hash stringlengths 32 32 | doc_id stringlengths 5 12 | section stringlengths 5 1.47k | content stringlengths 0 6.67M |
|---|---|---|---|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 5.2.1 Description
| To support the SMS delivery to the Emergency Response Centre via NAS based on local regulations, following aspects are included:
- study how to route the SMS via NAS procedures for the support of SMS delivery to local Emergency Response Centre, e.g. UE location determination, via SMS service centre of the serving PLMN;
NOTE 1: Identification of SMS delivery to Emergency Response Centre is based on the conclusion of other KIs.
- how to support Emergency Response Centre callback for sending short messages using regular SMS delivery service.
The key issue covers SMS delivery via NAS both in EPS and 5GS.
NOTE 2: The solutions for EPS and 5GS are based on same principles.
The key issue covers both roaming and non-roaming scenarios.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 5.3 Key Issue #3: SMS over IP Routing to Appropriate PSAP
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 5.3.1 Description
| The following aspects are to be studied:
- how and when to trigger location determination and location data sharing when sending short messages using SMS over IP for routing to Emergency Response Centre, considering both 3GPP and non-3GPP access scenarios;
- how to route short messages using SMS over IP to Emergency Response Centre serving the UE's location, according to the local regulations (in roaming case, the regulations applicable to the UE's location);
- how to support PSAP callback capabilities for sending and routing regular short messages using SMS over IP.
The key issue covers SMS delivery via IP both in EPS and 5GS.
NOTE 1: The solutions for EPS and 5GS are based on same principles.
The key issue covers both roaming and non-roaming scenarios.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6 Solutions
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.0 Mapping of Solutions to Key Issues
| Table 6.0-1: Mapping of Solutions to Key Issues
Key Issues
Solutions
1
2
3
1
X
2
X
3
X
4
X
X
5
X
X
6
X
X
7
X
X
8
X
9
X
10
X
11
X
12
X
13
X
14
X
15
X
16
X
17
X
18
X
X
19
X
X
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1 Solution #1: Support of SMS to EC indication and SMS user data header for SMS to EC
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1.0 High level principles
| The following high-level principles are proposed for the support of SMS to Emergency Centre (EC) service:
- A header is introduced within the SMS-SUBMIT TPDU, specifically within the TP-UDH. The header may include emergency-related information such as the requested emergency service type, callback identifiers, or other parameters required for accurate routing to a PSAP.
- When the UE determines that a message is a SMS towards EC message, the UE composes the SMS-SUBMIT TPDU including the header with emergency-related information and submits it using a Service Centre (SC) address configured for handling SMS to EC as outlined in GSMA NG.119 [11]. The SC address is carried in the SMS-SUBMIT RPDU (Relay Protocol Data Unit).
- The UE may also indicate towards the network at NAS layer that the MO data transport contains a SMS to EC.
- The serving network forwards the SMS to the SMSC. The SMSC applies emergency-specific processing and delivers the message to the appropriate PSAP, supporting use cases such as Text-to-9-1-1 (see ATIS J-STD-110 [10]).
- For cases where the UE does not detect that the SMS is a SMS to EC, the message is composed as a normal SMS without header with emergency-related information. The SMSC may inspect the Destination Address (TP-DA) of the SMS. If the TP-DA matches an entry in the network's provisioned emergency-number list, the SMS is classified as a SMS to EC. The network shall then internally flag the SMS as a SMS to EC and ensure that it is routed to the correct PSAP in accordance with applicable regulatory requirements.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1.1 Description
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1.1.1 UE Detected and Non UE Detectable SMS to EC
| To support reliable detection and routing of SMS to EC, the UE may include a header within the TP-UDH of the SMS-SUBMIT TPDU. The header may carry critical information such as a callback number, emergency service type and location information e.g. pre-registered civic address for the purpose of emergency, GPS/device-based location, or network-based location. Provision of such information at the point of message origination enables the network to more reliably determine whether a MO SMS requires emergency handling and to ensure accurate routing to the appropriate Public Safety Answering Point (PSAP). This mechanism reduces the risk of misrouted or delayed SMS to EC and thereby improves user safety.
The Destination Address TP-DA shall correspond to an emergency short code (e.g. 112, 911). The header in TP-UDH may contain the following emergency-related information:
- indication that the TP-UD contains a message to EC;
- callback number, if available;
- location information (e.g. pre-registered civic address, GPS/device-based location, or network-based location), if available;
- emergency service type (e.g. police, ambulance, fire).
The serving network may download additional emergency numbers to the UE to enable the UE to detect a SMS to EC.
In the case of non-UE detectable SMS to EC, the message will be handled as a normal SMS. The SMSC shall inspect the TP-DA of the SMS-SUBMIT TPDU. If the TP-DA matches an entry in the provisioned emergency-number list, the message shall be flagged as emergency traffic and routed to the appropriate PSAP in accordance with regulatory requirements.
The SMSC or SMS Router shall inspect the SMS-SUBMIT TPDU. If the header with emergency-related information is present in the TP-UDH, the network shall extract the included information (e.g. callback number, emergency service type and location information) and classify the message as a SMS to EC. The network may query the location retrieval functionalities in the network to obtain authoritative location information, apply local routing policies and ensure that the message is delivered to the correct PSAP in the serving country or region.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1.2 Procedures
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1.2.1 Roaming Handling
| For emergency messages initiated by a roaming user, the principle of Local Breakout is maintained, prioritizing service from the VPLMN based on local regulations. If the UE does not know its own location, the UE may retrieve its location information from the VPLMN, e.g. LRF lookup and the VPLMN routes the message directly to the local PSAP. The user data header contained in the TPDU maybe used to choose the correct service-type PSAP.
Editor's note: It is FFS if VPLMN does not support the required capability to route MO SMS to the local PSAP.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1.2.2 Callback Handling
| When the PSAP replies, it sends the message back to the TP-OA (MSISDN).
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.1.3 Impacts to Services, Entities and Interfaces
| UE:
- Support the inclusion of a header with emergency-related information in the TP-UDH of SMS-SUBMIT when originating SMS to EC.
- Indicate towards the NAS layer that the MO data transport contains SMS to EC.
SMSC/SMS Router:
- Inspect SMS-SUBMIT TPDU for presence of the header with emergency-related information in TP-UDH.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2 Solution #2: Capability and Identification of the SMS delivery to Emergency Response Centre
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.0 High level principles
| This solution aims to address KI#1 with the following key principles:
- The serving network provides indication of support for SMS delivery to Emergency Response Centre and the emergency number list to UE during UE registration/attach and IMS registration (in case of non-roaming), if SMS delivery to Emergency Response Centre is supported by the serving network based on local policy.
- The SMS delivery to serving network SMS service centre is routed by MME/SMSF and IMS/IP-SM-GW, based on the Relay layer RP-DA which include SMS service centre address/emergency call number, to the serving network SMS service centre.
- The SMS service centre is responsible to identify different type of emergency service based on the provided emergency number and route the SMS to corresponding Emergency Response Centre.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.1 Description
| This solution addresses KI#1 with the principles as described in clause 6.2.0.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.2 Procedures
| During the registration/attach and IMS registration procedure (in case of non-roaming), the AMF/MME/S-CSCF provides the indication of the supporting SMS delivery to Emergency Response Centre in the serving network and the emergency number list based on local policy.
For the SMS delivery to Emergency Response Centre, it's further described in solutions for KI#2/KI#3.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.2.1 Registration Procedures in 5GS
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.2.1.1 Registration procedure for SMS over NAS
| The following procedures are based on clause 4.13.3 of TS 23.502 [3] with the following additions (in bold underline).
Figure 6.2.2.1.1-1: Based on TS 23.502 [3], Figure 4.13.3.1-1: Registration procedure supporting SMS over NAS
1. During Registration procedure in 5GS defined in Figure 4.2.2.2.2-1, to enable SMS over NAS transporting, the UE includes an "SMS supported" indication in Registration Request in step 1-3 indicating the UE's capability for SMS over NAS transport. The "SMS supported" indication indicates whether the UE supports SMS delivery over NAS.
2. Step 4 to step 14 of the Registration procedure in Figure 4.2.2.2.2-1 are performed. The AMF may retrieve the SMS Subscription data and UE Context in SMSF data using Nudm_SDM_Get. This requires that UDM may retrieve this information from UDR by Nudr_DM_Query. The UDM includes the SMSF information in the Nudm_SDM_Get response message if the stored SMSF belongs to the same PLMN of the AMF. After a successful response is received and if SMS service is allowed, the AMF subscribes to be notified using Nudm_SDM_Subscribe when the SMS Subscription data is modified and UDM may subscribe to UDR by Nudr_DM_Subscribe. For an MPS-subscribed UE, the subscription data may include the MPS priority for Messaging indication. If the AMF receives the MPS for Messaging indication from UDM, the AMF stores the MPS for Messaging indication in the UE context.
The AMF can also receive UE context information containing SMSF Information from old AMF. When AMF re-allocation happens during the Registration procedure, the old AMF transfers SMSF Information to the new AMF as part of UE context in step 5 of Figure 4.2.2.2.2-1.
NOTE 1: The AMF can, instead of the Nudm_SDM_Get service operation, use the Nudm_SDM_Subscribe service operation with an Immediate Report Indication that triggers the UDM to immediately return the subscribed data if the corresponding feature is supported by both the AMF and the UDM.
3. If the "SMS supported" indication is included in the Registration Request, the AMF checks in the SMS Subscription data that was received in step 2 whether the SMS service is allowed to the UE. If SMS service is allowed and the UE context received in step 2 includes an available SMSF of the serving PLMN, the AMF activates this SMSF Address and continues the registration procedure. If SMS service is allowed but an SMSF of the serving PLMN was not received in step 2, the AMF discovers and selects an SMSF to serve the UE as described in clause 6.3.10 of TS 23.501 [2]. If there are multiple SMSF instances in the network and the SMS delivery to Emergency Response Centre is only supported by certain SMSF instances, the AMF selects the SMSF instances that supports the SMS delivery to Emergency Response Centre (e.g. based on the SMSF profile that indicates the support of SMS delivery to Emergency Response Centre).
4. Step 15 to step 20 of the Registration procedure in Figure 4.2.2.2.2-1 are performed.
5. The AMF invokes Nsmsf_SMService_Activate service operation from the SMSF. The invocation includes AMF address, Access Type, RAT Type, Trace Requirements, GPSI (if available) and SUPI. AMF uses the SMSF Information derived from step 3. Trace Requirements is provided if it has been received by AMF as part of subscription data. When the AMF determines the UE has the MPS for Messaging indication in UE context as specified in step 2, the AMF includes a Message Priority header with a value appropriate for MPS to indicate priority treatment.
6. The SMSF discovers a UDM as described in clause 6.3.8 of TS 23.501 [2].
7a. If the UE context for the current Access Type already exists in the SMSF, the SMSF shall replace the old AMF address with the new AMF address.
Otherwise, the SMSF considers this a Registration request from a new Access Type and the SMSF registers with the UDM using Nudm_UECM_Registration with Access Type. As a result, the UDM stores the following information: SUPI, SMSF identity, SMSF address, Access Type(s) in UE Context in SMSF data. The UDM may further store SMSF Information in UDR by Nudr_DM_Update (SUPI, Subscription Data, UE Context in SMSF data).
If the Nsmsf_SMService_Activate request contains two Access Types and one of them is already registered in the SMSF, the SMSF shall replace the old AMF address with the new AMF address for that Access Type. The SMSF shall then register the other Access Type with the UDM using Nudm_UECM_Registration request.
7b-7c SMSF retrieves SMS Management Subscription data (e.g. SMS teleservice, SMS barring list) using Nudm_SDM_Get and this requires that UDM may get this information from UDR by Nudr_DM_Query (SUPI, Subscription Data, SMS Management Subscription data). After a successful response is received, the SMSF subscribes to be notified using Nudm_SDM_Subscribe when the SMS Management Subscription data is modified and UDM may subscribe to notifications from UDR by Nudr_DM_Subscribe.
