Patent Publication Number: US-11381612-B2

Title: Voice over long-term evolution (VoLTE) call normalization and alert policy system

Description:
RELATED APPLICATION 
     This application claims priority to a co-pending, commonly owned U.S. Provisional Patent Application No. 62/682,536 filed on Jun. 8, 2018, and titled “VoLTE Call Normalization and Alert Policy System,” which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     Telecommunication service providers typically offer wireless communications via a Public Land Mobile Network (PLMN) that is confined to a specific geographic region. A PLMN may comprise of several cellular technologies such as UMTS/3G, Long-Term Evolution (LTE) and 5G-New Radio. Since a PLMN is typically confined to a specific geographic region, subscribers to an HPLMN (i.e. a subscriber&#39;s Home PLMN) may initiate voice and text communications that omit a country code, which is generally common across an entirety of the PLMN. Instead, subscribers may use more granular identifiers specific to the HPLMN, such as a national destination code (NDC) or a number planning area (NPA) code. 
     At times, a subscriber to an HPLMN may initiate a wireless communication, such as a Voice over Long-Term Evolution (VoLTE) call, while roaming within a VPLMN, such as when traveling in a foreign country. In doing so, the subscriber may inadvertently omit the country code when initiating the VoLTE call request. By way of example, a subscriber to an HPLMN may save a phone number of a contact in a non-international format. Thus, if the subscriber initiates a VoLTE call to the contact, while roaming in a VPLMN, the HPLMN may be unable to establish the communicative connection due to being unable to determine whether the contact is associated with the HPLMN or VPLMN (i.e. due to the lack of a country code in the contact phone number). 
     Therefore, techniques to adjust a recipient call number to include a country code when initiating a VoLTE call from within a VPLMN may help facilitate establishing intended communication connections between a subscriber and their intended recipient. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The detailed description is set forth with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items or features. 
         FIG. 1  illustrates an exemplary computing environment of a Normalization and Alert Policy (NAP) system that facilitates a subscriber device roaming within a VPLMN and initiating a VoLTE call request to a recipient device with the HPLMN of the subscriber device. 
         FIG. 2  illustrates an exemplary computing environment of a NAP system that facilitates a subscriber device roaming within a VPLMN and initiating a VoLTE call request to a recipient device within the same, or another VPLMN. 
         FIG. 3  illustrates a block diagram of various components of the NAP system. 
         FIG. 4  illustrates a process for generating an adjusted recipient call number for delivery to a Telephone Application Server (TAS). 
         FIG. 5  illustrates a process for determining whether initiating a VoLTE communication based on an adjusted recipient number is likely to trigger an alert condition. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure describes techniques to normalize a Voice over Long-Term Evolution (VoLTE) call initiated via a subscriber device while roaming in a Visited Public Land Mobile Network (VPLMN). In one example, the VoLTE call may be intended for a recipient device associated with the HPLMN of the subscriber device. In a second example, the VoLTE call may be intended for a recipient device associated with the VPLMN from which the subscriber device is roaming. In a third example, the VoLTE call may be intended for another VPLMN that is different from the VPLMN that the subscriber device is roaming. In each of these examples, a Normalization Alert Policy (NAP) system may be configured to intercept VoLTE call requests at the Telephone Application Server (TAS) of the Home Public Land Mobile Network (HPLMN) of the subscriber device. In doing so, the NAP system may analyze a recipient number associated with the VoLTE request and further generate an adjusted recipient number by including a country code that was omitted from the recipient number in the VoLTE call request. By way of example, a subscriber to an HPLMN may save a phone number of a contact in a non-international format. Thus, if the subscriber initiates a VoLTE call to the contact, while roaming in a VPLMN, the HPLMN may be unable to establish the communicative connection due to being unable to determine whether the contact is associated with the HPLMN or VPLMN (i.e. due to the lack of a country code in the contact phone number). 
     Therefore, the NAP system may be configured to include the country code of the HPLMN in response to a determination that the recipient number does not include the country code and that the recipient number is associated with the HPLMN. Alternatively, the NAP system may include the country code of the VPLMN from which the subscriber device is roaming, in response to a determination that the recipient number does not include a country code and that the recipient number is associated with the VPLMN. 
     Further, the NAP system may be configured to generate a VoLTE call alert to a VoLTE call initiated by a subscriber device while roaming in a VPLMN. The VoLTE call may be intended for a recipient device that is associated with another VPLMN. In the first example, the alert may correspond to the cost of the VoLTE call. In a second example, the alert may correspond to a detection of likely fraud, based on the recipient number associated with the recipient device. 
