Mehtod and apparatus for fraud control in cellular telephone systems utilizing RF signature comparison
First Claim
1. An apparatus for preventing fraud in a cellular telephone system, comprising:
- (a) RF signature means, coupled to an antenna at a receiving site in the cellular telephone system, for receiving radio frequency (RF) signals from a cellular telephone and for representing the RF signals as a digital RF signature substantially unique to the radiotelephone; and
(b) a control processor, coupled to the RF signature means, for comparing the digital RF signature to a database of stored identifiers when a call is received from the cellular telephone, for determining whether the cellular telephone is fraudulent based on the comparison, and for interrupting the call from the cellular telephone when the comparison indicates that the cellular telephone is fraudulent.
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0 Petitions
Reexamination
Accused Products
Abstract
A method and apparatus for fraud control in cellular telephone systems. Call records from a switch are scanned to identify a fraudulent cellular phone based on its behavior. An identifier, e.g., a radio frequency (RF) signature, representative of the fraudulent phone is stored in a control channel editor at a cell site. A database of identifiers may comprise a positive validation database storing the identifiers for all valid phones used in the cellular telephone system, or it may be a negative validation database storing the identifiers for known fraudulent phones. A control channel editor intercepts a call origination request transmitted by a phone, and a control processor compares one or more characteristics of the phone transmitting the call origination request to the database of identifiers. The control processor then prevents the call origination request from completing when the comparison indicates that the phone is fraudulent. The call origination request can be prevented from completing by (1) re-routing the call to a customer service or "fraud hot line" number, (2) interrupting the call origination request, (3) transmitting a "hang-up" message to the phone, (4) transmitting a "hang-up" message to the cell site, or (5) transmitting a "tear-down" message to a switch
246 Citations
16 Claims
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1. An apparatus for preventing fraud in a cellular telephone system, comprising:
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(a) RF signature means, coupled to an antenna at a receiving site in the cellular telephone system, for receiving radio frequency (RF) signals from a cellular telephone and for representing the RF signals as a digital RF signature substantially unique to the radiotelephone; and (b) a control processor, coupled to the RF signature means, for comparing the digital RF signature to a database of stored identifiers when a call is received from the cellular telephone, for determining whether the cellular telephone is fraudulent based on the comparison, and for interrupting the call from the cellular telephone when the comparison indicates that the cellular telephone is fraudulent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for preventing fraudulent calls in a controlled access radiotelephone system, comprising the steps of:
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(a) scanning call records from a switch to identify fraudulent radiotelephones based on their behavior; (b) storing an identifier for each of the fraudulent radiotelephones in an electronic memory, wherein the identifier is a digital radio frequency (RF) signature representative of a characteristic of RF signals transmitted by the fraudulent radiotelephone; (c) receiving a call transmitted from a radiotelephone; (d) detecting the characteristic of the RF signals transmitted by the radiotelephone transmitting the call; (e) generating the digital RF signature from the detected characteristic; (f) comparing the digital RF signature to the stored identifiers in the electronic memory; and (f) preventing the call from completing when the comparison indicates that the radiotelephone is fraudulent. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification