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Introduce key technologies TD-SCDMA ? 1, TD-SCDMA mobile phones to play, how to find you? - Integrated address (multiple access) mode 1, TD-SCDMA air interface used four kinds of multiple access technologies: TDMA, CDMA, FDMA, SDMA (Smart Antenna). 2, the allocation of technical resources, comprehensive utilization of four different point of view of freedom, can be dynamically adjusted by the optimal allocation of resources. Second, flexible downlink time slot allocation Flexible downlink time slot allocation at any time to meet your phone, Internet browsing, downloading files, video services and other needs, ensure that you clear, smooth and enjoy 3G services. 3, TD overcome the effects of respiratory effects and distance What is Respiration? In the CDMA system, when a district of the interference signal is very strong, effective and efficient base station coverage area will be reduced; When a cell of the interference signal is weak, the real base station will increase the effective coverage. In short, the respiratory effects of performance for the coverage radius increases with the number of users contraction. Lead to respiratory effect is mainly due to CDMA system is a self-interference system, the user increases the increase leading to interference effects coverage. For TD-SCDMA, the FDMA and TDMA by low bandwidth to the main interference suppression system, a single slot in the CDMA technology used to improve system capacity, and through joint detection and smart antenna technology (SDMA technology) to overcome more than a single time slot interference between users, and thus a significant factor in respiratory effects of reduction, which is no longer a TD system interference limited system (the system from interference), unlike the CDMA coverage radius as a result of the increase in the number of users was significantly reduced, thus that the TD system is not breathing effect. What is the distance effect? As the mobile phone users are randomly distributed within a cell, and is constantly changing, sometimes in the same cell phone users may be the edge, and sometimes close to the base station. If the phone&#39;s transmitting power according to the design maximum communication distance, then when the phone close to the base station, the power must be a surplus, and the formation of harmful electromagnetic radiation. Solution to this problem is based on the different communication distance, real-time mobile phone transmit power adjustment, or power control. Power control principle is that when the spread of the channel conditions suddenly changed for the better, the power control unit should be quick to respond within a few microseconds, in order to prevent a sudden increase and the signal produced additional interference to other users; contrary when the propagation conditions suddenly deteriorate, the power adjustment can be relatively slower pace. That is, rather short period of time a single user&#39;s signal quality deterioration, but also prevent many other users have a greater background interference. 4, smart antenna (Smart Antenna) In the TD-SCDMA system, base station system through the digital signal processing technology and the adaptive algorithm, dynamic way to make smart antennas formed in Fugaikongjian the directional beam for a particular user, Chongfenliyong downlink signal Neng Liang and maximum restraint Ganrao signal. Smart antenna base station through the entire district of tracking mobile terminals, such terminals are signal to noise ratio has been greatly improved, to improve quality of service. 5, dynamic channel allocation (DCA, Dynamic Channel Allocation) First of all, look at what channel? When you call the channel is occupied by the communication link (line) resources, as you drive on the roads, you are using the lanes, traffic signs, traffic light signals, these resources are essential for your journey; in TD-SCDMA communication, the channel frequency, time slot (time), characterized by the use of code words of radio resources. Dynamic channel allocation, in accordance with the needs of users in real-time dynamic resource (frequency, time slot, code words, etc.) distribution. Dynamic channel allocation of the benefits: 1, high bandwidth efficiency 2, no network planning in the pre-planning of channel 3, can automatically adapt to network load and interference changes. Dynamic channel allocation (DCA) under the adjustment rate is divided into: slow DCA and fast DCA. Slow DCA will be allocated to the cell range wireless channel, and fast DCA points to the channel business. RNC is responsible for the management of district resources available, and the dynamic allocation to the user. RNC allocation of resources depends on the system load, operational parameters such as QoS requirements. DCA is based on the most current interference measurement algorithm, which will be based on feedback from the user mobile terminal real-time measurements of interference distribution channel. The first phase of China Mobile TD tender results Bidding Time: February 2008 Brand Model Number category country firms The new Post mobile phones through new domestic postal links N268 21000 Hisense Hisense T68 10500 phone Lenovo Lenovo TD800 10500 E ZTE ZTE U980 9000 Yulong Cool Yulong Coolpad 6260 Foreign Samsung Electronics Samsung L288 4500 LG Electronics LG KD876 4500 On the card ZTE ZTE 10,000 domestic Datang Mobile Datang 5000 CDMA2000 and WCDMA, TD-SCDMA difference 1. CDMA2000 is used to refer to TIA standards organization the name of the third generation of CDMA. The TIA applies to 3G CDMA standard known as IS-2000, the technology itself is known as CDMA2000. The first phase, also known as CDMA2000 1x, it makes the existing IS-95 system has a communications company can double its overall system capacity, and can