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EP-4498666-B1 - METHOD, APPARATUS AND COMPUTER PROGRAM FOR MONITORING TELEPHONE CALLS

EP4498666B1EP 4498666 B1EP4498666 B1EP 4498666B1EP-4498666-B1

Inventors

  • MINOW, Jascha
  • JAHN, CARL
  • EL-MALLOUKI, Said

Dates

Publication Date
20260513
Application Date
20230725

Claims (14)

  1. Method for monitoring telephone calls, the method comprising the following steps: Determining (10) that a telephone call is being made from an originator to a recipient, wherein the originator and the recipient are each associated with a subscriber identifier, TNI, in a list of subscriber identifiers (2000), wherein each TNI (100, 200, 300, 400) from the list of subscriber identifiers is associated with an interaction set of further subscriber identifiers (120, 220, 320, 420), and wherein each of these associations comprises an interaction metric (123, 124; 321, 324; 421, 423) with respect to the TNI and the respective further TNI of the interaction set; Determining (20) a call metric for the telephone call, based on the interaction set of the originator TNI and the interaction set of the recipient TNI; Processing (30) the telephone call based on the call metric, wherein the processing comprises at least one of forwarding to the recipient or not forwarding the telephone call, wherein the call metric is reduced relative to the interaction metric of the originator with respect to the recipient, if a call volume in the telephony service network exceeds a network load threshold.
  2. Method according to claim 1, further comprising: Updating (40) the interaction set associated with the originator and/or the recipient based on at least one parameter of the telephone call, wherein the updating preferably comprises an adjustment of the interaction metric.
  3. Method according to claim 2, wherein the at least one parameter of the telephone call comprises the acceptance or non-acceptance of the telephone call by the recipient, or the duration of the conversation.
  4. Method according to any one of claims 2 or 3, wherein the interaction set (220) of further subscriber identifiers associated with the originator TNI does not comprise an association of the recipient TNI, and the updating (40) of the interaction set associated with the originator and/or the recipient comprises an inclusion of the recipient TNI in the interaction set associated with the originator TNI and/or an inclusion of the originator TNI in the interaction set associated with the recipient TNI.
  5. Method according to any one of claims 2 to 4, wherein the updating (40) of the interaction set associated with the originator and/or the recipient comprises increasing the interaction metric of the originator with respect to the recipient, if the telephone call was accepted.
  6. Method according to claim 5, wherein the increase depends on the duration of the telephone call.
  7. Method according to any one of claims 2 to 4, wherein the updating (40) of the interaction set associated with the originator and/or the recipient comprises decreasing the interaction metric of the originator with respect to the recipient, if the call was not accepted, was rejected by the recipient, or if the duration of the call was shorter than a call duration threshold.
  8. Method according to any one of claims 2 to 7, wherein the updating (40) of the interaction set associated with the originator and/or the recipient comprises: Determining a first number of TNIs in the interaction set of the originator that have received at least one incoming call; Determining a second number of TNIs in the interaction set of the originator that have only outgoing calls from the originator; wherein the interaction metric of the originator with respect to the recipient is increased if the ratio of the first number to the second number is above a call direction threshold.
  9. Method according to any one of the preceding claims, wherein determining the call metric comprises: Determining a first number of TNIs in the interaction set of the originator that have received at least one incoming call; Determining a second number of TNIs in the interaction set of the originator that have only outgoing calls from the originator; wherein the call metric is increased relative to the interaction metric of the originator with respect to the recipient, if the ratio of the first number to the second number is above a call direction threshold.
  10. Method according to any one of the preceding claims, wherein determining the call metric is obtainable by: Mapping a relationship between the recipient TNI and the originator TNI in a tree diagram; Determining whether the recipient TNI is obtainable as a result of an N-level search in the tree diagram, starting from the originator TNI or the interaction set associated with the originator TNI.
  11. Method according to claim 10, wherein the call metric is not changed or is reduced relative to the interaction metric of the originator with respect to the recipient, if the number N of the search corresponds to more than a threshold value of levels.
  12. Method according to claim 10, wherein the call metric is increased relative to the interaction metric of the originator with respect to the recipient, in accordance with a frequency indicating how often the recipient TNI is obtainable in a level of the search.
  13. Device comprising means configured to carry out the method according to any one of claims 1 to 12.
  14. Computer program comprising program instructions which, when the program is executed by a computer, cause the computer to carry out all steps of the method according to any one of claims 1 to 12.