SMSF also creates a UE context to store the SMS subscription information and the AMF address that is serving this UE.
NOTE 2: The SMSF can, instead of the Nudm_SDM_Get service operation, use the Nudm_SDM_Subscribe service operation with an Immediate Report Indication that triggers the UDM to immediately return the subscribed data if the corresponding feature is supported by both the SMSF and the UDM.
8. The SMSF responds back to the AMF with Nsmsf_SMService_Activate service operation response message. The AMF stores the SMSF Information received as part of the UE context.
9. The AMF includes the "SMS allowed", indication and "SMS over NAS delivery to Emergency Response Centre supported/allowed" based on local policy (e.g. the function is supported in serving AMF/SMSF) to the UE in the Registration Accept message of step 21 of Figure 4.2.2.2.2-1 only after step 8 in which the AMF has received a positive indication from the selected SMSF.
The "SMS allowed" indication in the Registration Accept message indicates to the UE whether the network allows the SMS message delivery over NAS. The "SMS over NAS delivery to Emergency Response Centre allowed/supported" indicates to UE whether the network allows the SMS over NAS delivery to Emergency Response Centre. The AMF may also include the emergency number list to UE if the "SMS over NAS delivery to Emergency Response Centre allowed" is set.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.2.1.2 Attach procedure in EPS
| The SMS over NAS delivery to Emergency Response Centre is similar to 5GS procedure with the change that the MME takes to role of AMF/SMSF.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.2.2 IMS Registration procedure
| The following procedures are based on TS 23.204 [8] with the following additions (in bold underline). This procedure is considered when UE is in non-roaming.
Figure 6.2.2.2-1: Based on TS 23.204 [8], Figure 6.1: Registration procedure
1) The UE establishes IP connection.
2) At any time after the establishment of the IP connection, the UE registers at the S-CSCF according to the IMS registration procedures. Based on local policy (e.g. the function is supported in IMS/IP-SM-GW), the S-CSCF also indicates the support of SMS over IP delivery to Emergency Response Centre by including e.g. "+g.3gpp.smsip-delivery to Emergency Response Centre" parameter in the Feature-Caps field header in 200 (OK) response. The "+g.3gpp.smsip-delivery to Emergency Response Centre" parameter indicates to UE whether the network allows the SMS over IP delivery to Emergency Response Centre.
NOTE 1: For simplicity, not all messages between UE and S-CSCF and between S-CSCF and HSS are shown in detail.
3) S-CSCF checks the initial filter criteria retrieved from the HSS during the IMS registration procedure.
4) After successful IMS registration and based on the retrieved initial filter criteria, the S-CSCF informs the IP-SM-GW (AS) about the registration of the user. IMSI is informed to the IP‑SM‑GW (AS) when there is no MSISDN in the UE's IMS subscription profile.
5) The IP-SM-GW (AS) returns OK to the S-CSCF.
6) The IP-SM-GW (AS) sends IP-SM-GW Register Req to the HSS.
7) The HSS stores the received IP-SM-GW address if necessary or for MT-SMS without MSISDN (see clause 6.0a.2), uses it as an indication that the UE is available to be accessed via the IMS to trigger an Alert service centre message if the message waiting flag is set and responses to the IP-SM-GW (AS) with IP‑SM‑GW Register Res. IP‑SM‑GW gets the IMPU (SIP URI) for SMS delivery without TEL-URI from registration event package.
NOTE 2: IP-SM-GW Register Res can include the SC address to be used for this user in the subscriber data (see also clause 6.7).
NOTE 3: If the IP‑SM‑GW address stored in the HSS via registration procedure is not the same as the preconfigured IP‑SM‑GW address (if any), then the short message delivery attempted during registration can be unnecessarily delayed.
8) After successful registration of the IP‑SM‑GW address at the HSS the HSS checks whether message waiting data are stored and alerts all SCs using procedures described in TS 23.040 [13] (see also clause 6.5b).
Editor's note: Roaming scenario is FFS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.2.3 Impacts to Services, Entities and Interfaces
| UE:
- Handling "SMS over NAS delivery to Emergency Response Centre allowed" indication and emergency number list in Registration/Attach Accept messages.
- Support the handling of SMS over IP delivery to Emergency Response Centre during IMS registration procedure, e.g. support of "+g.3gpp.smsip-delivery to Emergency Response Centre" field header handling.
AMF/MME:
- Support the indication and in Registration/Attach accept with "SMS over NAS delivery to Emergency Response Centre allowed" indication and emergency number list.
S-CSCF:
- Support the "+g.3gpp.smsip-delivery to Emergency Response Centre" field header handling during IMS registration procedure.
SMSF/MME/IP-SM-GW:
- Support of SMS delivery to SMS service centre of the serving PLMN based on identification of SMS service centre address/emergency number.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.3 Solution #3: Identification of SMS to EC
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.3.0 High level principles
| The following principles are applied to this solution:
- During initial attach/registration, a UE indicates support for SMS to EC and may be provided with local emergency numbers corresponding to different service types as specified in TS 23.167 [9] for emergency calls.
- The UE detects a MO SM to EC.
- If SMS to EC is supported by the network, the UE sends a SM with the destination corresponding to the emergency number.
- Additionally, the UE may send emergency-related information within the body text of the Short Message, within the size limit. This information, e.g. "police", "person injured at x location", may be treated once it reaches the visited SMSC.
- Upon reception of the Short Message, the network detects that it corresponds to an SMS to EC based on the used emergency number. It can then route the SM to the appropriate EC.
- This solution is applicable to both SMS over NAS and SMS over IMS, via EPS or 5GS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.3.1 Description
| The solution addresses KI#1 by enabling the UE and the network to be aware of the support of SMS to EC, the available emergency numbers and their related emergency service type.
The UE indicates its support of SMS to EC during initial attach/registration. If the network supports SMS to EC, it shall indicate it to the UE during MME/AMF attach/registration complete message. The attach/registration message may also contain a list of local emergency numbers and their corresponding emergency type, reusing the procedure for emergency calls as described in TS 23.167 [9].
Other emergency-related information may be relevant to the network or EC. For instance, accurate UE location information, but any other user-related information could be useful. Typically, the use of SMS instead of call may be motivated by the user not being able or willing to make an emergency call, be it due to accessibility issues or other circumstances. Thus, some information, within the limit of SM may be included. This can be used by the SMSC and forwarded to the EC.
From the network side, being able to provide SMS to EC and having registered with the UE, it will be able to identify a SM addressed to an EC and send it according to the used emergency number as well as other potential additional information in the body of the SM.
With all the previous steps achieved, the network can successfully identify a Short Message addressed to an Emergency Centre and forward it to the appropriate EC.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.3.2 Procedures
|
Figure 6.3.2-1: Detection of a Short Message to Emergency Centre
1a. The UE indicates its support of SMS to EC during initial attach/registration and the network acknowledges it.
1b. Depending on local PLMN emergency services and regulations, MME/AMF may provision the UE with local emergency numbers and service types according to TS 23.167 [9].
2. Upon detection of a MO SM to EC, the UE prepares the SM with the corresponding emergency number and emergency type and may include additional emergency-related information in the SM body.
3. The UE sends the emergency SM to the MME/AMF/IMS with the corresponding emergency number/type. Additional emergency-related information, e.g. UE location, may be included in the SM body. For SMS over NAS, early indication in the UL NAS type may be included to indicate that this is a SMS to EC.
4. The MME/AMF/IMS can detect the SMS to EC according to the used emergency number. Additionally, in case of a SM over NAS, UL NAS type may indicate SMS to EC.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.3.3 Impacts to Services, Entities and Interfaces
| UE:
- Indicates support for SMS to EC to the network.
- Addresses SM to EC with appropriate emergency number.
- In the case of SMS over NAS, includes an UL NAS type "SMS to EC".
MME/AMF:
- Reports support of SMS to EC during attach/register complete message.
- In the case of SMS to EC over NAS, detects SM to be sent to EC with UL NAS type.
MME/AMF/IMS:
- Detects SMS to EC based on emergency number and type.
SMSC:
- May inspect body of the SM for emergency-related information.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.4 Solution #4: SMS to PSAP over NAS
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.4.0 High level principles
| The high-level principles of the proposed solution are as follows:
- The proposed solution focuses on SMS to Emergency Response Centre (SMS2EC) or PSAP over NAS.
- UE sends SMS2EC to the network via UL NAS TRANSPORT.
- There should be an emergency identifier included in the UL NAS TRANSPORT message content.
- The emergency identifier reuses the existing mechanism as emergency call.
- Whether to trigger Emergency Response Centre to callback via regular SMS delivery service depends on the UE support for regular SMS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.4.1 Description
| This solution addresses Key Issue#1 and Key Issue#2.
Currently the addresses of Emergency Response Centres/PSAPs vary in different areas even they belong to the same country. When UE triggers the request of SMS2EC service, it would be more flexible if the UE only needs to report certain emergency type identifier which is similar with the URN applied in emergency call. It is up to the network to reflect the received emergency type identifier to certain destination address of Emergency Response Centre/PSAP based on the local policy and deployment.
To assist the Emergency Response Centre/PSAP locate the UE more accurately, both the UE and the AMF may provide more UE location related information in the SMS2EC.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.4.2 Procedures
|
Figure 6.4.2-1: SMS to PSAP over NAS in 5GS
Editor's note: Procedure for EPS is FFS.
The steps of figure 6.4.2-1 are described as follows:
1. The UE performs initial registration for SMS over NAS and includes the 5GS update type IE in the REGISTRATION REQUEST message with the SMS requested bit set to "SMS over NAS supported", as described in clause 5.5.1.2.2 of TS 23.501 [2].
2. The UE triggers the request for SMS2EC over NAS with dedicated emergency type (e.g. sos.police, sos.ambulance, sos.fire, etc.). The UE encapsulates the NAS message with emergency type and UE location information included. The emergency type identifier is encapsulated in the Request Type IE of UL NAS TRANSPORT and UE location information may be encapsulated in the Payload container of UL NAS TRANSPORT.
3. The UE sends the NAS message to the AMF via UL NAS TRANSPORT.
4. The AMF identifies the UL NAS message as SMS2EC with the emergency type information in the NAS message IE.
5. The AMF forwards the SMS2EC to the SMSF by invoking Nsmsf_SMService_UplinkSMS service operation, including SUPI, SMS payload, emergency type identifier, UE location information and optionally UE location trends (e.g. from NWDAF) etc. The SMS payload may include the callback indication which could indicate the Emergency Response Centre whether to callback via regular SMS delivery service.
As it is an SMS2EC, the AMF may include the message priority indication in the request to SMSF.
6a. The SMSF determines the target address of the Emergency Response Centre/PSAP based on the emergency type identifier received from AMF and includes it in the SMS2EC destination address header.
6b-6c. The SMSF perform the reconstruction of SMS2EC. The SMSF may include the UE location information both from the UE and the AMF in the SMS2EC payload to assist the Emergency Response Centre/PSAP locate the UE more accurately.
In the case of excessive SMS2EC payload, the SMSF may need to manage the length the SMS payload within certain limit, or process the SMS2EC with Segmentation.
7. The SMSF sends the reconstructed SMS to the Emergency Response Centre/PSAP through SMSC. The Emergency Response Centre/PSAP may further send a callback regular SMS to the UE based on the callback indication included in the SMS payload.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.4.3 Impacts to Services, Entities and Interfaces
| Editor's note: Impacts on EPS entities is FFS.
UE:
- Encapsulates the NAS message with emergency type and UE location information included.
AMF:
- Identifies the SMS2EC over NAS by emergency type identifier.
- Determines the message priority of SMS2EC over NAS.
- Enhances the UE location information.