increase the data rate of up to 614kbps. CDMA2000 1x higher than technical progress, including 1xEV (high-speed data rate). Introduced by the QCT MSM5000 ? chipset solution backward compatible CDMA2000 cdmaOne (IS-95 CDMA). CDMA2000 standard developed by the 3GPP2 organization, the version including the Release 0, Release A, EV-DO and EV-DV, Release 0 follows the main characteristics of the core based on ANSI-41D network, the wireless access network and core network to increase support for packet services network entities, this version has been stable. Unicom&#39;s CDMA Phase II will open is the version used, the highest single-carrier downlink rate can reach 153.6kbit / s. Release A Release 0 is the strengthening of the highest rates of single-carrier can reach 307.2kbit / s, and support voice services and packet services concurrency. EV-DO uses a separate carrier to support data services available in the standard 1.25MHz carrier, while providing voice and high-speed packet data service, maximum speed up to 3.1Mbit / s 2.WCDMA full name is Wideband CDMA, Chinese translation of &quot;Broadband Code Division Multiple Access&quot;, which can support ranging from 384Kbps to 2Mbps data transfer rate, in the fast-moving state, providing 384Kbps data rate, the low-speed or indoor environment, can provide transmission rates up to 2Mbps. The GSM system can only send 9.6Kbps, fixed-line rate of 56Kbps Modem only, we can see WCDMA wireless broadband communications. In addition, with a number of transmission channels, it also provides circuit-switched and sub-exchange services, so consumers can receive calls while using the exchange method, and then sub-exchange access to the Internet, this technology can improve the mobile efficient use of telephone, makes us more than can do more at the same time, the service voice or data transmission limitations. In terms of costs, WCDMA because the technology with sub-exchange, so the cost of the network used to access time is not calculated, but the amount of consumer data to set. In Europe, the United States and the joint efforts of Japanese manufacturing companies, the Japanese NTT DoCoMo&#39;s WCDMA test system has been commercialized in 2001, we can see that the so-called third generation mobile communications to users the convenience of the. 3.TD-SCDMA, the standard is set by the China 3G standard alone, June 29, 1999, China&#39;s former Ministry of Posts and Telecommunications Science and Technology Research Institute (Datang Telecom) presented to the ITU. The standard intelligent wireless, synchronous CDMA, and software radio technology of today&#39;s leading international financial in which, in the spectrum efficiency, support business flexibility, cost, frequency flexibility and unique advantages. Also, given the huge domestic market, the standard by all the major telecom equipment vendors attention for more than half of the world of equipment manufacturers have announced to support TD-SCDMA standard. Mobile 21 billion yuan in 28 cities will be built to support TD-building 3G networks China Mobile, September 12, 2008 on the site &quot;to expand China Mobile&#39;s TD-SCDMA trial network size of the network technology the second phase of wireless network equipment procurement tender notice,&quot; the official launch of domestic 3G standard TD-SCDMA&#39;s two tendering . Under the arrangement, the tender will cover 28 cities, namely, Shijiazhuang, Taiyuan, Hohhot, Dalian, Changchun, Harbin, Nanjing, Hangzhou, Ningbo, Hefei, Fuzhou, Nanchang, Jinan, Zhengzhou, Wuhan, Changsha, Nanning, Hainan, Chongqing, Chengdu, Guiyang, Kunming, Lhasa, Xi&#39;an, Lanzhou, Xining, Yinchuan and Urumqi. This means that the residents of these cities can be made the next batch of 3G service users experience. Scale from the procurement point of view, TD-SCDMA construction of the planned deployment of two 23,000 wireless base stations, calculated in accordance with the wireless set, compared with 160,000 fans. After China Mobile CEO Wang had Artesyn Technologies introduced, TD-SCDMA in a network of 15 billion yuan investment to build a 16,000 base stations. If the price index under the same projection, two network construction investment should be at 210 billion yuan. China Mobile in the tender called for bids to join the companies to actively participate in TD-SCDMA wireless network equipment and technology research and development, and to a certain degree of TD-SCDMA wireless network equipment, supply and service capabilities, in addition, need to bid products Ministry of Industry and Information Technology (or the former Ministry of Information Industry) presented on the TD-SCDMA wireless network equipment, telecom equipment network access license products. The tender requirements, clearly provides that &quot;TD-SCDMA wireless network tender equipment shall meet the technical specifications of China Mobile, and a mature, stable commercial products.&quot; When the first commercial test based China Mobile third-party survey commissioned survey conducted by institutions, the current TD-SCDMA is the biggest problem actually comes from the terminal and network coverage, in addition, base stations and other equipment are not mature enough. With the TD-SCDMA commercial trial process accelerated in the face two tender information, the equipment manufacturers have made the appropriate response, in a tender to acquire more shares of ZTE, Datang Mobile and Shanghai Bell Alcatel, the new postal communication, war, Putian, and other enterprises will continue to participate in two tenders, but Huawei and Nokia Siemens joint venture will be out of TD, respectively, by the participation of Huawei and Nokia Siemens Networks. In the Ministry of Industry and Information Technology, driven by China Mobile for TD-SCDMA R &amp; D has become a required course equipment