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China is the world's largest TV production and sales company with more than 400 million TV sets. The annual production of TV sets is nearly 50 million units. At the end of the last century, the global digital TV revolution began. This is a rare historical opportunity for China's development industry, and it is also a severe test for China's ability to independently develop the digital TV industry. If, like South Korea adopts the US terrestrial digital TV transmission standard, each TV pays a patent fee of 30 US dollars, then the digitalization of China's existing TV sets will require up to 12 billion US dollars in royalties to the country's diplomacy. China's TV industry will Repeat the mistakes of the DVD industry.
It can be seen that it is extremely urgent to formulate digital TV standards with independent intellectual property rights as soon as possible, which is related to the development of China's digital TV industry. On August 1, 2006, the first mandatory national standard in the field of digital TV transmission in China - the national standard for digital TV terrestrial transmission (GB20600-2006, English abbreviated as DTMB) was officially implemented, which also means that China's television industry bid farewell to " In the era of wage earners, they are no longer subject to foreign standards.
Independent research and development to form a patent
"The opportunity of the word TV revolution breaks through the bottleneck of wireless broadband transmission technology, such as: frequency-domain multi-carrier technology for broadband transmission, channel estimation technology for high-speed mobile transmission channel characteristics, and long-delay multipath interference caused by large-scale coverage. The equalization technology forms China's independent basic invention patents, and based on these basic invention patents, China's terrestrial digital TV transmission standards are formulated. In this way, China not only does not have to pay diplomatic patent fees to the country, but also can receive foreign patents into the Chinese market. Yang Zhixing, director of the Digital TV Transmission Technology R&D Center of Tsinghua University, has a deep understanding of the introduction of China's terrestrial digital TV standards.
In an interview with the reporter of China Electronics News, he said that after the successful inception of these invention technologies from the digital TV field, it will promote the optimization and upgrading of related technologies in the field of information transmission. TV replacement, urban emergency video system, military mobile video network promotion and application have potential huge economic, social and military benefits; the development of a variety of new services will promote the upgrading of industry structure and product upgrading in related fields, and promote telecommunications, TV and data triple play.
To this end, the Chinese government has set up a special project for digital TV R&D and industrialization with 1.5 billion yuan of funds, which has been included in the 12 major special projects of the national “10th Five-Year Planâ€. The National Leading Group for Digital Television was established by the National Development and Reform Commission, the Ministry of Information Industry, the State Administration of Radio, Film and Television, the Ministry of Science and Technology, and the State Administration of Quality Supervision, Inspection and Quarantine. The first meeting of the National Leading Group for Digital TV made it clear that it is necessary to independently develop digital TV terrestrial transmission standards (instead of selecting foreign standards for foreign countries).
It’s early in the morning, catching up with a late set
As early as 1994, the international research and development of digital TV transmission standards has just started. With the support of the Ministry of Science and Technology, China has conducted a strategic study on digital TV technology, led by Academician Ye Pei.
In 1996, following the two major international standards - the United States ATSC and the European DVB-T, the Ministry of Science and Technology set up a major project for the development of digital TV terrestrial broadcasting systems, the project is affiliated to the National Academy of Broadcasting Science (referred to as the Academy of Sciences). The establishment of the digital TV group (referred to as the overall group), Zhejiang University and Xi'an University of Electronic Science and Technology respectively tracked the development of the US ATSC and European DVB-T standard prototype. The State Administration of Radio, Film and Television has invested more than one billion yuan to carry out the digital television broadcast of the 50th anniversary of the National Day using the tracking program prototype made by the Academy of Sciences and the overall group.
In 1999, the National Development and Reform Commission set up a special program for digital TV R&D and industrialization, and related research on terrestrial digital TV was transferred to standard R&D and industrialization. In addition to the special funds for the R&D funds, the special funds also established three pilot cities for terrestrial digital TV broadcasting in Beijing, Shanghai and Shenzhen. Each pilot city received a grant for the purchase of a prototype of the broadcast equipment and the overall group.