     Further, the term “techniques,” as used herein, may refer to system(s), method(s), computer-readable instruction(s), module(s), algorithms, hardware logic, and/or operation(s) as permitted by the context described above and through the document. 
       FIG. 1  illustrates an exemplary computing environment of a Normalization and Alert Policy (NAP) system  102  that facilitates a subscriber device  104 , roaming within a VPLMN  106 , initiating a VoLTE call request to a recipient device  108  with the HPLMN  110  of the subscriber device  104 . In one example, the VPLMN  106  may correspond to a different country or regional area, relative to the HPLMN  110 . 
     When the subscriber device  104  connects to the VPLMN  106 , there may be communications between the VPLMN  106  and the HPLMN  110  to register the subscriber device  104  on the VPLMN  106 . During the process of registering the subscriber device  104 , a P-VPLMN-ID (PVNI) may be stored on the subscriber device  104 , which indicates the country (i.e. VPLMN  106 ), or geographic region, within which the subscriber device  104  currently resides. The PVNI may comprise of a two-digit or a three-digit country code (MCC), which identifies a country or a geographic area, and a mobile network code (MNC), which identifies an HPLMN  110  of the subscriber device. 
     In the illustrated example, the subscriber device  104  may initiate a VoLTE call while roaming within the VPLMN  106 . In doing so, a VoLTE call request may be sent to the HPLMN  110 , via a base station  112  and gateway  114  of a core network  116  of the HPLMN  110 . The VoLTE call request may be further routed from the gateway  114  and via an IP Multimedia Subsystem (IMS) core  118 , to a Telephone Application Server (TAS)  120  that interacts with the Normalization and Alert Policy (NAP) system  102 . 
     In response to an interaction between the TAS  120  and NAP system  102 , the TAS  120  may facilitate establishing the VoLTE communication associated with the VoLTE call request between the subscriber device  104  that is roaming within the VPLMN  106  and the recipient device  108  within the HPLMN  110 . 
     In the illustrated example, the HPLMN  110 , and VPLMN  106 , may provide telecommunications and data communications in accordance with one or more technical standards, such as Enhanced Data Rates for GSM Evolution (EDGE), Wideband Code Division Multiple Access (W-CDMA), High Speed Packet Access (HSPA), Long Term Evolution (LTE), CDMA-2000 (Code Division Multiple Access 2000), 5G-New Ratio (5G-NR), and/or so forth. The computing environment  100  may include a core network  116 . The core network  116  may provide telecommunication and data communication services to multiple client devices, such as a 3G-compatible client device, an LTE-compatible client device, and a 5G-NR-compatible device collectively referred to the subscriber device  104 . The subscriber device  104  may correspond to any sort of electronic device operating on the telecommunications network, such as a cellular phone, a smartphone, a tablet computer, an electronic reader, a media player, a gaming device, a personal computer (PC, a laptop computer), etc. The subscriber device  104  may have a subscriber identity module (SIM), such as an eSIM, to identify the respective electronic device to a telecommunications service provider network (also referred to herein as “telecommunications network”). 
     The core network  116  may further include an IMS core  118 , the Telephony Application Server (TAS)  120 , and the NAP system  102 . The TAS  120  may emulate calling features traditionally provided by a Public Switched Telephone Network (PSTN), such as call forwarding, voicemail, conference bridges, and/or so forth. In the illustrated example, the TAS  120  may facilitate establishing a VoLTE communication between a subscriber device and recipient device using an adjusted recipient call number from the NAP system  102 . 
     The HPLMN  110  may include multiple base stations, such as base station  112 , as well as a core network  116  that serves one or more subscriber device(s), such as the subscriber device  104 . In the illustrated example, the subscriber device  104  may be associated with a subscriber account, such as a telecommunications service account. The subscriber account may include a plurality of subscribers, each of whom shares access to service features accessible via the HPLMN  110 . The service features may include various mediums of communication, such as voice communications and text communications (i.e. SMS and MMS). 
     Further, the gateway  114  may include one or more servers and related components that are tasked with providing connectivity between the IMS core  118 , the subscriber device  104  and the internet. More specifically, the gateway  114  may act as a point of entry and exit for data traffic. 
