2. 1995 The first generation of digital mobile phones can only make voice calls.
3. The second generation digital mobile phones from 1996 to 1997 have added the function of receiving data, such as receiving emails or web pages.
The main difference between the third generation and the first two generations is that the speed of transmitting sound and data has increased. It can handle various media forms, such as images, music and video streams, and provide various information services, including web browsing, teleconference and e-commerce.
5. At present, there are three 3G standards: WCDMA, CDMA 2000 and TD-SCDMA.
(1)W-CDMA (Wideband Code Division Multiple Access) standard mainly originated from the early third-generation wireless research activities in Europe and Japan. The system is used on the existing GSM network and can be easily converted by system providers. The main supporters of this standard are Europe, Japan and South Korea.
(2)CDMA 2000 (Multi-carrier Wavelength Division Multiplexing Spread Spectrum Modulation) system is mainly proposed by Qualcomm North America Company, and its construction cost is relatively low. Its main supporters include Japan, South Korea and North America.
(3)TD-SCDMA (time division-synchronous code division multiple access Access) standard was first proposed by China. Based on this radio transmission technology (RTT), TD-SCDMA standard was completed and became a member of CDMA TDD standard.