In 2001, the National Leading Group for Digital Television entrusted the State Administration of Radio, Film and Television to collect terrestrial digital TV broadcasting transmission standard programs nationwide and to test the five standard programs collected. They are Tsinghua's DMB-T solution, the single-carrier VSB scheme and the multi-carrier COFDM scheme of the digital TV group, and the QAM scheme of the Academy of Science and Technology and the OFDM scheme of the University of Electronic Science and Technology. In April 2002, according to the test results at that time, the test group and the supervision team organized by the National Radio and Television Standardization Committee believed that there was still a considerable gap between the overall performance of the equipment under test and the requirements for the development of China's terrestrial digital TV transmission standards. Under the leadership of the National Digital TV Research and Development and Industrialization Leading Group, it is necessary to organize domestic production, research, and use departments to jointly research and develop systems and equipment that truly have China's independent intellectual property rights.
Accordingly, the National Digital TV Leading Group decided to establish a Digital TV Standardization Working Group and entrusted the State Intellectual Property Office to conduct an intellectual property assessment of five domestic programs. On the basis of retrieving a large number of documents and researching relevant domestic and foreign patents, the State Intellectual Property Office formed the “Patent Evaluation Report for Digital TV Ground Transmission Technology Program†on September 30, 2002. The report gives an overall evaluation of the five options.
At the beginning of 2003, the National Digital TV Leading Group decided to entrust the Chinese Academy of Engineering to evaluate the performance of Tsinghua DMB-T and Shanghai Jiaotong University ADTB. The Chinese Academy of Engineering, led by Academician Lu Jianxun, Director of the Department of Information and Electronic Engineering, formed the team of 40 experts. The chief engineer of Zhang Zhiyi was the leader of the test team and the academician Tong Zhipeng was the leader of the supervision team.
Yang Zhixing, director of the Digital TV Transmission Technology R&D Center of Tsinghua University, recalled the situation at the time: "In mid-2003, the evaluation test report concluded that the performance of Tsinghua equipment and Jiaotong University equipment met the basic requirements of terrestrial digital TV transmission standards; overall technical performance The Shangqinghua system is superior to the Jiaotong University system; in terms of technological innovation, the Tsinghua system has a greater advantage."
In October 2003, the National Development and Reform Commission set up a research and development project for terrestrial digital TV transmission standards. The deputy director of the Chinese Academy of Engineering, Academician He Hezhen, was appointed as the project leader, Tsinghua University, Shanghai Jiaotong University, Broadcasting Academy, Beijing Aerospace University, Xi'an Jiaotong University, Beijing. 11 universities including Beijing University, Beijing University of Posts and Telecommunications, Xi'an University of Electronic Science and Technology, Chengdu University of Science and Technology, National University of Defense Technology, and Zhejiang University attended the event. The project set up a national standard task force for digital TV terrestrial transmission, and jointly developed multi-carrier and single-carrier fusion solutions based on Tsinghua DMB-T, Shanghai Jiaotong University ADTB, and the Institute of Science and Technology TIMI.
In June 2006, the National Radio and Television Standardization Technician Committee organized the terrestrial digital television transmission standard test group to standardize the standard transmitter provided by the special working group and the terrestrial digital television transmission standard system based on the frequency domain equalization standard receiver provided by Tsinghua University. Test, the test conclusion is: the tested system can basically meet the technical requirements of terrestrial digital TV broadcasting, channel coding and time domain synchronization technology are advanced, and the overall performance multi-carrier working mode is better than single-carrier operation in high and low bit rate modes. The parameters and functions identified by the conformance test are consistent with the standard consultation draft, and 36 of the 198 working modes of the standard consultation draft have been realized. The achieved working mode transmission code rate range covers 4.813M to 32.486Mbps, single, Multi-carrier implementations are repetitive and can be substituted for each other.
At the same time, in response to the practical application and industrialization needs of China's terrestrial digital TV broadcasting, Shanghai HD Digital Technology Industry Co., Ltd., Shanghai Jiaotong University, Shanghai Chip Technology Co., Ltd. and other units have developed a set of international leading ADTB-T ground digital. The television transmission system technology overcomes the international problem of high-speed mobile reception and single-frequency networking in single-carrier systems.