       FIG. 2  illustrates an exemplary computing environment  200  of a NAP system  102  that facilitates a subscriber device  104  roaming within a first VPLMN  202  and initiating a VoLTE call request to a recipient device within a second VPLMN  204 . In one example, the second VPLMN  204  is a different telecommunication network to the first VPLMN  202 . In another example, the second VPLMN  204  is the same telecommunication network as the first VPLMN  202 . 
     The computing environment  200  includes various components that are the same or substantially similar to the computing environment  100  described with reference to  FIG. 1 , except for the routing of the VoLTE call communication to a recipient device in the same, or another VPLMN. As such, for brevity and ease of description, various details relating to the computing environment  200  are omitted herein to the extent that the same or similar details have been provided above with reference to  FIG. 1 . 
     In the illustrated example, the subscriber device  104  may initiate a VoLTE call request while roaming within the first VPLMN  202 . In doing so, a VoLTE call request may be sent to the HPLMN  110 , via a base station  112  and gateway  114  of the core network  116 . The VoLTE call request may be further routed from the gateway  214  and via the IMS core  118 , to the TAS  120  that interacts with the NAP system  102 . 
     In response to an interaction between the TAS  120  and NAP system  102 , the TAS  120  may selectively establish a VoLTE communication between the subscriber device  104  that is roaming within the first VPLMN  202  and the recipient device  108  that is associated with the second VPLMN  204 . 
       FIG. 3  illustrates a block diagram of various components of the Normalization and Alert Policy (NAP) system. The NAP system  102  may be configured to detect a VoLTE call request with a recipient call number that lacks a country code, and whereby the VoLTE call request is initiated by a subscriber device while roaming in a VPLMN. The NAP system  102  may analyze the VoLTE call request to determine an intended country code and adjust the recipient call number to include the country code. Further, the NAP system  102  may analyze the adjusted recipient call number to determine whether initiating a VoLTE call in response to the VoLTE call request may trigger an alert condition. An alert condition may relate to determining that the VoLTE call request may initiate a cost-prohibitive VoLTE communication or that the VoLTE call request relates a fraudulent communication. 
     The NAP system  102  may include input/output interface(s)  302 . The input/output interface(s)  302  may include any type of output interface known in the art, such as a display (e.g. a liquid crystal display), speakers, a vibrating mechanism, or a tactile feedback mechanism. Input/output interface(s)  302  also include ports for one or more peripheral devices, such as headphones, peripheral speakers, or a peripheral display. Further, the input/output interface(s)  302  may further include a camera, a microphone, a keyboard/keypad, or a touch-sensitive display. A keyboard/keypad may be a push button numerical dialing pad (such as on a typical telecommunication device), a multi-key keyboard (such as a conventional QWERTY keyboard), or one or more other types of keys or buttons, and may also include a joystick-like controller and/or designated navigation buttons, or the like. 
     Additionally, the NAP system  102  may include network interface(s)  304 . The network interface(s)  304  may include any sort of transceiver known in the art. For example, the network interface(s)  304  may include a radio transceiver that performs the function of transmitting and receiving radio frequency communications via an antenna. In addition, the network interface(s)  304  may also include a wireless communication transceiver and a near-field antenna for communicating over unlicensed wireless Internet Protocol (IP) networks, such as local wireless data networks and personal area networks (e.g. Bluetooth or near field communication (NFC) networks). Further, the network interface(s)  304  may include wired communication components, such as an Ethernet port or a Universal Serial Bus (USB). 
     Further, the NAP system  102  may include one or more processor(s)  306  that are operably connected to memory  308 . In at least one example, the one or more processor(s)  306  may be a central processing unit(s) (CPU), graphics processing unit(s) (GPU), or both a CPU and GPU or any other sort of processing unit(s). Each of the one or more processor(s)  306  may have numerous arithmetic logic units (ALUs) that perform arithmetic and logical operations as well as one or more control units (CUs) that extract instructions and stored content from processor cache memory, and then executes these instructions by calling on the ALUs, as necessary during program execution. The one or more processor(s)  306  may also be responsible for executing all computer applications stored in the memory, which can be associated with common types of volatile (RAM) and/or non-volatile (ROM) memory. 
     In some examples, memory  308  may include system memory, which may be volatile (such as RAM), non-volatile (such as ROM, flash memory, etc.) or some combination of the two. The memory may also include additional data storage devices (removable and/or non-removable) such as, for example, magnetic disks, optical disks, or tape. 
