What is the TD code of the information industry?

TD-scdma- time division-synchronous code division multiple access (time division-synchronous code division multiple access technology).

TD-SCDMA, as the third generation mobile communication standard (3G for short) proposed by China, was formally submitted to ITU (International Telecommunication Union) from 1998. It has been more than ten years since it completed a series of international standardization work such as expert group evaluation, ITU approval and publication, integration with 3GPP (3rd generation partnership project) system, and introduction of new technical features, thus making TD-SCDMA the first standard. This is an important milestone in the telecom history of China. (Note: 3G has three international standards, and the other two are CDMA2000 led by the United States and WCDMA led by Europe. )

Development course of TD-SCDMA

At the beginning of 1998, 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. It was submitted to ITU on June 30th (1998), which was the deadline for ITU to collect the third generation wireless transmission technology candidates for IMT-2000, so it became one of the 15 candidates for IMT-2000. ITU synthesized the evaluation results of all evaluation teams. At the ITU-RTG8/ 1 8th meeting held in Helsinki in June 2000 and the ITU-R plenary meeting held in Istanbul in May, TD-SCDMA was officially 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 suggested to 3GPP that TD-SCDMA should be included in the work of 3GPP standards and specifications. 1999 12 At the 3GPP conference held in Nice, France, China's proposal was accepted by the plenary session of 3GPP (Radio Access Network), and it was formally decided to include TD-SCDMA in the work plan of Release 2000 (later split into R4 and R5), which was referred to as TD-SCDMA LCRTDD (low chip rate TDD scheme) for short.

After more than a year, dozens of working group meetings and discussion of hundreds of submitted manuscripts, at the RAN plenary meeting held in Palm Springs in March 2006, with the official release of 3GPPR4 version specifications including TD-SCDMA standard, the integration of TD-SCDMA in 3GPP reached its first goal.

So far, TD-SCDMA has been recognized and accepted by global operators and equipment manufacturers, both in form and in essence, forming a real international standard.

Present situation of TD-SCDMA standard

Since the release of 3GPPR4 in March, 2006, the substantive work of TD-SCDMA standard specification has been mainly completed under 3GPP system. In more than two years after the release of R4 standard, Datang, together with many industry operators and equipment manufacturers, revised and improved the physical layer processing, high-level protocol stack messages, network and interface signaling messages, radio frequency indicators and parameters, conformance testing and other contents of TD-SCDMAR4 standard through many 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 difference of duplex mode, all technical features and advantages of TD-SCDMA can be embodied in the physical layer of air interface. 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 commonalities 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.

Subsequent development of TD-SCDMA standard

With the rapid development of 3G technology and system, all 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, including smart antenna technology and TDD time division duplex technology, they are considered as 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 3GPP version released after R4, TD-SCDMA standard also introduces new technical features to further improve the system performance, including: synchronizing between base stations through air interface as another backup scheme for base station synchronization, which is especially suitable for ensuring the reliability of communication networks in emergency; Terminal positioning function, which can locate 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; Uplink enhancement technology adopts adaptive modulation and coding, hybrid ARQ technology, rapid allocation of dedicated/shared resources and corresponding physical layer and high-level signaling support mechanisms to enhance uplink channels and service 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.

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.

The nature of the alliance:

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 in the alliance, promote the rapid and healthy development of TD-SCDMA communication industry, and realize the promotion 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, so as 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 members:

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

Chongqing zhongji 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.

Advantages and disadvantages of China TD and US-Europe handover technology

superiority

1. High spectrum utilization TD, carrier frequency 1.6M W, carrier frequency 10 M.

2. The requirements for power control are low, TD 0 ~ 200mz, w 1500 MHz (note: but the power control rate is very slow).

3. Smart antenna and joint detection have introduced the so-called antenna classification, but the effect needs to be verified (note: smart antenna cannot be used at present).

4. Avoid the influence of different services on the size of coverage area, and facilitate network planning.

Disadvantages:

1.td [1] needs GPS synchronization, and the accuracy of synchronization affects whether the whole system works normally.

2. The limited code resource TD has only 16 codes, which is far less than the number of codes required by business requirements.

3. Interference: There may be interference between uplink and downlink, local cell and neighboring cells.

4. Slow driving TD120km/HW 500km/h.

5. The measured drop rate of relay handover is equivalent to that of hard handover.