Can't find network when stay at home

Four day ago, my Z10 got a problem. It cannot find any mobile network when i stay at home. I try to go out of the house about 50m, it work, i can place call, use data service. I also try to use this sim card with another mobile phone at home. It work too.
At first, i think that sim was fault, so i change a new sim (use old number) but can't solve this problem.

Before that day, my z10 work very well.
Have anyone caught this problem?
Please give me an advise.

Thanks!!

UPDATE: if i select 2G as network mode. i can place call, and slow data service. If i change to 3G, it change to Emergency call only immediately.