Routed emergency calls over non-terrestrial networks

Abstract

A solution for routing an emergency call over a non-terrestrial network (NTN) includes receiving, by the NTN, an emergency call from a user equipment (UE); not selecting, by the NTN, a Public Safety Answering Point (PSAP) for routing the emergency call; selecting, by the NTN, a packet data network (PDN) gateway (GW) in a terrestrial network (TN) to route the emergency call thereto; and routing the emergency call to the selected PDN GW. The solution further comprises receiving, by the TN from the NTN, an emergency call issued by a UE that is using the NTN; determining, by the TN, a location of the UE; selecting, by the TN, a PSAP using the location of the UE; and routing the emergency call to the selected PSAP.

Description

Background Art

[0001] Non-terrestrial networks (NTNs) complement ground-based terrestrial networks, such as cellular networks, by providing coverage in remote locations that are difficult for TNs to serve. NTN service providers can partner with TN service providers by leasing radio spectrum and acting as roaming operators (e.g., service / access networks).

[0002] Cellular network is configured to meet standardized operation, such as the operation produced by the 3rd Generation Partnership Project (3GPP).3GPP technical standard (TS) 23.401 is one of control TS for cellular network, and currently requires emergency call, such as enhanced 911 (E911) call is to be processed by service / access network.This means that the NTN as service / access network is required to process E911 to the routing of public safety answering point (PSAP).PSAP is the call center for answering emergency calls (such as 911 calls).Yet, only just there are thousands of PSAPs in the U.S. The selection of processing each PSAP and the routing to each PSAP need a large amount of investment to infrastructure, thereby raising the cost for NTN. Summary of the Invention

[0003] The following summary is provided to illustrate examples disclosed herein but is not meant to limit all examples to any specific configuration or sequence of operations.

[0004] A solution for routing emergency calls made through a non-terrestrial network (NTN) includes: receiving, by the NTN, an emergency call from a user equipment (UE); not selecting, by the NTN, a public safety answering point (PSAP) for routing the emergency call; selecting, by the NTN, a packet data network (PDN) gateway (GW) in a terrestrial network (TN) to which the emergency call is to be routed; and routing the emergency call to the selected PDN GW. The solution also includes: receiving, by the TN, an emergency call placed by a UE using the NTN from the NTN; determining, by the TN, a location of the UE; selecting, by the TN, a PSAP using the location of the UE; and routing the emergency call to the selected PSAP. The solution also includes: determining, by the UE, the location of the UE; sending, by the UE, an emergency call to the NTN, wherein the emergency call includes a message containing the location of the UE and an identification of the UE's home public land mobile network (HPLMN). BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The disclosed examples are described below with reference to the following drawings, in which:

[0006] Figure 1 An exemplary architecture for advantageously routing emergency calls through a non-terrestrial network (NTN) is shown;

[0007] Figure 2 Shown for Figure 1 further details of the user equipment (UE);

[0008] Figure 3 Shown for Figure 1 Further details of the emergency call;

[0009] Figure 4 Shown for Figure 1 further details of one of the components of the architecture;

[0010] Figure 5 It shows that the Figure 1 Message sequence diagrams (also called swim lane diagrams) of example messages that appear in the architecture;

[0011] Figure 6 Shown with Figure 1 Flowcharts of exemplary operations associated with examples of the architecture;

[0012] Figure 7-9 Shown with Figure 1 Additional flow charts of exemplary operations associated with examples of the architecture of

[0013] Figure 10 A block diagram of a computing device suitable for implementing various aspects of the present disclosure is shown.

