Can't connect to 3G and 4G

[paraprove]

I bought a sim card with 800mb per month. But I can't seem to get the data enabled. I'm using android bought from Japan, do I need to set up an access point name?

Others are doing fine with their phone amd data. Not sure what's wrong with my phone.

[ZhangKaiRong]

which operator do you use? as far as I know, only the China Unicom's 3G/4G is compatible with the non-Chinese 3G/4G standard.

[paraprove]

I use unicom

[ZhangKaiRong]

Who was your carrier in Japan? (if you had a carrier at all?)

The following is the problem:

 

- China Unicom uses W-CDMA as a 3G standard

- China Telecom uses CDMA2000 as a 3G standard

- China Mobile uses TD-SCDMA as a 3G standard (but we can forget it as basically no phones outside China come with this).

 

A rule of thumb is, that Unicom's W-CDMA goes well with all European, US AT&T and Japanese NTT carriers' phones, while CDMA2000 goes weill with US Verizon, Sprint and Japanese KDDI carriers' phones.

 

Do you have a friend who has a China Telecom SIM card that you can try? If you can connect to 3G on that SIM, it would mean that your phone uses CDMA2000 as a standard, and you should change your carrier to China Telecom.

[paraprove]

I had it all figured out now. I had to set up an APN for my phone and now 3G is enabled.

[Alex_Hart]

@Zhang Thanks for the post anyway! That was pretty helpful - i had used China Mobile last time I was in China and could never use 3G/4G. Bought an international phone this time. Will need to look out for the spectrum, I guess!