CDMA2000, WCDMA, TD SCDMA are all 3G protocols, why do they have to have their own mobile phone manu

Landlord, what you said, it is theoretically possible, but it is a bit difficult to connect with reality. Here's why:

Now there are mobile phones on the market that support both CDMA2000 and WCDMA standards, but there are no mobile phones that support all three standards, because there are only the first two types of 3G commonly used in the world, and China Mobile's TD-SCDMA is not included. Because this is a system developed in China, there is no one in the world. So there is no corresponding mobile phone support.

Even if it can support all formats,1. The mobile phone is only so big, and if it supports two standards, it has to be installed with two mobile phone cards, and if all three are supported, it is not necessary to install three mobile phone cards, then the mobile phone will become larger again. It's not easy to carry around.

2。Even if there are mobile phones that support all three standards, then, when you pay the ** fee at the end of the month, then you don't have to go to three operators to pay the phone bill, don't you feel tired? Now the three operators can't be combined into one. Hehe.

Therefore, the technical problems that the landlord thinks can be solved, but in fact, it is not easy to operate.

..It may be possible that the copycat machine can be realized in the future.

Only ZTE's recently launched Nubia Z5S series does. The Xiaomi Telecom version does not support TD-SCDMA. However, the Nubia Z5 series cannot support TDD-LTE and FDD-LTE at the same time.

1. From a technical point of view, CDMA and CDMA2000 use the same technology, both CDMA1X and CDMA-EVDO. But in order to distinguish, we call the one that works at 800m frequency 2G or, and the one that works at 2200 frequency is called 3G. In fact, the essence is the same.

2. The 870-880m and 2110-2115m you mentioned are the wireless communication frequencies of the downlink (base station), while the 825-835m and 1920-1935m are the wireless communication frequencies of the uplink (mobile phone).

3. CDMA1X is a voice and data compatibility mode, while CDMA-EVDO is a data-specific mode. Since there are 7 frequencies in 870-880M, some of the frequencies can be used for CDMA1X and additionally for CDMA-EVDO.

The CDMA800 can implement both 2G and 3G technologies.

CDMA2000 is the 3G technology of CDMA.

The CMDA800-1X is a 2G network.

The CDMA800-EVDO is a 3G network.

That is, 3G and 2G can be achieved under 800M, and Telecom rarely opens 3GWCDMA on 2000M, which is Unicom 3G

TD is mobile, and TD is divided into TD-A, TD-F, TD-ETD-LTE is 4G technology.

What you said 800M is the communication frequency (maybe I'm not professional, that's probably what it means) Just like every radio station has a frequency, which one you can only use that one assigned to you, it has nothing to do with network speed, I estimate that you understand 800M as network speed, and now the fastest 3G network is Unicom's WCDMA, and the downlink rate can reach 21Mbps seconds.

CDMA2000 is not strictly 3G