[0014] Corresponding reference characters indicate corresponding parts throughout the drawings, where applicable. Reference in this disclosure to specific exemplary embodiments is provided for illustrative purposes only and is not meant to limit all implementations or to be construed to exclude the existence of other implementations that also incorporate the described features. DETAILED DESCRIPTION

[0015] A solution for routing emergency calls made through a non-terrestrial network (NTN) includes: receiving, by the NTN, an emergency call from a user equipment (UE); not selecting, by the NTN, a public safety answering point (PSAP) for routing the emergency call; selecting, by the NTN, a packet data network (PDN) gateway (GW) in a terrestrial network (TN) to which the emergency call is to be routed; and routing the emergency call to the selected PDN GW. The solution also includes: receiving, by the TN, an emergency call placed by a UE using the NTN from the NTN; determining, by the TN, a location of the UE; selecting, by the TN, a PSAP using the location of the UE; and routing the emergency call to the selected PSAP. The solution also includes: determining, by the UE, the location of the UE; sending, by the UE, an emergency call to the NTN, wherein the emergency call includes a message containing the location of the UE and an identification of the UE's home public land mobile network (HPLMN).

[0016] Various aspects of the present disclosure improve public safety while increasing the efficiency of NTN operations. NTN can advantageously delegate the responsibility of routing emergency calls (such as enhanced 911 (E911) or E112 calls) to the UE's home network or any other designated TN, rather than the NTN itself routing emergency calls to the PSAP. An E911 call automatically provides the caller's location to the 911 dispatcher. 911 is a universal emergency number, at least in North America. In the European Union (EU), the emergency number is 112, and therefore the emergency number on a cellular network is an E112 call. Emergency calls sent from some vehicles are referred to as eCalls.

[0017] By allowing the established TN to handle emergency calls to the NTN, which already has a proven infrastructure for routing emergency calls to the appropriate PSAP, the NTN does not need to invest resources in duplicative efforts. The intention behind requiring the serving network to handle emergency calls rather than routing them through the caller's home network is that, due to the geographic distribution of traditional cellular networks and the communication range of traditional cellular phones, the PSAP closest to the caller is likely to be located in the same geographic area as the serving network. Because the NTN uses satellites to communicate with UEs, assumptions about the geographic location of network coverage may not apply to the same extent as with the TN.

[0018] Referring now to the accompanying drawings, Figure 1 An architecture 100 is shown for advantageously making routing emergency calls through an NTN 110. In the architecture 100, a UE 200 is located near a PSAP 102 and is therefore within the jurisdiction 104 of the PSAP 102. The jurisdiction 104 is the area of ​​responsibility for the PSAP 102 such that callers with emergency situations within the jurisdiction 104 should have their emergency calls routed to the PSAP 102 so that the PSAP 102 can dispatch appropriate responders (e.g., police, file, ambulance responders).

[0019] UE 200 is served by NTN 110, so that NTN 110 serves as a visited public land mobile network (VPLMN) for UE 200. A public land mobile network (PLMN) is a combination of wireless communication services (such as cellular communication services) provided by a specific operator in a specific location. UE 200 has a home PLMN (HPLMN) that stores subscriber information for UE 200. For example, the user of UE 200 will be a customer of UE 200's HPMLN, and UE 200's HPMLN will be a TN.

[0020] When UE 200 moves to an area outside the coverage of its HPMLN and is covered by another TN, and UE 200 has roaming coverage, the other TN is a visited PLMN (VPLMN). Figure 1 In the illustrated scenario, when UE 200 is served by NTN 110, NTN 110 is the roaming carrier for UE 200, and the HPMLN connection with UE 200 is similar to a roaming TN. Therefore, NTN 110 acts as a VPLMN for UE 200, even though the NTN has a non-terrestrial component, satellite 111. In some scenarios, TN 130 is the HPMLN for UE 200. However, in other scenarios, TN 130 is not the HPMLN for UE 200, but is simply designated to handle emergency calls in place of the HPMLN for UE 200.

[0021] UE 200 communicates with NTN 110 via air interface 106a with satellite 111. Satellite 111 communicates with a ground-based terrestrial gateway (G GW 112) via air interface 106b. G GW 112 is communicatively connected to NTN 110's Mobility Management Entity (MME) 113 and Serving Gateway (SGW) 114. MME 113 is communicatively connected to SGW 114 and Diameter Routing Agent (DRA) 115. The MME is the control node for cellular networks, and since NTN 110 functions as a cellular network, NTN 110 has its own MME. The MME is responsible for UE paging to select a serving gateway. The DRA is a functional element that ensures that messages are routed between the correct elements in the network.