- Forwards the SMS2EC to SMSF with emergency type information.
SMSF:
- Stores the association between emergency type identifier and address of emergency response centre/PSAP.
- Identifies the SMS2EC by emergency type information.
- Includes the received UE location information in the message payload.
- Determines the address of emergency response centre/PSAP based on the emergency type information.
- Sends the message to the related Emergency Response Centre/PSAP.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5 Solution #5: Support of Short Message to Emergency Response Centre via SMS over NAS
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5.0 High level principles
| This solution aims to resolve Key Issue #1 & #2, i.e. "Support of Short Message to Emergency Response Centre via SMS over NAS". The solution principles shall follow the architectural assumptions described in clause 4.
To address the issue described in WT-1, the following solutions are proposed:
- UE sends a new indication during the Attach/Registration procedure with EPS/5GS, whether the UE supports emergency SMS over NAS and/or emergency SMS over IP.
- When the serving network receives the above indication from the UE, the serving network sends an indication in response to Attach/Registration procedure whether the serving PLMN supports emergency SMS over IP and/or emergency SMS over NAS.
- A UE receiving an indication that emergency SMS over NAS is supported in a serving PLMN but failed to send the SMS over NAS attempts emergency SMS over IP if configured in the UE, unless emergency SMS over NAS is supported over Non-3GPP access. In this case, the UE attempts to send the emergency SMS over NAS via Non-3GPP access first, prior to using emergency SMS over IP.
- If both emergency SMS over NAS and emergency SMS over IP are not supported in the serving network, it is up to the UE implementation how to proceed. The UE can, for example, try to choose another network to send the emergency SMS over IP or SMS over NAS (e.g. the UE can choose another network at the time when it detects that an SMS to EC needs to be sent). The UE can also try to establish an emergency call or indicate to the user that emergency SMS over IP or SMS over NAS is not possible.
To address the issue described in KI#-1, the following solutions are proposed:
- The UE uses the same mechanisms (local configuration and handling of emergency Number/emergency service and sub-service type received over NAS during attach/registration procedure).
The UE detects emergency SMS over IP and/or SMS over NAS based on used emergency numbers. Provisioning of emergency numbers and associated types or URN information as specified in clause 4.1 bullets 2a, 2b) and 2c) in TS 23.167 [9] applies.
To address the issue described in KI#1-1, the following solutions are proposed:
- When UE detects the sos emergency number and it does not have emergency registration for SMS, then UE shall complete emergency registration for SMS. During UE registration, when UE sends a registration request to the 5GC, the SMSF sends back the indication to the UE about emergency SMS service availability feature in the serving PLMN to the AMF and then AMF forwards the same indication (i.e. emergency SMS over NAS and SMS over IMS are allowed) to the UE in the registration accept.
- In the case of SMS over NAS in EPS during combined attach, the MSC/VLR can inform the MME on the support of emergency SMS routing or based on MME's local configuration (e.g. SGd interface case). The MME informs the UE about the emergency SMS routing in the serving PLMN.
- Any SMS sent back by the PSAP to the UE is handled as a regular SMS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5.1 Description
| This solution addresses Key Issue #1 & #2.
- The SMSF, if configured with local emergency support, sends the EM availability indication during the registration procedure. AMF informs the UE about the EM SMS feature.
- UE needs to do access control for a new upper layer event (e.g. EM SMS) to trigger a service request with the indication of emergency SMS.
- The AMF informs the SMSF that the SMS payload is for an emergency. The AMF also prioritises the NAS procedure based on the emergency indication.
- The SMSF do not need to use subscription data for emergency SMS cases and routes the SMS to local SMSC/PSAP. The SMSF can replace the RP-DA with a local SMSC address. It may also set a higher transport priority (e.g. the DRMP).
Editor's note: The security implication if any due to RP-DA replacement is to be studied in SA WG3.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5.2 Procedures
| During EPS/5GS registration, the UE indicates its capability to support SMS over NAS and/or SMS over IP. The serving network also indicates its capability to support these services in the registration response.
If the serving network has provided the above-mentioned SMS over NAS indication, then UE invokes the following procedures to send a Short Message to an Emergency Response Centre.
- Route a Short Message to the Emergency Response Centre via SMS over NAS via 5GS.
- Route a Short Message to the Emergency Response Centre via SMS over NAS via EPS (via MSC/VLR).
- Route a Short Message to the Emergency Response Centre via SMS over NAS via EPS (via SGd interface).
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5.2.1 Short Message routing to the Emergency Response Centre via SMS over NAS via 5GS
|
Figure 6.5.2.1-1: Short Message to Emergency Response Centre via SMS over NAS via 5GS
0. UE registration to the 5GS follows clause 4.13.3.1 of TS 23.502 [3] with the additional indication as described in clause 6.5.2. This additional indication can be sent by AMF.
1. If the UE is in the CM-IDLE state, then the UE follows the same procedure defined in clause 4.13.3.3 of TS 23.502 [3]. UE indicates the emergency cause indicator in the service request.
2. If the UE is in the CM-CONNECTED state, it follows the same procedure defined in clause 4.13.3.3 of TS 23.502 [3] and it sends an uplink SMS message then, the UE needs to do access control for a new upper layer event (EM SMS in the SMS body of the NAS payload) to trigger a service request. The UE trying to send SMS to EC uses a different payload type in UL NAS transport.
3. The AMF forwards this message to the SMSF. The AMF provides the UE location and informs the SMSF that the SMS payload is for EM.
4. The SMSF does not lookup subscription data and routes the SMS to the local SMSC/PSAP. The SMSF can replace the RP-DA with a local SMSC address, if it is not sending the SMS payload directly to PSAP. It may also set a higher transport priority (e.g. the DRMP).
5. If in step 2 the UE includes a short message service centre address in the RP-DA instead of the NAS payload type as "EM SMS", then the SMSF routes to the serving PLMN SMSC.
The SMSC/PSAP forwards the SMS /Submit report to the SMSF.
6. The SMSF forwards to the AMF.
7. The AMF forwards the SMS submit report to the UE.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5.2.2 Short Message routing to the Emergency Response Centre via SMS over NAS via EPS (via MSC/VLR)
|
Figure 6.5.2.2-1: Short Message to Emergency Response Centre via SMS over NAS via EPS (via MSC/VLR)
0. The attach procedure follows the procedure as specified in clause 5.2 of TS 23.272 [7] with the additional indication in the Attach Request/Response as described in clause 6.5.2. This indication can be sent by either MME or MSC/VLR.
1. The UE in idle-Mode or active-Mode follows the same procedure as defined in 8.2.2 of TS 23.272 [7] with additionally sending Emergency SMS as a different payload type in UL NAS transport.
2. The MME includes the location information (cell ID, tracking area, location area) and the payload type is EM SMS and forwards to the MSC/VLR in an Uplink Unidata message.
3. For roaming UEs, the MME does not send the EM SMS payload to the H-PLMN MSC/VLR; instead, it sends it to the local SMS-IWMSC.
4. If in step 3 the MME includes the short message service centre address in the RP-DA instead of the NAS payload type as "EM SMS", then the MSC/VLR routes it to the serving PLMN SMSC.
5. Alternatively, the MME can send the serving PLMN support of EM SMS based on local configuration without depending on the MSC/VLR. The MME forwards the EM SMS to the local SMSC for a roaming subscriber.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5.2.3 Route a Short Message to Emergency Response Centre via SMS over NAS via EPS (via SGd interface)
|
Figure 6.5.2.3-1: Short Message to Emergency Response Centre via SMS over NAS via EPS (via SGd interface)
0. The attach procedure follows the procedure as specified in clause 5.3.2.1 of TS 23.401 [5] with the additional indication in the Attach Request/Response as described in clause 6.5.2. This indication can be sent by MME.
1. The UE in idle-mode or active-mode follows the same procedure as defined in clause 5.3.4.1 of TS 23.401 [5] with additionally sending Emergency SMS as a different payload type in UL NAS transport.
2. The MME mandatorily includes the location info (cell ID, tracking area, location area) and the payload type is EM SMS, towards the SMSC.
3. If in step 2 the UE includes the short message service centre address in the RP-DA instead of the NAS payload type as "EM SMS", then the SMSF routes to the serving PLMN SMSC.
4. For roaming UEs, the MME does not send the Emergency SMS payload to the H-PLMN SMSC but rather sends it to a local SMSC.
5. The local SMSC identifies the EM service type and forwards it to the appropriate SMS-IWMSC/PSAP.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.5.3 Impacts to Services, Entities and Interfaces
| The solution has the following impacts:
UE:
- Need to support network feature indication from EPS and 5G core on the availability of Emergency Messaging.
AMF:
- Need to support a new NAS payload type for SMS meant for EC.
- Need to support feature indication to indicate serving PLMN's support for SMS routing to EC.
MME:
- Need to support a new NAS payload type for SMS meant for EC.
- Need to support feature indication to indicate serving PLMN's support SMS routing to EC.
SMSF:
- Replacement of RP-DA.
- Need to route to local SMSC for EM SMS.
MSC/VLR:
- Need to support SMS routing to EC.
- SMS to EC support indication to UE.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6 Solution #6: Support of Short Message Service Routing to Emergency Response Centre via NAS
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.0 High level principles
| This solution addresses KI#1 and KI#2.
The principles of this solution are listed below:
- The UE detects Short Message Service to Emergency Centre (SMS2EC) based on the used emergency number.
- If the UE detects that the destination number of an Short Message is an valid emergency number, UE includes the emergency number, associated emergency service type and UE's location in the SMS-SUBMIT TPDU. If the local SMSC address in the serving PLMN is available, the RP-DA is set to the local SMSC address.
- If the SMSF/MSC determines that the destination number is an emergency number and the RP-DA is not a local SMSC address in the serving PLMN (in the event the UE did not detect SMS2EC), the SMSF/MSC replaces the RP-DA with local SMSC address. SMSF/MSC may also obtain the UE's location from AMF/MME or GMLC/E-SMLC and provide it to the SMSC.
- Based on the emergency number, associated emergency service type and the UE's location, SMSC delivers the SMS2EC to the local emergency response centre (i.e. PSAP).
- The emergency number, local SMSC address and associated emergency service type are provided to the UE via mobility management procedures in EPS and 5GS.
- If the Emergency Response Centre (i.e. PSAP) needs to respond to the UE, the PSAP sends the reply message to the SMSC in PSAP's HPLMN. SMSC treats the reply message as regular MT SMS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.1 Description
| In order to support routing of Short Message to the Emergency Centre, the network provides the emergency numbers, local SMSC address and associated emergency service types to the UE during the Attach, TAU, Initial registration and Mobility registration update procedure. Additionally, the network signals an indicator indicating its capability to support routing of SMS2EC to the UE through mobility management procedures in both EPS and 5GS. The MO Short Message consists of CP-DATA/RP-DATA/TPDU/SMS-SUBMIT parts as defined in TS 23.040 [13].
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.1.1 UE detecting Short Message Service to Emergency Centre
| The following figure depicts how a Short Message is routed to the local PSAP in case of UE detecting SMS2EC.
Figure 6.6.2.1-1: MO SMS routed to the local PSAP in case of UE detecting SMS2EC
If UE detects that the destination number is an emergency number, the UE replaces the RP-DA with local SMSC address (e.g. a local SMSC number) and hence the Short Message can be delivered to a local SMSC. In addition, the UE also includes the emergency number and associated emergency service type and UE's location (e.g. Latitude and longitude, etc.) in the TPDU part of the SMS2EC. The local SMSC forwards the received Short Message to the corresponding PSAP, considering the emergency number and associated emergency service type extracted from the SMS-SUBMIT TPDU.
An example of RP-DATA included in SMS2EC is as below:
RP-DATA:
- RP-OA: Address of the originating UE.
- RP-DA: Address of the SMSC, e.g. local SMSC number.
- RP-User-Data:
- TP-OA: Address of the originating UE.
