For the purposes of the present document, the terms and definitions given in TR 21.905 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905. Commercial Mobile Alert System (aka, Wireless Emergency Alert): Earthquake and Tsunami Warning System: Notification Area: PWS-UE: ePWS-UE:

For the purposes of the present document, the abbreviations given in TR 21.905 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905. CBC CBE CBS CMAS EOC ETWS KPAS PWS WEA ePWS

Recently there has been an interest to ensure that the public has the capability to receive timely and accurate alerts, warnings and critical information regarding disasters and other emergencies irrespective of what communications technologies they use. As has been learned from disasters such as earthquakes, tsunamis, hurricanes and wild fires; such a capability is essential to enable the public to take appropriate action to protect their families and themselves from serious injury, or loss of life or property. This interest to enhance the reliability, resiliency, and security of Warning Notifications to the public by providing a mechanism to distribute Warning Notifications over 3GPP systems is the impetus for this Public Warning System Technical Specification.

The following list gives the high level general requirements for Warning Notification delivery:

• PWS shall be able to broadcast Warning Notifications to multiple users simultaneously with no acknowledgement required.
• PWS shall be able to support concurrent broadcast of multiple Warning Notifications.
• Warning Notifications shall be broadcast to a Notification Area which is based on the geographical information as specified by the Warning Notification Provider.
• PWS capable UEs (PWS-UE) in idle mode shall be capable of receiving broadcasted Warning Notifications.
• PWS shall only be required to broadcast Warning Notifications in languages as prescribed by regulatory requirements.
• Warning Notifications are processed by PWS on a first in, first out basis, subject to regulatory requirements.
• Reception and presentation of Warning Notifications to the user shall not pre-empt an active voice or data session.
• Warning Notifications shall be limited to those emergencies where life or property is at imminent risk, and some responsive action should be taken.

PWS shall not modify or translate the Warning Notification content specified by the Warning Notification Provider. It is expected that Warning Notifications would likely include the following five elements:

• Event Description
• Area Affected
• Recommended Action
• Expiration Time (with time zone)
• Sending Agency

Additional elements may be present, based on regulatory requirements. There is a concern that URLs or telephone numbers in a Warning Notification could exacerbate wireless network congestion at a time when network traffic is already dramatically increasing as individuals contact police, fire, and rescue personnel, as well as their loved ones. Therefore, Warning Notifications should not contain anything that would drive immediate and debilitating traffic loads into the PLMN (i.e., URLs or dialable numbers) unless required by regional regulation.

Requirements for the granularity of the distribution of Warning Notifications include:

• Based on the geographical information indicated by the Warning Notification Provider, it shall be possible for the PLMN operators to define the Notification Area based on their network configuration of the area coverage such as distribution of cells, Node Bs, RNCs, etc.

PLMN operators shall, at a minimum, be able to support the following functionalities through interaction with Warning Notification Providers:

• Activation of Warning Notification delivery
  It shall be possible for multiple Warning Notifications to be activated concurrently from one or more Warning Notification Providers.
• Cancellation of Warning Notification delivery
  A cancellation is a command from the Warning Notification Provider to stop dissemination of a specific Warning Notification.
• Updating of Warning Notification delivery
  Warning Notification Providers update a previous Warning Notification to provide new instructions/information to the PLMN operator. When the Warning Notification Provider updates a previous Warning Notification they provide an identifier that allows the PLMN operator to associate the updated Warning Notification with the previous Warning Notification.

Additional functionality may be required based on regulatory or operator policy requirements.

It shall be possible for PWS-UEs that are enabled for Warning Notifications in the HPLMN to receive Warning Notifications from the VPLMN supporting PWS when roaming. A PWS-UE that does not support the PWS requirements of the VPLMN's PWS service may not receive Warning Notifications from that VPLMN.

Security requirements are as follows:

• PWS shall only broadcast Warning Notifications that come from an authenticated authorized source.

The following requirements only apply when not roaming internationally:

• When required by regional or national regulations, the integrity of the Warning Notification shall be protected. If no such regulatory requirement exists, there shall be no integrity protection of Warning Notifications, and all Warning Notifications shall be presented to the PWS application on the PWS-UE.
• When required by regional or national regulations, the PWS shall protect against false Warning Notification messages. If no such regulatory requirement exists, there shall be no protection against false Warning Notifications, and all Warning Notifications shall be presented to the PWS application on the PWS-UE.

The PWS offered by a PLMN may be subject to PWS regional regulatory requirements and thus, the PWS offered may differ from PLMN to PLMN as well as from region to region within a PLMN.

