3G standards

International Telecommunication Union (ITU) in May 2000 to determine W-CDMA, CDMA2000, TD-SCDMA, as well as the mainstream of the four WiMAX wireless interface standard, 3G technology into the guiding text of the "2000 International Mobile Communications Plan" (referred to as IMT-2000 ). CDMA is Code Division Multiple Access (CDMA) acronym, is the third generation mobile communication technology-based systems. The first generation of mobile communication system using frequency division multiple access (FDMA) analog modulation, the system is the fundamental flaw of the spectrum utilization low, signaling interfere with voice service. Second-generation mobile communications systems using time division multiple access (TDMA) digital modulation, to increase the capacity of the system, and an independent channel signal transmission, so that system performance greatly improved, but the TDMA system capacity is still limited, handoff Performance does not improve. CDMA system, with its simple frequency planning, system capacity, frequency reuse factor of high anti-multipath capability, good communication quality, capacity soft, soft switching characteristics, such as showing great potential for development. The following were some brief 3G standards:
(1) W-CDMA
Also known as WCDMA, called Wideband CDMA, also known as CDMA Direct Spread, which means broadband Code-Division Multiple Access, which is based on the GSM network developed 3G technology standard proposed by the European broadband CDMA technology in Japan The proposed broadband CDMA technology is basically the same as is currently being further integration. Its main supporter of the GSM system is mainly of European manufacturers, Japanese companies are more or less involved, including Europe and the United States of Ericsson, Alcatel, Nokia, Lucent, Nortel, as well as Japan's NTT, Fujitsu, Sharp , And other manufacturers. The system can be set up in the existing GSM network, the system providers can be moved less transition, and the GSM system very popular in Asia for the new technology acceptance is expected to be high. Therefore, W-CDMA has the inherent advantages of the market. The proposed standard GSM (2G)-GPRS-EDGE-WCDMA (3G) evolution strategy. GPRS is General Packet Radio Service (GPRS), referred to as, EDGE is Enhanced Data rate for GSM Evolution (Enhanced Data Rates for GSM Evolution), referred to as the two technologies called 2.5 generation mobile communication technology.
(2) CDMA2000
CDMA2000 is by the narrow-band CDMA (CDMA IS95) technology developed from broadband CDMA technology, also known as CDMA Multi-Carrier, from Qualcomm Inc. led the North American made, Motorola, Lucent, subsequently joined by South Korea's Samsung are involved in the process, South Korea Now become the dominant standard. The system is the digital standard from the narrowband CDMAOne derived from the original structure CDMAOne directly to upgrade to 3G, low-cost construction. However, the use of CDMA, only Japan, South Korea and North America, CDMA2000 is why supporters of more than W-CDMA. However, the CDMA2000 technology research and development is currently the fastest progress in standards, and many have been the first to launch 3G mobile phone. The proposed standards from the CDMA IS95 (2G)-CDMA20001x-CDMA20003x (3G) evolution strategy. CDMA20001x called 2.5 generation mobile communication technology. CDMA20003x and CDMA20001x the main difference is that the application of multi-carrier technology, so that through the use of three carrier to increase bandwidth. At present, China Unicom is using the program to transition to 3G and has built a network of CDMA IS95.
(3) TD-SCDMA
Full-called Time Division - Synchronous CDMA (Time Division Synchronous CDMA), by the standards of the Chinese mainland's development of its own 3G standard, June 29, 1999, China's former Ministry of Posts and Telecommunications Academy of Telecommunications Technology (Datang Telecom) made to the ITU. The intelligent wireless standard, synchronous CDMA radio and software, and so today the world's leading technology into one, in the spectrum utilization, and support for business flexibility, frequency and flexibility in areas such as the cost of the unique advantages. In addition, because of the huge domestic market, which is subject to major telecommunications equipment manufacturers attention, more than half of the global equipment manufacturers have announced to support TD-SCDMA standard. The proposed standard without going through the middle of the 2.5-generation link directly to the transition to 3G, is applicable to the GSM system upgrade to 3G.
(4) WiMAX
WiMAX is the full name of the Worldwide Interoperability for Microwave Access (Worldwide Interoperability for Microwave Access), also known as the 802.16 wireless MAN, is also a corporate and home users to provide "last mile" broadband wireless connection program. This technology and the need to avoid authority or authorized by the combination of microwave equipment, due to lower-cost, wireless broadband market will expand and improve the enterprises and service providers awareness. October 19, 2007, the International Telecommunication Union in Geneva at the plenary meeting of wireless communications, after most countries vote, WiMAX was approved to become official following the WCDMA, CDMA2000 and TD-SCDMA after the fourth of global 3G standards.