Method for detecting fraudulent use of a communication system

• US 5,777,558 A
• Filed: 02/29/1996
• Issued: 07/07/1998
• Est. Priority Date: 02/29/1996
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Pennypacker, Frank, Burke, Timothy M., Corrigan, Richard J.
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): TWEEL JR, JOHN ALEXANDER
• Application Number:
  US08/609,754
• Time in Patent Office: 859 Days
• Field of Search: 340/635, 379/62, 379/189, 379/59, 379/145, 379/95, 455/33.1, 380/23
• US Class Current: 340/635
• CPC Class Codes: H04M 15/00 Arrangements for metering, time-control or time indication ; Metering, charging or billing arrangements for voice wireline or wireless communications, e.g. VoIP
• CPC Class Codes: H04M 15/47 Fraud detection or prevention means
• CPC Class Codes: H04M 2215/0148 Fraud detection or prevention means
• CPC Class Codes: H04M 3/30 for subscriber's lines , for the local loop
• CPC Class Codes: H04M 3/36 Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks
• CPC Class Codes: H04W 12/126 Anti-theft arrangements, e.g. protection against subscriber identity module [SIM] cloning

Abstract

A method for detecting fraudulent use of a communication system (10) includes the steps of determining a system parameter associated with a subscriber unit (32). The system then compares the system parameter to a previous system parameter for the subscriber unit (32). An alarm is set when the system parameter differs more than a predetermined amount from the previous system parameter.

Claims

1. A method for detecting fraudulent use of a communication system, comprising the steps of:

(a) determining a system parameter associated with a subscriber unit;

(b) comparing the system parameter to a previous system parameter for the subscriber unit;

(c) when the system parameter differs more than a predetermined amount from the previous system parameter, setting an alarm condition;

(d) determining the system parameter for a plurality of neighboring subscriber units; and

(e) when the system parameter differs more than the predetermined amount from the previous system parameter for more than a predetermined number of the plurality of neighboring subscriber units, canceling the alarm condition.

2. The method of claim 1, wherein step (a) includes determining a time delay between a base and the subscriber unit.

3. The method of claim 1, wherein step (a) includes determining a required transmit power level for the subscriber unit.

4. The method of claim 1, wherein step (a) includes determining a number of responses to a base query of the subscriber unit.

5. The method of claim 1, wherein step (a) includes determining a distance between a base unit and the subscriber unit.

6. The method of claim 1, further including the step of:

(d) measuring a distance to the subscriber unit.

7. A method for detecting fraudulent use of a communication system, comprising the steps of:

(a) initiating a communication session by a base unit to a subscriber unit;

(b) counting a number of times the subscriber unit responds to an alert transmitted by the base unit;

(c) when the number of times exceeds a predetermined number, determining an alarm condition exists;

(d) determining a delta delay value between the base unit and the subscriber unit;

(e) when the delta delay value exceeds a predetermined delta delay value, determining the alarm condition exists;

(f) determining the delta delay value for a plurality of neighboring subscriber units; and

(g) when the delta delay value for more than a predetermined number of the plurality of neighboring subscriber units exceeds the predetermined delta delay value, canceling the alarm condition.

8. A method for detecting fraudulent use of a communication system, comprising the steps of:

(a) measuring a delta time delay between a base unit and a subscriber unit;

(b) measuring a delta transmit power for the subscriber unit;

(c) when the delta time delay exceeds a maximum delta time delay, setting an alarm;

(d) when the delta transmit power exceeds a maximum delta transmit power, setting the alarm;

(e) when the alarm is set, measuring the delta time delay for a plurality of neighboring subscriber units; and

(f) when the delta time delay for a predetermined number of the plurality of neighboring subscriber units exceeds the maximum delta time delay, canceling the alarm.

9. The method of claim 8, further including the steps of:

(e) when the alarm is set, measuring the delta transmit power for a plurality of neighboring subscriber units; and

(f) when the delta transmit power for a predetermined number of the plurality of neighboring subscriber units exceeds the maximum delta transmit power, canceling the alarm.

10. A method for detecting fraudulent use of a communication system, comprising the steps of:

(a) initiating a communication session by a base unit to a subscriber unit;

(b) counting a number of times the subscriber unit responds to an alert transmitted by the base unit;

(c) when the number of times exceeds a predetermined number, determining an alarm condition exists

(d) determining a delta transmit power for the subscriber unit; and

(e) when the delta transmit power exceeds a predetermined delta transmit power value, determining the alarm condition exists;

(f) determining the delta transmit power for a plurality of neighboring subscriber units; and

(g) when the delta transmit power for more than a predetermined number of the plurality of neighboring subscriber units exceeds the predetermined delta transmit power value, canceling the alarm condition.