[0022] NTN 110 is connected to TN 130 via interconnect 120. TN 130 includes DRA 135, Home Subscriber Server (HSS) 136, PDN GW 134, Policy and Charging Rules Function (PCRF) 137, MME 133, Internet Protocol (IP) Multimedia System (IMS) IMS Core 132, and Text Control Center (TCC) 131. In some applications, the PDN GW is also referred to as a Packet Gateway (PGW). The HSS is a subscriber database that provides subscriber information to other nodes in TN 130. The PCRF accesses the subscriber database in real time and initiates dedicated bearers for IMS services. IMS provides an architectural framework for delivering IP-based multimedia services. Interconnect 120 may use Internet Packet Exchange (IPX) or IP Security (IPsec) protocols.

[0023] DRA 135 is communicatively connected to HSS 136 and MME 133. PDN GW 134 is communicatively connected to PCRF 137, MME 113, IMS core 132, and Internet 160. IMS core 132 is also the IMS core 132 to the public switched telephone network (PSTN) 161, TCC 131, and PSAP 102. TCC 131 processes text messages sent between IMS core 132 and PSAP 102. PSAP 102 is also communicatively connected to PSTN 161.

[0024] When UE 200 places an emergency call 300 through NTN 110, NTN 110 uses information stored within MME 113 to select PDN GW 134 in TN 130 and routes the emergency call 300 to PDN GW 134. TN 130 uses information stored within MME 133 to select PSAP 102 and routes the emergency call 300 to PSAP 102. A voice session 528 is established for the emergency call 300 so that the caller using UE 200 can speak with the emergency dispatcher within PSAP 102.

[0025] In some examples, TN 130 includes a fifth generation technology (5G) cellular network, a fourth generation technology (4G) cellular network, or another network (e.g., a future 6G network). In some examples, NTN 110 simulates a 5G cellular network or another network (e.g., a future 6G network).

[0026] Figure 2 Further details are shown for UE 200. UE 200 has a subscriber identity module (SIM) card 202 that holds an International Mobile Subscriber Identity (IMSI) 204. IMSI 204 includes a Mobile Country Code (MCC) 206, a Mobile Network Code (MNC) 208, and a Mobile Subscription Identification Number (MSIN) 210. MCC 206 and MNC 208 together form an HPMLN identifier (ID) 212 for UE 200. This is because MCC 206 is the MCC for the country where TN 130 is located, while MNC 208 is the MNC for TN 130 within that country. MSIN 210 is a unique numeric code used by UE 200's HPMLN to identify UE 200. In some examples, IMSI 204 has 15 digits. In some examples, NTN 110 uses a non-geographic MCC, such as 901.

[0027] UE 200 sends its own location 224 in E911 and E112 calls. To determine its own location 224, UE 200 receives Global Positioning System (GPS) signals 220 and decodes them using a GPS receiver 222. In some examples, location 224 is expressed using GPS coordinates.

[0028] Figure 3 Further details are shown for emergency call 300. In some examples, emergency call 300 includes Session Initiation Protocol (SIP) Invite 302. Emergency call 300 includes UE location 224 and at least HPLMNID 212. In some examples, emergency call 300 includes the entire IMSI 204, and HPLMNID 212 is included as part of IMSI 204. In some examples, UE location 224 and IMSI 204 are within SIP Invite 302.

[0029] Figure 4 Further details are shown for the MME 113 of the NTN 110. The MME 113 has a data store 402 that holds an Emergency PDN GW Identity field 404. The contents of the conventional Emergency PDN GW Identity field are specified in Table 5.7.2-1 of the Third Generation Partnership Project (3GPP) Technical Standard (TS) 23.401. However, the Emergency PDN GW Identity field 404 has a mapping table 406.