In August 2006, based on the ADTB-T terrestrial digital TV transmission system technology, the "Digital Television Terrestrial Broadcast Transmission System Frame Structure, Channel Coding and Modulation" standard was incorporated into the technical achievements of several research units such as Tsinghua University and the Broadcasting Science Research Institute. Referred to as "China's terrestrial digital TV transmission standard", the standard number "GB 20600-2006"; in August 2007, China's terrestrial digital TV transmission standard was officially mandatory.
Breaking through the technical bottleneck of convergence
People in the industry generally understand that the US ATSC single carrier system and the European DVB-T multi-carrier system are two standards of two different technical routes, and both single-carrier and multi-carrier have their own characteristics. Therefore, after the terrestrial digital TV standard is determined as a single-multi-carrier fusion scheme (referred to as a landmark), there is a "site splicing of two systems of single and multi-carrier", "an apple and a pear in a basket" or "Fusion is the two systems plus a switch" and so on.
From 2004 to 2006, one of the main research results of the National Standards Task Force for Digital Television Terrestrial Transmission was to solve the problem of single-carrier and multi-carrier being carried as a parameter option in a system. Similar to the European multi-carrier number of the DVB-T standard, there are two options of 2K and 8K. The multi-carrier option of the landmark has two options of 4K and 1K. It only involves two optional parameters of a specific operation link in many data processing steps required by the system. Other system parameters, including error correction coding, interleaving, timing synchronization, frame structure, signal bandwidth and shaping, etc. The multi-carrier mode of operation is uniform, they are just two alternative modes of operation on the same technology and intellectual property platform.
Its technical basis is TDS-FOM, which itself is a modulation method of time domain single carrier and frequency domain multi-carrier fusion. Its multi-carrier frame body is a data signal, which can be respectively loaded onto multiple sub-carriers, and is not exclusive. All frame body data is loaded onto one subcarrier. The national standard DTMB TDS-OFDM is different from the European DVB-T C-OFDM. Its originality not only provides the technical basis for single and multi-carrier system fusion, but also reserves the function of time and frequency two-dimensional segmentation for multimedia information broadcasting. Expand the space.
Shanghai HD is in the national standard, the difference between single and multi-carrier modulation is only in the modulation part for the following three reasons. 1. The single and multi-carrier options are only valid in the data frame body part, the data frame header uses single-carrier modulation as the training sequence; 2. There is no known discrete information in the frame body data part, and only the system protected by the same method Information; 3. The standard uses a unified channel coding method - low density check code LDPC.
Wang Wei, assistant to the president of Shanghai HD, said in an interview with China Electronics News: "Because the difference between single and multi-carrier modulation is only in the modulation part, the difference between single- and multi-carrier digital modulation techniques lies only in the difference in the number of carriers used. It is entirely possible to use the same receiving method to achieve single- and multi-carrier reception in the national standard. At present, Shanghai HD has already developed a full-mode modulator and a single- and multi-carrier full-mode fusion receiver based on the equalizer."
Of course, the DTMB standard based on the fusion scheme does have some redundancy, which is limited by various factors, and the special working group can't optimize the ideal. It is hoped that the landmarks will accept market application choices, and further separation of redundancy in user selection will highlight its advanced features. Since the promulgation of the national standard, many trial cities have highly consistent opinions on the choice of the national standard work mode: “market choice†may easily surpass the “academic debateâ€.
Have complete independent intellectual property rights
In addition to the single-carrier (C=1) option of the “Double Pilot Insertion†technology, the redundant option was granted by the Korean Samsung Company for Chinese patents, and the national intellectual property rights of the national standard are complete. There is no problem with patent controlled foreign countries.
