Technological and Market Analysis of TD-SCDMA
2000年5月，在土耳其伊斯坦布尔召开的国际电联大会上，TD-SCDMA被国际电联接纳为第三代移动通信系统标准之一，这标志着中国在移动通信技术领域已经进入世界先进行列。
TD-SCDMA was acceptedby ITU as one of 3G standards at the ITU conference held in Istanbul, Turkey, in May 2000. This shows that China has been among the world’s advanced in mobile communication technology.
TD-SCDMA技术优势
Technological Advantages of TD-SCDMA
2000年5月，在土耳其伊斯坦布尔召开的国际电联大会上，TD-SCDMA被国际电联接纳为第三代移动通信系统标准之一，这标志着中国在移动通信技术领域已经进入世界先进行列。
TD-SCDMAwasaccepted by ITU as one of 3G standards at the ITU conference held in Istanbul, Turkey, in May 2000. This shows that China has been among the world’s advanced in mobile communication technology.
TD-SCDMA系统具有其突出的特点：在第三代移动通信系统的三种主流标准中惟一采用时分双工（TDD）方式，在频谱利用上具有较大的灵活性。该系统综合采用了智能天线、同步CDMA、联合检测、软件无线电等无线通信中的先进技术，解决了这些技术应用中的各种问题，使系统具有较高的性能和频率利用率，这些也是国际组织之所以采纳这一系统的原因。
TD-SCDMA has its prominent characteristics: being the only standard of the three 3G standards that adopts TDD, it has greater flexibility in spectrum utilization. This system comprehensively adopts smart antenna, synchronous CDMA, joint detection, software defined radio and other advanced technologies in wireless communications, and solves various problems in the application of these technologies, giving the system higher performance and frequency utilization efficiency. These are also reasons why the international organization has adopted this system.
频谱规划方便、利用灵活、利用率高
Easy Planning,Flexible Use and Higher Utilization Efficiency of Spectrum
与FDD系统相比，TD-SCDMA采用时分双工方式，上下行无需对称频段，可以见缝插针，灵活方便地规划使用日益紧张的频谱资源。
Compared with the FDD system, TD-SCDMA adopting TDD, has no need of symmetrical frequency bands for uplink and downlink, and enables flexible and convenient planning and use of increasingly scarce spectrum resources.
在通信技术的发展中，将广泛采用无线接入方式，特别是大数据量业务的应用将需要很大的频谱带宽，频谱这种不可再生的资源越来越稀少，FDD技术所要求的一定间隔的对称频段分配将面临巨大的挑战。采用TDD技术的运营商可较容易地得到可用频段，有利于业务的未来拓展。另外，由于TD-SCDMA集FDMA、TDMA、CDMA的技术优点于一体，采用智能天线等先进无线技术，使得其频谱利用率较高。采用FDD进行全国组网，至少需要上下行共15MHz×2，即30MHZ频率,而在保持相同容量的前提下，TDD全国组网仅需15到20MHz频率。TD-SCDMA高频谱利用率的特点，不但有利于降低用户接入及频谱使用的平均成本，而且适合我国人口居住密集的覆盖需求，可有效地提高运营商的竞争力。
In the development of telecom technologies, wireless access mode will be widely applied. Application of large data traffic service will require very large spectrum bandwidth. Spectrum, a non-renewable resource, becomes increasingly scarce. Assignment of symmetrical bands with certain spacing FDD requires will face huge challenges. Operators adopting TDD can get usable bands easily, which is beneficial to future expansion of services. Additionally, as TD-SCDMA integrates technological advantages of FDMA, TDMA and CDMA, and adopts smart antenna and other advanced wireless technologies, its spectrum utilization efficiency is relatively high. To adopt FDD for national networking, a total of 15MHz×2, namely, 30MHz is needed at least for uplink and downlink. But on the premise of maintaining the identical capacity, nationwide networking with TDD requires only 15-20MHz. The characteristic of high spectrum utilization efficiency of TD-SCDMA not only helps lower the average cost of subscriber access and spectrum use, but also suits China’s densely populated coverage demand, effectively increasing the competitiveness of operators.
特别适合不对称数据业务
Especially Suiting Asymmetrical Data Service
TD-SCDMA在提供高质量话音业务的同时，由于其采用TDD模式，还可以灵活地设置上下行业务占用时间，能最大限度地利用带宽和系统资源，经济地满足不对称数据业务的需求，这种优势是FDD模式所不具备的。对于一个TD-SCDMA网络，运营商可根据用户在不同区域或不同的时间段的上下行业务比例需求，设置不同的上下行带宽切换点；也可动态调整，随时满足用户业务变化的需求。TD-SCDMA的这个特点，提升了网络接入的有效性，避免了运营商在业务特性变化后的额外投入，降低了运营维护费用。
TD-SCDMAcanflexiblyset occupying time for uplink and downlink services thanks to its TDD mode while providing high-quality voice service, can use bandwidth and system resources to the maximum extent, economically meet asymmetrical data service needs. Such an advantage is what FDD lacks. For a TD-SCDMA network, operators can set different bandwidth switchover point for uplink and downlink according to subscribers’ demands for the proportion of uplink to downlink services in different regions or different time periods; or can make dynamic adjustment to meet subscribers’ changing service demands. This characteristic of TD-SCDMA improves the effectiveness of network access, saves operators extra input after service characteristic changes, and lowers O&M expenses.