- TP-DA: Emergency number and associated emergency service category value as defined in TS 24.008 [19], e.g. 1121, where "112" is the emergency number and "1" is for police.
- UE's location related TPDU parameter: Latitude and longitude are typically stored as double-precision floating-point numbers. Each value requires 8 bytes, so a combined pair uses 16 bytes. UE's location related TPDU parameter can be an existing TPDU parameter (e.g. TP-User-Data-Header) or a new parameter.
Editor's note: How to support SMS2EC in the scenario where the UE is not provided with a local SMSC address is FFS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.1.2 UE not detecting Short Message Service to Emergency Centre
| The following figure depicts how a Short Message is routed to the local PSAP in case of UE not detecting SMS2EC.
Figure 6.6.2.2-2: MO SMS routed to the local PSAP in case of UE not detecting SMS2EC
For the non-UE detectable emergency number, UE treats the SMS2EC as a regular Short Message. Upon determining that the destination number is an emergency number and the RP-DA is not a local SMSC address in the serving PLMN (which suggests the UE did not detect an emergency), the SMSF substitutes the RP-DA with the local SMSC address. Besides, the SMSF may also provide the UE's location to the SMSC. The UE's location can be the ULI provided by AMF, or the precise location information acquired from GMLC. The emergency number and associated emergency service type is configured in SMSC, so that the SMSC can figure out the emergency service type using emergency number. Based on the emergency number, emergency service type and UE's location, SMSC forwards the Short Message to the corresponding PSAP.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.2 Procedures
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.2.1 MO SMS over NAS in EPS
| The following figure depicts the mobile originating procedure for SMS2EC in EPS.
Figure 6.6.2.1-1: MO SMS over NAS in EPS
0-1: If a UE that supports SMS2EC under CM-IDLE state is sending a Short Message, then UE and network perform the UE Triggered Service Request procedure firstly to establish a NAS signalling connection to MME. If the UE is under CM-CONNECTED state, steps 0-1 are skipped.
2a: UE builds a Short Message to be sent as defined in TS 23.040 [13] (i.e. the Short Message consists of CP-DATA/RP-DATA/TPDU/SMS-SUBMIT parts).
Scenario 1: UE detecting SMS2EC.
If the UE detects the used number is an emergency number, the UE includes the local SMSC address in the RP-DA and also includes the emergency number, associated emergency service type, UE's location in the SMS-SUBMIT TPDU. UE can obtain the local SMSC address (i.e. local SMSC number) during Attach or TAU procedures.
The type of emergency service for an emergency number is derived from the emergency service category value as specified in clause 10.5.4.33 of TS 24.008 [19]). The emergency service value is included in the TP-DA together with the emergency number. For example, to call the police, the TP-DA can be set to 1121, where 112 is the emergency number and 1 is the code for police.
The UE's location (e.g. latitude and longitude) can be included in an existing TPDU parameter (e.g. TP-User-Data-Header) or a new parameter.
The SMS2EC is encapsulated in an NAS message and sent to MME.
Scenario 2: UE not detecting SMS2EC.
Editor's note: How to support SMS2EC in EPS in scenarios where the UE cannot detect SMS2EC is FFS.
2b: MME sends the Short Message to MSC.
2c: MSC acknowledges receipt of the Short Message to MME.
2d: The MME forwards the SMS ack message from the MSC to the UE using downlink unit data message.
3-4: MSC forwards the Short Message to SMS-IWMSC. SMS-IWMSC establishes the connection to the SMSC and transfers the Short Message to SMSC.
Scenario 1: UE detecting SMS2EC.
MSC forwards the Short Message to the local SMSC based on the RP-DA. Based on the emergency number, emergency service type and UE's location obtained from the SMS TPDU, SMSC forwards the Short Message to the corresponding PSAP.
5: SMSC returns a Submit Report for the receipt of the Short Message to MSC.
6: MSC sends the Submit Report to MME. MME encapsulates the Submit Report in DL NAS message and send it to the UE. UE acknowledges receipt of the Submit Report to MME.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.2.2 MO SMS over NAS in 5GS
| The following figure depicts the mobile originating procedure for SMS2EC in 5GS.
Figure 6.6.2.2-1: MO SMS over NAS in 5GS
0-1: If a UE that supports SMS2EC under CM-IDLE state is sending a Short Message, then UE and network perform the UE Triggered Service Request procedure firstly to establish a NAS signalling connection to AMF. If the UE is under CM-CONNECTED state, steps 0-1 are skipped.
2a: UE builds a Short Message to be sent as defined in TS 23.040 [13] (i.e. the Short Message consists of CP-DATA/RP-DATA/TPDU/SMS-SUBMIT parts).
Scenario 1: UE detecting SMS2EC.
If the UE detects the used number is an emergency number, the UE includes the local SMSC address in the RP-DA and also includes the emergency number, associated emergency service type and UE's location in the SMS-SUBMIT TPDU. UE can obtain the local SMSC address (i.e. local SMSC number) during registration procedures.
The type of emergency service for an emergency number is derived from the emergency service category value as specified in clause 10.5.4.33 of TS 24.008 [19]). The emergency service value is included in the TP-DA together with the emergency number. For example, to call the police, the TP-DA can be set to 1121, where 112 is the emergency number and 1 is the code for police.
The UE's location (e.g. latitude and longitude) can be included in an existing TPDU parameter (e.g. TP-User-Data-Header) or a new parameter.
The SMS2EC is encapsulated in an NAS message and sent to AMF.
Scenario 2: UE not detecting SMS2EC.
If the UE cannot detect the used number is an emergency number, the SMS2EC is treated as a regular SMS by the UE, i.e. the UE includes the home SMSC address in the RP-DA and also includes the emergency number in the SMS-SUBMIT TPDU.
2b: AMF sends the Short Message to SMSF. For roaming scenario, the AMF discovers and selects an SMSF in VPLMN.
2c: SMSF acknowledges receipt of the Short Message to AMF.
2d: The AMF forwards the SMS ack message from the SMSF to the UE using downlink unit data message.
3-4: SMSF forwards the Short Message to SMS-IWMSC. SMS-IWMSC establishes the connection to the SMSC and transfers the Short Message to SMSC.
Scenario 1: UE detecting the Short Message.
SMSF forwards the Short Message to the local SMSC based on the RP-DA. Based on the emergency number, associated emergency service type and UE's location obtained from the SMS TPDU, SMSC forwards the Short Message to the corresponding PSAP.
Scenario 2: UE not detecting SMS2EC.
The SMSF checks the SMS management subscription data. Upon determining that the destination number is an emergency number, if the RP-DA is not a local SMSC address in serving PLMN (which suggests the UE did not detect an emergency), the SMSF substitutes the RP-DA with the local SMSC address in serving PLMN. The local SMSC address can be preconfigured in SMSF. Besides, the SMSF may also obtain the UE's location from AMF or GMLC and provide it to the SMSC. The emergency number and associated emergency service type is configured in SMSC, so that the SMSC can figure out the emergency service type using emergency number. Based on the emergency service type and UE's location, SMSC forwards the Short Message to the corresponding PSAP.
5: SMSC returns a Submit Report for the receipt of the Short Message to SMSF.
6: SMSF sends the Submit Report to AMF. AMF encapsulates the Submit Report in DL NAS message and send it to the UE. UE acknowledges receipt of the Submit Report to AMF.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.2.3 Emergency Response Centre Callback
| If the Emergency Response Centre (i.e. PSAP) needs to respond to the UE, the PSAP sends the reply message to the SMSC in PSAP's HPLMN. SMSC treats the reply message as regular MT SMS and the procedures for delivering MT SMS to the UE are described in clause 4.13.3 of TS 23.502 [3] and clause 8.2 of TS 23.272 [7].
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.6.3 Impacts to Services, Entities and Interfaces
| UE:
- Support to include SMSC address in the serving PLMN in RP-DA field and also include emergency number, associated emergency service type and UE's location in the SMS-SUBMIT TPDU part of the Short Message Service to Emergency Centre.
SMSF:
- Support to replace RP-DA with local SMSC address in the serving PLMN, upon determining that the destination number is an emergency number and the RP-DA is not a local SMSC address.
- Support to obtain UE's location from GMLC/E-SMLC via Location services and provide it to SMS-SC.
AMF/MME:
- Providing emergency numbers, associated emergency service types, local SMSC address in the serving PLMN to the UE.
- Support to indicate to the UE whether network supports routing of SMS to emergency centre.
- Support to select an SMSF/MSC that is enabled to support SMS2EC.
SMS-SC:
- Support to deliver the Short Message to the PSAP based on the emergency number, associated emergency service type and UE's location.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7 Solution #7: Enabling SMS over NAS for conditional local routing to Emergency Response Centre
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.0 High level principles
| This solution addresses KI#1 and KI#2 by enhancing short messages delivery using SMS over NAS and routing to local emergency response center (i.e. PSAP). This solution is proposed with the following principles:
- P1. Emergency Authentication Trigger: During Emergency Registration, the UE shall include a new authentication indication IE or set the new SMS Authentication Required bit in the 5GS update type IE. This explicit indication mandates the AMF/MME to perform immediate primary authentication to establish the necessary NAS security context for secure SMS transfer.
- P2. Negotiation of UE capability and network support for Conditional LBO Policy Override: For UEs in the Normal Registration State, Local Breakout for PSAP-destined SMS is negotiated between the UE and the Visted AMF as a conditional override to the default roaming policy.
- P3. Emergency Number Provisioning: The AMF shall provide the UE with the VPLMN's local Emergency Number List to ensure the UE uses the correct destination address in the MO SMS TPDU. This is based on existing mechanism.
- P4. Explicit Routing Trigger: The UE shall use a specific indicator in the Uplink NAS Transport message to explicitly signal to the AMF that the embedded SMS is for routing to a PSAP and requires the conditional LBO route.
- P5. Home Routed Fallback for routing efficiency: When Conditional LBO is not supported by the VPLMN, Home Routed SMS is enhanced by optionally passing the Visited SMSC Address to the UE, allowing the Home SMSC to perform efficient, direct routing to the local PSAP.
- P6. Non-Modification of TPDU: The core network functions (AMF/SMSF) shall maintain the integrity of the SMS-TPDU payload during transit.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.1 Description
| The solution requires the following enhancements to the existing protocols and network functions:
1. Clarification of Emergency Authentication:
- When a UE performs Emergency Registration and includes a new authentication indication IE or sets the SMS requested bit in the 5GS update type IE in the Registration Request message, the AMF/MME shall initiate primary authentication to ensure the creation of the NAS security context required for secure SMS over NAS transfer.
NOTE 1: The UE is not in limited state.
Editor's note: It is FFS whether and how the emergency registration procedure is used for UE not in limited state.
2. Conditional LBO Capability Negotiation:
- The UE network capability IE in the Registration Request message is extended to include a new SMS for LBO Support indication, to indicate the UE's capability and preference for MO SMS delivery using conditional LBO for routing to local PSAP.
- The Registration Accept message is extended to include a new optional IE, e.g. SMS for LBO Allowed indication, if the Visited AMF is configured to support this service for the roaming user.
3. Local PSAP Discovery:
- The Registration Accept message is enhanced to include the Emergency Number List IE to provide the local emergency numbers and emergency service types to the UE.
4. LBO Message Signalling:
- If the UE receives SMS for LBO Allowed indication during registration procedure and detects the emergency number for MO SMS, the UE indicates to the network using MO SMS over NAS delivery for LBO routing to local PSAP.
- In the Uplink NAS Transport message, a new value is defined for the Payload container type IE or a new emergency indication to explicitly signal to the AMF that the embedded SMS TPDU is destined for a PSAP and requires Local Breakout routing. The UE is also responsible for including current location information (e.g. Additional Mobile Location - AML) within the SMS-TPDU payload.