Warning Notifications are expected to be delivered to the users while satisfying the following requirements:

• Quick Warning Notification delivery after the occurrence of Earthquake or Tsunami.
  Earthquake and Tsunami propagate very fast. The duration time between the actual occurrence of the disaster and its arrival is very short. The order of the duration time is around seconds or minutes at most. Therefore the Warning Notifications shall be delivered quickly to the users in the emergency impacted area so that they could take any actions to escape from danger.
• Accurate Warning Notification delivery.
  Warning Notification delivery urges the users to take the actions such as evacuation. Therefore, the Warning Notification shall be delivered to the users accurately in the Notification Area and the content of Warning Notification should be understandable for many types of users (i.e. impaired persons, foreigners).

Duration of the delivery time for PLMN operators is the time from the receipt of the Warning Notification by the PLMN operator, i.e. the edge of the 3GPP network, to the time that the Warning Notification is successfully delivered to the UEs. Provisioning of delivery of Primary and Secondary Notification may be required:

• Primary Notification shall be delivered within 4 seconds to the UE in the Notification Area even under congestion situation.
• Secondary Notification is delivered to the users in the Notification Area even under congestion situation.

The following are the requirements from the perspective of information element and amount of data. Both Primary and Secondary Notification shall:

• support at least 2 types of emergency events, which are Earthquake and Tsunami;
• be able to indicate the preferred UE behaviours when receiving Warning Notification, (e.g. whether to display text in the foreground, whether to ring a buzzer, whether to vibrate);
• be distinguishable from notifications generated for the purpose of testing, training and other notification services;
• be sent in an optimized type and amount of data, for example, a text with a certain length, by considering the delivery platforms for ETWS.

Primary Notification shall:

• convey data which is small enough to be sent quickly on the network.
• convey small amount of data to indicate the imminent occurrence of Earthquake and Tsunami, etc.

Secondary Notification may:

• convey a large amount of data in order to deliver text, audio to instruct what to do / where to get help, graphical data such as a map indicating the route from present position to evacuation site, time table of food distribution.

Requirements from the perspective of priority are as follows:

• Primary Notification has higher priority than Secondary Notification.
• Notifications shall be able to be sequenced by the PLMN according to priority of notification in case that Primary Notification and Secondary Notification should exist at the same time in PLMN.

Upon receiving Primary Notification which includes small amount of data to indicate the imminent occurrence of an Earthquake and/or Tsunami, the UE shall display the Warning Notification in a way that is easy to understand by the user, such as an icon or picture.

The Warning Alert and Response Network (WARN) Act was passed by the United States Congress in September 2006 and was signed into law on October 13, 2006, known then as CMAS. CMAS was later renamed as Wireless Emergency Alert (WEA). The Federal Communication Commission (FCC) released several Report and Order rulings for the Commercial Mobile Alert System. [1], [2], [3], [8] and [10]. As a result of these legislative and regulatory actions the Alliance for Telecommunications Industry Solutions (ATIS) and the Telecommunications Industry Association (TIA) agreed to develop ATIS and TIA standards to support the deployment of CMAS. This standard is listed in Clause 2. The scope of these specifications includes the support of Commercial Mobile Alert System (CMAS) alert message via the GSM/UMTS Cell Broadcast functionality and warning message delivery via E-UTRAN. These specifications covers the mapping of CMAS messages onto the 3GPP-defined Cell Broadcast functionality and warning message delivery functionality, as well as the CMAS application layer functionality from the reception of the CMAS alert message from the Warning Notification Provider to the point of reception by the CMAS capable mobile device. The CMAS functionality does not require modifications to the 3GPP-defined cell broadcast functionality. The following functional reference model is based on the diagram from Section III.B.10 of the FCC First Report and Order for the Commercial Mobile Alert System, FCC 08-99 [1]:

