TD-SCDMA[ 1], as the third generation mobile communication standard proposed by China, was formally submitted to ITU (International Telecommunication Union) from 1998. This standard has been evaluated by experts, approved and issued by ITU, integrated with 3GPP (3rd generation partnership project) system and introduced with new technical features for more than ten years. As a result, TD-SCDMA [3] standard became the first international standard for wireless communication proposed by China, mainly based on China's intellectual property rights, and was widely accepted and recognized internationally. This is an important milestone in the telecom history of China. (Note: 3G*** has four international standards, and the other three are CDMA2000 led by the United States and WiMAX and WCDMA led by Europe. )
[Edit this paragraph] Overview of ]TD-SCDMA technology
Time division-synchronous code division multiple access (TD-SCDMA) is one of the three 3G standards approved by ITU, which started later than the other two major 3G standards (CDMA2000 or WCDMA).
This standard is a 3G standard formulated by China. 1On June 29th, 999, the former Institute of Telecommunications Science and Technology of China Ministry of Posts and Telecommunications (now Datang Telecom Technology Co., Ltd.) proposed the standard to ITU. This standard integrates smart antenna, synchronous CDMA and SDR. In addition, due to the huge communication market in China, the standard has attracted the attention of major telecom equipment manufacturers, and more than half of the equipment manufacturers in the world have announced that they can produce telecom equipment supporting TD-SCDMA standard.
TD-SCDMA has unique advantages in spectrum utilization, business support flexibility, frequency flexibility and cost.
TD-SCDMA adopts time division duplex, and the uplink and downlink channel characteristics are basically the same, so it is easier for the base station to estimate the uplink and downlink channel characteristics according to the received signal. In addition, TD-SCDMA has inherent advantages in using smart antenna technology, which introduces the advantages of SDMA, which can reduce the interference between users and improve the spectrum utilization.
TD-SCDMA also has the advantages of TDMA, which can flexibly set the ratio of uplink and downlink time slots and adjust the ratio of uplink and downlink data rates, and is especially suitable for occasions with less uplink data and more downlink data in Internet services. However, the variability of uplink and downlink switching points increases the complexity of co-frequency networking.
TD-SCDMA is time division duplex, and it doesn't need paired frequency bands. Therefore, compared with the other two 3G standards of frequency division duplex, it is more flexible in the division of frequency resources.
It is generally believed that TD-SCDMA can greatly simplify the complexity of the system by adopting smart antenna and synchronous CDMA technology, and is suitable for adopting software radio technology, so the equipment cost is expected to be lower.
However, due to the shortcomings of the time division duplex system, TD-SCDMA is considered to lag behind the frequency division duplex system in terms of terminal allowable moving speed and cell coverage radius.
At the same time, TD can only have 500 people online, which is a problem.
[Edit this paragraph ]TD-SCDMA network testing and commercial investigation
In 2006, Romania built a TD-SCDMA trial network.
In 2007, SK Telecom, the largest mobile communication operator in South Korea, built a TD-SCDMA trial network in Seoul, the capital of South Korea. In the same year, France Telecom, the second largest telecom operator in Europe, built a TD-SCDMA trial network.
From June 5438 to October 2007 10, Japanese telecom operator IP Mobile originally planned to build and operate TD-SCDMA network, but the company eventually went bankrupt due to financial difficulties.
On June 5438+ 10, 2008, China Mobile built TD-SCDMA trial networks in China, Beijing, Shanghai, Tianjin, Shenyang, Guangzhou, Shenzhen, Xiamen and Qinhuangdao. China Telecom Group Corporation has built a TD-SCDMA trial network in Baoding, China. The former China Network Communications Group Company (now China United Network Communications Group Co., Ltd.) built a TD-SCDMA trial network in Qingdao, China.
On April 1 day, 2008, China Mobile launched TD-SCDMA social service testing and trial commercial use in Beijing, Shanghai, Tianjin, Shenyang, Qingdao, Guangzhou, Shenzhen, Xiamen, Qinhuangdao and Baoding. By the end of 2008, the number of 3G mobile phone users using TD-SCDMA network in China has reached 465,438+900,000. However, many problems appeared on the first day of TD-SCDMA mobile phone numbering, such as imperfect network construction and incomplete development of functions, so many mobile phone users still hold a wait-and-see attitude.