- The V-SMSC or the VPLMN's location function needs to validate or update the location data based on available network-based positioning data to ensure the most accurate location is provided to the local PSAP.
5. Home Routed Fallback Enhancements:
- Home Routed Fallback Enhancement: if Conditional LBO is not supported by the VPLMN, the AMF can optionally provide the visited SMSC Address to the UE in the Registration Accept message for use during Home Routed fallback.
- TPDU Integrity: All core network functions (AMF/SMSF/Home SMSC) shall maintain the integrity of the SMS-TPDU payload (TP-DA, TP-UD, etc.) during transit.
- The SMS-TPDU is enhanced with in a new dedicated routing field to carry the visited SMSC Address when provided by the UE in the Home Routed fallback scenario.
6. The principle of the MO SMS delivery using SMS over NAS include:
- UE Role: The UE builds the full message stack: SMS-SUBMIT TPDU (Telephony Protocol Data Unit) wrapped inside an RP-DATA PDU (Relay Protocol Data Unit). This entire package is the SMS-RPDU.
- NAS Transport: The UE places this SMS-RPDU inside the Payload Container of the Uplink NAS Transport message.
- AMF Role: The AMF extracts the payload. When the AMF interacts with the SMSF (Visited SMS Function) using the 5GC service operation, it forwards the core SMS-RPDA message. While the AMF doesn't necessarily transmit the SMS-RPDU directly to the SMSF (it uses the Nsmsf service), the AMF's job is to extract and handle the SMS-RPDU payload it received from the UE.
NOTE 2: The above principles are applied for EPS and 5GS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.2 Procedures
| Editor's note: It is FFS how the same principles are applied for EPS and 5GS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.2.1 MO SMS over NAS in 5GS
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.2.1.1 Emergency Registration Procedure in 5GS
| Figure 6.7.2.1.1-1 shows Emergency Registration procedure in 5GS.
Figure 6.7.2.1.1-1: Emergency Registration Procedure in 5GS
The following are the required enhancement for Emergency Registration Procedure:
1: The UE sends a Registration Request to the AMF. The message includes:
- 5GS registration type set to "emergency registration".
- A new Authentication indication IE or 5GS update type IE with the SMS requested bit set to "SMS over NAS supported" and a new SMS authentication required bit set to true (acting as an authentication trigger).
1a. The AMF recognizes the Emergency Registration and the explicit authentication need for SMS over NAS support. The AMF overrides the default deferral policy and initiates the primary authentication procedure immediately with the AUSF/UDM. The AMF performs authentication procedures to interact with UDM to ensure that the UE's credentials are validated before enabling SMS services.
2: AMF uses the Nudm_UECM_Registration operation/Nudm_UEAuthentication/ Service/ Nudm_SDM_Get/Nudm_SDM_Subscription service operations to interact with UDM.
3: Upon successful authentication, the AMF derives the NAS security context and continues the registration procedure. The AMF provides the VPLMN Emergency Number List and 5GS registration result indicating "SMS allowed" bit that confirms successful authentication and SMS for routing to local PSAPs services are authorized. If primary authentication fails, the AMF sends registration accept message with 5GS registration result indicating SMS not allowed to notify the UE that SMS over NAS is not possible for emergency registration due to lack of a security context or authorization, recommending fallback to another mechanism, e.g. normal registration procedure enhanced with SMS for LBO routing to PSAP as described in clause 6.7.2.1.2.
4: The AMF sends Registration Accept message to the UE indicating Emergency services supported and SMS service allowed/disallowed in the 5GS registration result.
5: The UE stores 5GS registration result for UE allowed/disallowed in UE context.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.2.1.2 Registration Procedure (VPLMN LBO Supported) in 5GS
| Figure 6.7.2.1.2-1 shows Registration procedure in 5GS.
Figure 6.7.2.1.2-1: Registration Procedure (VPLMN LBO Supported) in 5GS
The following are the procedure for Normal Registration (Negotiating Conditional LBO Capability):
1: The UE sends a Registration Request to the AMF, including the UE network capability IE with the SMS for LBO Support indication.
2: AMF includes SMS for LBO Support indication when using the Nudm_UECM_Registration operation/ Nudm_SDM_Get/Nudm_SDM_Subscription service operations to interact with UDM.
3- 7: Same as step 3-Step 8 in Figure 4.13.3.1-1: Registration procedure supporting SMS over NAS in TS 23.502 [3].
8: The V-AMF determines network support of SMS over NAS and SMS for LBO routing.
9: If conditional LBO for PSAP-destined SMS is allowed, the AMF sends a Registration Accept message to the UE, including the SMS for LBO Allowed indicator and the VPLMN Emergency Number List. The AMF may optionally include the visited SMSC Address IE.
9a: If conditional LBO for PSAP-destined SMS is not allowed, the AMF sends a Registration Accept message to the UE, omitting the MO PSAP SMS LBO Allowed indicator. The AMF includes the VPLMN Emergency Number List and may optionally include the visited SMSC Address IE.
10: The UE stores SMS allowed indication and SMS for LBO allowed indication (if available) in UE context.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.2.1.3 MO SMS over NAS Delivery in 5GS (VPLMN LBO Supported)
| Figure 6.7.2.1.3-1 shows MO SMS over NAS Delivery using LBO routing to local PSAP.
Figure 6.7.2.1.3-1: MO SMS over NAS delivery using LBO routing to local PSAP
The following are the procedure for MO SMS Delivery (Conditional LBO Trigger):
1: The UE performs Registration procedure as in Figure 6.7.2.1.2-1, or Emergency registration procedure in Figure 6.7.2.1.1-1.
2: The UE generates the SMS-SUBMIT TPDU with the local emergency number in the TP-DA field.
3: Based on SMS for LBO Allowed indication received and stored in UE context in step 1 and detected local emergency number, the UE sends SMS over NAS using an Uplink NAS Transport message with emergency indication or a new Payload container type IE, e.g. set to SMS for LBO routing.
4: The AMF receives the message and detects the emergency indication. The AMF overrides the default policy and selects a locally configured V-SMSF. If the AMF receives the "emergency indication" for MO SMS routing to local PSAP but the UE was not explicitly granted the SMS-LBO Allowed indication during registration (step 9 in Figure 6.6.2.1.2-1), the AMF shall ignore the emergency indication and follow the default Home Routed policy as described in Figure 6.7.2.1.4-1.
5: The AMF sends Nsmsf_SMService_UplinkSMS message including SMS-TPDU payload for LBO routing and SMS for emergency indication to the V-SMSF.
6: The V-SMSF determines that the MO SMS is for LBO routing.
7: The V-SMSF forwards MO SMS to the V-SMSC.
8: The V-SMSC identifies the MO SMS for LBO and routes it to local PSAP based on emergency number, emergency service type and location information, e.g. AML, indicated in the SMS-TPDU payload.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.2.1.4 MO SMS over NAS (VPLMN LBO Not Supported/Allowed - Home Routed Fallback)
| If MO SMS for LBO routing to local PSAP is not supported, the visited AMF applies the Home Routed policy. Figure 6.7.2.1.4-1 shows MO SMS over NAS Delivery in 5GS UE (VPLMN LBO Not Supported/Allowed- Home Routed Fallback).
Figure 6.7.2.1.4-1: MO SMS over NAS Delivery in 5GS (VPLMN LBO Not Supported/Allowed - Home Routed Fallback)
The following are the procedure for MO SMS over NAS Delivery in 5GS (VPLMN LBO Not Supported/Allowed - Home Routed Fallback) in Figure 6.7.2.1.4-1:
1: The UE performs Registration procedure as in Figure 6.7.2.1.2-1, or Emergency registration procedure in Figure 6.7.2.1.1-1.
2: The UE generates the SMS-SUBMIT TPDU with the local emergency number in the TP-DA field. If the UE received the visited SMSC Address IE in Registration procedure, the UE includes this address in a new dedicated routing field within the SMS TPDU.
3: Without SMS for LBO Allowed indication stored in UE context, the UE sends SMS over NAS using an Uplink NAS Transport message to the AMF.
4: The AMF receives the message and follows the default Home routed roaming policy, selecting the Home SMSF.
5: The visited AMF transmits/handles the SMS-RPDU which contains the SMS-TPDU and forwards the received SMS-RPDU message to the visited SMSF by invoking the Nsmsf_SMService_UplinkSMS service operation, including the full SMS message.
6: The V-SMSF retrieves the SMS-TPDU payload from SMS-RPDU and forwards SMS-TPDU payload to H-SMSF. The H-SMSF determines that the MO SMS TPDU is with emergency number and forwards MO SMS to the H-SMSC.
7: The H-SMSC identifies the MO SMS for routing to local PSAP in VPLMN based on emergency number, emergency service type and location information, e.g. AML, indicated in the SMS-TPDU payload. The H-SMSC also inspects the SMS TPDU payload for the visited-SMSC Address (if included by the UE). If present, the H-SMSC uses this address for direct routing to the visited SMSC Address for routing to local PSAP. If the visited SMSC Address is not present, the H-SMSC inspects the TP-DA and uses its global routing policy to route the message back to the appropriate visited SMSC for routing to local PSAP.
8: The H-SMSC routes the message to the V-SMSC.
9: The V-SMSC identifies the MO SMS and routes it to local PSAP based on emergency number, emergency service type and location information, e.g. AML, indicated in the SMS-TPDU payload.
Editor's note: It is FFS how to support Callback MT SMS over NAS delivery for local routing via V-SMSF.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.7.3 Impacts to Services, Entities and Interfaces
| Editor's note: The impacts for EPS is FFS.
UE:
- Negotiate the new UE capability using SMS for LBO Support indication for Conditional LBO Support for SMS routing to local PSAP for normal registration procedure.
- Indicate a new Authentication IE or 5GS update type IE with the SMS requested bit set to "SMS over NAS supported" and a new SMS authentication required bit set to true (acting as an authentication trigger) for emergency registration procedure.
- Store the optional visited SMSC Address IE if received from the AMF and include the stored visited SMSC address in a new routing field within the TPDU during Home Routed Fallback.
- Use the new explicit emergency indication for MO SMS delivery and routing to local PSAP when LBO is allowed.
AMF/MME:
- Handle the network support and new UE capability indication for SMS for LBO negotiation.
- Trigger primary authentication to establish NAS security context during Emergency Registration when SMS is requested.
- Optionally provide visited SMSC Address to the UE in the Registration Accept.
- Use SMS for LBO Allowance status and Payload container type or emergency indication to determine SMS routing path for MO SMS delivery using LBO vs. Home routed.
SMSF/MSC (VPLMN):
- Manage the lifecycle of the Local Routing Context using a dedicated timer and delete it upon expiry and successful MT Callback delivery.
- Support interworking with a V-SMSC supporting routing to local PSAP.
SMSC (Home PLMN):
- Need to be configured to support the optional visited SMSC Address in the TPDU payload for efficient Home Routed fallback.
- Maintain a global routing policy (inspecting TP-DA) for all Home Routed SMS when the new visited SMSC address field is absent or unsupported.
- Need to support roaming interface to forward SMS to visited SMSC.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8 Solution #8: SMS over NAS delivery to Emergency Response Centre based on emergency call numbers
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8.0 High level principles
| This solution aims to address KI#2 with the following key principles (considering the solutions for KI#1):
- The UE uses emergency call numbers/serving PLMN SM service centre address as RP-DA-destination.
- The SMSF/MME is responsible to deliver the SMS to the SM service centre based on the identification of the emergency number/serving PLMN SM service centre address.
- The serving SMS service centre is responsible to forward the SMS to the local Emergency Response Centre.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8.1 Description
| In this proposal, it is also assumed that UE is aware of the supporting capability of the network based on the solutions provided for KI#1 (e.g. UE is informed that SMS over NAS delivery to Emergency Response Centre is supported by the network during the UE Registration/Attach procedure).
