CLIAMS:We claim:
1. A method for implementing in-band dual-tone multi-frequency call interception, comprising:
receiving a call intercept request for a target user number at a soft switch;
initiating, by one or more processors, call monitoring of a call from a calling user to a call proxy system to capture in-band dual-tone multi-frequency signaling; and
determining whether the dual-tone multi-frequency signaling corresponds to the target user number.
2. The method of claim 1, further comprising:
initiating lawful interception for the call, after determining that the dual-tone multi-frequency signaling corresponds to the target user number.
3. The method of claim 1, further comprising:
determining whether the call is being initiated to the target user number, after determining that the dual-tone multi-frequency signaling corresponds to the target user number.
4. The method of claim 1, wherein:
the call intercept request is by a law enforcement agency.
5. The method of claim 1, wherein:
determining whether the dual-tone multi-frequency signaling corresponds to the target user number is based on at least one of: an inter-digit interval, an interval between a tone and the start of the dual-tone multi-frequency signal, tones of the dual-tone multi-frequency signaling, or whether any real-time transport protocol packets are exchanged between one or more digit tones.
6. The method of claim 5, wherein:
the inter-digit interval threshold and the threshold interval between the tone and the start of the dual-tone multi-frequency signaling is dynamically adapted based on at least one of: a distance of the calling user from the media gateway, a distance of the call proxy system from the media gateway, and a congestion level of a path in the network over which media content for the call is transported.
7. The method of claim 6, wherein:
the dual-tone multi-frequency signaling includes in-band audio signals on a public switched telephone network or a public land mobile network.
8. The method of claim 6, wherein:
the dual-tone multi-frequency signaling is at least one of an audio signal in a packet payload or specific dual-tone multi frequency coding in real-time packet protocol packets.
9. The method of claim 1, further comprising:
determining a confidence level for a match between the in-band dual-tone multi-frequency signaling and the target user number; and
determining that the in-band dual-tone multi-frequency signaling includes the target user number comprises determining that the confidence level exceeds a first predefined threshold.
10. The method of claim 9, wherein:
when the confidence level does not exceed the first predefined threshold and does exceed a second predefined threshold, initiating communication of signaling information, but not media content, and not initiating call recording for the call, and
the first predefined threshold corresponds to a higher confidence level than the second predefined threshold.
11. The method of claim 10, wherein:
when the confidence level exceeds the first predefined threshold, initiating communication of signaling information and media content, and initiating call recording for the call.
12. The method of claim 11, wherein:
the confidence level is based on the in-band dual-tone multi-frequency signaling and call history data for at least one of: the calling user and a called user.
13. A method for implementing proxy call interception, comprising:
receiving a call intercept request for a target user number at a soft switch;
initiating, by one or more processors, call monitoring of a call from a calling user to a call proxy system to capture signaling plane data; and
determining whether the signaling plane data transmitted after initial call setup of the call corresponds to the target user number.
14. A method for implementing in-band dual-tone multi-frequency call interception, comprising:
receiving a call intercept request for a target user number at a soft switch;
sending, by one or more processors, to a neighboring media gateway controller, a request for call monitoring of a call from a calling user to a call proxy system to capture in-band dual-tone multi-frequency signaling;
receiving, by the one or more processors, from the neighboring media gateway controller, the in-band multi-frequency signaling; and
determining whether the dual-tone multi-frequency signaling corresponds to the target user number.
15. The method of claim 14, further comprising:
initiating lawful interception for the call, after determining that the dual-tone multi-frequency signaling corresponds to the target user number.
16. The method of claim 14, wherein:
the in-band dual-tone multi-frequency signaling is received over an extended interface.
17. The method of claim 16, wherein:
the in-band dual-tone multi-frequency signaling is received in an enhanced Signal Initiation Protocol INFO message.
18. The method of claim 14, wherein:
the neighboring media gateway controller is a neighboring node on the signal path.
19. The method of claim 14, further comprising:
responsive to determining that the dual-tone multi-frequency signaling includes the target user number, determining whether the call is being initiated to the target user number.
20. The method of claim 19, wherein:
the call intercept request is an interception from a law enforcement agency.
21. The method of claim 20, wherein:
determining whether the dual-tone multi-frequency signaling corresponds to the target user number is based on at least one of: an inter-digit interval threshold, a threshold interval between a tone and the start of the dual-tone multi-frequency signal, the tones of the dual-tone multi-frequency signaling, or whether any real-time transport protocol packets are exchanged between one or more digit tones.
22. The method of claim 21, wherein:
the inter-digit interval threshold and the threshold interval between the tone and the start of the dual-tone multi-frequency signaling is dynamically adapted based on at least one of: a distance of the calling user from the media gateway, a distance of the call proxy system from the media gateway, and a congestion level of a path in the network over which media content for the call is transported.
Dated this 13th day of February, 2015
Swetha S.N
Of K&S Partners
Agent for the Applicant
,TagSPECI:TECHNICAL FIELD
This disclosure relates generally to call interception techniques, and more particularly to systems and methods for improved lawful interceptions for calls involving in-band DTMF signaling.