另外，针对不对称数据业务，TD-SCDMA以接近WCDMA2倍的频谱利用率，高效传输非对称IP数据业务，这将极大地降低用户接入成本，提升运营商在数据应用上的竞争力。
Additionally,forasymmetricaldata services, TD-SCDMA will greatly cut subscriber access cost and raise operators’ competitiveness in data applications with its spectrum utilization efficiency close to two times that of WCDMA and highly efficient transmission of asymmetrical IP data service.
网络规划优化简单、接入质量稳定、运维成本低
SimpleNetworkPlanningand Optimization, Stable Access Quality And Low O&M Cost
第一，由于TD-SCDMA采用了时分技术和智能天线，极大地降低了CDMA的自干扰和互干扰，FDD制式具有的呼吸效应在TD-SCDMA中不明显，因而TD-SCDMA的网络规划优化相对简单，网络性能易于控制和掌握，用户的业务接入质量稳定。在用户容量增加而必须对网络扩容时，二次网络规划方便，可大大降低网络扩容的费用。第二，TD-SCDMA采用接力切换而不是软切换技术，可节省15%～20%的网络传输资源，降低运营成本。第三，采用软件无线电技术，在系统功能增加、技术升级时，只需进行软件升级而不需要更换设备硬件，这样也就降低了系统维护与升级的成本。第四，采用了多天线技术，在基站射频部分具有天然的容灾容错能力，设备失效风险分散化，设备维修费用低。第五，在运营商提出设备需求拓展或变更时，由于TD-SCDMA从标准到设备主要是由国内厂家控制，设备供应商有条件以合理的费用及时地满足运营商的设备升级需求。第六，TD-SCDMA的各种业务覆盖距离基本相同，不会造成WCDMA系统对高速业务覆盖不连续的问题。TD-SCDMA对用户的服务质量会更有保证。
First,thankstoits TD technology and smart antenna, TD-SCDMA greatly reduces self-interference and mutual interference of CDMA, and the sniff effect of the FDD system is not conspicuous in TD-SCDMA, therefore, TD-SCDMA network planning and optimization are relatively simple, network performance is easy to be controlled and subscriber service access quality is stable. When subscriber capacity increase necessities network capacity expansion, secondary network planning is easy, greatly cutting the cost of network capacity expansion. Second, TD-SCDMA adopts relay switch instead of softswitch technology, which can save 15%-20% network transmission resource and reduce operational cost. Third, adopting software defined radio technology, when system functions increase and technology upgrades, only software upgrading is needed and no hardware upgrading is required, thus reducing system maintenance and upgrading costs. Fourth, adopting multi-antenna technology gives the radio frequency part of base station natural disaster/fault-tolerant capability, decentralizes risks of equipment failure, and lowers equipment maintenance cost. Fifth, when operators put forth their demand for equipment expansion or change, for TD-SCDMA from standard to equipment is manly controlled by domestic manufacturers, equipment providers are in a position to timely meet operators’ equipment upgrading requirement at a reasonable cost. Sixth, TD-SCDMA has largely identical coverage distance for various services, will not cause the problem of coverage discontinuity of the WCDMA system for high-speed services. TD-SCDMA will provide subscribers more assured quality of service.
组网灵活
Flexible Networking
3G的频率特性及其支持业务的特点，导致2G的移动设备组网经验已不再适用于3G的情况。3G必须支持高容量的数据业务，可采用立体分层组网方式。如何减少覆盖盲点以及解决好室内覆盖问题将是今后运营企业要面临的巨大挑战。
For 3G’sfrequencycharacteristic and service support of 3G, the experience in mobile equipment networking of 2G is no longer applicable to 3G. 3G must support high capacity data services, and may adopt stereo hierarchical networking. How to decrease coverage blind and address the issue of indoor coverage will be a big challenge we face.
TD-SCDMA技术不但具有独立组网能力，而且非常适合立体分层组网方式。第一，采用智能天线使宏小区覆盖范围相对更大。第二，多天线技术可以为室内覆盖提供多个信号源，也可用多个天线分别覆盖室内的不同区域或楼层。第三，在相同的带宽情况下，TD-SCDMA的频点数是WCDMA的6倍，有利于立体分层组网的频点规划，减少互干扰，提升网络的覆盖性能。
TD-SCDMAnotonlyhas independent networking capability, but also is very good for stereo hierarchical networking. First, adoption of smart antenna makes the macro cell coverage relatively larger. Second, multi-antenna technology enables provision of multiple signal sources for indoor coverage, or allows coverage of different indoor areas or building floors with more antennas. Third, under identical bandwidth, the number of frequencies of TD-SCDMA is six times that of WCDMA, which is advantageous to the frequency planning of stereo hierarchical networking, helps reduce mutual interference and raise the network coverage performance.
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