METHOD AND SYSTEM FOR SYNCHRONISING STATIONS WITHIN COMMUNICATIONS NETWORKS AND STATIONS FOR USE THEREIN
First Claim
1. A system for synchronising stations in a communications network comprising:
- at least one airborne or space-based vehicle; and
at least two stations, each station having receiver means in data communication with the at least one airborne or space-based vehicle and control means in data communication with the receiver means and in control communication with a communication means,where, when each receiver means receives a synchronisation signal from the at least one airborne or space-based vehicle;
each receiver means forwards the synchronisation signal to its respective control means;
each control means processes the synchronisation signal to determine the operational frequency required by its respective communication means to maintain or establish communication with the other station; and
each control means controls its respective communication means to change to the determined operational frequency.
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Accused Products
Abstract
A system for synchronising stations in a communications network comprising: at least one airborne or space-based vehicle; and at least two stations, each station having receiver means in data communication with the at least one airborne or space-based vehicle and control means in data communication with the receiver means and in control communication with a communication means. When each receiver means receives a synchronisation signal from the at least one airborne or space-based vehicle each receiver means forwards the synchronisation signal to its respective control means. The respective control means processes the synchronisation signal to determine the operational frequency required by its respective communication means to maintain or establish communication with the other station. The respective control means also operates to control its respective communication means to change to the determined operational frequency.
25 Citations
56 Claims
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1. A system for synchronising stations in a communications network comprising:
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at least one airborne or space-based vehicle; and at least two stations, each station having receiver means in data communication with the at least one airborne or space-based vehicle and control means in data communication with the receiver means and in control communication with a communication means, where, when each receiver means receives a synchronisation signal from the at least one airborne or space-based vehicle; each receiver means forwards the synchronisation signal to its respective control means; each control means processes the synchronisation signal to determine the operational frequency required by its respective communication means to maintain or establish communication with the other station; and each control means controls its respective communication means to change to the determined operational frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
where; F=the new operational frequency Fb=the start frequency of the hopping band currently being used for transmission, as determined by values stored in reference table; C=the present value of the pseudo-random algorithm, or a part thereof; Fr=the maximum allowable range of frequency hop in Hz; and Y=2(the number of bits used by C)
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7. A system for synchronising stations in a computer system according to claim 6, where Y=256.
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8. A system for synchronising stations in a communications network according to claim 2, where the iterated value of the pseudo-random algorithm is cross-referenced with a frequency table to determine the operational frequency required to maintain or establish communication with the other station.
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9. A system for synchronising stations in a communications network according to any one of claims 2 to 8, as dependent on claim 2, where each station includes a synchronisation unit for emitting a synchronisation pulse, and where the synchronisation signal includes time information, the time information being used to calibrate the synchronisation unit and the pseudo-random algorithm being iterated on receipt of each synchronisation pulse.
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10. A system for synchronising stations in a communications network according to claim 9, where the synchronisation unit emits a predetermined number of synchronisation pulses (R) a second.
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11. A system for synchronising stations in a communications network according to claim 10, where R is in the range 5≦
- R≦
10.
- R≦
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12. A system for synchronising stations in a communications network according to claim 11, where R=5.
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13. A system for synchronising stations in a communications network according to any one of claims 2 to 12, as dependent on claim 2, where, when a new station joins the communications network, synchronisation of the new station with existing stations is attained by setting the value of the pseudo-random algorithm to the initial code and iterating the pseudo-random algorithm according to the formula:
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I=S×
Rwhere; I=number of iterations of the pseudo-random algorithm to be performed; S=number of seconds that have passed since the last predetermined amount of time elapsed; and R=the predetermined number of synchronisation pulses a second.
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14. A system for synchronising stations in a communications network according to any one of claims 2 to 13, as dependent on claim 2, where after a predetermined amount of time the pseudo-random algorithm resets its value to equal an initial code, the initial code being the initial value of the pseudo-random algorithm.
