Cellular telephone anti-fraud system
First Claim
1. A transmitter identification system for identifying a transmitter which produces a transmitter signal in which information is encoded by manipulating a carrier, the transmitter signal including external signal traits resulting from said manipulation that are characteristic of said transmitter, comprising:
- receiving means located remote from said transmitter for receiving said transmitter signal;
characterizing means connected to said receiving means for generating a plurality of characterizing signals for said transmitter by measuring features of said external signal traits resulting from said manipulation that are characteristic of said transmitter; and
converting means connected to said characterizing means for converting said plurality of characterizing signals into a current security pattern wherein said current security pattern is used to identify said transmitter,wherein said converting means produces said current security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, andwherein a feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows;
(a) if said characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division;
(b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and
(c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said features codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values.
11 Assignments
0 Petitions
Accused Products
Abstract
Authorized use of a wireless subscriber system, e.g. cellular telephone system, is distinguished from unauthorized use by electronically observing a plurality of external signal traits which represent alterations in the radio frequency signal due to physical characteristics identified with a particular transmitter. Examples of such external signal traits include those which are produced as a consequence of manipulating the carrier to encode information upon it and those produced by transmitter timing circuit idiosyncrasies. The external signal traits are converted into a signature code or security pattern which is then stored along with the existing subscriber system identification code to generate a historic security pattern database for use in subsequent authorized use validation.
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Citations
44 Claims
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1. A transmitter identification system for identifying a transmitter which produces a transmitter signal in which information is encoded by manipulating a carrier, the transmitter signal including external signal traits resulting from said manipulation that are characteristic of said transmitter, comprising:
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receiving means located remote from said transmitter for receiving said transmitter signal; characterizing means connected to said receiving means for generating a plurality of characterizing signals for said transmitter by measuring features of said external signal traits resulting from said manipulation that are characteristic of said transmitter; and converting means connected to said characterizing means for converting said plurality of characterizing signals into a current security pattern wherein said current security pattern is used to identify said transmitter, wherein said converting means produces said current security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, and wherein a feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows; (a) if said characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division; (b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and (c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said features codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values. - View Dependent Claims (2, 3)
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4. Apparatus for identifying a wireless subscriber unit and for granting or denying said wireless subscriber unit access to a subscriber service, said wireless subscriber unit generating a wireless subscriber signal in which data is encoded by manipulating a carrier, said wireless subscriber signal containing external signal traits resulting from said manipulation that are characteristic of said wireless subscriber unit, and said data including an identification code, comprising:
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receiving and transmitting means located remote from said wireless subscriber unit for receiving said wireless subscriber signal; characterizing means connected to said receiving and transmitting means for generating a plurality of characterizing signals for said wireless subscriber unit by measuring features of said external signal traits resulting from said manipulation that are characteristic of said wireless subscriber unit; and converting means connected to said characterizing means for converting said plurality of characterizing signals into a current security pattern wherein said current security pattern and said identification code are used to identify said wireless subscriber unit, wherein said converting means produces said current security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, and wherein a feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows; (a) if said characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division; (b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and (c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said feature codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 25, 26)
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23. Apparatus for identifying a wireless subscriber unit and for granting or denying said wireless subscriber unit access to a subscriber service, said wireless subscriber unit generating a wireless subscriber signal in which data is encoded by manipulating a carrier, the wireless subscriber signal containing external signal traits resulting from said manipulation that are characteristic of said wireless subscriber unit, and said data including an identification code, comprising:
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receiving and transmitting means located remote from said wireless subscriber unit for receiving said wireless subscriber signal; characterizing means connected to said receiving and transmitting means for generating a plurality of characterizing signals for said wireless subscriber unit by measuring features of said external signal traits resulting from said manipulation that are characteristic of said wireless subscriber unit; converting means connected to said characterizing means for converting said plurality of characterizing signals into a current security pattern, wherein said current security pattern and said identification code are used to identify said wireless subscriber unit, wherein said converting means produces said current security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, and wherein a feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows; (a) if said characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division; (b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and (c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said feature codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values; historic security pattern storing means for storing historic security patterns, each including a plurality of feature codes, for a plurality of wireless subscriber units; first comparing means connected to said converting means and said historic security pattern storing means for comparing each of said feature codes of said current security pattern of said wireless subscriber unit to corresponding feature codes of at least one of said wireless subscriber units stored in said historic security pattern storing means corresponding to said identification code of said wireless subscriber unit, wherein said first comparing means generates feature confidence levels, separately for each feature, related to a difference between each of said feature codes of said current security pattern and said corresponding feature codes of said at least one of said historic security patterns, and wherein said first comparing means generates an overall wireless subscriber unit confidence level from said feature confidence levels; access means connected to said first comparing means for granting or denying access to said wireless subscriber unit to said subscriber service based upon said overall wireless subscriber unit confidence level.
