Method for establishing DAMA radiotelephone conversations by single-span satellite transmission
First Claim
1. A method for establishing DAMA radiotelephone conversations by single-span satellite transmission between subscribers of peripheral stations forming part of a system having a central station on the ground and a plurality of peripheral stations, comprising the steps of:
- causing the central station to transmit a synchronization signal, at least within the time intervals during which the peripheral stations are capable of calling the central station, on a specialized unidirectional channel which is common to the entire communication system and is designated as a "presentation-event synchronization channel" (PESC), andcausing each of the requests randomly presented by said peripheral stations for establishment and/or interruption of communications to be transmitted by said peripheral stations in synchronism at a predetermined time with respect to said synchronization signal so as to avoid conflicts arising from simultaneous call demands.
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Accused Products
Abstract
In a radiotelephone system comprising a ground central station and a plurality of peripheral stations having access to a geostationary satellite, demand-assignment multiple-access (DAMA) conversations are established by single-span transmission between subscribers of the peripheral stations. In order to prevent conflicts arising from two simultaneous call demands, a rectangular-wave synchronization signal is transmitted by the central station to the peripheral stations in a specialized channel and the demands are caused to coincide with the active wavefronts of the synchronization signal.
42 Citations
8 Claims
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1. A method for establishing DAMA radiotelephone conversations by single-span satellite transmission between subscribers of peripheral stations forming part of a system having a central station on the ground and a plurality of peripheral stations, comprising the steps of:
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causing the central station to transmit a synchronization signal, at least within the time intervals during which the peripheral stations are capable of calling the central station, on a specialized unidirectional channel which is common to the entire communication system and is designated as a "presentation-event synchronization channel" (PESC), and causing each of the requests randomly presented by said peripheral stations for establishment and/or interruption of communications to be transmitted by said peripheral stations in synchronism at a predetermined time with respect to said synchronization signal so as to avoid conflicts arising from simultaneous call demands. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A communication system for establishing DAMA radiotelephone conversations by single-span satellite transmission between subscribers of a plurality of peripheral stations each having intermediate-frequency modulators/demodulators of the single-channel-per-carrier (SCPC) type, telephone junctor circuits and ringer circuits and a central station comprising:
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means at the central station for transmitting a synchronization signal, at least within the time intervals during which the peripheral stations are capable of calling the central station, on a specialized unidirectional channel common to each of said peripheral stations, means at the central station for inserting messages in said synchronization signal, DAMA circuit means at each peripheral station coupled to said modulators/demodulators and said junctor and ringer circuits for controlling and interfacing said SCPC channels for causing randomly presented requests by said peripheral stations to be transmitted at a given time with respect to said synchronization signal to avoid conflicts arising from simultaneous call demands. - View Dependent Claims (8)
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Specification