@NordineLotfi Haven't heard of which company? -
1G uses a few different standards, NMT among them. The company
SkyLink only operates in Russia. The other companies mentioned in the link are: Nokia (then Mobira), Ericsson, Storno (then owned by General Electric, later taken over by Motorola) and AP (later taken over by Philips) - I'm guessing that you've heard of those.