manufacturers, recently, more than a dozen colleges and universities in the joint Datang Mobile TD-SCDMA technology to carry out a special study and and the recently announced Alcatel Shanghai Bell signed an R &amp; D TD-SCDMA technology, strategic cooperation agreement. China Mobile said that TD-SCDMA has been the evolution of aspects of the long-term planning, and more than outside operators, equipment manufacturers to explore TD-LTE (the equivalent of, after the evolution of the 4G technology TD) Frequency and code planning TD-SCDMA system is using 155MHz spectrum, which is a stage 2010MHz ~ 2025MHz band, interference is small, divided into three 5MHz band. Each carrier frequency bandwidth is 1.6MHz, thus the 5M, 10M, 15M bandwidth, respectively, 3,6,9 a carrier frequency can support, you can network with the frequency or different frequency network. Frequency network with high spectrum efficiency, interference of the same frequency in neighboring cells, the loss must be the capacity for performance improvement; different frequency network with neighboring cells can be effective in reducing the impact of frequency interference and improve system performance, but low spectral efficiency, need more frequency resources. TD system, the current frequency plan to use more N frequency program that is configured for each N-sector carrier, which contains a main carrier frequency, N-1 个 secondary carrier frequency. Public control channel are fitted to the main carrier frequency, auxiliary service channel carrier frequency allocation. The main carrier frequency and the secondary carrier frequency using the same scrambling code and the mi-damble code. N frequency programs can reduce the system interference, increase system capacity, improve system performance with the network frequency. TD-SCDMA system uses the relationship with the corresponding downlink pilot code, the uplink pilot code, scrambling code and Midamble code. 128 TD-SCDMA system, the basic scrambling codes in numerical order and divided into 32 groups of four, each basic scrambling code used for downlink UE distinguish between different communities. Planning in the code, first determine each logic cell in the downlink pilot code 32 code groups corresponding optional serial number, and then the sequence in which the 4 position in the corresponding scrambling codes for cell interference to select a suitable code. Basic Midamble codes correspond with the scrambling code can be identified with the determined scrambling code. WCD-MA compared to codeword 512, TD-SCDMA system, code resources and relatively small, so TD scrambling code planning more demanding than the WCDMA network. Coverage Planning TD-SCDMA system coverage performance depends primarily on two aspects, first, to protect the up and down the length of time slot conversion restrictions on the cover, second is link budget. TD-SCDMA time slot in the downlink and uplink pilot pilot slot 96 between the chip-wide protection zone, limited cell coverage can not exceed 11.25km. If the DCA locked by the first upstream slot, base station coverage from the theory can be further expanded. Link budget is the TD-SCDMA network coverage planning the key is divided into upstream and downstream. Downlink budget complexity and the base station transmitting power is far greater than the general mobile phone transmit power, it is generally determined by calculating the uplink cell coverage radius, and from the limited coverage area to estimate the number of base stations. TD-SCDMA link budget target frame by its unique structure, TDD duplex mode, smart antennas, joint detection and relay switching impact of key technologies. According to TD-SCDMA a unique frame structure, to consider separately the pilot channel, BCH channel and other public channel and traffic channel power allocation, interference reserves and antenna gain. Practical engineering design, TD-SCDMA system link budget should be based on the specific wireless network communication environment, network design objectives, factory equipment performance, specific projects for specific parameter settings and other adjustments. Capacity Planning TD-SCDMA system uses a variety of key technology allows cell interference within and outside the basic cell was inhibited, the greater spectrum efficiency and capacity. TD-SCDMA system capacity characteristics are: diameter covered with a variety of basic business, cell breathing effect is not obvious, there is no macro diversity Relay switch, switch more easily controlled, the proportion of downlink capacity and time slots and the maximum transmit power. A variety of interference suppression technology adoption, so that TD-SCDMA system, showing limited capacity of diversity (that is power limited, the code is limited and interference limited resources), but the main code resource-constrained. In dense urban and complex environments will be reflected in the interference limited, in general, urban, suburban and rural areas such as environmental and resource constraints in the performance of the code, so TD-SCDMA system capacity planning should be treated differently in different environments. TD estimates the current capacity of the system are three main methods: formula, BRU law and child law Cambay. BRU Law and Campbell introduced the basic resource unit law, business resources, the concept of strength for TD-SCDMA this resource-constrained systems, such interference does not apply to limited WCDMA system. WCDMA system capacity planning generally limited interference-based formula, but formula and TD-SCDMA is different. TD Status TD as an independent intellectual property rights standards, by the strong support of the relevant license issued to the strongest of China Mobile. In the joint efforts of TD Industry Alliance, TD technology matures.
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