In September 2008, China Putian Information Industry Group Corporation built a TD-SCDMA trial network for Italian communication company MYWAVE, which was completed and opened on September 12. It's only 1 1 day from the construction project, so it should be a small enterprise network.
On June 7, 2009, the China Municipal Government officially issued a TD-SCDMA business license to China Mobile, and China Mobile has also started the second phase of TD-SCDMA network construction in 28 municipalities, provincial capitals and cities with separate plans. It is expected to be completed and put into commercial operation in June 2009. The company plans to reach 20 1 1, and the TD-SCDMA network will cover Chinese mainland 100% cities.
The development process of TD-SCDMA 65438+ At the beginning of 0998, under the direct leadership of the Science and Technology Department of the Ministry of Posts and Telecommunications at that time, the Institute of Telecommunications Science and Technology organized a team to study and draft a draft proposal for TD-SCDMA in China that met the requirements of IMT-2000. The main features of the draft standard are smart antenna, synchronous code division multiple access, relay switching and time division duplex. On June 30th, 1998, the deadline for ITU to collect the third generation wireless transmission technology candidates for IMT-2000, it was submitted to ITU, thus becoming one of the 15 candidates for IMT-2000. ITU synthesized the evaluation results of all evaluation teams. At the +0999+0 1 Helsinki ITU-RTG8/ 1 th meeting in June 2000 and ITU-R plenary meeting in Istanbul in May 2000, TD-SCDMA was formally accepted as one of the schemes of CDMATDD system.
CWTS (China Wireless Communication Standards Research Group), as a regional standardization organization representing China, joined the 3GPP in May 1999. After four months of full preparation and a lot of coordination work with 3GPPPCG (project coordination group) and TSG (technical specification group), in September of the same year, it was suggested to 3GPP that TD-SCDMA should be included in the work of 3GPP standards and specifications. 1999 12 At the 3GPP conference in Nice, France, China's proposal was accepted by the 3GPP (Radio Access Network) plenary meeting, and it was formally decided to include TD-SCDMA in the work plan of Release 2000 (later split into R4 and R5).
After more than a year, after dozens of working group meetings and discussion of hundreds of submitted manuscripts, at the plenary meeting of RAN in Palm Springs in March 20001,with the official release of the R4 version of 3GPP including TD-SCDMA standard, the integration of TD-SCDMA in 3GPP reached the first goal.
So far, TD-SCDMA has been recognized and accepted by operators and equipment manufacturers all over the world, both in form and in essence, forming a real international standard.
[Edit this paragraph] Status of ]TD-SCDMA standard
Since the release of 3GPPR4 in March, 20001,the substantive work of TD-SCDMA standard specification has been mainly completed under the 3GPP system. In more than two years after the release of R4 standard, Datang, together with many other industry operators and equipment manufacturers, revised and improved some contents of TD-SCDMAR4 standard, such as physical layer processing, high-level protocol stack messages, network and interface signaling messages, radio frequency indicators and parameters, conformance testing and so on, through numerous meetings and email group discussions, which made TD-SCDMA R4 standard reach a quite stable and mature level so far.
Under the framework of 3GPP, due to the different duplex modes, all technical features and advantages of TD-SCDMA can be reflected in the air interface physical layer. The difference of physical layer technology is the main difference between TD-SCDMA and WCDMA. In the core network, TD-SCDMA and WCDMA adopt exactly the same standards and specifications, including the same Iu interface between the core network and the wireless access network; TD-SCDMA and WCDMA are also the same in the high-level protocol stack of air interface. These similarities ensure seamless roaming, handover, consistency of service support and QoS guarantee between the two systems, and also ensure that TD-SCDMA and WCDMA maintain considerable consistency in the subsequent development of standard technology.
65438+20061October 20th has been declared as the national communication standard of China. 65438+ 10. It was stipulated by the Ministry of Information Industry as an industry standard, not a national communication standard.
[Edit this paragraph] The subsequent development of ]TD-SCDMA standard
With the rapid development of 3G technology and system, various equipment manufacturers, operators, research institutions, governments and ITU have begun to study the technical development direction after 3G. Among several technical development directions determined by ITU, smart antenna technology and TDD time division duplex technology are considered as the future development trends. Smart antenna and TDD time division duplex technology have been well embodied and applied in the current TD-SCDMA standard system. From this point, we can also see that TD-SCDMA standard technology has considerable development prospects.