[0030] 4. The mapping table 406 has a PLMN column 408 and a PDN GW identification (ID) column 410. As shown, the mapping table 406 has five (5) rows of table entries, although it should be understood that some implementations may use a different number of rows. Table entry 411 maps a PLMN value of 310XXX to an IP address for the PDN GW, and table entry 412 maps a PLMN value of 310 310YYY to an IP address for the PDN GW. Table entry 413 maps a PLMN value of 310ZZZ to a fully qualified domain name (FQDN) for the PDN GW. Table entry 414 maps a PLMN value of 262AA to an IP address for the PDN GW, and table entry 415 maps a PLMN value of 262BB to an IP address for the PDN GW. The PDN GWs identified in the various table entries of the mapping table 406 may all be different, or some may be common to two or more table entries. A PLMN value prefix of 310 or 310 indicates a PLMN located in North America, and a PLMN value prefix of 310 or 310 indicates a PLMN located in Germany. Other countries use various different PLMN value prefixes,

[0031] When the MME 113 receives the emergency call 300 (e.g., receives the SIP Invite 302), the MME 113 extracts the HPMLN ID 212 and locates a matching value in the PLMN column 408. The corresponding PDN GW identification (IP address or FQDN) is found in the PDN GW ID column 410. This is how the NTN 110 selects the PDN GW 134 for the UE 200.

[0032] The table entries in mapping table 406 can map a PLMN value to a PDN GW within the same PLMN, or can map a PLMN value to a PDN GW within a different PLMN. When a PLMN value is mapped to a PDN GW within the same PLMN, any UE that provides that PLMN as the HPLMN ID in an emergency call will have its call routed to its HPLMN. However, when a PLMN value is mapped to a PDN GW within a different PLMN, the UE will have its emergency call routed to a designated PLMN that is different from its HPLMN.

[0033] Various schemes can be used to determine which TNs provide routing for emergency calls. For larger TNs, each TN can accept and route emergency calls for its own subscribers (e.g., a UE's emergency call is routed to the UE's HPMLN), and can also provide emergency calls for smaller TNs and cellular operator distributors (e.g., a UE's emergency call is routed to a designated HPMLN instead of the UE's HPMLN).

[0034] In contrast to the operation of the MME 113 , when the PDN GW 134 receives the emergency call 300 , the MME 133 of the TN 130 retains the legacy Emergency PDN GW Identity field specified by 3GPP TS 23.401 that identifies the PSAP 102 .

[0035] Figure 5 A message sequence chart 500 is shown representing example messages that may occur in architecture 100. UE 200 registers for voice services with NTN 110 using message 502. UE 200 obtains its location at 504 and initiates an emergency call 300 to G GW 112 via satellite 111 using SIP INVITE 302 in message 506. G GW 112 forwards the emergency call 300 to MME 113 using message 508. MME 113 selects PDN GW 134 at 510 and notifies SGW 114 using message 512.

[0036] The SGW 114 forwards the emergency call 300 to the PDN GW 134 using message 514, and the PDN GW 134 routes the emergency call 300 to the IMS core 132 using message 516. In some examples, the IMS core 132 routes the emergency call 300 to the PSAP 102 according to the procedures specified in 3GPP TS 23.167. In some examples, the IMS core 132 has its own table to identify the PSAP 102 based on the location 224 of the UE 200. In such an example, the IMS core 132 selects the PSAP 102 at 518.

[0037] However, in some examples, IMS core 132 utilizes emergency PDN GW identification field 404 stored in MME 133. In such examples, IMS core 132 queries MME 133 using query 520, MME 133 selects PSAP 102 at 522, and responds to IMS core 132 with the identification of PSAP 102 in response 524.

[0038] In either case, when IMS core 132 identifies PSAP 102 as the appropriate PSAP for location 224 of UE 200, IMS core 132 routes emergency call 300 to PSAP 102 using message 526. A voice session 528 is established for emergency call 300 to enable the caller using UE 200 to speak with the emergency dispatcher within PSAP 102.

