What is meant by IDEN?

Digital trunked communications iDEN system (Zheng Zuhui) In the ITU recommended several digital trunking system, there are three kinds are highly concerned about our country, they are iDEN, TETRA and FHMA, but at present our country has only iDEN system has physical available for use and visit, which is the iDEN network operated by Fujian Trunked Wireless Telephone Company. iDEN (integrated Digital Enhancde Network) is a **** frequency, for command, scheduling with a dedicated digital trunking communications system. It adopts Time Division Multiple Access (TDMA) technology, the latest VSELP (Vcetor Sum Excited Linear Prediction) vector and excitation linear prediction coding technology and M-16QAM (Quadrature Amplitude Modeulation) orthogonal amplitude modulation technology with strong anti-jamming capability. It also adopts the same duplex call structure and special frequency multiplexing method as that of GSM system. The system has the characteristics of low power, large capacity and wide area coverage. iDEN digital trunking communication system can provide command and dispatch, duplex interconnection, data and short message services. Its command and dispatch communication and packet data exchange function plus and GSM system the same wireless telephone communication makes the system function is more perfect, also is to the personal mobile communication of the favorable supplement, digital trunking communication and analog trunking compared with the performance is more reliable, the coverage is more broad, the business is more diversified, especially for the transmission of data is more advantageous, the cost is more inexpensive, the confidentiality is more strong. It is not only convenient, fast, can realize one-to-one private calls, but also in a group of various ways of communication. iDEN system works in the 800MHz band, which is just in line with China's no committee regulations of digital trunking communications band. In Fujian Province, China's first digital trunked communications network is in 1994 by the Zhuhai New Galaxy International Electronics Co., Ltd. and the United States Motorola *** with an investment of nearly 300 million yuan to set up, this network uses the Motorola development, production of the iDEN digital trunked communications system, the effect is good. Fujian Province, the formation and operation of trunked wireless telephone company iDEN system is actually also affected by the development of the United States digital trunked communications *** network, the United States in the formation of digital trunked communications *** network is done earlier and better, such as the United States of America's NE XTEL company using the iDEN system in the United States to form and operate the national *** network has been more than 4.5 million users. Due to the *** network in *** with frequency, *** with channel, *** enjoy the coverage area, *** with communication services, etc. is very good, so it is particularly suitable for a region (such as a province, a basin, etc.) to establish a large network, mainly to provide a variety of groups of users (of course, can also be used for a single user). In 1998, the iDEN digital trunking communication network was built from Fuzhou, Xiamen to Zhangzhou, which has been agreed by the former Ministry of Posts and Telecommunications and the State Council as a specially approved experimental network for commercial operation in 1999. At present, the number of users is not very large, but the user base involves government agencies, public security, traffic police, city management, military, armed police forces, disaster relief, medical rescue, commercial and financial, security, transportation, port and aviation, hotel services, construction. The following is an overview of iDEN digital trunking communication network in Fujian Province. Fujian iDEN digital trunked communication network is a trunked *** network, the first phase *** built 32 base stations (30 have been built), has opened Fuzhou through Xiamen to Zhangzhou, a line of coastal economic areas, set up a 50,000-door switch in Fuzhou, according to the scheduling of 45,000, 20,000 telephone users design. It has been opened and put into operation. With the increasing number of users, the second phase of the project will gradually expand inland and will complete the construction of projects in all major areas of the entire Fujian Province, and will eventually cooperate with Motorola's iDEN digital trunking communication system in other provinces, cities and regions to establish a cross-provincial network to achieve a larger coverage. Since the whole system only took shape in July 1997, and the system was gradually improved only by the end of 1998, the trunked wireless phone company developed some trial users in this nearly one year, so that the users can find and timely correct the problems in the system, equipment and wireless coverage in the continuous trial, and thus gained the understanding and favorable comments from the trial customers. For the selection of trial customers in the early stage, the company adopts the sieve first way, selects some economic strength, influential industry representative enterprises as the first batch of trial customers, with the help of their trial, in the industry to play a very good role in publicity. At the same time in the customer in the trial process, and carried out a number of use of the survey, found and summarized some of the problems, and took positive measures to improve, so that the problem with the construction of the project and the continuous optimization of the network and the gradual corresponding solution. In addition, the trunked wireless phone company has provided some cell phones as the command and scheduling tools of the conference during the trial operation and official operation of the network for several large-scale conferences and activities held in Fujian Province and Fuzhou City, and each time it is well received, that the iDEN system is very effective in command and scheduling, and the user's cost is also very low, and at the same time its duplex interconnection call is also very convenient, so it is very popular among the users, especially the group users. Especially, it is welcomed by group users. Therefore, the trunked wireless phone company also determined that the users of the network are mainly located in the group users. The Fujian iDEN system was initially operated in TDMA 6 time slots (6:1), which, of course, would allow the system to have a much higher capacity. However, in the survey of the users, most of the users put forward different opinions on the voice quality, in order to meet the users' requirements on the call quality, after many large-scale tests, the company has changed from the original 6 time slots (6:1) to the current 3 time slots (3:1). Of course, after the change to 3 time slots, the number of users will certainly be reduced accordingly, but in this network will not be affected for the time being. And from the computer derived from this time the voice coding rate has increased from 4.2kb/s to 10kb/s or so. Experts and people believe that TDMA 6 time slot voice quality is comparable to GSM, which has a subjective evaluation score (MOS) of about 3.5, while at 3 time slots, the MOS has reached about 4.5, which is comparable to the voice quality of the CDMAIS-95 system. The initial trial handset offered to users was a Motorola B-70 cell phone, which was commonly used by users in the United States at the time. Users generally found the phones offered to be large, heavy, and with short battery life, and wished to use smaller phones. The smaller 1000 cellular phone, which is now in common use, was soon offered, and is light, small, and has a battery standby time of up to 75 hours. Motorola has announced that this new Model 1000 fourth-generation cellular phone has dropped to under $400 for a bare-bones unit and is expected to drop to $300 in 2000, while both a GSM-compatible fifth-generation dual-band cellular phone and a sixth-generation cellular phone with packet-data transmission will be available in 2000. Their specific charges are as follows: A. Monthly basic call charges: 30 yuan/part, month for single dispatch; 50 yuan/part, month for telephone plus dispatch. B. (1) The tariff unit is 15 seconds for one call, less than 15 seconds is counted as 15 seconds; (2) Private calls are charged in both directions, and there is no charge for group calls called; (3) Inter-area call charges include long-distance scheduling charges (counted as 50% of the duplex long-distance call charges) and long-distance surcharges (according to the current regulations); (4) Implementation of a maximum of 120 yuan/month/parts of call charges for scheduling calls in this area (excluding the monthly basic charge), and call charges lower than 120 Yuan/month/part, according to the actual cost. C. Telephone charges: the same as the mobile telephone charges of Fuzhou Telecommunications Bureau. With the continuous growth of mobile communications business, the demand for mobile data services will be more and more, digital trunking communications can just meet this demand, so I believe it will better serve the community, and to enhance the Group's users self-development capabilities, to achieve a virtuous cycle to add a force.