In addition, in the release of 3GPP version after R4, TD-SCDMA standard also introduced new technical features to further improve the performance of the system, including: synchronization between base stations through the air interface as another backup scheme for base station synchronization, especially suitable for ensuring the reliability of communication networks in emergency; Terminal positioning function, which locates the position of the terminal user by using the arrival angle of the signal through the smart antenna, so as to better provide location-based services; High-speed downlink packet access adopts hybrid automatic retransmission and adaptive modulation and coding to realize high-speed downlink packet service support; Multi-antenna input-output technology (MIMO), which adopts multi-antenna technology of base station and terminal and signal processing to improve the performance of wireless system; The uplink enhancement technology adopts adaptive modulation and coding, hybrid ARQ technology, rapid allocation of dedicated/* * * resources, and corresponding physical layer and high-level signaling support mechanisms to enhance the uplink channel and business capabilities.
With the full support of the government and operators, TD-SCDMA industrial alliance and industrial chain have been basically established, product development has been further promoted, and more and more equipment manufacturers have participated in the development camp of TD-SCDMA products. With the large-scale development and field test of equipment, TD-SCDMA standard will be further verified and strengthened.
[Edit this paragraph ]TD-SCDMA Industry Alliance
In order to accelerate the industrialization of TD-SCDMA and form a complete industrial chain and multi-vendor supply environment at an early date, the TD-SCDMA industrial alliance was established in Beijing on June 30th, 2002. The number of TD-SCDMA industry alliance members has grown from 7 at the beginning to 30 at present, covering all links of TD-SCDMA industry chain from systems, chips, terminals to test instruments.
Alliance nature
TD-SCDMA Industry Alliance is a voluntary social organization composed of enterprises and institutions actively engaged in the research, development, production, manufacturing and service of TD-SCDMA standards and products.
Alliance purpose
Integrate and coordinate industrial resources, improve the R&D and manufacturing level of mobile communication enterprises within the alliance, promote the rapid and healthy development of TD-SCDMA communication industry, and realize the popularization and application of TD-SCDMA in China and the global communication market.
Alliance business scope
TD-SCDMA industry alliance mainly focuses on TD-SCDMA technology to promote and improve standards, as well as industry management and coordination, to promote resource sharing and mutual benefit among enterprises. It is suggested that the government should formulate major industrial policies that are beneficial to the development of TD-SCDMA and enhance the group competitiveness of communication enterprises within the alliance.
Within the TD-SCDMA industrial alliance, a unified intellectual property management policy is implemented, and technical information and market information are highly shared. Promote the rapid and healthy development of TD-SCDMA industry through close communication and reasonable division of labor.
Alliance member
Institute of Telecommunications Science and Technology (Datang Telecom Science and Technology Industry Group)
Huali group co., ltd
Huawei technologies co., ltd.
Lenovo (Beijing) Limited
Shenzhen zhongxing communication co., ltd
China Electronic Information Industry Group Corporation
China Putian information industry group company
Beijing Tianqi technology co., ltd
Beijing rixun online technology co., ltd
Chongqing changyuan xinke co., ltd.
Hisense Group Limited
Ming Kai Information Technology Co., Ltd.
Xi an Haitian antenna technology co., ltd
Zhanxun Communication (Shanghai) Co., Ltd.
Beijing zhong Chuang Xin ce technology co., ltd
Hubei Zhong You Science and Technology Industry Co., Ltd.
Alcatel Shanghai bell co., ltd
Shanghai dibite industry co., ltd
UT starcom company
Yinghuada (Shanghai) Electronics Co., Ltd.
Zhongshan tongyu communication equipment co., ltd
Qingdao Haier communication co., ltd
Shanghai ketai century technology co., ltd
Wuhan post and telecommunications science study institute
TCL group
Guangzhou xinyou communication equipment co., ltd
Andrew Telecom Equipment (China) Co., Ltd.
Ding Xin Communication (Shanghai) Co., Ltd.
Beijing Xinghe Liangdian Communication Software Co., Ltd.
Jingxin Communication Technology (Guangzhou) Co., Ltd.
China Electronics Technology Group Corporation No.14 Institute
Mobi Antenna Technology (Shenzhen) Co., Ltd.
Ruidike Micro-electrons (Shanghai) Co., Ltd.
Beijing Han Ming Xin tong technology co., ltd
Ningbo Bird Company Limited
China electronics technology group company no.41 institute
Yiyang xintong co., ltd
Shenzhen changfang network technology co., ltd
Yulong Computer Communication Technology (Shenzhen) Co., Ltd.
