(my country's terrestrial cellular digital mobile communication network GSM communication system selects 900MHz and 1800MHz frequency bands: GSM900MHz frequency band is: 890~915 (mobile station sends, base station receives), 935~960 (base station sends, mobile station receives); DCS1800MHz frequency band is: 1710~1785 (transmitted by mobile station, received by base station), 1805~1880 (transmitted by base station, received by mobile station))