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24. A method for identifying a wireless subscriber unit and for granting or denying said wireless subscriber unit access to a subscriber service, said wireless subscriber unit generating a wireless subscriber signal in which data is encoded by manipulating a carrier, the wireless subscriber signal containing external signal traits resulting from said manipulation that are characteristic of said wireless subscriber unit, and said data including an identification code, comprising the steps of:
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providing receiving and transmitting means located remote from said wireless subscriber unit for receiving said wireless subscriber signal; characterizing said wireless subscriber unit by generating a plurality of characterizing signals for said wireless subscriber unit by measuring a plurality of features of said external signal traits resulting from said manipulation that are characteristic of said wireless subscriber unit; converting said plurality of characterizing signals to a security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, and wherein a feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows; (a) if said characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division; (b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and (c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said feature codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values; storing said security pattern and said identification code in an ordered relationship; subsequently utilizing said security pattern to grant or deny access to said subscriber service to a requesting wireless subscriber unit with same identification code. - View Dependent Claims (27, 28)
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29. A transmitter identification system for identifying a transmitter which produces a transmitter signal in which information is encoded by manipulating a carrier, the transmitter signal including external signal traits resulting from transmitter timing idiosyncrasies that are characteristic of said transmitter, comprising:
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receiving means located remote from said transmitter for receiving said transmitter signal; characterizing means connected to said receiving means for generating a plurality of characterizing signals for said transmitter by measuring features of said external signal traits resulting from said transmitter timing idiosyncrasies that are characteristic of said transmitter; and converting means connected to said characterizing means for converting said plurality of characterizing signals into a current security pattern wherein said current security pattern is used to identify said transmitter, wherein said converting means produces said current security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, and wherein a feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows; (a) if said characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division; (b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and (c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said feature codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values. - View Dependent Claims (30, 31)
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32. Apparatus for identifying a wireless subscriber unit and for granting or denying said wireless subscriber unit access to a subscriber service, said wireless subscriber unit generating a wireless subscriber signal in which data is encoded by manipulating a carrier, said wireless subscriber signal containing external signal traits resulting from wireless subscribing unit timing idiosyncrasies that are characteristic of said wireless subscriber unit, and said data including an identification code, comprising:
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receiving and transmitting means located remote from said wireless subscriber unit for receiving said wireless subscriber signal; characterizing means connected to said receiving and transmitting means for generating a plurality of characterizing signals for said wireless subscriber unit by measuring features of said external signal traits resulting from said wireless subscriber unit timing idiosyncrasies that are characteristic of said wireless subscriber unit; and converting means connected to said characterizing means for converting said plurality of characterizing signals into a current security pattern wherein said current security pattern and said identification code are used to identify said wireless subscriber unit, wherein said converting means produces said current security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, and wherein said feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows; (a) if a characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division; (b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and (c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said feature codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. Apparatus for identifying a wireless subscriber unit and for granting or denying said wireless subscriber unit access to a subscriber service, said wireless subscriber unit generating a wireless subscriber signal in which data is encoded by manipulating a carrier, the wireless subscriber signal containing external signal traits resulting from wireless subscriber unit timing idiosyncrasies that are characteristic of said wireless subscriber unit and said data including an identification code, comprising:
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receiving and transmitting means located remote from said wireless subscriber unit for receiving said wireless subscriber signal; characterizing means connected to said receiving and transmitting means for generating a plurality of characterizing signals for said wireless subscriber unit by measuring features of said external signal traits resulting from said wireless subscriber unit timing idiosyncrasies that are characteristic of said wireless subscriber unit; converting means connected to said characterizing means for converting said plurality of characterizing signals into a current security pattern, wherein said current security pattern and said identification code are used to identify said wireless subscriber unit, wherein said converting means produces said current security pattern by generating feature codes for said plurality of characterizing signals by establishing, separately for each feature, a scale dividing a range of possible values of a characterizing signal for said feature into a predetermined number of divisions, each division being associated with a unique code, said scale divisions including an upper division and a lower division, and wherein a feature code for said feature is produced by assigning said characterizing signal to one of said predetermined number of divisions, as follows; (a) if said characterizing signal is above a first predetermined value, assigning said characterizing signal a feature code corresponding to said upper division; (b) if said characterizing signal is below a second predetermined value, assigning said characterizing signal a feature code corresponding to said lower division; and (c) if said characterizing signal is not above said first predetermined value and not below said second predetermined value, assigning said characterizing signal a feature code, intermediate said feature codes which fall between said upper and lower divisions, reflecting the relationship said characterizing signal bears to said first and second predetermined values; historic security pattern storing means for storing historic security patterns, each including a plurality of feature codes, for a plurality of wireless subscriber units; first comparing means connected to said converting means and said historic security pattern storing means for comparing each of said feature codes of said current security pattern to corresponding feature codes of at least one of said wireless subscriber units stored in said historic security pattern storing means corresponding to said identification code of said wireless subscriber unit, wherein said first comparing means generates feature confidence levels, separately for each feature, related to a difference between each of said feature codes of said current security pattern and said corresponding feature codes of said at least one of said historic security patterns, and wherein said first comparing means generates an overall wireless subscriber unit confidence level from said feature confidence level; access means connected to said first comparing means for granting or denying access to said wireless subscriber unit to said subscriber service based upon said overall wireless subscriber unit confidence level.
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Specification