There are currently four standards for 3G: CDMA2000, WCDMA, TD-SCDMA, and WiMAX.
CDMA2000 is a broadband CDMA technology developed from narrowband CDMA (CDMA IS95) technology, also known as CDMA Multi-Carrier. This system is derived from the narrow-band CDMAOne digital standard and can be directly upgraded from the original CDMAOne structure to 3G with low construction costs. This standard proposes an evolution strategy from CDMA IS95 (2G)-CDMA20001x-CDMA20003x (3G). CDMA20001x is called the 2.5th generation mobile communication technology. The main difference between CDMA20003x and CDMA20001x is the application of multi-carrier technology, which increases the bandwidth by using three carriers.
WCDMA, the full name is Wideband CDMA, also known as CDMA Direct Spread, which means wideband code division multiple access. This is a 3G technical specification developed based on the GSM network and a broadband CDMA technology proposed by Europe. , which is basically the same as the broadband CDMA technology proposed by Japan, and is currently being further integrated. This standard proposes the evolution strategy of GSM (2G)-GPRS-EDGE-WCDMA (3G). This system can be set up on the existing GSM network, making the transition easier for system providers. The acceptance of this new technology in Asia, where the GSM system is quite popular, is expected to be quite high. Therefore, W-CDMA has inherent market advantages.
The full name of TD-SCDMA is Time Division - Synchronous CDMA (Time Division Synchronous CDMA). This standard is a 3G standard independently developed by mainland China. On June 29, 1999, the Telecommunications Science and Technology Research Institute of the former Ministry of Posts and Telecommunications of China Institute (Datang Telecom) proposed to ITU. This standard integrates today's leading international technologies such as smart wireless, synchronous CDMA and software radio, and has unique advantages in spectrum utilization, flexibility in business support, frequency flexibility and cost. This standard proposes a direct transition to 3G without going through the 2.5 generation intermediate link, which is very suitable for the upgrade of GSM systems to 3G.
The full name of WiMAX is Worldwide Interoperability for Microwave Access, also known as 802·16 wireless metropolitan area network. It is another "last mile" solution for enterprise and home users. ” broadband wireless connectivity solution. Combining this technology with licensed or license-exempt microwave equipment will expand the broadband wireless market and improve awareness among enterprises and service providers due to its lower cost. On October 19, 2007, at the World Radiocommunication Conferences held in Geneva by the International Telecommunication Union, WiMAX was officially approved by a majority of countries to become the fourth global wireless network after WCDMA, CDMA2000 and TD-SCDMA. 3G standard.
The third generation mobile communication technology (3rd-generation, 3G) refers to cellular mobile communication technology that supports high-speed data transmission. 3G service can transmit voice and data information at the same time, and the rate is generally above several hundred kbps.
The International Telecommunications Union (ITU) determined the four mainstream wireless interface standards of W-CDMA, CDMA2000, TD-SCDMA and WiMAX in May 2000, and wrote them into the 3G technical guidance document "International Mobile Communications 2000" Plan" (referred to as IMT-2000).