TETRA (Terrestrial Trunked Radio System) is a wireless trunked mobile communication system based on digital time division multiple access (TDMA) technology. It is a digital trunked communication system standard formulated by the European Telecommunications Standards Organization (ETSI). It is a dedicated mobile communication radio standard based on the digitization of the traditional regional dispatch communication system.
TETRA digital trunking communication system can provide command and dispatch, data transmission and telephone services on the same technical platform. It not only provides multi-group dispatching functions, but also provides short data information services and packet data services. and digital, full-duplex mobile phone service. The TETRA digital trunking system also supports the powerful mobile station direct-through (DMO) mode, which can realize authentication, air interface encryption and end-to-end encryption. The TETRA digital trunking system has a virtual private network function, which enables a physical network to serve multiple unrelated organizations and has rich service functions, higher frequency utilization, high communication quality, and flexible networking methods. Many new applications (such as vehicle positioning, image transmission, mobile Internet, database query, etc.) have been implemented in TETRA.
In the past two years, the TETRA digital trunking system has been widely used around the world, especially in the European market. As of December 2004, the total number of TETRA contracts signed worldwide was 615, a year-on-year increase of 90% from 2003. These contracts belong to 70 countries around the world, of which Europe accounts for 75% of the total global contracts. Since the digital cluster market in the Asia-Pacific and Middle East regions is in a rapid development stage, it also provides good market opportunities.
Judging from the current data, in the development of TETRA in various regions around the world, the Asia-Pacific region has the fastest growth in the number of contracts signed year-on-year, with a growth rate of 139; followed by the Middle East, with a growth rate of 114; The growth rate in Western Europe also reached 110.
In terms of the number of contracts, the top three countries that signed the largest number of TETRA contracts in 2004 were the United Kingdom, France, and the Netherlands - mainly in Europe.
In China, among several digital trunking communication technology systems, the TETRA system currently accounts for the majority of applications, and is mainly used in government, railways, subways, aviation, airports, water conservancy and other departments.
Because TETRA has unique technical advantages, it is more attractive for private networks of powerful departments. Currently, its global users are mainly distributed in public security/transportation/PAMR/utilities/government/military/ Petroleum/industry and other fields, among which the public security and transportation sectors account for more than 65% of the market share. In the Asia-Pacific region, it is currently basically used in the fields of public safety/transportation/PAMR/utilities, and the market development potential is huge.
However, at present, some technologies for external interconnection of TETRA networks have not yet been fully disclosed. TETRA products of different manufacturers have not yet fully realized interconnection. There are still some problems in the interoperability of users and services between different networks and even in remote roaming. . In addition, TETRA's system equipment procurement, network construction costs and terminal prices are relatively high, which to a certain extent restrict TEREA's further development. iDEN (Integrated Digital Enhanced Network) is a digital trunked mobile communication system developed and produced by Motorola in the United States. Its predecessor was the MIRS system. It was originally designed for trunked network applications. Therefore, in addition to focusing on command and dispatch services In addition, it also has duplex telephone interconnection, data and short message functions.
In terms of technology, iDEN has the following characteristics:
First of all, in terms of functions, iDEN absorbs a lot of the advantages of digital cellular communication systems and enhances the It has the telephone interconnection function, and its wireless telephone function is on the same level as the personal mobile communication system. At the same time, the value-added services of the digital cellular communication system such as short message service, voice mailbox and circuit data based on IWF are applied to the iDEN system;
Second, iDEN can use traditional spectrum more efficiently. iDEN adopts the traditional 800MHz spectrum (806MHz~825MHz, 85lMHz~870MHz). Except for Europe, this spectrum is widely used in clusters around the world. Communication requires no adjustment. iDEN can use discontinuous frequency points, which facilitates operators to flexibly configure frequency resources. Through TDMA technology, iDEN divides a 25kHz physical channel into 6 digital communication time slots, and the frequency utilization rate is high;
Thirdly, iDEN adopts the unique MI6QAM modulation technology, which enables the rate of each 25kHz physical channel (including 6 communication time slots) to reach 64Kbps, while enabling the adjacent channel suppression to exceed 60dB. This highly efficient modulation Technology ensures the coexistence of digital and analog systems in the process of digitizing trunk communications. iDEN’s voice coding method adopts 4.2Kbps VSELP, which can ensure voice quality under 6:1 compression;
Chapter Fourth, the cellular cell structure improves the coverage capacity of the network. iDEN adopts a 7×3 cell reuse method and divides a base station into sector cells to expand the capacity of the cell and improve the networking capabilities of large areas. At the same time, it can also Adopt the omnidirectional base station method and use the 12×1 omnidirectional cell multiplexing method to adapt to local conditions and gradually develop;
Fifth, cross-system scheduling communication can be achieved.