[0039] Figure 6 A flowchart 600 illustrates exemplary operations associated with routing an emergency call 300 through the NTN 110 in the architecture 100. In some examples, at least a portion of the flowchart 600 may be used. Figure 10 100 (e.g., any network node of the architecture 100 may use an example of the computing device 1000). Flowchart 600 begins with UE 200 registering for voice call service with NTN 110 in operation 602, such that NTN 110 provides the voice call service as a serving network for UE 200.

[0040] In operation 604, the UE 200 determines its location 224. Operation 604 is performed using operation 606, in which the GPS receiver 222 derives the location 224 of the UE 200 from the GPS signals 220 received by the UE 200.

[0041] In operation 608, UE 200 sends an emergency call 300 to NTN 110. Emergency call 300 includes a message containing UE 200's location 224 and HPLMN ID 212, which is an identifier of the HPLMN of UE 200. In some examples, emergency call 300 includes an E911 voice call or an E112 voice call. In some examples, sending emergency call 300 to NTN 110 includes sending a SIP Invite 302, and SIP Invite 302 includes the location 224. In some examples, sending emergency call 300 by UE 200 includes sending the IMSI 204 of SIM card 202 within UE 200. In some examples, IMSI 204 is stored within SIM card 202 within UE 200. In some examples, the HPLMN of UE 200 is identified within IMSI 204.

[0042] In operation 610, NTN 110 receives emergency call 300 from UE 200. In some examples, receiving emergency call 300 by NTN 110 includes receiving SIP INVITE 302. As shown in block 612, NTN 110 does not select a PSAP for routing emergency call 300 (i.e., NTN 110 does not select PSAP 102). Instead, NTN 110 determines a PDN GW that is indicated to handle emergency calls for the HPLMN of UE 200.

[0043] Operation 614 uses operations 616 and 618 to select a PDN GW 164 within the TN 130 to route the emergency call 300 to the PDN GW 164 in operation 614. In some examples, the TN 130 is the HPLMN of the UE 200, although in some other examples, the TN 130 is not the HPLMN of the UE 200 but is a designated PLMN designated for routing emergency calls from the UE 200. Operation 616 determines the HPLMN of the UE 200. In some examples, determining the HPLMN of the UE 200 includes receiving at least a portion of the IMSI 204 of the UE 200 from the UE 200. In some examples, determining the HPLMN of the UE 200 includes receiving the HPLMN ID 212 from the UE 200, and / or identifying the MCC 206 and the MNC 208. In some examples, the HPLMN of UE 200 is the TN 130 with the selected PDN GW 164. In some examples, the HPLMN of UE 200 is different from the TN 130 with the selected PDN GW 164.

[0044] Operation 618 uses the HPMLN of UE 200 to identify PDN GW 164. In some examples, this includes identifying PDN GW 164 in emergency PDN GW identification field 404. This may involve identifying PDN GW 164 in mapping table 406 stored in MME 113 of NTN 110. In some examples, identifying PDN GW 164 includes identifying the FQDN of PDN GW 164 or the IP address of PDN GW 164. Operation 620 routes the emergency call 300 to the selected PDN GW 164. In some examples, routing the emergency call 300 to the selected PDN GW 164 includes forwarding the SIP INVITE 302 to the selected PDN GW 164.

[0045] In operation 622, the TN 130 receives the emergency call 300 from the NTN 110. In some examples, receiving the emergency call 300 by the TN 130 includes receiving the SIP invite 302 from the NTN 110. In operation 624, the TN 130 retrieves the location 224 of the UE 200. Some examples perform operation 624 using operation 626, where the TN 130 extracts the location 224 of the UE 200 from the received emergency call 300 (e.g., from within the SIP invite 302).