     The memory  308  may further include non-transitory computer-readable media, such as volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. System memory, removable storage, and non-removable storage are all examples of non-transitory computer-readable media. Examples of non-transitory computer-readable media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium which can be used to store the desired information. 
     In the illustrated example, the memory  308  may include an operating system  310 , an interface module  312 , a number plan analysis module  314 , a call number adjustment module  316 , an alert module  318 , and a data store  320 . The operating system  310  may be any operating system capable of managing computer hardware and software resources. The operating system  310  may include an interface layer that enables applications to interface with the input/output interface(s)  302  and the network interface(s)  304 . The interface layer may comprise public APIs, private APIs, or a combination of both. Additionally, the operating system  310  may include other components that perform various other functions generally associated with an operating system. 
     The interface module  312  may be configured to interface with a TAS  120  associated with an HPLMN  110 . The TAS  120  may be a component of a telecommunication network that emulates calling features traditionally provided by a PSTN, such as call forwarding, voicemail, conference bridges, and/or so forth. The interface module  312  may interface with the TAS to capture a recipient call number from a VoLTE call request initiated by a subscriber device at a VPLMN, and to return an adjusted recipient call number that includes a missing country code. 
     First, the interface module  312  may receive, from the TAS, a VoLTE call request initiated by a subscriber device, while the subscriber device is roaming in a VPLMN. In doing so, the interface module  312  may facilitate the NAP system  102  in verifying that the recipient call number associated with the VoLTE call request includes a country code and that the VoLTE call request, when initiated from the VPLMN, does not trigger an alert condition. The TAS may be configured to push a VoLTE call request to the interface module  312 . Alternately, the interface module  312  may monitor the TAS, via a monitoring agent, and dynamically intercept (i.e. pull) a VoLTE call request that is received at the TAS. 
     Second, the interface module  312  may transmit to the TAS, an adjusted recipient call number that includes a missing country code. In some examples, the interface module  312  may also transmit an indication to the TAS to terminate the VoLTE call request based on a detected alert condition. 
     The interface module  312  may be further configured to interface with a subscriber device and provide the subscriber device with selectable options to proceed with, or terminate, a VoLTE call request based on a detected alert condition. For example, the alert module  318  may determine that initiating a VoLTE call request using an adjusted recipient number from within the VPLMN may result in a VoLTE communication that incurs an inordinately high unit cost per increment of time. Therefore, the interface module  312  may transmit computer-executable instructions to the subscriber device that cause a display of the subscriber device to present an alert notification and selectable options to proceed with, or terminate, the VoLTE call request. The alert notification may describe the nature of the alert condition (i.e. fraudulent call number or cost-prohibitive VoLTE communication). In response to receiving a selection to proceed with, or terminate, the VoLTE call request, the interface module  312  may communicate the same to the TAS for implementation. 
     The number plan analysis module  314  may analyze a recipient call number associated with a VoLTE call request to determine whether the recipient call number includes a country code. In cases where a country code is missing from the recipient call number, the number plan analysis module  314  may use one or more trained machine learning algorithms to determine the country code based at least in part on the recipient call number. 
     The number plan analysis module  314  may include a call number format component  322 , a jurisdiction analysis component  324  and a subscriber account analysis component  326 . The call number format component  322  may determine whether a recipient call number associated with a VoLTE call request initiated at a VPLMN is lacking a country code. The call number format component  322  may analyze the prefix two or three digits of a recipient call number to determine whether a country code has been included. The call number format component  322  may analyze the recipient call number relative to a list of country codes included with the data store  320 . 
     In response to detecting a country code, the call number format component  322  may determine whether the call number format for the recipient call number corresponds to the detected country code. For example, a VoLTE call request may include a recipient call number of 0151-1234. The call number format component  322  may detect that the 0151 relates to a non-geographic area code for a German mobile device, thus the 0151 may be considered as the country code. However, the call number format component  322  may compare the call number format of the recipient call number with a total number of digits for a German mobile number. In this example, three digits are missing. Therefore, the call number format component  322  may determine that since the number of digits of the recipient call number (i.e. 8 digits long) is fewer than the total number of digits for a German mobile number (i.e. 11 digits, including the trunk code 0), the recipient call number is not properly formatted with a country code (i.e. German country code in this example). 
     In response, in determining that a recipient call number does not include a country code, the jurisdiction analysis component  324  and the subscriber account analysis component  326  may, individually, or in combination, determine or infer a likely country code for the recipient call number. The NAP system  102  may be configured to invoke the jurisdiction analysis component  324  and the subscriber account analysis component  326  to determine the country code. As discussed in further detail below, the NAP system  102  may invoke each component sequentially in any order, in parallel, cooperatively, or individually. 
