Electronic device and method for blocking cellular communication
First Claim
1. A method for prevention of cellular telephone calls in a cellular communication system within a given area, said method comprising:
- determining a plurality of control frequency existing within the area for establishing cellular telephone calls, said at least one control frequency containing information thereon, said information being transmitted as coded signals and commands; and
generating an interference signal which interferes with said at least one control frequency by preventing decoding of said signals and commands, said interference signal preventing generation of handshake signals in the system, to prevent establishment of a cellular phone call with a portable cellular telephone, wherein said interference signal is generated continuously on said at least one control frequency; and
wherein generating comprises mixing said determined control frequency with a predetermined frequency to develop a phase modulated signal, wherein the interference signal blocks decoding of a forward control channel signal by introducing phase noise in said portable cellular telephone.
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Accused Products
Abstract
A method and device for achieving reliable prevention of cellular telephone calls, within a given area. In the preferred embodiment, the device and method operate to block the control frequencies of the cellular system within a given area. The device broadcasts a blocking signal with a low power output, which interferes with the reception ability and decoding of signals and commands broadcast at the control frequency. Thus, the handshake routine of the telephone/cellular subscriber with the local cellular system is prevented. Operation of the device is achieved in several ways, manually, automatically, and/or by remote control. Its operation prevents cellular communication ability by subscribers within the area or within the effective blocking range, which is derived from the effective radiated power (ERP) of the blocking signal, its type and the type of communications/or blocked system. Using the inventive device, a given area normally accessible by cellular communications is blocked from such access, thus providing a security-related, cultural or other safeguard. The given area is thereby isolated from cellular communications, and access can only be achieved by physically relocating the user of a blocked cellular telephone.
74 Citations
21 Claims
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1. A method for prevention of cellular telephone calls in a cellular communication system within a given area, said method comprising:
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determining a plurality of control frequency existing within the area for establishing cellular telephone calls, said at least one control frequency containing information thereon, said information being transmitted as coded signals and commands; and
generating an interference signal which interferes with said at least one control frequency by preventing decoding of said signals and commands, said interference signal preventing generation of handshake signals in the system, to prevent establishment of a cellular phone call with a portable cellular telephone, wherein said interference signal is generated continuously on said at least one control frequency; and
wherein generating comprises mixing said determined control frequency with a predetermined frequency to develop a phase modulated signal, wherein the interference signal blocks decoding of a forward control channel signal by introducing phase noise in said portable cellular telephone. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for prevention of cellular telephone calls in a communication system within a given area, said device comprising:
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means for determining at least one control frequency existing within the given area for establishing cellular telephone calls, said control frequency containing information transmitted thereon, said information being transmitted as coded signals and commands; and
means for generating a signal which interferes with said control frequency by preventing decoding of said signals and commands, said signal preventing generation of handshake signals in the system, to prevent establishment of a cellular telephone call, wherein said means for generating comprises a mixer for mixing said determined control frequency with a predetermined frequency to develop a phase modulated signal, which blocks decoding of a forward control channel signal by introducing phase noise in said portable cellular telephone. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A method for prevention of cellular telephone calls in a cellular communication system within a given area, said method comprising:
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determining control frequencies existing within the area for establishing cellular telephone calls, said frequencies containing information thereon, said information being transmitted as coded signals and commands; and
generating an interference signal which interferes with said control frequencies by preventing decoding of said signals and commands, said interference signal preventing generation of handshake signals in the system, to prevent establishment of a cellular phone call with a portable cellular telephone, wherein said interference signal is generated simultaneously on a plurality of said control frequencies.
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19. A device for prevention of cellular telephone calls in a communication system within a given area, said device comprising:
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means for determining at least one control frequency existing within the given area for establishing cellular telephone calls, said control frequency containing information transmitted thereon, said information being transmitted as coded signals and commands; and
means for generating a signal which interferes with said control frequency by preventing decoding of said signals and commands, said signal preventing generation of handshake signals in the system, to prevent establishment of a cellular telephone call, wherein said means for generating comprises a mixer for mixing said determined control frequency with a frequency representing the deviation between duplex forward and reverse control channel frequencies, thereby developing an unstable positive feedback in one of said control channel frequencies, and blocking decoding by introducing phase noise in said portable cellular telephone. - View Dependent Claims (20, 21)
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Specification