[0046] In operation 628, the TN 130 selects a PSAP 102 using the location 224 of the UE 200. In some examples, selecting the PSAP 102 by the TN 130 includes using the MME 133 of the TN 130, and in particular, an emergency PDN GW identification field stored in a database within the MME 133. In some examples, selecting the PSAP 102 includes determining a PSAP having a jurisdiction 104 that includes the location 224 of the UE 200. In operation 630, the TN 130 routes the emergency call 300 to the selected PSAP 102.

[0047] Figure 7 A flowchart 700 illustrates exemplary operations associated with an example of the architecture 100 for routing emergency calls made through an NTN. In some examples, at least a portion of the flowchart 700 may be used. Figure 10 Flowchart 700 begins with operation 702, which includes receiving an emergency call from a UE by the NTN. As shown in 704, the NTN does not select a PSAP for routing the emergency call. Operation 706 includes the NTN selecting a PDN GW in the TN to route the emergency call, and operation 708 includes routing the emergency call to the selected PDN GW.

[0048] Figure 8A flowchart 800 illustrating exemplary operations associated with an example of architecture 100 is shown. In some examples, at least a portion of flowchart 800 may be used. Figure 10 800 is executed by one or more computing devices 1000. Flowchart 800 begins with operation 802, which includes receiving, by the TN, an emergency call from a UE using the NTN. Operation 804 includes determining, by the TN, the location of the UE. Operation 806 includes selecting, by the TN, a PSAP using the location of the UE. Operation 808 includes routing the emergency call to the selected PSAP.

[0049] Figure 9 Flowchart 900 illustrates exemplary operations associated with an example of architecture 100. In some examples, at least a portion of flowchart 900 may be used. Figure 10 1000. Flowchart 900 begins with operation 902, which includes determining, by the UE, a location of the UE. Operation 904 includes sending, by the UE, an emergency call to the NTN, wherein the emergency call includes a message containing the location of the UE and an identifier of the HPLMN of the UE.

[0050] Figure 10 A block diagram of a computing device 1000 that can be used as any component described herein that may require computing or storage capacity is shown. The computing device 1000 has at least a processor 1002 and a memory 1004 that stores program code 1010, a data area 1020, and other logic and storage devices 1030. The memory 1004 is any device that allows information (such as computer-executable instructions and / or other data) to be stored and retrieved. For example, the memory 1004 may include one or more random access memory (RAM) modules, flash memory modules, hard disks, solid-state drives, permanent storage devices, and / or optical disks. The program code 1010 includes computer-executable instructions and computer-executable components, including any instructions required to perform the operations described herein. The data area 1020 stores any data required to perform the operations described herein. The memory 1004 also includes other logic and storage 1030 that performs or facilitates other functions disclosed herein or required by the computing device 1000. The input / output (I / O) component 1040 facilitates receiving input from users and other devices, and generates displays for users and outputs for other devices. The network interface 1050 allows communication over the network 1060 with a remote node 1070, which may represent another implementation of the computing device 1000. For example, the remote node 1070 may represent another of the aforementioned nodes within the architecture 100.

[0051] Additional Examples

[0052] An example method of making an emergency call through an NTN includes: receiving, by the NTN, an emergency call from a UE; not selecting, by the NTN, a PSAP for routing the emergency call; selecting, by the NTN, a PDN GW in the TN to which to route the emergency call; and routing the emergency call to the selected PDN GW.

[0053] An example system for routing emergency calls made through an NTN, comprising: a processor; and a computer-readable medium storing instructions that, when executed by the processor, are capable of: receiving, by the NTN, an emergency call from a UE; not selecting, by the NTN, a PSAP for routing the emergency call; selecting, by the NTN, a PDN GW in the TN to which to route the emergency call; and routing the emergency call to the selected PDN GW.

[0054] One or more example computer storage devices having computer-executable instructions stored thereon, which, when executed by a computer, cause the computer to perform operations including: receiving, by the NTN, an emergency call from a UE; not selecting, by the NTN, a PSAP for routing the emergency call; selecting, by the NTN, a PDN GW in the TN to which to route the emergency call; and routing the emergency call to the selected PDN GW.

