. (Developer: China Telecom Joint Industrial Chain Partner)
2. New six-mode full netcom: it can support multi-mode and multi-frequency equipment, TD-LTE, FDD-LTE, TD-SCDMA, CDMA2000(EVDO), WCDMA and GSM, covering China Telecom, China Unicom, China Mobile and 4G/3G/2G networks. Users can change operators at will without changing their mobile phones.
* * The difference between the old six modules and the new six modules: * *
1.2G band
2, China GSM900 frequency.
① China Mobile
● Uplink band: 890-909 MHz
● Downlink frequency band: 935-954 Mhz
② China Unicom.
● Uplink band: 909-9 15 MHz.
● Downlink band: 954-960 Mhz.
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.
GSM system architecture
2.3G band
After the issuance of 3G licenses, the relevant state departments have distributed 3G frequency bands to the three major operators, among which TD-SCDMA has obtained the total ***35M frequency band, WCDMA and CDMA have each obtained 30M frequency band, which shows that the country is still leaning towards TD-SCDMA in terms of spectrum resources.
3.TD-LTE frequency band allocation scheme:
Take the 4G standard LTE as an example. LTE has many frequency bands. LTE FDD*** has 22 frequency bands with the label 1~22. No frequency bands are defined except that the frequency bands labeled 15 and 16 are reserved frequency bands. LTE TDD*** has nine frequency bands numbered 33~4 1. At present, China's LTE is divided into four frequency bands: A-band, D-band, E-band and F-band, and their frequency bands are 20 10 MHz~2025 MHz and1880mhz ~/920mhz respectively.
1.3GPP
The goal of 3GPP is to realize the smooth transition from 2G network to 3G network, ensure the backward compatibility of future technologies, and support easy network building and roaming as well as compatibility between systems. Its function: 3GPP mainly formulates the third generation technical specification based on GSM core network and UTRA(FDD is W-CDMA technology and TDD is TD-CDMA technology) as the wireless interface.
China and 3GPP.
China Wireless Communication Standards Research Group (CWTS) officially signed the contract in June 1999, and joined 3GPP and 3GPP2 at the same time, becoming the organization partner mainly responsible for 3rd generation partnership project. Prior to this, China participated in the standardization activities of these two partners as an observer.
2.3GPP2
3rd generation partnership project 2 (3GPP2) was established in 1999 65438+ 10. It was initiated by four standardization organizations, namely TIA of the United States, ARIB of Japan, TTC of Japan and TTA of South Korea, and was formally signed by China Wireless Communication Standards Research Group (CWTS) in Korea1June 1999. 3GPP2 claims to be committed to the global development of (3G) mobile phone system specifications in the IMT-2000 plan of ITU. In fact, it is the standardization organization of CDMA2000 standard system developed from 2G CDMA One or IS-95, and it is supported by Qualcomm, which owns many patents of CDMA key technologies. The corresponding 3GPP is committed to the transition from GSM to WCDMA(UMTS), so there is some competition between the two institutions.