Simitong Information Technology (Shanghai) Co., Ltd.
Qi Long Holdings Limited.
[Edit this paragraph] Advantages and disadvantages of TD in China and handover technology in the United States and Europe.
superiority
1. The spectrum utilization rate is high TD, with a carrier frequency of 1.6M W and a carrier frequency of 5M.
2. The requirement for power control is low, TD 0 ~ 200 MHz W 1500 MHz.
3. The so-called antenna classification is introduced by using smart antenna and joint test, but the effect needs to be verified.
4. It avoids the slight influence of different services on the coverage area in respiratory effects TD, and is easy for network planning.
5. Support multiple communication interfaces: TD-SCDMA meets multiple interface requirements of Iub, A, Gb, Iu and IuR. The base station subsystem can be used as an extension of the 2G and 2.5G GSM base stations, and can also be used as a base station subsystem in the 3G network, which can take into account the current demand and the long-term development in the future.
disadvantaged
1. TD with high synchronization requirements needs GPS synchronization, and the accuracy of synchronization affects whether the whole system works normally.
2. The limited code resource TD is only 16 code, which is far less than the number of codes required by business requirements.
3. Interference: uplink and downlink, there may be interference between this cell and neighboring cells.
4. the moving speed is slow TD120km/hw500km/h.
[Edit this paragraph ]TD-SCDMA social service testing and trial commercial use
On March 28th, 2008, China Mobile held a press conference today, officially announcing that it will officially launch the domestic 3G (TD-SCDMA) social service test and commercial trial in its eight Olympic cities of Beijing, Tianjin, Shanghai, Qingdao, Qinhuangdao, Shenyang, Shenzhen and Guangzhou from April 1. China Mobile said that during the trial commercial period, the basic monthly rental fee for domestic 3G mobile phones was 50 yuan/month, and the calling party and the called party were exempted from local basic call charges. The domestic long-distance call charge is 0.07 yuan /6 seconds.
50% discount during the trial commercial period.
It is understood that this trial commercial mobile phone uses the paragraph 157 instead of the previously rumored paragraph 159. China Mobile will invite 20,000 representative users from different industries and departments to participate in the all-round testing of 3G terminals, networks and services in China, provide free test mobile phones and data cards worth 2,000 to 4,000 yuan, and provide 800 yuan phone fee subsidy for each test user with a discount of 3.
China Mobile said that during the trial commercial period, users can enjoy a 50% discount on the communication expenses generated by TD network, and the terminals purchased by China Mobile in the first batch will be lower than the purchase price100-200 yuan sells in the business hall, giving certain discounts to social cooperation channels, and the reward for TD numbering is twice as high as that of GSM, with additional sales incentives.
From April 1 day, users can purchase TD Pioneer cards in mobile business halls and some cooperative channels in 8 cities, and the unified price is 20 yuan/piece. The specific charging standard is the basic monthly fee of 50 yuan/month, and the calling/called local basic call fee is 4 cents. The domestic long-distance call charge is 0.07 yuan /6 seconds. The calling party of the video call is 0.6 yuan/min, and the called party is free; Long distance call 0. 1 yuan /6 seconds; The calling party of domestic video call roaming is 0.9 yuan/min, and the calling party is 0.6 yuan/min.
In addition, China Mobile has prepared three kinds of TD tariff packages for 28 yuan, 58 yuan and 88 yuan, among which the 28 yuan package includes 150-minute video call, caller ID, Olympic mobile phone newspaper and 10M T network traffic; 58 yuan package includes 350-minute videophone, caller ID, Olympic mobile phone newspaper, 10M T- network traffic and color ring back tones; 88 yuan package includes 600 minutes of visual call and caller ID, Olympic mobile phone newspaper, 10M T network traffic and color ring back tones.
TD broadband data access includes two packages: 100 yuan and 200 yuan, in which 100 yuan package includes 2G traffic, and 200 yuan contains 5G traffic, which exceeds the traffic by 0.0 1 yuan /k and is 0.03 yuan /k for non-package users. In addition, the data traffic is capped at 1000 yuan per month, and the communication fee is 50% off.
60,000 terminals in 8 cities began to be numbered uniformly.
According to the introduction of China Mobile, there are 8 pilot cities, instead of 10, to expand the trial network.
