Attachment: 3G background information
On June 7th, 2009, the Ministry of Industry and Information Technology issued three 3G licenses, namely TD-SCDMA for Mobile, WCDMA for Unicom and CDMA2000 for Telecom.
TD-SCDMA is a 3G network technology independently developed by China. It has been more than ten years since its development, but its defects are still very obvious:
1, the technology is immature, and the whole industrial chain is immature, which leads to quite a few problems from the computer room, the base station to the middle end of the mobile phone.
2. The transmission speed is slow and unstable. The theoretical peak speed is 384 k/s, you know, the peak speed of 2.5G edge has reached 480k/s at present. In actual use, it is true. The average download speed on the Internet is only about 10k, so I wonder why it is called 3G.
Network problem is the most fatal. Because of its huge base station equipment (single base station: about 2m, 500kg-800kg), the radiation is serious, which will definitely bring great obstacles to its future deployment of full coverage network. It has been nearly a year since the commercial trial in April, and there are almost no base stations in Fuzhou, let alone network coverage.
4. Because the coverage of TD network can't be seamless, where there is no TD network, mobile phone users need to communicate through GSM network (currently, the 2G networks used by China Mobile and China Unicom belong to GSM network). So now TD mobile phones all adopt GSM and TD dual-mode structure. A big disadvantage of this structure is power consumption, which is a common problem of dual-mode mobile phones. Another fatal disadvantage is that, up to now, TD mobile phones have not been able to solve the problem of network switching crash between TD and GSM, and GSM to TD, including Samsung i688, the best TD mobile phone on the market at present. When the network switches, it often crashes. That is to say, when you drive through the TD coverage area, get off the subway or enter the underground garage, when there is no signal in TD, or unconsciously, your mobile phone has crashed because the network has not been successfully switched. On the other hand, TD and GSM dual-mode chips are domestic technologies, which we should support, but it is irresponsible for consumers to push them to the market when the technology is immature! )
5. There is no international roaming. TD's mobile phone can't use 3G when going to Europe and America. WCDMA is the most widely roaming 3G network in the world, including Europe, America, Australia, Hong Kong, Macao and Taiwan, Japan and South Korea, the Middle East, South America and Africa. At present, CDMA2000 is only owned by the United States, Japan and South Korea, and India and Australia, which have CDMA, have indicated that their 3G development direction is WCDMA.
6, mobile phone terminal problems. At present, TD mobile phones on the market are all TD~GSM dual-mode, and only domestic brands such as ZTE, Lenovo and Coolpad and Samsung are the only international brands. LG and dopod each produced a product of this kind, which has not been listed yet. Interested friends may wish to visit the mobile phone website or business hall. Except Samsung i688, other TD mobile phones are rough and unsightly. I believe everyone wants to use 3G, unlike the cottage's domestic mobile phone. You can also compare the price difference between Samsung i688 and Hong Kong licensed version of Samsung's WCDMA mobile phone. This illustrates a problem, TD's mobile phone price is not high.
WCDMA: There are no other shortcomings except foreign technology. In fact, Huawei in China also owns 7% of WCDMA core patented technology. Compared with other standards, WCDMA has the following advantages:
1, through the development of 10 for more than six years and its commercialization, has become the most mature 3G technology in the world. 80% of 3G users all over the world have the same choice.
2. Fast Internet access. At present, the theoretical peak download speed of advanced WCDMA is 14.4M/s, and the upload speed is 6.8M/s, far exceeding the speed of general home broadband and the other two 3G.
3. High signal coverage. At present, the smallest WCDMA base station can directly hit the wall, about the size of a wall lamp. Many developed countries in Europe and America are home base stations, which are the same equipment as wireless routers at home. Considering the functions of wireless Internet access and telephone signals, they are very small and light. When it comes to building a base station, people will object to building a base station with a length of about 2 meters and a weight of 500 kilograms like TD. Then directly hang a WCDMA base station with the size of a light box on the street lamp in the community, saying that it can improve the quality of telephone calls and has little radiation. Will anyone object? In the long run, WCDMA coverage and signal in China will be the best in 3G!
4. The network quality is good. Because of good coverage, WCDMA can ensure that you can enjoy 3G services at will in the main city. It doesn't matter whether you are on a business trip or driving out of the 3G coverage area. Mobile phones can smoothly transition to GSM network, because WCDMA is originally an upgraded version of GSM. There will be no disconnection and network switching problems.
5. International roaming is optional. As mentioned above, WCDMA can roam in Europe, America, Middle East, South America, Africa and other developed areas, and enjoy 3G services, including Japan, South Korea, Hong Kong, Macao and Taiwan.
6. There are many mobile terminals. At present, there are more than 3,000 kinds of WCDMA mobile phones for consumers to choose from, and the prices are cheaper than the other two. At present, the world's star mobile phones, such as Apple, Google, Samsung, Nokia, dopod, Sony Ericsson, LG, Motorola and so on. , are gradually discontinued 2G mobile phones, and the new mobile phones are all 3G mobile phones supporting WCDMA.
CDMA2000: This technology is American, and its disadvantages mainly include:
1, the network coverage can't reach a high level. Because the base station of CDMA2000 is basically huge, it faces the same dilemma as mobile. Moreover, because the diffraction ability of 3G network is much worse than that of 2G, it is estimated that it is difficult to cover indoors, especially in large office buildings and underground shopping malls.
2. The transmission speed is not enough. At present, the published data is the peak speed of 2-3m/s, which is obviously inferior to WCDMA's14.4 m/s.
3. Mobile terminals are more expensive. Because of the high patent fees charged by Qualcomm, the chip maker of CDMA2000, and because the sales volume has not kept up with WCDMA mobile phones, in contrast, the price of CDMA2000 mobile phones is on the high side, and consumers have fewer choices because of the lack of Nokia, the mobile phone giant. At present, Tianyi low-end mobile phones are all 100% 2G mobile phones.
To sum up, only Unicom 3G can bring us the best 3G enjoyment.