     The jurisdiction analysis component  324  may be configured to analyze a recipient call number that is missing a country code and determine the country code. The jurisdiction analysis component  324  may retrieve, from the data store  320 , a number plan registry that includes call numbers for one or more jurisdictions (i.e. countries). In some examples, a single number plan registry may include call numbers for the HPLMN and one or more VPLMNs, including the VPLMN from which the subscriber device initiated the VoLTE call request. In other examples, individual number plan registries may correspond to each of the HPLMN and one or more VPLMNs. Thus, the jurisdiction analysis component  324  may analyze the recipient number relative to the plurality of number plan registries in order to determine or infer a likely country code. 
     In one example, the jurisdiction analysis component  324  may use one or more trained machine learning algorithms to identify a national destination code (NDC) or a number planning area (NPA) code, within the recipient call number, that is indicative of a particular jurisdiction. For example, the recipient call number may include a “310” area code, and a comparison of the recipient call number with a U.S. number plan registry may indicate that the “310” area code is associated with a California mobile number. Thus, the jurisdiction analysis component  324  may determine that the missing country code is “+1” (i.e. the United States country code). 
     In another example, the jurisdiction analysis component  324  may identify one or more jurisdictions that share a common NDC code or NPA code. For example, the area code “310” may correspond to a mobile device in Berlin, Germany, or a mobile device in California, USA. In these instances, the jurisdiction analysis component  324  may analyze the recipient call number format (i.e. number of digits) to infer a likely jurisdiction. Alternately, the jurisdiction analysis component  324  may cooperate with the subscriber account analysis component  326  to determine the missing country code. 
     The subscriber account analysis component  326  may be configured to determine a missing country code by analyzing a subscriber account associated with the subscriber device. For example, the subscriber account analysis component  326  may retrieve, from the data store  320 , a subscriber account from a data store  320 . The subscriber account may include a set of historical communication records associated with one or more subscriber devices. The set of historical communications records may include VoLTE calls initiated and received by subscriber devices associated with the subscriber account over a predetermined time interval. The predetermined time interval may be any time interval. The time interval may correspond to a billing cycle or the length of time that the subscriber account has been active. 
     In one example, the subscriber account analysis component  326  may use one or more trained machine learning algorithms to analyze the recipient call number relative to the set(s) of historical communication records within the subscriber account. In this way, the subscriber account analysis component  326  may determine the country code for the recipient call number by matching the recipient call number with a call number within at least one record of the set(s) of historical communication records. 
     In another example, the subscriber account analysis component  326  may interact with the jurisdiction analysis component  324  to determine the country code of the recipient call number. As discussed earlier, the jurisdiction analysis component  324  may determine that the recipient call number relates to a plurality of jurisdictions. Therefore, the subscriber account analysis component  326  may analyze the set(s) of historical communication records to determine whether the recipient call number has been historically dialed by a subscriber device of the subscriber account. Alternately, the subscriber account analysis component  326  may infer a likely jurisdiction based on the prevalence of historical communications within one of the jurisdictions in the set(s) of historical communication records. For example, consider an indication from the jurisdiction analysis component  324  that the recipient call number is likely associated with Germany or the United States. The subscriber account analysis component  326  may infer a country code of “+1” for the United States based on the prevalence of historical communications with mobile devices within a United States PLMN and the relative lack of historical communications with mobile devices within a German PLMN. Additionally, or alternatively, the subscriber account analysis component  326  may infer a country code based on the HPLMN of the subscriber device, or the VPLMN from which the subscriber device has initiated the VoLTE call request. 
     The call number adjustment module  316  may be configured to generate an adjusted recipient call number that includes the country code as a prefix to the recipient call number. In this example, the call number adjustment module may interact with the interface module  312  and the number plan analysis module to retrieve the recipient call number and the country code. 
     The alert module  318  may be configured to determine whether initiating a VoLTE call request using the adjusted recipient call number (i.e. recipient call number that includes the determined country code) is likely to trigger an alert condition. In some examples, the alert condition may relate to determining that the VoLTE call request may initiate a cost-prohibitive VoLTE communication or that the VoLTE call request relates a fraudulent communication. 
