM中，因为它是能够尽快将OFDM波形设计正确的信道处理独立的时间符号。 OFDM的这一方面极大地简化了处理。接收nantennas由mantennas发送的信号。所接收的信号的处理可以提供几个性能的改进：范围，接收到的信号和频谱效率的质量。原则上，MIMO是更有效时收到了许多多径信号。蜂窝部署的性能仍然受到研究和模拟。然而，人们普遍承认，在频谱效率增益是直接关系到天线中的链路的最小数目。3.4 Handover and Mobility Handover technologies based on mobile IP technology have been considered for data and voice.Mobile IP techniques are slow but can be accelerated with classical methods (hierarchical, fast mobile IP). These methods are applicable to data and probably also voice. In single-frequencynetworks, it is necessary to reconsider the handover methods. Several techniques can be used when the carrier to interference ratio is negative (e.g. VSFOFDM, bit repetition), but the drawback of these techniques is capacity. In OFDM, the same alternative exists as in CDMA, which is to use macro-diversity. In the case of OFDM, MIMO allows macro-diversity processing with performance gains. However, the implementation of macro-diversity implies that MIMO processing is centralized and transmissions are synchronous. This is not as complex as in CDMA, but such a technique should only be used in situations where spectrum is very scarce.3.4交接和移动基于移动IP技术的切换技术被认为是用于数据和语音。移动 IP技术是缓慢的，但可以通过传统方法（层次，快速移动IP）加速。这些方法适用于数据，可能也适用于语音。在单频网络中，考虑切换的方法是有必要的。当载波干扰比是负数的，这几种技术可运用在此（例如VSFOFDM，比特重复），但这些技术的缺点是容量的问题。在OFDM中，相同形式存在于CDMA，这是使用宏分集。在OFDM的情况下，MIMO允许具有性能增益宏分集的处理。然而，宏分集的实施意味着MIMO处理是集中式和传输是同步的。在CDMA中这没那么复杂，但这样的技术只能在频谱是十分有限的情况下使用。4. Caching and Pico Cells Memory in the network and terminals facilitates service delivery. In cellular systems, this extends the capabilities of the MAC scheduler, as it facilitates the delivery of real-time services. Resources can be assigned to data only when the radio conditions are favorable. This method can double the capacity of a classical cellular system. In pico cellular coverage, high data rate (non-real-time) services can be delivered even whenreception/transmission is interrupted for a few seconds. Consequently, the coverage zone within which data can be received/transmitted can be designed with no constraints other than limiting interference. Data delivery is preferred in places where the bit rate is a maximum. Between these areas, the coverage is not used most of the time, creating an apparent discontinuity. In these areas, content is sent to the terminal cache at the high data rate and read at the service rate. Coverages are discontinuous. The advantage of coverage, especially when designed with caching technology, is high spectrum efficiency, high scalability (from 50 to 500 bit/s/Hz), high capacity and lower cost. A specific architecture is needed to introduce cache memory in the network. At the entrance of the access network, lines of cache at the destination of a terminal are built and stored. When a terminal enters an area in which a transfer is possible, it simply asks for the line of cache following the last received between the terminal and the cache. A simple, robust and reliable protocol is used between the terminal and the cache service delivered in this type of coverage.4.缓存和微蜂窝在网络和终端内存中有利于提供服务。在蜂窝系统中，这扩展了MAC调度器的功能，因为它有助于实时服务的递送。资源被分配到的数据仅对无线电的情况有利。这种方法可以加倍经典蜂窝系统的容量。在微蜂窝覆盖下，高数据速率（非实时）服务可以输送即使接收/发送器中断几秒钟。因此，发送在覆盖范围区域内的可以被接收和传输数据可设计成没有约束不同于限制性的干扰。数据被认为在比特率最大的地方递送比较好。在这些区域之间的覆盖并不使用大部分时间来产生一个明显的不连续性。在这些领域中，内容会以高数据速率和读取服务速率发送到终端的缓存。覆盖范围是“不连续的”。覆盖的特别优势在于缓存技术的设计：高频谱效率，高可扩展性（从50到500比特/秒/赫兹），高容量和更低的成本。一个具体的架构，需要在网络中引入高速缓冲存储器。在接入网口，建造和储存终端的目标行缓存。当终端进入一个可以传输的区域，它会简单地请求高速缓存的以下的终端和高速缓存之间最后的一次接收。一个简单的，坚固的，可靠的协议被用于在终端和在这种类型的覆盖输送的缓存服务之间。2、 请找出最前沿技术