Description

Field of invention The invention relates to a method, a device and a computer program for monitoring telephone calls in a telephony service network. background In telephony service networks, subscribers can establish voice connections with each other. Each subscriber line in a telephony service network is assigned a subscriber identifier (TNI) known within the network. A TNI can be a telephone number, which may include an area code, a network prefix, and/or a country code. A TNI can also be an identifier in a digital telephony service network, such as a Session Initiation Protocol (SIP) address, an International Subscriber Identity (IMSI) of a mobile network, or another unique identifier for a subscriber line. Telephony services can be provided in both analog networks, often referred to as Public Switched Telephone Networks (PSTN) or Plain Old Telephone Services (POTS), and digital networks. These latter digital networks can include both fixed-line networks (e.g., Integrated Services Digital Network (ISDN), Session Initiation Protocol (SIP) networks, etc.) and mobile networks (e.g., 3GPP, 3GPP2, GSM, UMTS, LTE, 5G NR) and IP Multimedia Subsystem (IMS) networks. While traditional telephony service networks are generally circuit-switched, digital networks, at least in lower network layers, often operate on a packet-switched basis, for example, using the Internet Protocol (IP). To make a telephone call, a calling party (hereinafter referred to as the "originator") establishes a telephone connection using the TNI of a receiving party (hereinafter also referred to as the "receiver"). A telephony service network can also determine the originator's TNI or transmit it to the receiver's terminal for display. The receiver can then, for example, decide whether to accept the call based on the originator's TNI being displayed. Regardless of the technology used by a telephony service network, accepting a telephone call requires that a certain, possibly variable, transmission bandwidth be provided and maintained by the telephony service network for the duration of the call. The load on a telephony network can be measured, for example, in Erlangs, which represent the number of telephone calls of a specific duration per unit of time. Every telephony network has a finite load limit. Furthermore, in digital networks (including mobile networks), the bandwidth available for telephony services must be shared with other digital services (e.g., for data transmission for web, video, documents, etc.). Therefore, network operators need to monitor the telephone calls routed through the network to keep the load low and prevent network congestion. One way to reduce the load on a telephony network is to not forward unwanted calls, or not forward them immediately. Not forwarding can involve rejecting the call, so the originator has no way to reach the recipient. Alternatively, a warning can be displayed on the recipient's device indicating that it is a potentially unwanted call, thus preparing the recipient for the call and increasing their likelihood of rejecting it. Furthermore, not forwarding can involve transferring the originator's call to voicemail. Both the aforementioned warning and forwarding to voicemail can reduce the Erlang load on the telephony network, at least statistically. Forwarding to voicemail can also include verification of the originator via voice or keypad input. This can, for example, prevent calls from automated telephone systems (phone bots, robocallers). An unsolicited telephone call can be a call made without the recipient's express prior consent or against their express wishes, a call perceived by the recipient as disturbing or inappropriate, or a call related to illegal activities. Activities such as fraud, identity theft, or extortion are included. Examples are telemarketing calls, spam calls, or stalking calls. Telephone calls can be filtered using appropriate technical devices, which are installed, for example, in a participant's terminal device or in the telephony service network; that is, it is determined whether a telephone call is forwarded to the recipient or not. Call filters based on a so-called whitelist or blacklist mechanism are well-known. This means that calls originating from a subscriber identifier stored in a whitelist are always forwarded (possibly with or without further verification), while calls originating from a subscriber identifier stored in a blacklist are blocked, i.e., not forwarded. It is also known that specific subscriber identifiers, such as telephone numbers, can be assigned different ringtones on the recipient's device or even icons on the recipient's device display. BALASUBRAMANIYAN VA ET AL: "CallRank: Combating SPIT Using Call Duration, Social Networks and Global Reputation" refers to a call screening framework that uses a "reputation score" of a caller against a called party. The reputation score is based on the duration of previous calls between the caller and the cal