     The alert module  318  may further include an alert condition analysis component  328  and a notification component  330 . The alert condition analysis component  328  may analyze initiating a VoLTE communication using the adjusted recipient call number at the VPLMN based at least in part on one or more alert parameters. The one or more alert parameters may include criteria that relate to detecting a fraudulent VoLTE communication at the VPLMN or a cost-prohibitive VoLTE communication initiated at the VPLMN. 
     The alert condition analysis component  328  may use the one or more alert parameters to generate an alert score, based at least in part on an analysis of initiating the VoLTE call request. The alert score may be configured to indicate a likelihood that a particular alert condition (i.e. fraudulent or cost-prohibitive VoLTE communication) is triggered by initiating a VoLTE communication using the adjusted recipient call number at the VPLMN. 
     In one example, consider an alert condition that relates to the unit cost per increment of time for an established VoLTE communication associated with the VoLTE call request. In this example, an operator of the NAP system  102 , an administrator of the HPLMN, or a subscriber associated with the subscriber account, may set alert parameters that define a permissible unit cost per increment of time for a VoLTE communication while the subscriber device is roaming in a VPLMN. Therefore, the alert condition analysis component  328  may analyze the actual unit cost per increment of time for initiating a VoLTE communication associated with a VoLTE call request and derive an alert score based on a comparison of the projected unit cost and the permissible unit cost. A VoLTE communication with a particular unit cost may produce a high alert score when compared to another VoLTE communication with a relatively lower unit cost. 
     Continuing with this example, the alert condition analysis may generate an alert score based on the unit cost per increment of time. The alert score may be an alpha-numeric expression (i.e. 0 to 10, or A to F), a descriptive expression (i.e. low, medium, or high), based on color (i.e. green, yellow, red), or any other suitable scale that reflects a likelihood that an alert condition is initiated by a VoLTE communication. A high alert score may correspond to 8-10, D to F, or red, and a low alert score may correspond to 1-3, A-B, and low. 
     Further, the alert condition analysis component  328  may compare the alert score with one or more predetermined alert thresholds, with each predetermined alert threshold triggering a separate set of actions. For example, in response to the alert score being less than a predetermined alert threshold, the alert condition analysis component  328  may transmit the adjusted recipient call number to the TAS, whereby the TAS may facilitate establishing a VoLTE communication using the adjusted recipient call number. Alternatively, in response to the alert score being greater than a predetermined alert threshold, the alert condition analysis component  328  may transmit an indication to the TAS to terminate the VoLTE call request. For example, continuing with the previous example, the predetermined alert threshold for an alert condition relating to the unit cost per increment of time for a VoLTE communication may be set at a predetermined permissible unit cost. Thus, in response to the alert score for the projected unit cost being greater than the predetermined alert threshold (i.e. the projected unit cost being greater than the permissible cost), the alert condition analysis component  328  may transmit an indication t the TAS to terminate the VoLTE call request. 
     In some examples, the alert condition analysis component  328  may be configured to analyze the alert score relative to more than one predetermined alert threshold, with each predetermined alert threshold triggering a separate set of actions. For example, the alert condition analysis component  328  may determine that an alert score is greater than a first predetermined alert threshold but less than a second predetermined alert threshold. In this instance, rather than transmitting an indication to the TAS to terminate the VoLTE, the alert condition analysis component  328  may generate computer executable instructions for delivery to a subscriber device that initiated the VoLTE call request. The computer-executable instructions may cause the subscriber device to present an alert notification and selectable options to terminate the VoLTE call request or proceed with the VoLTE call request. Similarly, the alert condition analysis component  328  may determine that an alert score is greater than the first and second predetermined alert threshold, and in doing so, transmit an indication to the TAS to terminate the VoLTE call request. 
     Moreover, the alert condition analysis component  328  may analyze alert conditions that relate to fraudulent VoLTE communications associated with the VoLTE call request. In one example, a fraudulent VoLTE communication may be detected by identifying a likely instance of “traffic pumping.” Traffic pumping, also known as access stimulation, occurs when a local network (i.e. the VPLMN) inflates the volume of incoming calls (i.e. VoLTE communication) into another PLMN (i.e. the HPLMN or another VPLMN), and profits from the intercarrier compensation fees. In this case, the alert condition analysis component  328  may detect instances of traffic pumping based on the jurisdiction within which the VoLTE call request was initiated and the jurisdiction within which the recipient of the adjusted recipient call number resides. For example, if traffic pumping is historically prevalent between Iceland and Germany, then the alert condition analysis component  328  may infer that a VoLTE call request initiated in Iceland and intended for a recipient call number that resides in Germany may be related to “traffic pumping.” In some examples, the alert condition analysis component  328  may interact with the number plan analysis module  314  to determine whether the recipient call number is valid, irrespective of the originating and receiving jurisdictions (i.e. indications of traffic pumping). 