[0055] Another example method of routing an emergency call made through the NTN includes: receiving, by the TN, an emergency call placed by a UE using the NTN from the NTN; determining, by the TN, a location of the UE; selecting, by the TN, a PSAP using the location of the UE; and routing the emergency call to the selected PSAP.

[0056] An example method of placing an emergency call by a UE through an NTN includes: determining, by the UE, a location of the UE; and sending, by the UE, an emergency call to the NTN, wherein the emergency call includes a message including the location of the UE and an identifier of the HPLMN of the UE.

[0057] As an alternative or in addition to other examples described herein, examples include any combination of the following:

[0058] - Emergency calls include: E911 voice calls or E112 voice calls;

[0059] - Receiving emergency calls from NTN including: receiving SIP INVITE

[0060] - Routing the emergency call to the selected PDN GW includes: forwarding the SIP invite to the selected PDN GW;

[0061] -Selecting the PDN GW includes: determining the HPLMN of the UE;

[0062] - Selecting a PDN GW includes determining: a PDN GW indicated to handle emergency calls for the HPLMN of the UE;

[0063] -PDN GW is within the TN;

[0064] - Selecting the PDN GW includes: identifying the PDN GW in the emergency PDN GW identification field;

[0065] - Selecting the PDN GW includes: identifying the PDN GW in a mapping table stored in the MME of the NTN;

[0066] - Determining the HPLMN of the UE comprises: receiving at least a portion of the IMSI of the UE from the UE;

[0067] -UE includes: cellular phone;

[0068] - NTN provides voice call services to UE as a serving network;

[0069] -NTN is used as VPLMN for UE;

[0070] -SIP INVITE contains the UE's location;

[0071] - Receiving an emergency call by the NTN includes: receiving a SIP invite from the UE;

[0072] - Determining the HPLMN of the UE comprises: receiving an identification of the HPLMN from the UE;

[0073] -The UE's HPLMN is identified within the UE's IMSI;

[0074] -The UE's IMSI is stored in the SIM card inside the UE;

[0075] - Determining the HPLMN of the UE includes: identifying the MCC and MNC of the HPLMN;

[0076] - The UE's HPLMN is the TN with the selected PDN GW;

[0077] - The UE's HPLMN is different from the TN with the selected PDN GW TN;

[0078] - Identifying the PDN GW includes: identifying the FQDN of the PDN GW or the IP address of the PDN GW;

[0079] - Receiving an emergency call by the TN includes: receiving a SIP invite from the NTN;

[0080] -Determining the location of the UE by the TN includes: extracting the location of the UE from the received emergency call;

[0081] - Selecting a PSAP comprises: determining a PSAP having a jurisdiction that includes the location of the UE;

[0082] -TN is not the UE's VPLMN;

[0083] -TN is not the UE's HPLMN;

[0084] -TN is the UE's HPLMN;

[0085] -TN is the designated PLMN designated for routing emergency calls from the UE;

[0086] -Selecting the PSAP by the TN includes: using the MME of the TN to identify the PSAP;

[0087] -Sending an emergency call to NTN includes: sending a SIP INVITE;

[0088] -Registering the voice call service by the UE with the NTN, so that the NTN includes a serving network for the UE;

[0089] - determining, by the UE, the location of the UE comprising: retrieving the location of the UE from a GPS signal received by the UE;

[0090] -Sending an emergency call by the UE includes sending the IMSI of the SIM card in the UE.

[0091] Unless otherwise specified, the execution or fulfillment order of the operations in the examples of the present disclosure shown and described in this article is not important. That is, unless otherwise specified, operations can be performed in any order, and the examples of the present disclosure may include additional or fewer operations than the operations of the present disclosure. For example, it is contemplated that it is within the scope of the aspects of the present disclosure to perform or execute a specific operation before, simultaneously or after another operation. It should be understood that the above-mentioned benefits and advantages may relate to one embodiment, or may also relate to several embodiments. When introducing the elements of various aspects of the present disclosure or their examples, the articles "one", "an", "the" and "said" are intended to mean one or more of the elements present. The terms "comprise", "comprising" and "having" are intended to be inclusive, and mean that other elements may exist in addition to the listed elements. The term "exemplary" is intended to mean "an example of..."

