Method and apparatus for system synchronization in a messaging system
First Claim
1. A method for providing time synchronization in a non-real time messaging system, comprising the steps of:
- (a) receiving source information from a satellite, the source information having timing information and originating from a control point satellite uplink, the source information being received by a plurality of receivers remote from the control point satellite uplink;
(b) receiving an absolute time reference coupled to one of the plurality of receivers;
(c) generating an offset signal calculated from the difference between the absolute time reference and the timing information of the source information;
(d) providing the control point satellite uplink with the offset signal in order to adjust the timing information to synchronize with the absolute time reference within subsequent source information transmissions from the control point satellite uplink.
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Accused Products
Abstract
A selective call messaging system comprises a control point satellite uplink (24) for transmission of source information to a satellite (12), the source information having timing information, a base station (16) for receiving the source information from the satellite and for retransmitting the source information to a receiver 18. A synchronization controller 29 is coupled to the receiver 18 and remotely coupled to the control point satellite uplink. The synchronization controller comprises a decoder (40) for decoding the timing information received from the base station to provide actual timing information, an absolute time source (28) that generates a reference time, a comparator (42) for comparing the actual timing information with the reference time to provide an offset signal (44) and a transmitter for forwarding the offset signal to the control point satellite uplink to adjust timing information at the control point satellite uplink.
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Citations
22 Claims
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1. A method for providing time synchronization in a non-real time messaging system, comprising the steps of:
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(a) receiving source information from a satellite, the source information having timing information and originating from a control point satellite uplink, the source information being received by a plurality of receivers remote from the control point satellite uplink; (b) receiving an absolute time reference coupled to one of the plurality of receivers; (c) generating an offset signal calculated from the difference between the absolute time reference and the timing information of the source information; (d) providing the control point satellite uplink with the offset signal in order to adjust the timing information to synchronize with the absolute time reference within subsequent source information transmissions from the control point satellite uplink. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for providing time synchronization in a non-real time messaging system, comprising the steps of:
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(a) receiving source information at a base station from a satellite, the source information having timing information and originating from a control point satellite uplink; (b) transmitting the source information from the base station using a synchronized time division protocol to a plurality of receivers remote from the control point satellite uplink; (c) receiving an absolute time reference coupled to one of the plurality of receivers; (d) generating an offset signal calculated from the difference between the absolute time reference and the timing information of the source information; (e) providing the control point satellite uplink with the offset signal in order to adjust the timing information to synchronize with the absolute time reference within subsequent source information transmissions from the control point satellite uplink. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for providing time synchronization in a non-real time messaging system using simulcast transmissions by a plurality of base stations, comprising the steps of:
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(a) receiving source information originating from a control point satellite uplink at a base station from a satellite, the source information having timing information derived from a Global Positioning System receiver coupled to the control point satellite uplink; (b) transmitting the source information from the base station using a FLEX synchronized time division protocol to a plurality of receivers remote from the control point satellite uplink; (c) receiving an absolute time reference at a Global Positioning System receiver coupled to one of the plurality of receivers; (d) generating an offset signal calculated from the difference between the absolute time reference and the timing information of the source information; (e) providing the control point satellite uplink with the offset signal in order to adjust the timing information to synchronize with the absolute time reference within subsequent source information transmissions from the control satellite uplink.
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14. A synchronization controller for use in a selective call messaging system, comprising:
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a decoder for decoding timing information received from a selective call transmitter base station to provide actual timing information; an absolute time source that generates a reference time, the absolute time source received from a Global Positioning System receiver; a comparator for comparing the actual timing information with the reference time to provide an offset signal, the offset signal further used to either offset a set of embedded time marks in future transmissions by the selective call base station transmitter or to offset a launch time by the selective call base station transmitter; and a transmitter for forwarding the offset signal to a control point satellite uplink to adjust timing information to synchronize with the absolute time source at the control point satellite uplink. - View Dependent Claims (15)
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16. A selective call messaging system, comprising:
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a control point satellite uplink for transmission of source information to a satellite, the source information having timing information; a base station for receiving the source information from the satellite and retransmitting the source information using a time division protocol; a receiver for receiving the source information as transmitted from the base station; and a synchronization controller coupled to the receiver and remotely coupled to the control point satellite uplink, comprising; a decoder for decoding the timing information received from the base station to provide actual timing information; an absolute time source that generates a reference time; a comparator for comparing the actual timing information with the reference time to provide an offset signal; a transmitter for forwarding the offset signal to the control point satellite uplink to adjust timing information to synchronize with the absolute time source at the control point satellite uplink. - View Dependent Claims (17, 18, 19, 20)
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21. A selective call messaging system, comprising:
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a control point satellite uplink for transmission of source information to a satellite, the source information having timing information encoded in a FLEX time division protocol; a base station for receiving the source information from the satellite and retransmitting the source information using the FLEX time division protocol; a fixed base receiver for receiving the source information as transmitted from the base station; a synchronization controller coupled to the fixed base receiver and remotely coupled to the control point satellite uplink, comprising; a decoder for decoding the timing information received from the base station and derived from the FLEX time division protocol to provide actual timing information; an absolute time source derived from a Global Positioning System receiver to generate a reference time; a comparator for comparing the actual timing information with the reference time to provide an offset signal; and a transmitter for forwarding the offset signal to the control point satellite uplink to adjust timing information to synchronize with the absolute time source at the control point satellite uplink.
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22. The synchronization controller for use in a selective call messaging system, comprising:
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a first phase lock loop for receiving an absolute time reference at the input of a first phase detector and creating a first divided down signal; a second phase lock loop for receiving the first divided down signal at a second phase detector and creating a second divided down signal; a multiplexer within the first phase lock loop for multiplexing the first divided down signal and the second divided down signal; and an algorithm for maintaining a constant phase difference between the first phase lock loop and the second phase lock loop.
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Specification