The Tsinghua DMB-T program based on Tsinghua University's service invention patents has passed the two rounds of evaluation by the State Intellectual Property Office in 2003 and 2005, and both have been identified as basic innovations. No problems have been found in the payment of fees to foreign patents. On the basis of the Tsinghua DMB-T program, the national standard has absorbed the characteristics of the TIMI program of the Academy of Sciences and the ADTB program of the Shanghai Jiaotong University. There are four main changes: the C=1 option is added on the basis of C=3780; the RS and volume are changed. The product combination error correction coding is an LDPC error correction code; the system information is redefined and designed; a frame header format and 4QAM-NR and 32QAM modulation modes are added. Some of the above changes are open technologies, and some have been protected by patents applied by Tsinghua University or Shanghai Jiaotong University.
In January 2005, Tsinghua University issued a letter of clearing to the National Development and Reform Commission, the Ministry of Information Industry, the State Administration of Radio, Film and Television, the Ministry of Science and Technology, and the National Standards Committee [2005] No. 5 solemnly promised: "In the country's future digital TV ground transmission standards, where With the patents of Tsinghua University, all of our schools will provide them to the state."
In March of the same year, 11 units including Tsinghua and China signed the “Technical Sharing Agreement on China's Digital TV Terrestrial Transmission Standardsâ€, and all parties solemnly promised: “In the technology used by transmitters and receivers corresponding to China's digital TV terrestrial transmission standards. The patents and technologies originating from all parties contribute to the country, and constitute the patent pool of this standard." In 2006, Tsinghua University's 43 invention patents submitted to the Chinese Academy of Engineering were Tsinghua University's service invention patents, of which 29 invention patents fully protected the national standard signal format and system solution and its implementation technology, and 20 invention patents were fully protected. The national standard receiver implementation technology and receiving system solution. Yang Zhixing said: "No unit or individual can interfere with Tsinghua University's complete and independent disposal rights to these patents."
In terms of single carrier, Shanghai HD and its affiliates have a patent for the national standard terrestrial digital TV transmission system in the national standard intellectual property system. Shanghai HD and Shanghai Chip have patents for the complete national standard terrestrial digital TV receiving system. Shanghai HD is a complete state-owned enterprise. Shanghai Chip is a domestic company with absolute control of Shanghai HD. The shareholders of the company fully agree with the state's requirements for the industrialization of the national standard. Shanghai HD, Shanghai Jiaotong University and Shanghai Chip have independently mastered the core patents and key technologies of the national standard, and have complete patent protection for the national standard transmission and receiving system.
Industrialization already has mandatory conditions
During the long and arduous development of terrestrial digital TV transmission standards in 1999-2006, the Tsinghua team of Tsinghua University Digital TV Transmission Technology R&D Center was responsible for DMB-T system R&D and performance testing under the support of Tsinghua University Key Discipline Construction Project, Legend Silicon With the help of Tsinghua University, Corp. has repeatedly invested in venture capital to focus on developing DMB-T chips. After the national standard was promulgated, Tsinghua University optimized its own algorithms and implementation technologies on its own software simulation and hardware implementation platform. Legend Silicon Corp. is fully committed to the mass production of the national standard receiving chip.
Legend Silicon Corp.'s national standard receiving chip 8913 was successfully streamed in China. Tsinghua University's transmitter modulators in line with the national standard support Beiguang, Jizhao, Toshiba and other companies to produce national standard transmitters, which meet the national standard receiver algorithm and implementation technology. Provide Shanghai Fudan University, Fudan Micro-Electronics Co., Ltd. and Shenzhen Lihe Microelectronics Co., Ltd. to develop national standard receiving special chips. They plan to mass-produce national standard receiving chips before the end of this year. In June this year, Fudan Micro-Electronics Co., Ltd. has successfully developed the national standard receiving chip "Zhongshi No. 2 FDC1101".
In March 2011, Hong Kong rigorously tested the coverage and reception of the national standard DTMB and the European standard DVB-T in Hong Kong using the single-frequency networking system. The test results prove that the national standard DTMB is significantly better than the European standard DVB-T. At the same time, dozens of companies producing key components and receiving and dispatching equipment at home and abroad have demonstrated their products in Hong Kong. The industrialization of the national standard has met the requirements of the implementation of the national standard project. Hong Kong ATV and TVB two TV stations have broadcast the national standard DTMB TV signal, the Hong Kong government decided to use the national standard officially broadcast in October, plans to reach 200,000 receiving terminals (including set-top boxes and digital TVs) during the year.