     In another example, a fraudulent VoLTE communication may relate to a VoLTE call request intended for an impermissible call number. In this example, the alert condition analysis component  328  may retrieve, from the data store  320 , a list of impermissible call numbers associated with the VPLMN within which the VoLTE call request was initiated, and the PLMN (i.e. HPLMN or other VPLMN) within which the adjusted recipient call number resides. The alert condition analysis component  328  may compare the adjusted recipient call number with the list of impermissible call numbers to determine whether a match exists. In doing so, the alert condition analysis component  328  may generate an alert score, based on whether a match exists, and the degree to which the impermissible call number poses a fraud risk. 
     Similar to the example relating to the unit cost of a VoLTE communication, the alert condition analysis component may determine whether the alert score for the fraudulent VoLTE communication is greater than or equal to one or more predetermined alert thresholds, with each predetermined alert threshold triggering a separate set of actions. Consider an example with a first predetermined alert threshold and a second predetermined threshold that is higher than the first predetermined alert threshold. In response to the alert score being less than a first predetermined threshold, the alert condition analysis component  328  may transmit the adjusted recipient call number to the TAS, whereby the TAS may facilitate establishing a VoLTE communication using the adjusted recipient call number. In response to the alert score being greater than a first predetermined alert threshold but less than the second predetermined alert threshold, the alert condition analysis component  328  may generate computer executable instructions for delivery to a subscriber device that presents an alert notification and selectable options to terminate the VoLTE call request or proceed with the VoLTE call request. In response to the alert score being greater than the second predetermined threshold, the alert condition analysis component  328  may transmit an indication to the TAS to terminate the VoLTE call request. 
     The notification component  330  may generate notifications intended for the TAS. These notifications may indicate to the TAS to facilitate establishing a VoLTE communication associated with the VoLTE call request or terminating the VoLTE call request. Further, the notification component  330  may generate notifications intended for a subscriber device. These notifications may indicate to the subscriber device, the nature of an alert condition (i.e. cost-prohibitive VoLTE communication or a fraudulent VoLTE communication) and provide one or more selectable options to proceed with the VoLTE call request or terminate the VoLTE call request. 
     The data store  320  may include one or more data records used by the number plan analysis module  314  and the alert module  318 . For example, the data store  320  may include a number plan registry, a listing of country codes along with non-geographic area codes commonly designated to mobile devices within one or more countries. For example, a “0151” non-geographic area code is presently assigned to T-MOBILE (Registered Trademark) GSM/UMTS mobile devices. 
     The data store  320  may further include a subscriber account data associated with subscribers of the HPLMN. The data store  320  may also include a list of impermissible call numbers used to identify a fraudulent VoLTE communication. 
       FIGS. 4 and 5  present processes  400  and  500  that relate to operations of the Normalization and Alert Policy (NAP) system. Each of processes  400  and  500  illustrate a collection of blocks in a logical flow chart, which represents a sequence of operations that can be implemented in hardware, software, or a combination thereof. In the context of software, the blocks represent computer-executable instructions that, when executed by one or more processors, perform the recited operations. Generally, computer-executable instructions may include routines, programs, objects, components, data structures, and the like that perform particular functions or implement particular abstract data types. The order in which the operations are described is not intended to be construed as a limitation, and any number of the described blocks can be combined in any order and/or in parallel to implement the process. For discussion purposes, the processes  400  and  500  are described with reference to the first computing environment  100  of  FIG. 1  and the second computing environment  200  of  FIG. 2 . 
       FIG. 4  illustrates a process for generating an adjusted recipient call number for delivery to a TAS. Specifically, process  400  includes steps for a NAP system to detect a VoLTE call request that is initiated by a subscriber device that is roaming in a VPLMN. The VoLTE call request may include a recipient call number that lacks a country code. Therefore, process  400  further describes determining a country code and adjusting the recipient call number to including the country code. 
     At  402 , the NAP system may receive from the TAS and at an HPLMN, a VoLTE call request from a subscriber device that is roaming within a VPLMN. The VoLTE call request may include a recipient call number that lacks a country code. Since the VoLTE call request is initiated from a VPLMN, the country code may implicitly relate to the VPLMN. Alternatively, the VoLTE call request may be intended for a recipient call number within the HPLMN of the subscriber device, or a different VPLMN altogether. 