The main change is SMSF/MME deliver the SMS to the SMS service centre based on the RP-DA field.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8.2 Procedures
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8.2.1 MO SMS over NAS delivery procedures
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8.2.1.1 MO SMS over NAS in CM-IDLE in 5GS
| The following procedures are based on clause 4.13.3 of TS 23.502 [3] with the following additions (in bold underline).
Figure 6.8.2.1.1-1: Based on TS 23.502 [3], Figure 4.13.3.3-1: MO SMS over NAS
1. The UE performs domain selection for UE originating SMS as defined in clause 5.16.3.8 of TS 23.501 [2] if SMS delivery via non 3GPP access is allowed and possible. If an UE under CM-IDLE state is going to send uplink SMS message, then UE and network perform the UE Triggered Service Request procedure firstly as defined in clause 4.2.3.2 to establish a NAS signalling connection to AMF.
2a. The UE builds the SMS message to be sent as defined in TS 23.040 [13] (i.e. the SMS message consists of CP-DATA/RP-DATA/TPDU/SMS-SUBMIT parts). The SMS message is encapsulated in an NAS message with an indication indicating that the NAS message is for SMS transporting. The UE send the NAS message to the AMF. When UE builds the SMS message to be sent to Emergency Response Centre, the RP-DA field includes the SMS service centre address/the emergency service number provided by the AMF when AMF sets the "SMS over NAS delivery to Emergency Response Centre allowed" indication during UE registration procedure.
2b. The AMF forwards the SMS message and SUPI to the SMSF serving the UE over N20 message by invoking Nsmsf_SMService_UplinkSMS service operation. In order to permit the SMSF to create an accurate charging record, the AMF adds the IMEISV, the current UE Location Information (ULI) of the UE as defined in clause 5.6.2 of TS 23.501 [2] and if the UE has sent the SMS via 3GPP access, the local time zone.
When the AMF determines that the UE has the MPS for Messaging indication set (enabled) in the UE context, the AMF includes a Message Priority header to indicate priority information. Other NFs relay the priority information by including the Message Priority header in service-based interfaces, as specified in TS 29.500 [14].
2c. The SMSF invokes Namf_Communication_N1N2MessageTransfer service operation to forward SMS ack message to AMF.
2d. The AMF forwards the SMS ack message from the SMSF to the UE using downlink unit data message.
3-5. The SMSF checks the SMS management subscription data. If SMS delivery is allowed, the procedure defined in TS 23.040 [13] or in TS 23.540 [15] applies. If the Message Priority header received in step 2 contains a value that indicates MPS, the SMSF may set the transport priority (e.g. the DRMP) to a value appropriate for MPS. If the RP-DA includes the serving SMS service centre address/emergency service number, the SMSF delivers the SMS to the SMS service centre of the serving PLMN. The SMS service centre delivers the SMS to corresponding Emergency Response Centre based on emergency numbers.
6a-6b. The SMSF forwards the submit report to AMF by invoking Namf_Communication_N1N2MessageTransfer service operation which is forwarded to UE via Downlink NAS transport. If the SMSF knows the submit report is the last message to be transferred for UE, the SMSF shall include a last message indication in the Namf_Communication_N1N2MessageTransfer service operation so that the AMF knows no more SMS data is to be forwarded to UE.
NOTE: The behaviour of AMF based on the "last message indication" is implementation specific.
If the UE has more than one SMS message to send, the AMF and SMSF forwards SMS /SMS ack/submit report the same way as described in step 2a-6b.
6c-6d. When no more SMS is to be sent, UE returns a CP-ack as defined in TS 23.040 [13] to SMSF. The AMF forwards the SMS ack message by invoking Nsmsf_SMService_UplinkSMS service operation to SMSF.
Editor's note: Undetectable SMS delivery to Emergency Response Centre is FFS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8.2.2 MO SMS over NAS delivery procedures in EPS
| The SMS over NAS delivery to Emergency Response Centre is similar to 5GS procedure with the change that the MME takes to role of AMF/SMSF.
Editor's note: SGs interface based on SMS delivery is FFS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.8.3 Impacts to Services, Entities and Interfaces
| UE:
- Support the capability of SMS over NAS delivery to Emergency Response Centre during registration procedure, e.g. accept "SMS over NAS delivery to Emergency Response Centre allowed/supported" indication in Registration Accept.
- Formulates the RP-DA in the RP-DATA with serving PLMN SMS service centre or emergency number provided by the AMF.
AMF/MME:
- Support the capability of SMS over NAS delivery to Emergency Response Centre during registration procedure, e.g. accept "SMS over NAS delivery to Emergency Response Centre allowed/supported" indication in Registration Accept.
SMSF/MME:
- Support of SMS delivery to SMS service centre of the serving PLMN based on the identification of the SMS service centre address/emergency number.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9 Solution #9: Support of SMS to Emergency Centre over NAS
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.0 High level principles
| This clause describes support for the emergency Short Message Service (SMS) over NAS. This solution is based on the architectures for SMS over NAS (see TS 23.272 [7], TS 23.401 [5], TS 23.501 [2], TS 23.502 [3]) and the architectural principles of Emergency Services (see TS 23.167 [9]).
SMS to Emergency Centre over NAS in this context is SMS over NAS using an emergency number as destination address. A key requirement for this service is that the emergency Short Message (SM) must be routed to a PSAP in the country where the UE initiating the emergency SM is located. This implies that SMS to Emergency Centre for roaming subscribers cannot be home routed while regular SMS is typically home routed.
This solution applies to UE detectable emergency numbers.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.1 Description
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.1.1 General
| This clause lists the additional functionality that is required to support SMS to Emergency Centre over NAS for roaming and non-roaming users.
High level description and signalling flows are described in TS 23.272 [7] Annex C for EPS and TS 23.502 [3] for 5GS. SMS to Emergency Centre over NAS in 5GS is based on the architecture defined in clause 4.4.2. It can be supported over 3GPP and non-3GPP access.
There is no capability negotiation between the UE and AMF. The UE that supports SMS to Emergency Centre over NAS shall replace the SMSC Address with the country code and the detected emergency number and the detected emergency number as destination address as defined in TS 23.167 [9] for the UE functionality.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.1.2 Service assumptions
| The following service assumptions are considered for supporting SMS to Emergency Centre over NAS:
- The UE that supports SMS to Emergency Centre over NAS and detects SMS to Emergency Centre over NAS based on used emergency numbers. Provisioning of emergency numbers and associated types as specified in clause 4.1 bullets 2a and 2b) of TS 23.167 [9].
- SM messages from the PSAP to the UE are routed like any other SM.
- Serving network can support SMS to Emergency Centre over NAS for own subscribers and inbound roamers.
- SMS Centre in the serving network supports SMS to Emergency Centre over NAS.
- There is no indication from the serving PLMN to the UE that SMS to Emergency Centre in supported. After the UE sends SMS to Emergency Centre over NAS it can get informed about the success or failure based on the existing SMS delivery notification using existing procedures.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.1.3 How the solution solves the key issues
| How does the solution address the study item
- How to identify a Short Message to Emergency Response Centre based on the use of emergency numbers.
- This is based on the existing routing of SMS and the emergency number used by the UE which is provisioned with emergency numbers and associated types. PLMNs already support detection of emergency numbers and the SMSF or the MME selects the Emergency Response Centre based on the emergency number
- Address aspects when serving PLMN does not support this feature, but UE supports it.
- Serving PLMNs are assumed to support emergency services to configured emergency numbers and thus support SMS to Emergency Centre over NAS and the ability to identify a Short Message to Emergency Response Centre.
- Whether and how to identify the type of emergency service (police, ambulance, fire brigade, etc.) using the same identification mechanism as for emergency calls.
- The UE uses the provisioned emergency numbers which identify the type of service and the user selects e.g. from UI of the phone with mechanisms out of scope of 3GPP.
- How to route a Short Message to Emergency Response Centre (i.e. PSAP) serving the UE's location, according to the local regulations (in roaming case, the regulations applicable to the UE's location).
- This is based on existing mechanisms for routing of SMS and in addition the SMSF or MME uses the UE location and the emergency number to select the PSAP.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.1.4 UE Functionality
| The UE that supports SMS to Emergency Centre over NAS shall support the functionality listed below (which needs to be added to TS 23.167 [9]):
- Identify the need to send SMS to Emergency Centre over NAS based on the use of emergency numbers.
- Performs domain selection for SMS to Emergency Centre over NAS as described in TS 23.221 [12].
- Replaces the SC Address that is configured with country code of the UEs serving PLMN and the emergency number e.g. +32112.
NOTE 1: If UE cannot determine country from serving PLMN, UE can use methods out of scope of the present solution to determine the county.
NOTE 2: After the UE sends SMS to Emergency Centre over NAS it can get informed about the success or failure based on the SMS delivery notification using existing procedures.
Editor's note: Whether the UE needs to replace the SC Address or an alternative solution with no SC Address replacement is preferred needs to be determined during evaluation phase.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.1.5 Domain Selection for UE originating SMS
| To allow for appropriate domain selection for SMS delivery, the Domain Selection for UEs originating SMS in TS 23.221 [12] needs to be augmented with the following:
- If the UE does not support SMS to Emergency Centre over IMS and if the UE supports SMS to Emergency Centre over NAS and UE detects that the SM destination address is an emergency number as defined in TS 23.167 [9], the UE shall attempt to deliver the SMS over NAS signalling.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.2 Procedures
| The MO SMS over NAS in CM-IDLE (baseline) procedure in clause 4.13.3.3 of TS 23.502 [3] is modified with the following additions (in bold underline).
Figure 6.9.2-1: MO SMS over NAS
1. The UE performs domain selection for UE originating SMS as defined in clause 5.16.3.8 of TS 23.501 [2] if SMS delivery via non 3GPP access is allowed and possible. If an UE under CM-IDLE state is going to send uplink SMS message, then UE and network perform the UE Triggered Service Request procedure firstly as defined in clause 4.2.3.2 to establish a NAS signalling connection to AMF.
2a. The UE builds the SMS message to be sent as defined in TS 23.040 [13] (i.e. the SMS message consists of CP-DATA/RP-DATA/TPDU/SMS-SUBMIT parts). The SMS message is encapsulated in an NAS message with an indication indicating that the NAS message is for SMS transporting. The UE send the NAS message to the AMF. For SMS to Emergency Centre the UE follows the procedures in TS 23.167 [9].
2b. The AMF forwards the SMS message and SUPI to the SMSF serving the UE over N20 message by invoking Nsmsf_SMService_UplinkSMS service operation. In order to permit the SMSF to create an accurate charging record, the AMF adds the IMEISV, the current UE Location Information (ULI) of the UE as defined in clause 5.6.2 of TS 23.501 [2] and if the UE has sent the SMS via 3GPP access, the local time zone.
When the AMF determines that the UE has the MPS for Messaging indication set (enabled) in the UE context, the AMF includes a Message Priority header to indicate priority information. Other NFs relay the priority information by including the Message Priority header in service-based interfaces, as specified in TS 29.500 [14].
Editor's note: Whether there are any implications related to MPS for Messaging as defined in TS 23.501 [2] is FFS.
2c. The SMSF invokes Namf_Communication_N1N2MessageTransfer service operation to forward SMS ack message to AMF.
2d. The AMF forwards the SMS ack message from the SMSF to the UE using downlink unit data message.
3-5. The SMSF checks the SMS management subscription data. If SMS delivery is allowed, the procedure defined in TS 23.040 [13] or TS 23.540 [15] applies. The SMSF sets proper DRMP value based on received Message Priority header in step 2. If the SMSF supports SMS to Emergency Centre and detects from the SMSC Address and the destination address contained in the SM the SMSF that the SM is for emergency, it sends the SM to the local SMS-GMSC/IWMSC for emergency.