Up to now, ten provincial and municipal TV stations have adopted the national standard DTMB trial broadcast, and some of them have completed the bidding of 30 national standard transmitters and the orders of tens of thousands of receiving terminals. With the promulgation of the national standard, Shanghai HD and other units have become an important technical force and industrial base to promote the industrialization of China's terrestrial digital TV. Since August last year, the core work of Shanghai HD has included actively cooperating with industry authorities to develop standards for terrestrial digital TV. On the other hand, it has accelerated the industrialization of national standard core technologies and improved the national standard industrial chain by coordinating domestic and foreign industrial partners. Design a national standard full business solution.
Wang Wei said: "In terms of national standard transmitting equipment, Shanghai HD has already developed various modulators that fully comply with the national standard and support single carrier/multi-carrier/single-carrier and multi-carrier combination." CCBN exhibition in March this year Shanghai, HD launched the first national standard full-mode modulator, the national standard new products include MOD1000 national standard terrestrial digital TV single-point single-carrier modulator, MOD2000 national standard terrestrial digital TV full-mode modulator, MOD3000 national standard terrestrial digital TV single-frequency network modulation Device. At present, transmitter companies including Beiguang Technology, Beijing Jizhao, and Toshiba have already completed equipment integration with Shanghai HD. The comprehensive technical authorizations of Shanghai HD and Beiguang Technology and other units have also been substantially launched. So far, in Shanghai, Hunan, Shandong, Anhui, Henan and other places, the transmission equipment using single-carrier technology has been in commercial operation for nearly 2 years.
In addition, Shanghai HD has extended its reach to the rural market. Xia Pingjian, president of Shanghai HD, said in an interview with China Electronics News: “China currently has 349 million households, and one third of them can access up to five or six through a wired network. Ten sets of TV programs; while the remaining two-thirds of families can only see five or six sets of analog TV programs wirelessly, and the viewing effect is very poor. Therefore, when making digital TV national standard promotion, it must be considered from the market perspective. One problem is that people who can only see five or six programs can see fifty or sixty TV programs at home. Do we develop digital TV technology to do the icing on the cake, or do it in the snow? We decided to do it first. The charity in the snow."
Due to such strategic considerations, Shanghai HD Company has been applied in more than 20 cities in more than 10 provinces, municipalities and autonomous regions in China, using national standard technology. It is also used in Fengyang, Anhui, Anyang, Anhui, Shanghai, Chongming, and Zhuzhou, Hunan. After nearly two years of operation test, the system is stable and reliable, and has been warmly welcomed by the grassroots radio and television and the general public. At present, more than 100 provincial and municipal radio and television departments have established cooperative relationships with Shanghai HD and its partners, and will use this technology for system construction.
At the same time, Lingxun cooperated with the national standard equipment manufacturers Beijing Jiuzhao, Beiguang, Kaiteng Sifang, Digital Sight, Germany RS, Dalian Toshiba, Dalian UBS, etc.; national standard test equipment, cooperated with German RS and Japan Zhizhi and other manufacturers. , have completed the needs of the national standard industrialization. In terms of national standard receivers, Lingxun products cooperated with receiver manufacturers to develop different types of terminal products. Terminal product forms include all-in-ones, set-top boxes (fixed and in-vehicle), computer-related receiving terminals (USB DTV receiving sticks and PC built-in receiving cards), and portable devices (PMPs and other portable terminals). The cooperative manufacturers include Changhong, Skyworth, Konka, Hisense, Haier, TCL, SVA, Lihe, Tongfang, Ancai, Jiuzhou and Tongzhou.
It can be seen that the two major developers of the national standard have carried out the industrialization promotion work. However, at the initial stage of the implementation of the national standard, the relevant enterprises also hope that the relevant government departments will step up the formulation of supporting standards and actively guide the national standard users to correctly select the national standard according to their own business characteristics. The application work mode guides the production enterprises to implement other work modes in stages and at different levels.
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