     At  404 , the NAP system may analyze the recipient call number to determine a country code. In one example, the NAP system may determine a likely country code by analyzing the recipient call number relative to a number plan registry that includes call numbers for one or more jurisdictions. In some examples, the NAP system may identify an NDC or NPA code within the recipient call number that is indicative of a particular jurisdiction. 
     Additionally, or alternatively, the NAP system may analyze the recipient call number relative to one or more sets of historical communication records associated with a subscriber account of the subscriber device. Each set of historical communication records may include VoLTE communications initiated by and received at subscriber devices associated with the subscriber account over a predetermined time interval. 
     At  406 , the NAP system may generate an adjusted recipient call number associated with the VoLTE call request. The adjusted recipient call number may include the determined country code as a prefix to the recipient call number provided in the VoLTE call request. 
     At  408 , the NAP system may transmit the adjust recipient call number to the TAS. In some examples, the TAS may be configured to establish a VoLTE communication at the VPLMN using the adjusted recipient call number. 
       FIG. 5  illustrates a process for determining whether initiating a VoLTE communication based on an adjusted recipient number is likely to trigger an alert condition. In various examples, the alert condition may relate to determining that the VoLTE call request may initiate a cost-prohibitive VoLTE communication or that the VoLTE call request relates to a fraudulent communication. 
     At  502 , the NAP system may generate an adjusted recipient call number for a VoLTE call request that is initiated by a subscriber device roaming within a first VPLMN. The process by which the NAP system may generate the adjusted recipient call number is discussed in detail with reference to process  400  and  FIG. 4 . 
     At  504 , the NAP system may generate an alert score that indicates a likelihood that a particular alert condition is triggered by initiating a VoLTE communication using the adjusted recipient call number at the VPLMN. The alert score may be based on one or more alert parameters that provide criteria to assess a VoLTE request. For example, consider an alert parameter that describes a permissible unit cost per increment of time for a VoLTE communication. This alert parameter may be used to generate an alert score for an alert condition relating to a cost-prohibitive VoLTE communication. 
     Similarly, consider another alert parameter that indicates particular combinations of PLMNs that are historically responsible for traffic pumping. This alert parameter may be used to generate an alert score for an alert condition relating to a fraudulent VoLTE communication. 
     At  506 , the NAP system may determine whether the alert score associated with the recipient call number is greater than a first predetermined alert threshold. By way of example, the predetermined alert threshold for a cost-prohibitive alert condition may correspond to a predetermined permissible unit cost per increment of time for a VoLTE communication. The permissible cost may be set by an operator of the NAP system, an administrator of the HPLMN, or a subscriber associated with the subscriber account. 
     At  508 , the NAP system may determine that the alert score is less than or equal to the first predetermined alert threshold. In doing so, the NAP system may transmit the adjusted recipient call number to the TAS, whereby the TAS may facilitate establishing a VoLTE communication using the adjusted recipient call number. 
     At  510 , the NAP system may determine that the alert score is greater than the first predetermined alert threshold. The NAP system may then compare the alert score relative to an additional predetermined alert threshold. In some examples, the NAP system may compare the alert score with more than one predetermined alert thresholds, with each predetermined alert threshold triggering a separate set of actions. 
     At  512 , the NAP system may determine that the alert score is greater than the second predetermined alert threshold. The NAP system may then transmit an indication to the TAS to terminate the VoLTE request. In this example, the second predetermined alert threshold represents an upper limit to an alert condition. Continuing with the example of a cost-prohibitive VoLTE communication, the second predetermined alert threshold may represent the upper limit of the permissible unit cost per increment of time. 
     At  514 , the NAP system may determine that the alert score is less than the second predetermined alert threshold. The NAP system may generate computer executable instructions for delivery to the subscriber device that cause the subscriber device to present an alert notification and selectable options to terminate the VoLTE call request or proceed with the VoLTE call request. The alert notification may describe the nature of the alert condition (i.e. fraudulent call number or cost-prohibitive VoLTE communication). In response to receiving a selection to proceed with the VoLTE call request to terminate the VoLTE call request, the NAP system may communicate the same to the TAS for implementation. 
     Conclusion 
     Although the subject matter has been described in language specific to features and methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described herein. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claims.