Mobile terminals 201 to 203 measure strength of the received signal from plurality of base station antennas 101 to 105 and transmits it to network system 300. Network system 300 determines proximity state between plurality of base station antennas 101 to 105 based on the strength of the received signal from plurality of base station antennas 101 to 105 transmitted from mobile terminals 201 to 203. From that determination, the base station antennas proximity state matching a position or features of an antenna of the mobile terminal can be recognized.