6a-6b. The SMSF forwards the submit report to AMF by invoking Namf_Communication_N1N2MessageTransfer service operation which is forwarded to UE via Downlink NAS transport. If the SMSF knows the submit report is the last message to be transferred for UE, the SMSF shall include a last message indication in the Namf_Communication_N1N2MessageTransfer service operation so that the AMF knows no more SMS data is to be forwarded to UE.
NOTE: The behaviour of AMF based on the "last message indication" is implementation specific.
If the UE has more than one SMS message to send, the AMF and SMSF forwards SMS /SMS ack/submit report the same way as described in step 2a-6b.
6c-6d. When no more SMS is to be sent, UE returns a CP-ack as defined in TS 23.040 [13] to SMSF. The AMF forwards the SMS ack message by invoking Nsmsf_SMService_UplinkSMS service operation to SMSF.
Editor's note: Whether this procedure can be reused for EPS by replacing AMF+SMSF by MME is FFS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.9.3 Impacts to Services, Entities and Interfaces
| UE:
- detects that the SM destination address is an emergency number based on existing mechanisms and replaces the SC Address that is configured with country code of the UEs serving PLMN and the emergency number e.g. +32112.
SMSF/MME:
- process all MO-SMS and detects from the SMSC Address and the destination address contained in the SM the SMSF that the SM is for emergency, it sends the SM to the local SMS-GMSC/IWMSC for emergency.
- is configured to recognize emergency numbers of other countries for which inbound roamers are allowed to send SMS to Emergency Centre.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.10 Solution #10: SMS over NAS in 4G/5G to Support SMS Delivery to the Emergency Response Centre
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.10.0 High level principles
| To support SMS delivery to Emergency Response Centres via NAS, the following high-level solution principles apply for both EPS and 5GS:
- The UE may include an explicit indication towards MME/AMF to indicate the MO data containing SMS to Emergency Response Centre (EC).
- For cases where the UE cannot detect the SMS to EC, the message is transmitted as a normal SMS, with identification of SMS to EC performed by the network.
- Upon detection of a SMS to EC, the MME/AMF may trigger UE location retrieval.
- Location information may be provided together with the SMS towards the SMSC/SMS Router for delivery to the Emergency Response Centre. The functionalities of SMS Router are specified in TS 23.040 [13], TS 23.204 [8] and TS 23.272 [7].
- The MME in EPS or SMSF in 5GS forwards the SMS TPDU to the appropriate SMS-GMSC/SMS-IWMSC/SMS Router for onward routing.
- The SMSC, based on user data header information in TPDU described in Solution 1, forwards the SMS to the operator's dedicated emergency service network or directly to the Emergency Response Centre, in accordance with local regulatory requirements.
These principles apply to both roaming and non-roaming scenarios. Callback from the Emergency Response Centre to the UE is supported by reusing the regular SMS delivery service. The SMS from the Emergency Response Centre is delivered via the standard SMS path through the serving PLMN's SMSC.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.10.1 Description
| In EPS, the UE delivers the SMS to EC using SMS over NAS. If the UE is in idle mode and detects the intent to send an SMS to EC, it initiates the UE-triggered Service Request procedure. If both the UE and the MME support Control Plane (CP) CIoT EPS Optimisation for SMS transfer, the UE initiates a Control Plane Service Request (CPSR).
When CP CIoT EPS Optimisation is used, the UE encapsulates the SMS-SUBMIT TPDU in a CPSR message towards the MME. Otherwise, the SMS to EC is encapsulated within the Uplink NAS Transport message. The UE may include an explicit SMS to EC indicator in the NAS message to inform the MME that the payload contains a SMS to EC in the SMS TPDU.
If the SMS is identified as a SMS to EC, the UE may include an emergency indication. The MME may use this indication to trigger UE location retrieval using EPC Network Induced Location Request (EPC-NI-LR) as specified in clause 9.1.17 of TS 23.271 [18] and/or bypass applicable barring checks. The MME then forwards the SMS TPDU, along with the obtained location information, to the SMS-GMSC/SMS-IWMSC/SMS Router over the SGd interface using the MO-Forward-Short-Message-Request procedure. The SMSC subsequently delivers the SMS to the Emergency Response Centre in accordance with local regulatory requirements.
In 5GS, the UE delivers the SMS to EC via an Uplink NAS Transport message towards the AMF. When the SMS is identified as a SMS to EC, the UE includes an indication in the NAS message. The AMF may use this indication to bypass barring checks and/or to trigger UE location retrieval using the 5GC Network Induced Location Request (5GC-NI-LR) as specified in clause 6.10 of TS 23.273 [17].
The AMF forwards the SMS to the serving SMSF using the Nsmsf_SMService_UplinkSMS operation. The SMSF examines the RP-DA, and forwards it to the appropriate SMS-GMSC/SMS-IWMSC/SMS Router, which delivers the message to the SMSC. The SMSC, based on information contained in SMS user data header, transfers the SMS to the Emergency Response Centre as required by local regulation.
Callback from the Emergency Response Centre to the UE is supported using the regular SMS delivery service. The Emergency Response Centre sends the SMS via the operator's SMSC and the SMS is delivered to the UE over the standard downlink SMS path.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.10.2 Procedures
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.10.2.1 SMS in MME for 4G
| Figure 6.10.2.1-1 shows the procedures for SMS delivery to the Emergency Response Centre via SMS over NAS using the SMS in MME architecture option as described in Annex C of TS 23.272 [7].
Figure 6.10.2.1-1: Procedures for Emergency SMS Delivery via SMS over NAS in EPC
0. The UE attaches to the network using either Initial attach or Emergency Attach.
1. If the UE is in idle mode and detects the intent to send a SMS to EC, it initiates the UE-triggered Service Request procedure. If both the UE and the MME support Control Plane (CP) CIoT EPS Optimisation for SMS transfer, the UE initiates a Control Plane Service Request (CPSR).
When CP CIoT EPS Optimisation is used, the CPSR message carries the SMS-SUBMIT TPDU directly. Otherwise, in step 1a, the SMS is encapsulated within the Uplink NAS Transport message.
The UE may include an explicit SMS to EC indicator in the NAS message to inform the MME that the payload contains an emergency message in the SMS TPDU.
2. If the UE does not know its own location, the UE may retrieve its location information from the network. Or based on the indication described in step 1, the MME may trigger UE location retrieval using EPC Network Induced Location Request (EPC-NI-LR) in step 2a as specified in clause 9.1.17 of TS 23.271 [18] and/or bypass applicable barring checks.
3. The MME selects the target SMS-GMSC/SMS-IWMSC/SMS Router and forwards the SMS TPDU along with the location information using the MO-Forward-Short-Message-Request (OFR) message over the SGd interface, as specified in TS 29.338 [16].
4. The SMS-GMSC/SMS-IWMSC/SMS Router, based on the RP-DA to route the message to the appropriate SMSC.
5. The SMSC, based on the SMS-TPDU user data header information as described in Solution 1, forwards the message to the operator's dedicated emergency service network. For example:
- Advanced Mobile Location (AML) over NAS/SGd, defined in GSMA NG.119 [11], allows the visited SMSC to send the SMS directly to the PSAP or Emergency Call Centre network.
- Text-to-9-1-1, as specified in J-STD-110 [10], enables the SMSC to forward the SMS via the SMPP protocol to the Text Control Centre (TCC), which functions as a gateway to the PSAP.
6. The Delivery Report is sent to UE.
Editor's note: Whether this procedure can be reused for EPS deployment in SGs option is FFS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.10.2.2 SMS over NAS for 5G
| Figure 6.10.2.2-1 shows the procedures for SMS delivery to the Emergency Response Centre using SMS over NAS for 5G.
Figure 6.10.2.2-1: Procedures for Emergency SMS Delivery via SMS over NAS in 5G
0. The UE follows the procedures specified in clause 4.13.3 of TS 23.502 [3] for registration with SMS over NAS support. During the Registration procedure in 5GS, the UE includes an "SMS supported" indication in the Registration Request to indicate its capability for SMS over NAS transport.
1. If the UE is in CM-IDLE state and intends to send an uplink SMS message, the UE and the network perform the UE-triggered Service Request procedure as defined in clause 4.2.3.2 of TS 23.502 [3] to establish a NAS signalling connection to the AMF.
If the UE is in CM-CONNECTED state, this step is skipped and the procedure continues with step 2.
2. The UE builds the SMS message.
For a SMS to EC, the UE encapsulates the SMS in an Uplink NAS Transport message and includes a SMS to EC indication. The Uplink NAS Transport message is then sent to the AMF.
For a SMS to EC that is not detectable by the UE (e.g. based on number or configuration), the SMS is encapsulated in an Uplink NAS Transport message without the emergency indication and sent to the AMF.
3. If the UE does not know its own location, the UE may retrieve its location information from the network. Or based on the SMS to EC indication, the AMF may trigger UE location retrieval, using the 5GC Network Induced Location Request (5GC-NI-LR) in step 3a, as specified in clause 6.10 of TS 23.273 [17] and/or bypass applicable barring checks.
4. The AMF forwards the SMS to the appropriate SMSF serving emergency SMS by invoking the Nsmsf_SMService_UplinkSMS service operation.
5. The SMSF inspects the user data header contained in TPDU.
If the message is identified as a SMS to EC, the SMSF forwards it to the appropriate SMS-GMSC/SMS-IWMSC/SMS Router.
The SMSF then returns the SMS-Submit Report to the AMF using the Namf_Communication_N1N2MessageTransfer service operation. The AMF delivers the report to the UE via Downlink NAS Transport as described in clause 4.13.3.3 of TS 23.502 [3].
6. The SMS-GMSC/SMS-IWMSC/SMS Router, based on the RP-DA route the message to the appropriate SMSC.
7. The SMSC, based on the user data header information contained in TPDU, forwards the message to the operator's dedicated emergency service network. For example:
- Advanced Mobile Location (AML) over NAS/SGd, defined in GSMA NG.119 [11], enables the visited SMSC to deliver the SMS directly to the PSAP or Emergency Call Centre network.
- Text-to-9-1-1, as specified in J-STD-110 [10], enables the SMSC to forward the message via the SMPP protocol to the Text Control Centre (TCC), which functions as a gateway to the PSAP.
8. The Submit Report is sent to UE.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.10.3 Impacts to Services, Entities and Interfaces
| MME:
- MME uses SMS to EC indication to trigger location request.
AMF:
- AMF uses SMS to EC indication to trigger location request.
UE:
- UE indicates Emergency SMS indication towards MME/AMF.
SMSC:
- SMSC uses user data header information contained in TPDU to forward the message to a proper emergency service network.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.11 Solution #11: Emergency SMS to EC over NAS
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.11.0 High level principles
| The following principles are applied to this solution:
- The UE is normally registered with the network and emergency numbers are provisioned, as specified in TS 23.167 [9].
- SMS to EC via NAS is supported by both the UE and the network.
- The UE detects a MO SM addressed to an EC.
- The UE sending a SM to EC may send early indication of emergency communication via NAS.
- The SMSF and AMF send an acknowledgement to the UE.
- The SMSF forwards the report to the UE.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.11.1 Description
| Editor's note: EPS procedure is FFS.
This solution provides and end-to-end procedure to support the SMS to Emergency Response Centre via NAS.
After having registered to the network, the UE is authorised for SMS to EC. Depending on location and local regulation, it may also be provisioned with emergency numbers and corresponding service types (details will be addressed by solutions to KI#1).
Upon detecting an originating emergency SM, the UE sends an UL NAS transport message to the AMF containing the SMS body addressed to an EC. The AMF forwards it to the SMSF that requests the NRF and UDM for emergency SM service.
When granted service for emergency SMS, the SMSF forwards the emergency SM to the SMS-IWMSC or SMSC that sends it the appropriate EC and then the SMSF sends an ACK back to the UE.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.11.2 Procedures
| Editor's note: EPS procedure is FFS.