At present, iDEN technology system is mainly used in digital trunking network system applications, with America and Asia as its main markets. In the Americas, iDEN systems are deployed in the United States, Canada, Argentina, Brazil, Colombia, Mexico, Peru and other countries; in Asia, iDEN networks can be seen in Japan, South Korea, China, the Philippines, Singapore, Israel and other countries. Among them, the iDEN network operated by Nextel Corporation of the United States (now merged with other mobile operators) is currently the largest and most developed iDEN network in the world.
iDEN network serves a wide range of customers, including government agencies and various enterprise users, such as: construction industry, maintenance service industry, energy and power industry, commodity retail and wholesale, agriculture, forestry and mining industry, broadcasting and publishing industry, etc. .
However, since the iDEN system is exclusively manufactured by Motorola and the interfaces are not public, network equipment is currently mainly supplied by Motorola, so the cost of system equipment procurement, network construction and terminals is relatively high. Moreover, due to the earlier R&D period, although the technology is relatively mature, its ability to support new businesses is relatively weak. GOTA (Open Trunking Architecture) is a trunking communication system based on trunking network applications proposed by China ZTE. It is also the world's first digital trunking system based on CDMA technology. It has China's independent intellectual property rights and has fast connection and channel* **Enjoy other digital cluster company features. As a wireless network technology, GoTa is mainly used in the wireless network cluster market. Its main features are that it is more conducive to operators to build wireless network cluster networks, suitable for large-scale coverage, high spectrum utilization, business performance and In terms of capacity, it can better meet the needs of Internet cluster networks and business applications.
GoTa adopts the latest wireless technology and protocol standards currently used in mobile communication systems, and has optimized and improved them so that they can meet the technical requirements of trunking systems and at the same time have strong security. network operation capabilities and business development capabilities to meet the needs of the future development of the cluster.
The trunking services that GoTa can provide include: one-to-one private calls and one-to-many group calls; special services such as system paging, group paging, subgroup paging, and dedicated PTT services. ;Categories different traffic groups, such as permanent groups and temporary groups, and users can manage the members in their groups. In addition to cluster services, GoTa also has all new value-added services, such as short messaging, positioning, VPN, etc. These services, combined with cluster services, can provide comprehensive services to group users.
GoTa successfully solved the key technology of cluster business based on CDMA technology. In order to be able to carry out PTT communication on the CDMA network without affecting the business functions and performance of the original CDMA system, GoTa proposed solutions around the two key technologies of wireless channel sharing and fast link, so that the new Trunking services will not adversely affect traditional communication services and network resources. Compared with traditional cluster communication methods, GoTa technology has the following advantages: advanced technology, rich services, low investment, quick results, and low operating costs.
On March 19, 2004, the ZTE GoTa Industry Alliance was launched. Terminal manufacturers such as Guanri, Youth Network, and Southern Hi-Tech began to cooperate with ZTE to jointly promote the development of the GOTA industry.
At present, ZTE has cooperated with two basic telecom operators, China Railway Communications and China Satcom, to carry out GOTA digital cluster commercial trials. In addition, ZTE has also won awards from Russia, Norway, Malaysia, Thailand, Egypt, and Algeria. There are digital cluster projects in more than ten countries and regions, among which Norway and Malaysia are commercial networks.
Although from the current point of view, iDEN and TETRA technologies are relatively mature, the prices of both are too high; GoTa has good cost performance, clear forward development trajectory, strong multi-service value-added capabilities, The security, confidentiality and trustworthiness are good, but the maturity is relatively low and it takes time to improve. Therefore, within a certain period of time, TETRA, iDEN, GoTa, etc. will have different basic market positioning in the Chinese market. They will survive in the competition and their future development will be determined by the choice of market users. GT800 is another professional digital trunking technology based on time division multiple access proposed by Huawei with independent intellectual property rights in China. It provides professional users with high-performance and large-capacity trunking services through creative integration and innovation of TDMA and TD-SCDMA. and functionality. Technological innovation is concentrated in the realization and enhancement of cluster characteristics, and dozens of core cluster technology patents have been formed.
The technical advantages of GT800 are mainly reflected in the following points:
1. Wide coverage. Due to the adoption of TDMA technical system, the transmit power of each channel of GT800 is constant, and the coverage distance is only limited by It can achieve wide coverage without the influence of terrain, while sharing the channel. When the number of users increases, the cell coverage will not be affected. Each group can enjoy the entire GT800 network coverage service area, truly embodying the power of GT800 cluster. The characteristics of wide network coverage, wide scheduling, and full utilization of frequency resources;
2. Responding to one call, GT800 inherits the industry's mature digital trunking technology system and realizes true channel sharing. The number of users in the group is not limited, users will not interfere with each other, and truly respond to all calls;
3. Dynamic channel allocation, the channel is released during the voice gap, and the channel is allocated only when speaking, greatly It greatly increases the capacity of the system group, ensuring smooth calls for high-priority users even at the capacity load limit; fourth, it provides sustainable development capabilities for 3G. The first-stage GT800 system based on the TDMA standard can facilitate It will evolve to the GT800 system in the second stage of TD-SCDMA, fully embodying the design concept of protecting user investment.
In the past few years, six major domestic and foreign communication equipment and terminal manufacturers, including Huawei, SAGEM, Bird, Eastcom, Amoi and Kejian, jointly launched the "GT800 Digital Trunking Industry Alliance" and launched the GT800 digital Development of cluster communication technology and products.