Since the first half of last year, the TD trial has been expanded to 10 cities. Besides Beijing, Tianjin, Shanghai, Xiamen, Qinhuangdao and Shenyang, China Mobile has also added Guangzhou and Shenzhen. In addition, Qingdao is mainly tested by China Netcom, and Baoding is mainly tested by China Telecom. The source said that China Mobile has unified numbering in eight cities instead of 10, and the specific arrangements of Qingdao and Baoding depend on those of Netcom and Telecom.
It is reported that there are currently 1 1 mobile phone manufacturers who have obtained network access licenses. The 50,000 TD mobile phones currently collected by China Mobile are from the first batch of manufacturers who have obtained network access licenses, including ZTE, Samsung, LG, Hisense, Lenovo and New Post. In addition, China Mobile also collected 1 10,000 TD network cards from Datang Mobile. China Mobile said that these 60,000 TD terminals will be numbered in its own business halls in eight Olympic cities, and manufacturers can also sell TD terminals other than centralized procurement in their own sales channels.
Not long ago, during the two sessions, Wang Jianzhou, president of China Mobile, promised that TD would be commercialized during the Olympic Games. Recently, he said in an interview that TD would enter trial commercialization in April. An insider of China Mobile confirmed to Tencent Technology that "TD numbering is ready, just waiting for the group to determine the specific numbering date." In addition, he explained, "because of the problem of the terminal in place, the date of numbering was postponed."
On April 1 day, 2008, China Mobile started TD trial commercial numbering. TD numbering is another milestone in China's 3G history, which indicates that the national 3G standard TD has fully possessed the foundation of commercial operation. The trial operation of section 157 is still four and a half months before the Olympic Games, so there is enough time for network optimization, system management and tariff system improvement. In the future, a brand-new 3G standard will be presented to us during the Olympic Games.
China Mobile took the lead in bypassing the 3G license to launch TD, which was a great blow to China Unicom. Due to the uncertainty of restructuring and 3G license, it is impossible for China Unicom to launch 3G services immediately in the next 3-6 months. In the short term, users can only experience China Mobile's TD, which has a preconceived advantage in the future 3G business development, and will affect the advantages of China Unicom's data card business. It is not ruled out that there will be more serious user loss in the future. However, for domestic telecom equipment suppliers, the opening of TD will be a major positive. Once TD is launched, it means that there is no turning back, and the acceleration of TD investment will also be an inevitable trend. In the future, we have more reason to be optimistic about the development prospects of telecom equipment listed companies such as ZTE and ST Datang.
[Edit this paragraph ]TD-SCDMA wireless Internet access (TD wireless Internet access)
At present, 3G/TD-SCDMA wireless Internet access network can be used in the following cities: Beijing, Shanghai, Tianjin, Shenyang, Guangzhou, Shenzhen, Xiamen, Baoding, Qingdao, Qinhuangdao 10. Without TD-SCDMA network, it will be automatically converted into GPRS network for wireless Internet access. There is TD signal in the Fifth Ring Road in Beijing, which can cover 1-5km outside the Fifth Ring Road, large residential quarters and county towns (Shangdi, Huilongguan, county towns, etc.). ) There are covers outside the Fifth Ring Road. There is a TD-SCDMA signal within the outer ring of Shanghai. The main city of Tianjin and most parts of Guangzhou are covered by TD network. When the TD signal is good, the actual download speed of wireless Internet access is between 30-60K/S, which is equivalent to 5 12K ADSL broadband network speed. At present, TD wireless Internet service has become the key development direction of China Mobile.
[Edit this paragraph ]TD-SCDMA netbook (TD mini-computer)
At present, China Mobile has customized and released mini computers (netbooks) with well-known computer manufacturers, which can support TD-SCDMA wireless Internet access. TD netbooks belong to the lower-end product series launched by PC manufacturers, among which x86 and ARM processors with low cost and energy saving are the basis of netbooks. At the same time, TD internet module is implanted in the netbook, which saves the high-priced data card fee. In addition, China Mobile will subsidize the data traffic fee of TD netbooks in the future, and the total cost will not be very high. The screen size of TD netbook is about 7 to 10.2 inch.
[Edit this paragraph] China Mobile TD-SCDMA official website
China Mobile's TD-SCDMA social service testing and trial service is the only officially designated website, and the only officially opened domain name is tdtest.chinamobile.com.
