1.GSM: the most widely used mobile phone standard at present. 20 15 years, many GSM network operators around the world have determined 20 17 years as the year to close the GSM network. The reason for shutting down GSM and other 2G networks is to release radio frequency resources for building 4G and future 5G networks.
2.CDMA: Introduced to Qualcomm, USA, adopting the second, second and third generation technologies. Mainly used in the United States and Canada. CDMA is the development direction of mobile communication technology. In the 2G stage, CDMA enhanced IS95A and GSM are the same generation products in terms of technical system, and they provide roughly the same.
Second, 3G technology: Based on CDMA, three 3G standards, CDMA2000, WCDMA and TD-SCDMA, were born, which were introduced by Qualcomm.
1.CDMA 2000: CDMA 2000 is a technical standard under the CDMA framework. CDMA2000 has a smaller application range and fewer users and supporters. However, the research and development technology of CDMA2000 is the fastest among the current 3G standards, and many 3G mobile phones have taken the lead.
2.WCDMA: Europe and Japan are dominant. Based on CDMA technology, they all use some patented technologies from Qualcomm, but they all try to avoid patents from Qualcomm. WCDMA is a backward compatible GSM network, so WCDMA has the highest 3G coverage.
3.TD-SCDMA: time division-synchronous code division multiple access technology, 3G standard formulated by China. Siemens, Datang Telecom. Mainly used in China, led by China Mobile.
Third, 4G technology: Only the upgraded LTE Advanced can meet the requirements of the International Telecommunication Union for 4G. Developed in Europe.
LTE is a global standard based on OFDMA technology and formulated by 3GPP organization, including FDD and TDD modes of paired spectrum and unpaired spectrum. LTE-FDD, LTE-TDD, in China, LTE-TDD is called TD-LTE for short. The mainstream communication technology in the world is LTE-FDD.
With the upgrade of 2G, 3G and 4G, the Ministry of Industry and Information Technology said that at present, China has made clear the frequency planning and test frequency of the 5G intermediate frequency band, and formulated the relevant allocation scheme. Basic telecommunications companies have successively released plans related to 5G deployment, actively carried out 5G testing, and promoted network construction.
With the joint efforts of all parties in the industry, the current 5G technology and products are becoming more and more mature, and the main links of the industrial chain such as systems, chips and terminals have basically reached the commercial level, which is suitable for commercial deployment.
Baidu encyclopedia -2G
Baidu Encyclopedia -3G
Baidu encyclopedia -4G
People's Network-China 5G has basically reached the commercial level.