In addition to the General Requirements specified in Clause 4, the following requirements are specified for the deployment of CMAS. These CMAS specific requirements are based on the FCC Report and Orders listed in clause 6.1 and further specified in [4]. Warning Notifications shall support up to 360 characters of GSM 7 bit Default Alphabet [9] for E-UTRAN. The following classes of Warning Notifications shall be supported: Presidential, Imminent Threat, Public Safety, Child Abduction Emergency (e.g. AMBER) , and State/Local WEA Test. When a Presidential Warning Notification is received, it shall always be presented to the user whenever Cell Broadcast Service via GSM/UMTS or warning notification delivery via E-UTRAN is enabled on the UE. If the Presidential Warning Notification is received in English, then it shall be displayed by the UE. If the Presidential Warning Notification is received in a language other than English, then it shall only be displayed by the UE if the User has selected that language. A CMAS-capable User Interface (UI) shall support the ability for the user to opt-out of only the Imminent Threat, Public Safety and Child Abduction Emergency Warning Notifications. A CMAS-capable User Interface (UI) shall support the ability for the user to opt-in to the State/Local WEA Test notification. If the User has opted out of a Warning Notification class, then the Warning Notification for that class shall not be displayed by the UE. If the User has not opted out of a Warning Notification class, then any Warning Notifications for that class received in English shall be displayed by the UE. This also applies to Warning Notifications received in any additional languages that may be selected by the User. Warning Notifications may contain URLs and/or phone numbers. A CMAS-capable User Interface (UI) shall support the ability (e.g., a "click" touch input) for the user to navigate to the URL or initiate a voice call to the phone number which may be included in the Warning Notification [8]. The PLMN broadcasting CMAS Warning Notifications shall also broadcast corresponding CMAS Warning Notification Area(s) when the CMAS Warning Notification is required to adhere to the maximum 0,1 of a mile CMAS Warning Notification Area(s) overshooting as specified in [10]. This requirement applies only to LTE and NR accesses. A CMAS-capable UE shall utilize UE-Based Location Calculation (see TS 22.071) to determine whether it is located within the corresponding CMAS Warning Notification Area(s) in order to minimize overloading network LCS resources. Subject to opt-out and opt-in settings described above, a CMAS-capable UE shall present the CMAS Warning Notification sent if there is a corresponding CMAS Warning Notification Area(s) and if the CMAS-capable UE is able to determine that its location is within the corresponding CMAS Warning Notification Area(s). Otherwise, if a CMAS-capable UE is unable to or fails to determine its location, the CMAS-capable UE shall present the Warning Notification to the user. A CMAS-capable UE shall store presented Warning Notifications for at least 24 hours unless explicitly deleted by the user.

The generic name for the European Public Warning System is EU-ALERT. The letters EU will be replaced by characters identifying a particular country (e.g. NL-ALERT signifying the Netherlands, UK-ALERT signifying the United Kingdom). Such a strategy will allow each country to configure their own Public Warning System to meet their specific national requirements whilst adhering to a common core specification.

In addition to the General Requirements specified in Clause 4, the following requirements are specified for the deployment of EU-ALERT. These EU-ALERT specific requirements are further specified in ETSI TS 102 900 [6]. EU-ALERT shall support three types of Warning Notifications: Alert messages to warn citizens of an imminent emergency situation, Advisory messages of lesser urgency, and Amber alerts. The Alert messages shall be supported with three levels of severity. EU-Alert level 1 shall have no opt-out; levels 2 and 3 shall allow opt-out by the user. All levels of EU-ALERT messages shall be associated with a dedicated alerting indication. The Advisory messages have only one level. Advisory messages shall not be associated with any dedicated alerting indication. Depending on national requirements, Amber alerts may need to be broadcast as part of the EU-ALERT service. Amber alerts shall not be associated with any dedicated alerting indication. EU-ALERT shall support Warning Notifications in various languages. To support international roaming, it is expected that countries adopting EU-ALERT use the same Message Identifier for Warning Notifications in the local language. If Warning Notifications are broadcast in other languages besides the local language, then the Message Identifier for such Warning Notifications are expected to be the same across the countries adopting EU-ALERT. EU-ALERT shall be supported on GERAN, UTRAN, E-UTRAN and NG-RAN. EU-ALERT shall support that the PLMN broadcasting EU-ALERT Warning Notifications also broadcasts corresponding Warning Notification Area(s). This requirement applies only to E-UTRAN and NG-RAN. A EU-ALERT-capable UE shall utilize UE-Based Location Calculation (see TS 22.071) to determine whether it is located within the corresponding Warning Notification Area(s) in order to minimize overloading network LCS resources. Subject to opt-out and opt-in settings described above, a EU-ALERT-capable UE shall present the EU-ALERT Warning Notification sent if there is a corresponding Warning Notification Area(s) and if the EU-ALERT-capable UE is able to determine that its location is within the corresponding Warning Notification Area(s). Otherwise, if a EU-ALERT-capable UE is unable to or fails to determine its location, the EU-ALERT-capable UE shall present the EU-ALERT Warning Notification to the user.

Telecommunications Technology Association (TTA) has specified a Korean Public Alert System (KPAS) which is based on PWS in [7]. That specification includes the support of Korean Public Alert System (KPAS) messages via the LTE Warning Message Delivery functionality. The Korean Public Alert System (KPAS) specification [7] also specifies application layer functionality to handle the transmission of CBS data from CBE to CBC and support for transmission of the same public alert message to UEs belonging to different mobile network operators in Republic of Korea. The specification requires that the system supporting Korean Public Alert System (KPAS) shall transmit the public alert message with high priority in order to provide up-to-date information on emergency situations. (e.g. In Tsunami situation, it is recommended to deliver message between CBC and UE in several seconds.).