[Edit this paragraph] Introduction to key technologies of ]TD-SCDMA
1. How can I reach you by calling TD-SCDMA? -Integrated addressing (multiple access) mode
The air interface between 1 and TD-SCDMA adopts four multiple access technologies: TDMA, CDMA, FDMA and SDMA (Smart Antenna).
2. By comprehensively utilizing the degrees of freedom of the four technologies in resource allocation from different angles, the optimal resource allocation can be dynamically adjusted.
Second, flexible uplink and downlink time slot configuration.
Flexible time slot uplink and downlink configuration can meet your needs of making phone calls, surfing the Internet, downloading files and video services at any time, and ensure that you can enjoy 3G services clearly and smoothly.
Third, TD overcomes the respiratory effects and the near-far effect.
What is respiratory effect? In CDMA system, when the interference signal in a cell is strong, the actual effective coverage area of the base station will decrease; When the interference signal of a cell is weak, the actual effective coverage area of the base station will increase. In short, respiratory effects shows that the coverage radius decreases as the number of users increases. The main reason of respiratory effects is that CDMA system is a self-jamming system, and the increase of users leads to the increase of interference, which affects coverage.
For TD-SCDMA, low-bandwidth FDMA and TDMA are used to suppress the main interference of the system, CDMA technology is used to improve the system capacity of a single time slot, and joint detection and smart antenna technology (SDMA technology) are used to overcome the interference among multiple users in a single time slot, so the factors causing respiratory effects are obviously reduced, so TD system is no longer an interference-limited system (self-interference system) and the coverage radius is not obviously reduced because of the increase of users like CDMA, so it can be considered that TD system has no respiratory effects.
What is the near-far effect? Because mobile phone users are randomly distributed in a cell and often change, the same mobile phone user may sometimes be on the edge of the cell and sometimes near the base station. If the transmitting power of the mobile phone is designed according to the maximum communication distance, when the mobile phone is close to the base station, there will inevitably be excess power, which will form harmful electromagnetic radiation. The solution to this problem is to adjust the transmitting power of the mobile phone in real time according to the different communication distances, that is, power control.
The principle of power control is that when the propagation condition of the channel suddenly becomes better, the power control unit should respond quickly within a few microseconds to prevent the signal from suddenly increasing and causing additional interference to other users; On the contrary, when the propagation conditions suddenly deteriorate, the speed of power adjustment may be relatively slow. That is to say, it is better for the signal quality of a single user to deteriorate in a short time, and at the same time, it is necessary to prevent large background interference to many other users.
Four, Smart Antenna (smart antenna)
In TD-SCDMA system, the base station system uses digital signal processing technology and adaptive algorithm to make smart antennas dynamically form directional beams for specific users in the coverage space, make full use of downlink signal energy, and suppress interference signals to the maximum extent. The base station can track the movement of the terminal in the whole cell through the smart antenna, which greatly improves the signal-to-noise ratio obtained by the terminal and improves the service quality.
Verb (abbreviation of verb) dynamic channel allocation
First of all, what is a channel? Channel is the communication link (line) resource you occupy when you make a phone call, just like the driveway, traffic sign and traffic light you use when you drive on the road, it is essential for you to drive; In TD-SCDMA communication, the channel uses frequency, time slot and code word to represent the used radio resources.
Dynamic channel allocation refers to the allocation of real-time and dynamic resources (frequency, time slot, codeword, etc.). ) according to user needs.
Advantages of dynamic channel allocation:
1, high frequency band utilization rate
2. There is no need for channel pre-planning in network planning.
3. It can automatically adapt to the changes of load and interference in the network.
According to the adjustment rate, dynamic channel allocation (DCA) can be divided into slow DCA and fast DCA.
Slow DCA allocates wireless channels to cell ranges, while fast DCA allocates channels to services. RNC is responsible for managing the available resources in the cell and dynamically allocating them to users. The way RNC allocates resources depends on system load, service QoS requirements and other parameters. At present, DCA is mostly based on interference measurement algorithm, and will allocate channels according to the real-time interference measurement results fed back by users' mobile terminals.
[Edit this paragraph] China Mobile TD first-stage bidding results
Bidding time: February 2008
Category Country manufacturer brand Model Quantity
Mobile phone, new domestic postal service, new postal service N268 2 1000
Hisense mobile phone Hisense T68 10500
Lenovo Electronics Lenovo TD800 10500
In ZTE