System and method for geography-based correlation of cellular and WLAN identifiers
Methods and systems for tracking mobile communication terminals based on their identifiers. The disclosed techniques identify cellular terminals and Wireless Local Area Network (WLAN) terminals that are likely to be carried by the same individual, or cellular and WLAN identifiers that belong to the same multi-mode terminal. A correlation system is connected to a cellular network and to a WLAN. The system receives location coordinates of cellular identifiers used by mobile terminals in the cellular network, and location coordinates of WLAN identifiers used by mobile terminals in the WLAN. Based on the location coordinates, the system is able to construct routes that are traversed by the terminals having the various cellular and WLAN identifiers. The system attempts to find correlations in time and space between the routes.
1. A method for determining a WLAN identifier for a target terminal that communicates on both a cellular network and a wireless local area network (WLAN), the method comprising:
obtaining:
a location of the target terminal in the cellular network from a cellular identifier for the target terminal, and
locations of candidate terminals in the WLAN from WLAN identifiers for the candidate terminals;
comparing the location of the target terminal in the cellular network to the locations of the candidate terminals in the WLAN;
identifying, based on the comparison, candidate terminals in the vicinity of the target terminal at the same time;
repeating the obtaining, comparing, and identifying to determine the WLAN identifier of the target terminal.
2. The method according to claim 1 , wherein the repeating the obtaining, comparing and identifying to determine the WLAN identifier of the target terminal comprises:
eliminating, after each repetition, candidate terminals that were not identified in previous repetitions until one candidate terminal remains; and
determining the WLAN identifier of the target terminal as the WLAN identifier for the one remaining candidate terminal.
3. The method according to claim 1 , wherein the repeating the obtaining, comparing and identifying to determine the WLAN identifier of the target terminal comprises:
eliminating, after each repetition, candidate terminals that were not identified in previous repetitions until no candidate terminal remains; and
determining that the target terminal has no matching WLAN identifier.
4. The method according to claim 1 , wherein the repeating the obtaining, comparing and identifying to determine the WLAN identifier of the target terminal comprises:
computing a confidence level for each candidate terminal, wherein each confidence level for a particular candidate terminal corresponds to the number of repetitions that each the particular candidate terminal is in the vicinity of the target terminal at the same time; and
determining the WLAN identifier of the target terminal as the WLAN identifier for a candidate terminal having a confidence level above a threshold.
5. The method according to claim 4 , wherein the repeating is over a predefined length of a route.
6. The method according to claim 4 , wherein the repeating is during a predefined time interval.
7. The method according to claim 1 , further comprising:
receiving the cellular identifier for the target terminal from a monitoring center; and
communicating the WLAN identifier of the target terminal to the monitoring center.
8. The method according to claim 1 , further comprising:
tracking a target individual's location or network activity using the determined WLAN identifier.
9. The method according to claim 1 , wherein the cellular identifier comprises an international mobile subscriber identity (IMSI), a temporary mobile subscriber identity (TMSI), an international mobile equipment identity (IMEI), or a mobile station international subscriber directory number (MSISDN) of a mobile phone.
10. The method according to claim 1 , wherein the WLAN identifier comprises a medium accesses control (MAC) address or an internet protocol (IP) address of a mobile phone.
11. A system for obtaining a WLAN identifier for a target terminal that communicates on both a cellular network and a wireless local area network (WLAN), the system comprising
a cell interface connected to a cellular network and receiving cellular identifiers from terminals communicating on the cellular network;
a WLAN interface connected to one or more WLANs and receiving WLAN identifiers from terminals communicating on the one or more WLANs;
electronic memory storing software and data;
a correlation processor in communication with the cell interface, WLAN interface, and electronic memory, wherein upon execution, the software causes the processor to:
obtain a location of the target terminal in the cellular network from a cellular identifier for the target terminal, and locations of candidate terminals in the WLAN from WLAN identifiers for the candidate terminals;
compare the location of the target terminal in the cellular network to the locations of the candidate terminals in the WLAN;
identify, based on the comparison, candidate terminals in the vicinity of the target terminal at the same time;
repeat obtaining, comparing, and identifying to determine the WLAN identifier of the target terminal.
12. The system according to claim 11 , wherein the operation to repeat obtaining, comparing, and identifying to determine the WLAN identifier of the target terminal, comprises:
eliminating, after each repetition, candidate terminals that were not identified in previous repetitions until one candidate terminal remains; and
determining the WLAN identifier of the target terminal as the WLAN identifier for the one remaining candidate terminal.
13. The system according to claim 11 , wherein, the operation to repeat obtaining, comparing, and identifying to determine the WLAN identifier of the target terminal comprises:
eliminating, after each repetition, candidate terminals that were not identified in previous repetitions until no candidate terminal remains; and
determining that the target terminal has no matching WLAN identifier.
14. The system according to claim 11 , wherein, the operation to repeat obtaining, comparing, and identifying to determine the WLAN identifier of the target terminal comprises:
computing a confidence level for each candidate terminal, wherein each confidence level for a particular candidate terminal corresponds to the number of repetitions that each the particular candidate terminal is in the vicinity of the target terminal at the same time; and
determining the WLAN identifier of the target terminal as the WLAN identifier for a candidate terminal having a confidence level above a threshold.
15. The system according to claim 14 , wherein the repeating is over a predefined length of a route.
16. The system according to claim 14 , wherein the repeating is during a predefined time interval.
17. The system according to claim 11 , wherein the software further causes the processor to:
receive the cellular identifier for the target terminal from a monitoring center; and
communicate the WLAN identifier of the target terminal to the monitoring center.
18. The system according to claim 11 , wherein the software further causes the processor to:
track a target individual's location or network activity using the determined WLAN identifier.
19. The system according to claim 11 , wherein the cellular identifier comprises an international mobile subscriber identity (IMSI), a temporary mobile subscriber identity (TMSI), an international mobile equipment identity (IMEI), or a mobile station international subscriber directory number (MSISDN) of a mobile phone.
20. The system according to claim 11 , wherein the WLAN identifier comprises a medium accesses control (MAC) address or an internet protocol (IP) address of a mobile phone.