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15. A system for synchronising stations in a communications network according to claim 14, where the predetermined amount of time is 24 hours.
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16. A system for synchronising stations in a communications network according to claim 15 and any one of claims 10 to 12, where the pseudo-random algorithm performs at least 86400×
- R iterations before repeating.
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17. A system for synchronising stations in a communications network according to claim 4, where the control means operates to avoid determining an operational frequency falling within at least one predetermined hopping band.
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18. A system for synchronising stations in a communications network according to any one of claims 2 to 17, as dependent on claim 2, where the pseudo-random algorithm is at least a 31 bit algorithm.
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19. A system for synchronising stations in a communications network according to any one of claims 2 to 18, as dependent on claim 2, where, when the pseudo-random algorithm has a value equal to an initial code, the initial code being the initial value of the pseudo-random algorithm, the control means operates to iterate the pseudo-random algorithm a predetermined number of times.
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20. A system for synchronising stations in a communications network according to any one of claims 2 to 19, as dependent on claim 2, where the pseudo-random algorithm is based on the Digital Encryption Standard algorithm.
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21. A system for synchronising stations in a communications network according to claim 1, where the synchronisation signal includes time information and the time information is cross-referenced with a frequency table to determine the operational frequency required to maintain or establish communication with the other station.
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22. A system for synchronising stations in a communications network according to any preceding claim, where the communication means is a transceiver;
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23. A system for synchronising stations in a communications network according to any one of claims 1 to 21, where the communication means of at least one station is a transmitter or transceiver and the communication means of at least one station is a receiver.
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24. A system for synchronising stations in a communications network according to any preceding claim, where the at least one airborne or space-based vehicle is the global positioning system network of satellites.
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25. A system for synchronising stations in a communications network according to any one of claims 1 to 23, where the at least one airborne or space-based vehicle is a geosynchronous satellite.
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26. A system for synchronising stations in a communications network according to any one of claims 2 to 26, as dependent on claim 2, where each station includes a data input means, data input using the data input means operable to seed the pseudo-random algorithm with an initial value.
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27. A system for synchronising stations in a communications network according to any preceding claim, where each station also has a unique identification code and where, when one station, a calling station, communicates with another station, a receiving station:
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the calling station transmits a communication message including the unique identification codes of the calling station and receiving station on each frequency in a predetermined set of frequencies, commencing with the operational frequency; the receiving station records a value of at least one attribute in respect of the transmission signal encapsulating the communication message for each frequency in the predetermined set of frequencies; the receiving station sends a reply communication message including the unique identification codes of the calling station and receiving station on the frequency having the best recorded value or best combination of recorded values; and the calling station scans each frequency in the predetermined set of frequencies until the frequency on which the reply communication message has been sent is received, communications between calling station and receiving station thereafter continuing on that frequency.
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28. A system for synchronising stations in a communications network according to claim 27, where the calling station transmits a communication message including the unique identification codes of the calling station and receiving station on each frequency in a predetermined set of frequencies twice and where the receiving station records the best value of the at least one attribute in respect of the two transmission signals encapsulating the communication message for each frequency in the predetermined set of frequencies.
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29. A system for synchronising stations in a communications network according to claim 27 or claim 28, where the at least one attribute includes is at least one of the following:
- signal strength;
bit error rate.
- signal strength;
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30. A station for use in a system for synchronising stations in a communication network according to any preceding claim.
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31. A method of synchronising stations in a communications network comprising:
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receiving, at a first station, a synchronisation signal from at least one airborne or space-based vehicle; processing the synchronisation signal to determine the operational frequency required to maintain of establish communication with another station; and changing a communication means to communicate on the operational frequency. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A system for synchronising stations in a communications network substantially as described herein with reference to the drawings.
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55. A method of synchronising stations in a communications network substantially as described herein with reference to the drawings.
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56. A station for use in a system for synchronising stations in a communications network substantially as described herein with reference to the drawings.
Specification