In addition to the General Requirements specified in Clause 4, the following requirements are specified for the Korean Public Alert System (KPAS) [7]:

• Two classes of Warning Notification shall be supported; class 0 & class 1.
• The classes are differentiated per opt-out function. Class 0 shall have no opt-out and class 1 shall allow opt-out by the user.

Different types of Warning Notification shall be supported: Extreme Emergency, Emergency, Public Safety, and Amber. The Extreme Emergency type Warning Notifications are defined as class 0 and the other types are defined as class 1. The characteristics of the Warning Notification shall follow the requirements specified in clause 4. The current implementation requirement is for the message of up to 90 characters text. In addition, Warning Notifications using the UCS2 coding scheme [9] shall support up to 157 characters and Warning Notifications using the GSM 7 bit Default Alphabet coding scheme [9] shall support up to 360 characters from LTE onwards. KPAS shall support Warning Notifications in various languages. If a Warning Notification is received in a language other than Korean, then it shall only be displayed by the UE if the user has selected that language. A PWS-UE in KPAS shall support two dedicated alerting indication (audio attention signals). Warning Notifications may contain URLs and/or phone numbers. A UE shall allow the user to navigate to the URL or initiate a voice call to the phone number which may be included in the Warning Notification. KPAS shall support that the PLMN broadcasting KPAS Warning Notifications also broadcasts corresponding Warning Notification Area(s). A KPAS-capable UE shall utilize UE-Based Location Calculation (see TS 22.071) to determine whether it is located within the corresponding Warning Notification Area(s) in order to minimize overloading network LCS resources. Subject to opt-out and opt-in settings described above, a KPAS-capable UE shall present the KPAS Warning Notification sent if there is a corresponding Warning Notification Area(s) and if the KPAS-capable UE is able to determine that its location is within the corresponding Warning Notification Area(s). Otherwise, if a KPAS-capable UE is unable to or fails to determine its location, the KPAS-capable UE shall present the KPAS Warning Notification to the user.

Requirements specified in the clause 9 do not apply for US WEA and Japan ETWS. Enhancements of Public Warning System (ePWS) define behaviours for UEs with no user interface or with a user interface that is incapable of displaying text-based Warning Notifications when receiving a Warning Notification. In addition, enhancements of Public Warning System (ePWS) is intended to improve the comprehension of a Warning Notification to the following categories of users:

• Users with disabilities who have UEs supporting assistive technologies beyond text assistive technologies; and
• Users who are not fluent in the language of the Warning Notifications.

Requirements defined for PWS-UEs in clause 4 are applicable for ePWS-UEs unless dedicated ePWS-UE requirements described in clause 9 supersede them. Specifically, roaming requirements specified in clause 4.7 and security requirements specified in clause 4.8 are applicable for ePWS-UEs.

The 3GPP system shall allow the content of a Warning Notification to include information that can be mapped to an event or a disaster and is identifiable by the ePWS-UEs. NOTE: The information included in the content of a Warning Notification may be an identifier of an event or a disaster.

The ePWS-UE with a user interface providing accessibility extensions to mobile users with disabilities shall be able to support the reception of a Warning Notification broadcast from the 3GPP network. The ePWS-UE with a user interface providing accessibility extensions to mobile users with disabilities shall be able to support the extraction of any information on the type of a PWS notified event or disaster from the received Warning Notification The ePWS-UE with a user interface providing accessibility extensions to mobile users with disabilities shall support the presentation of the information that improves the comprehension of Warning Notification by the accessibility extensions. A PWS-UE may support the extraction and presentation of information representing a disaster or an event identifiable by Warning Notifications.

Requirements specified in the clause 10 do not apply for US WEA and Japan ETWS. 3GPP system specified the relay functionality that is useful to extend the coverage supported by 3GPP system. With the relay functionality, PWS-UEs and ePWS-UEs that play the role of a relay UE or a remote UE conform to behaviours specified in the clause 10 when receiving a Warning Notification via the relay functionality.

A remote ePWS-UE and a remote PWS-UE shall be able to support the reception of a Warning Notification that is transmitted from an UE that supports the relay functionality. A remote ePWS-UE and a remote PWS-UE shall be able to automatically suppress duplicated notifications. A duplicate is a repetition of a same notification as determined by unique parameters. A remote ePWS-UE and a remote PWS-UE receiving a Warning Notification transmitted via an UE that supports the relay functionality shall behave in the same fashion as if it received the message directly from a 3GPP network. An UE that supports the relay functionality shall unconditionally forward the Warning Notification broadcast received from the network.