Instructions on how to register 4G Viettel SIM is completely free
if you intend to use 4g network with fast speed of data download, you should not miss the opportunity when viettel operator is changing sim 4g for free.
Tags : how to register 4g sim
Things to know about 4G networks
currently, operators have implemented the program to exchange 4g sim for free. so what is 4g network and what's different from 2g and 3g?
How to know if your smartphone supports 4G?
currently, 4g networks have been gradually deployed and there are quite a number of people ordering to use 4g networks, because of the benefits that it brings compared to the