Radio paging system having a plurality of transmitter stations

Claim 1

In a global paging system for providing paging services for a plurality of paging receivers distributed in service areas of a plurality of base stations, a paging controller responsive to a paging call received from a subscriber of a Public Switched Telephone Network (PSTN) therethrough for producing a paging request signal containing a subscriber number of an owner of said paging receiver called, wherein each of said base stations are connected to said paging controller through one of a plurality of transmission lines having different transmission times, each of said base stations producing a plurality of radio frequency carriers having different frequencies and modulated synchronously with a digital paging signal corresponding to said paging request signal, respectively, said paging controller comprising: a delay time storage for preliminarily storing a first time value equal to a maximum value of the different transmission times of said transmission lines and a second time value required for converting said paging request signals to said digital paging signals at each of said base stations; a first GPS receiver responsive to signals received from a plurality of NAVSTAR GPS (global positioning system) satellites for producing a time reference signal; a first time reference circuit responsive to said time reference signal font producing high precision time signals having predetermined relation in time to a universal standard time; code producing means for producing codes indicative of a time after a time instance, which is obtained by adding a sum of the first time value and the second time value to a current time, to said paging request signal as transmission start time assigning codes, and codes to specify one of said plurality of radio frequency carriers as channel number codes; and a plurality of first transmitting means for transmitting said paging request signals, said transmission start time assigning codes, and said channel number codes to said base stations through a respective one of said plurality of transmission lines, each of said first transmitting means being connected to each of said base stations through a respective one of said transmission lines, a bit rate of said each transmission line being N times that of said plurality of radio frequency carriers; and said base stations each comprising: a reception buffer memory means for receiving said paging request signals and storing them temporarily; a second GPS receiver responsive to the signals from said GPS satellites for producing said time reference signal having a predetermined relation in time to the universal standard time; a second time reference circuit responsive to said time reference signal for producing a high precision time signal having a predetermined relation in time to the universal standard time; a coincidence circuit for detecting a coincidence between the transmission start time assigning code accumulated in said receiving buffer memory means and said high precision time signal from said second time reference circuit; a format conversion circuit for converting a format of said paging request signal into said digital paging signal from a time at which a coincidence output of said coincidence circuit is produced; and a plurality of second transmitting means for producing said plurality of radio frequency carriers by said channel number codes, respectively.