[0092] Having described aspects of the present disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of the aspects of the present disclosure as defined in the appended claims. As various changes could be made in the above-described structures, products, and methods without departing from the scope of aspects of the present disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A method of routing an emergency call made through a non-terrestrial network (NTN), the method comprising: Receiving an emergency call from a user equipment (UE) by the NTN; not selecting, by the NTN, a Public Safety Answering Point (PSAP) for routing the emergency call; a packet data network (PDN) gateway (GW) in a terrestrial network (TN) selected by the NTN to route the emergency call thereto; and The emergency call is routed to the selected PDN GW. 2 . The method of claim 1 , wherein the emergency call comprises an E911 voice call or an E112 voice call.

3. The method of claim 1 , wherein receiving the emergency call by the NTN comprises receiving a Session Initiation Protocol (SIP) invite, and wherein routing the emergency call to the selected PDN GW comprises forwarding the SIP invite to the selected PDN GW.

4. The method according to claim 1, wherein selecting the PDN GW comprises: Determining a Home Public Land Mobile Network (HPLMN) of the UE; as well as A packet data network (PDN) gateway (GW) is determined that is instructed to handle emergency calls for the HPLMN of the UE, wherein the PDN GW is within the TN.

5. The method according to claim 4, wherein selecting the PDN GW comprises: The PDN GW is identified in the Emergency PDN GW Identification field.

6. The method according to claim 4, wherein selecting the PDN GW comprises: The PDN GW is identified in a mapping table stored in a Mobility Management Entity (MME) of the NTN.

7. The method of claim 4, wherein determining the HPLMN of the UE comprises: At least a portion of an International Mobile Subscriber Identity (IMSI) of the UE is received from the UE.

8. A system for routing emergency calls made through a non-terrestrial network (NTN), the system comprising: processor; as well as A computer-readable medium storing instructions that, when executed by the processor, are operable to: Receiving an emergency call from a user equipment (UE) by the NTN; not selecting, by the NTN, a Public Safety Answering Point (PSAP) for routing the emergency call; a packet data network (PDN) gateway (GW) in a terrestrial network (TN) selected by the NTN to route the emergency call thereto; and The emergency call is routed to the selected PDN GW.

9. The system of claim 8, wherein the emergency call comprises an E911 voice call or an E112 voice call.

10. The system of claim 8, wherein receiving the emergency call by the NTN comprises receiving a Session Initiation Protocol (SIP) invite, and wherein routing the emergency call to the selected PDN GW comprises forwarding the SIP invite to the selected PDN GW.

11. The system of claim 8, wherein selecting the PDN GW comprises: Determining a Home Public Land Mobile Network (HPLMN) of the UE; as well as A packet data network (PDN) gateway (GW) is determined that is instructed to handle emergency calls for the HPLMN of the UE, wherein the PDN GW is within the TN.

12. The system of claim 11, wherein selecting the PDN GW comprises: The PDN GW is identified in the Emergency PDN GW Identification field.

13. The system of claim 11, wherein selecting the PDN GW comprises: The PDN GW is identified in a mapping table stored in a Mobility Management Entity (MME) of the NTN.

14. The system of claim 11 , wherein determining the HPLMN of the UE comprises: At least a portion of an International Mobile Subscriber Identity (IMSI) of the UE is received from the UE.

15. One or more computer storage devices having stored thereon computer-executable instructions that, when executed by a computer, cause the computer to perform operations comprising: Receiving an emergency call from a user equipment (UE) by a non-terrestrial network (NTN); not selecting, by the NTN, a Public Safety Answering Point (PSAP) for routing the emergency call; a packet data network (PDN) gateway (GW) in a terrestrial network (TN) selected by the NTN to route the emergency call thereto; and The emergency call is routed to the selected PDN GW.

Images