Editor's note: The deviation for the procedure of the MO SMS over NAS Figure 13.3.3-1 in TS 23.502 [3] is FFS.
The below figure shows the procedure to send an SMS to EC over the 5GS.
Figure 6.11.2-1: Procedure for SMS over NAS
0.0 Emergency number/information provisioning to the UE as specified in TS 23.167 [9].
0.1 UE originates a SM to EC.
1. The UE performs domain selection for UE originating SM as defined in clause 5.16.3.8 of TS 23.501 [2]
2a. The UE builds the SM to be sent to EC, as defined in TS 23.040 [13] (e.g. the SMS message consists of CP-DATA/RP-DATA/TPDU/SMS-SUBMIT parts). The SM is encapsulated in a NAS message with an indication indicating that the NAS message is for SMS to EC.
2b. In the 5GC, the AMF determines that the received message contains SMS to EC. The AMF forwards the SMS message/body and SUPI to the SMSF serving the corresponding UE2c. in the 5GC, the SMSF invokes Namf_Communication_N1N2MessageTransfer service operation to forward SMS ack message to AMF.
2d. The AMF forwards the SMS ack message from the SMSF to the UE using downlink unit data message via the RAN node.
3. The SMSF sends a Niwmsc_SMService_MoForwardSm service request to the URI of the serving SMS-IWMSC. The payload body of the request shall contain the SM record to be sent, the Service/emergency Centre address.
4. The SMS is delivered to EC from SMS-IWMSC or SMSC (for emergency services).
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.11.3 Impacts to Services, Entities and Interfaces
| The solution has the following impacts:
UE:
- Need to support indication to serving PLMN support for SMS to EC during Attach/Registration.
- Need to support a new NAS payload type for SMS to EC when initiating MO SMS to EC.
AMF:
- Need to support indication to UE of support for SMS to EC during Attach/Registration.
- Need to support a new NAS payload type for SMS to EC.
SMSF:
- Support routing to local SMS-IWMSC or SMSC for SMS to EC.
SMS-IWMSC or SMSC:
- Supports routing to EC.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.12 Solution #12: Support of Short Message Service to Emergency Response Centre via SMS over IP
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.12.0 High-level solution Principles
| This solution aims to resolve Key Issue #3, i.e. "Support of Short Message Service to Emergency Response Centre via SMS over IP". The solution principles shall follow the architectural assumptions as described in clause 4.
To address the issue described in WT-1, the following solutions are proposed:
- UE sends a new indication during the Attach/Registration procedure with EPS/5GS, whether the UE supports emergency SMS over IP and/or emergency SMS over NAS.
- When the serving network receives the above indication from the UE, the serving network sends an indication in response to the Attach/Registration procedure, whether the serving PLMN supports emergency SMS over IP and/or emergency SMS over NAS.
- A UE receiving an indication that emergency SMS over IP is supported in a serving PLMN but failed to send the SMS over IP attempts emergency SMS over NAS if configured in the UE, unless emergency SMS over IP is supported over Non-3GPP access. In this case, the UE attempts to send the emergency SMS over IP via Non-3GPP access first, prior to using emergency SMS over NAS.
- If both emergency SMS over IP and emergency SMS over NAS are not supported in the serving network, it is up to the UE implementation how to proceed. The UE can, for example, attempt to select an alternative network to send the emergency SMS over IP or SMS over NAS. The UE can also attempt to establish an emergency call or notify the user that emergency SMS over IP or SMS over NAS is not possible.
To address the issue described in WT-2, the following solutions are proposed:
- The UE uses the same mechanisms (local configuration and handling of emergency Number/emergency service and sub-service type received over NAS during attach/registration procedure).
The UE detects emergency SMS over IP and/or SMS over NAS based on the emergency numbers used. Provisioning of emergency numbers and associated types or URN information as specified in clause 4.1 bullets 2a, 2b) and 2c) in TS 23.167 [9] applies.
To address the emergency SMS over IP described in WT-3, the following solutions are proposed:
- When UE detects the SOS emergency number and it does not have emergency IMS registration for SMS, then UE shall complete emergency IMS registration for SMS. After completing the emergency IMS registration procedure, the UE sends an SMS as a SIP MESSAGE containing an emergency SMS in the payload to the P-CSCF in the serving PLMN. The P-CSCF forwards the SIP MESSAGE to an E-CSCF. The E-CSCF may optionally query the LRF to obtain the UE's location information. The E-CSCF then forwards the SIP MESSAGE, including the emergency short message, to an IP-SM-GW capable of handling emergency SMS. The IP-SM-GW selects an appropriate SMS-SC and forwards the emergency SMS to it. The SMS-SC selects an appropriate PSAP and delivers the emergency SMS to the selected PSAP based on the emergency service type.
- Any SMS sent back by the PSAP to the UE is handled as a regular SMS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.12.1 Description
| This solution addresses Key Issue #3.
- UE performs emergency IMS registration and sends SIP MESSAGE containing an R-URI set to the emergency number or sos-URN. The payload of the SIP MESSAGE contains the emergency SM.
- If E-CSCF queries the LRF and forwards the SIP MESSAGE to an IP-SM-GW able to handle emergency SMS.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.12.2 Procedures
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.12.2.1 Short Message routing to Emergency Response Centre via SMS over IP
| During EPS/5GS registration, the UE indicates its capability to support SMS over IP and/or SMS over NAS. The serving network also indicates its capability to support these services in the registration response.
If the serving network has provided the above-mentioned SMS over IP indication, and the UE decide to use SMS over IP for sending SMS to EC, then it follows the procedure below to send a Short Message to an Emergency Response Centre.
Figure 6.12.2.1-1: Procedure for Short Message to Emergency Response Centre via SMS over IP
0. UE emergency IMS registration follows the procedure as described in clause 7.2 of TS 23.167 [9].
1. If the UE decides to send an SMS over IP, then it sends a SIP MESSAGE to the P-CSCF in the serving network containing an R-URI set to either the SOS URN or an emergency number and includes the location of the UE. The SIP MESSAGE contains the emergency short message.
2. The P-CSCF forwards the SIP MESSAGE to an E-CSCF that is capable of handling emergency SMS over IP.
3. E-CSCF optionally queries the LRF to get user location information and determines a suitable PSAP address.
4. The E-CSCF includes the PSAP address in the SIP MESSAGE and forwards it to the IP-SM-GW configured in the E-CSCF.
5a. If the E-CSCF sends the PSAP address to the IP-SM-GW, the IP-SM-GW forwards the SMS to the PSAP based on the address received in step 4.
NOTE: The interface between the IP-SM-GW and the PSAP can be MAP-based or SIP over IP-based.
5b. If the IP-SM-GW receives the PSAP address from E-CSCF and can indicate the same to SMSC, then the IP-SM-GW will replace the destination address and send the SMS payload to SMSC.
6. SMSC sends the emergency SMS to the local PSAP This step is executed only if step 5b is used to deliver the emergency SMS via SMSC.
7. PSAP may send an acknowledgement to the IP-SM GW.
8-10. The successful response code 202, 'Accepted', is sent from the IP-SM-GW to the E-CSCF, then to the P-CSCF, and finally to the UE.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.12.3 Impacts on Services, Entities and Interfaces
| The solution has the following impacts:
UE:
- The UE needs to support sending and receiving feature support flag for emergency SMS over IP and/or SMS over NAS.
- The UE needs to support the IMS emergency registration when the UE needs to send an SMS to the emergency centre.
P/S/E-CSCF:
- P-CSCF needs to select E-CSCF during IMS emergency registration and route SMS to the emergency centre.
IP-SM-GW:
- IP-SM-GW needs to have the capability to forward emergency SMS to the local PSAP or local SMS-SC.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.13 Solution #13: Enhanced E-CSCF for SMS over IP Routing to Appropriate PSAP
| |
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.13.0 High level principles
| This solution addresses KI#3.
The E-CSCF functionality is expanded to support the SIP MESSAGE handling, routing decisions, policy control, and managing roaming messaging failures.
The SMS to EC message is primarily identified by the Emergency Service URN in the Request-URI. An explicit emergency service indication can be used in the signalling.
The messaging payload is expanded to include critical emergency metadata, such as the Service-Type (police/fire/ambulance), UE location, and a Callback ID.
The E-CSCF includes Emergency Services Query Key (ESQK) specified in TS 23.167 [9] or an equivalent call back identifier supported by the PSAP, in signalling toward the PSAP to serve as a number for the PSAP to call back the caller and as a key for the PSAP to query the LRF for updated location or identity information.
The solution principles apply across all access scenarios, including both EPS and 5GS, as they share the same fundamental IP-based emergency architecture.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.13.1 Description
| The proposed solution integrates SMS to EC functionality into the IMS core by enhancing the E-CSCF to manage SMS to EC handling, routing, location, and policy decisions. The entire architecture maintains consistency across both EPS and 5GS core networks.
The UE supports SMS over IP as specified in TS 23. 204, and is configured to use SMS over IP to send SMS to EC.
When the UE detects a request for SMS to EC, it initiates the service using an IMS Emergency Registration as specified in clause 7.2 of TS 23.167 [9].
The TP-UD in SMS-SUBMIT should contain specific Emergency Service-Type (police/fire/ambulance, etc.), UE location data (if available), and Callback Information (if available).
The UE then encapsulates the SMS to EC message contained in SMS-SUBMIT type PDU in a SIP MESSAGE method. The SIP message defined in RFC 3428 [25] should be enhanced to include proper Emergency Service Indication. For example, the UE constructs an Emergency Service URN (e.g. urn:service:sos.text) in the Request-URI, which the P-CSCF is configured to recognize.
The UE then forward the SIP MESSAGE to the P-CSCF. The P-CSCF recognizes the incoming SIP MESSAGE contains an Emergency Service Indication. It then forwards the message to E-CSCF.
If the UE does not detect the emergency request, the session initially follows a normal establishment path to the P-CSCF. The P-CSCF may be configured to check the message destination against a database of local emergency numbers. If the destination matches a local or well-known emergency number, the P-CSCF treats the message as an emergency candidate and forwards it to the E-CSCF for emergency handling.
The E-CSCF is enhanced to support the routing of the received SIP MESSAGE. Upon receiving the SIP MESSAGE containing the Emergency Service Indication, the E-CSCF queries the LRF (Location Retrieval Function) using standardized interfaces to obtain the UE's validated location, following procedures outlined in TS 23.167 [9].
The E-CSCF then utilizes the location and the requested Service-Type to consult its routing tables to proper PSAP, as described in clause 6.13.1.1 for the deployment with ESInet and clause 6.13.1.2 for the deployment without ESInet, respectively.
|
9c43cb92c6eaab1e5d4db7c1c4cfea9a | 23.700-65 | 6.13.1.1 Deployment with ESInet
| The ESInet (Emergency Services IP Network) is defined by NENA i3 standard, NENA-STA-024.1.1-2025 [20]. The ESInet is the fundamental IP infrastructure for Next Generation 9-1-1 (NG9-1-1) [21], enabling the direct reception of multimedia emergency communications (voice, text, video, and data) at the PSAP with SIP signalling capabilities. The ESInet is explicitly designed to serve as the secure, resilient backbone that connects the network provider's IMS architecture directly to the PSAP (Public Safety Answering Point).
ESRP (Emergency Service Routing Proxy) is an i3 functional element which is a SIP proxy server that selects the next-hop routing within the ESInet based on location and policy. There is an ESRP on the edge of the ESInet, usually at the entrance to an NG9 1 1 PSAP [21]. There may be one or more intermediate ESRPs between them.
The Enhanced E-CSCF directly resolves and routes the SIP MESSAGE (using the specific Service URN) to the Emergency Service Routing Proxy (ESRP) or an equivalent SIP entity within the ESInet. The ESRP, which is compliant with NENA's i3 standards, NENA-STA-024.1.1-2025 [20], uses its own location and policy logic to guide the message to the proper PSAP instance.
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.