Although the early start of China's CDMA, but has only recently begun to large-scale commercial. Currently set up China Unicom's new space-time Mobile Communication Co., Ltd., won the country's sole CDMA network construction and operation rights, will develop a nationwide CDMA mobile communications network, planned for completion in 2001 covering 160 cities, with a total capacity of 13.3 million The CDMA network. CDMA development in China ushered in the spring, but precisely because of this, in China's 3G process, the narrow-band CDMA 3G is how to realize a problem that must be considered. - Editor
Given the current user demand increases, Unicom New Space in the network construction of the building across the country determined to follow IS-95A +'s CDMA network in Beijing, Shanghai, Guangzhou and Tianjin, urban construction to support cdma2000-based data services The CDMA 1X network. In this regard, the equipment manufacturers Unicom's CDMA space-time commitment to provide system support: UIM card; international roaming; intelligent network; packet data access wireless Internet; protecting system investment, you can smooth the transition to cdma2000-1X.
As an important cdma2000 3G proposal is IS-95 system, the development of mobile communication system, the first phase of cdma2000-1X is technically mature, provides simultaneous voice and packet data services, the physical layer of the maximum rate of up to 307.2kbit / s. cdma2000-1X is already commercial in South Korea, which shows that the 2G IS-95 system, the system's transition to 3G taken a solid first step.
IS-95 system of mobile communication system is divided into IS-95 A and IS-95B, the two are similar to the GSM and HSCSD, IS-95B and HSCSD, but the difference is that IS-95B can simultaneously support eight yards bundled channel use, and HSCSD support only four slots for bundled use. IS-95A and IS-95B is no essential difference in the core technology, IS-95A system, each code channel data access speed of not more than 9.6kbit / s or 14.4kbit / s, IS-95A provides 9.6kbit maximum / s or 14.4kbit / s circuit-based data access; IS-95B supports eight yards bundled channel use, the maximum available 76.8kbit / s or 115.2kbit / s circuit-based data access.
From the technical analysis, cdma2000-1X system uses the anti-guide-frequency, coherent demodulation, forward fast power control, Turbo codes, diversity firing, long intertwined and complementary technologies such as pilot, and IS-95A / B system compared to greatly improve the overall system capacity and system performance.
In the reverse link, cdma2000-1X frequency channels to provide anti-wizard, which can be coherent demodulation, than IS-95 A / B system, the reverse channel used by non-coherent demodulation to improve 3dB gain. The forward link, using the former to the fast power control, diversity emission technique (OTD or STS), than the IS-95 A / B channel to improve the system prior to the 3dB gain. Meanwhile, cdma2000-1X high-speed data channels using Turbo codes, surpasses IS-95 A / B increased by the Convolutional coding gain of about 2dB.
For voice users, the system gain increase 3dB, the corresponding increase in the capacity of voice users for the IS-95 A / B system, twice, for high-speed data users, system gain is increased by about 5dB, the corresponding data user capacity increase for the IS-95 A / B system 3 times. Therefore, cdma2000-1X system to the IS-95 CDMA system, technical superiority is beyond doubt. On the other hand, cdma2000-1X system, baseband processor ASIC core technology with advanced manufacturing processes, higher integration and lower cost.
The key is, from the network side mobile terminal or from the side view, cdma2000-1X system (IOS 4.1 or later) provides the standard 2G and 3G-compatible interface, supports both circuit-switched and packet-switched voice services that support and circuit, packet data services, with the second phase of smooth evolution to 3G capacity. IS-95 A / B system also have to cdma2000-1X system as a bridge to the second stage of 3G evolution.
cdma2000-1X provides a complete data solution, the equipment manufacturers to provide equipment at the same time, operators also paints a bright application prospect. South Korea cdma2000-1X has been commercialized, and provides a wealth of applications, and data services in Japan, DoCoMo has also made successful, the operator brings good news.
With the domestic telecom operators in the market, return on investment is already the operator to consider the primary issue, therefore a need for an operator to meet the user requirements, to provide users with a good network of applications and services, rather than building a technically very advanced network. At present, although the 3G is a loud voice, but the mature system, terminal equipment and the application is true and we have a certain distance. Therefore, as cdma2000-1X can provide a wealth of applications, and from the system, terminal equipment, solutions are more mature, I believe cdma2000-1X is a good narrowband to broadband a bridge.
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