SIM-less calls to emergency services

Who you gonna call?

The policy for SIM-less calls to emergency services in CEPT countries has not changed in a decade but such calls can help save lives, says Vassil Krastev, ECO’s expert in numbering and network regulation.

The ability to initiate an emergency communication to summon help in distress is recognised as a citizen's right in many countries around the world. As a result of this and as required by legislation, special arrangements are made on electronic communications networks (ECNs) to carry emergency calls.

One can call for help 24/7 from fixed and mobile phones in case of an emergency by dialling an easy-to-remember short code, for example, the single European emergency number ‘112’ or other national emergency call numbers specified by the national regulatory authorities. The call is carried on the network with a high priority, and is free of charge to the caller.

Figure 1 Who you gonna call? [Source: deviantart.com]

While obviously not the Ghostbusters, a specially trained operator in the organisation in charge of first reception of emergency calls, the so-called Public Safety Answering Point (PSAP), will either deal with the emergency request directly or transfer the call to the most appropriate emergency service. Who they transfer the call to will depend on the national organisation of emergency services. Operators in many countries can answer the calls not only in their national language, but also in English or French, for example. If the callers do not know where they are, the operator will identify their physical location and pass it to the emergency authorities.

Some countries in Europe use the emergency number 112 only for any type of emergency, while others have different national, regional, or local numbers functioning alongside with ‘112’. In 2019 end-users in the EU called the single European emergency number 112 close to 150 million times. On average 73% of the calls were placed from mobile phones.

My phone says, "Emergency Calls Only / No SIM card"

To establish communication with the emergency services via a mobile phone the device must be able to connect to and register on a Public Land Mobile Network (PLMN). A PLMN has a geographical coverage area in which the base station(s) provide services (e.g., voice and data) to mobile subscribers. But how does the phone know which of the available PLMNs is its own? That kind of information, alongside others, is embedded in the Subscriber Identity Module (SIM)/Universal Subscriber Identity Module (USIM) card.

Figure 2 "Emergency calls only / No SIM card" (source: esato.com)

The SIM is used to identify and authenticate subscribers. A SIM card may contain a vast amount of information related to the subscriber, services or service provider-related information. There are two key identifiers stored on each SIM card: The International Mobile Subscriber Identity (IMSI) number and the Integrated Circuit Card Identifier (ICCID). The IMSI uniquely identifies the subscriber i.e., its account information and services. Its structure includes the Mobile Country Code (MCC), which indicates the country in which the network is located; Mobile Network Code (MNC), which identifies a network within a country; and a Mobile Subscription Identification Number (MSIN), which identifies individual subscriptions. The combination of MCC and MNC identifies the home PLMN. The second key identifier, the ICCID, is its unique serial number which identifies the physical SIM card and the SIM card issuer.

Another important number linked to the IMSI is the Mobile Subscriber Integrated Services Digital Network (MSISDN) number. Despite the long and complicated name, it is basically the mobile phone number associated with the SIM card. The pairing of MSISDN and IMSI enables a voice call or an SMS to be sent using an MSISDN and to be routed to a specific IMSI. So, when we call a mobile phone, it is the MSISDN number of the mobile that we call, not the IMSI.

If a mobile device needs to acquire network services such as voice, data, and multimedia, the mobile device first needs to select a suitable PLMN and search for a cell (base station) within the coverage of the PLMN. After finding an available cell, it will then ‘camp’ on the cell and initiate registration.

Provisions have been made in technical specifications for a device not fitted with a SIM – a SIM-less device – to have the capability to make an emergency call. In this case it is possible for the device to register on an available network for the sole purpose of facilitating an emergency call. When a device connects to a network in this way without a SIM it is referred to as being in a "Limited Service State" (LSS).

Even a device fitted with a valid SIM which cannot find a network cell to register on can enter a LSS on an available network for other reasons including when:

• It is not possible to register on a cell on its home network because of limited or no coverage;
• In the case of international roaming, there is no roaming agreement between the home network and other available networks;
• The device is SIM-locked and, even if it is fitted with a valid SIM from another provider it cannot connect to any available network; or
• The device is fitted with a valid SIM, but it is not seated in the device correctly.

This is an important distinction to make as some European countries have implemented a policy of not permitting an emergency call from a device that is SIM-less while allowing an emergency call from a device fitted with a valid SIM but in LSS for another reason.

Questions on the legislation and technical details around SIM-less calls were recently brought in front of the Court of Justice of the European Union (CJEU) in case C-417/18. On 5 September 2019, the CJEU ruled that calls to 112 from devices that are SIM-less should be located. The Court's ruling holds that the Universal Service Directive (USD) requires EU Member States, subject to technical feasibility, to ensure that the undertakings concerned make caller location information available free of charge to the authority handling emergency calls to the pan-European emergency number 112 as soon as the call reaches that authority, including in cases where the call is made from a device that is SIM-less. The Court's ruling was based on the prevailing legislation at the time.

According to the EC’s opinion in its intervention in the Court’s ruling, Article 26(2), of the USD is to be interpreted as not imposing an obligation to provide access to emergency services by dialling 112 if the call is made from a mobile device not fitted with a SIM card. However, that provision does not preclude Member States from establishing such a provision or obligation in their national law. Where the national law provides for the possibility to call the European emergency number 112 in the absence of a SIM card, information relating to the caller location must be made available to the authority handling the emergency calls.

The ECC's Working Group Numbering and Networks (WG NaN) is engaged in its project team, NaN3 “Emergency Communications”, working on various aspects of emergency communications such as access to emergency services from electronic communications networks and services, emergency caller location information and eCall.

ECC Report 225 provides a comprehensive overview of the various methods to obtain emergency caller location information and provide that information to the PSAP.

NaN3 has recently discussed the outcome of the public consultation on draft ECC Report 324, Study of issues related to calls to emergency services from devices that are SIM-less or in Limited Service State for another reason, which is expected to be approved for publication in May 2021.

The purpose of this ECC Report is to examine the situation regarding calls to emergency services in Europe from devices that are SIM-less or from devices that are in LSS for another reason, in order to fully understand:

• What is meant, in the context of this Report, by emergency calls from devices that are SIM-less and emergency calls from devices that are in LSS for another reason and to explain how such calls work;
• How to differentiate between calls from devices that are SIM-less and calls from devices that are in LSS for another reason;
• How caller location information for such calls can be provided to the Public Safety Answering Point (PSAP); and
• To consider the technical and legal implications of the Court's ruling on the provision of caller location information for emergency calls made from devices that are SIM-less in Europe.

According to one of the draft report’s findings, there has been no change in the situation regarding calls to emergency services from devices that are SIM-less in the last 10 years. Some 21 CEPT countries allow calls from devices that are SIM-less and eight CEPT countries prohibit it. There are also no known plans by the latter to change their policies in the future.

What if the car initiates an emergency call – eCall?

The eCall is a specific type of emergency call aimed at providing swift assistance to drivers involved in a collision anywhere in Europe. eCall has been mandatory from 31 March 2018 for all "new type" cars sold in Europe.

Regulatory and technical challenges of eCall, including the provision of a sustainable numbering framework, were already introduced in two ECC Newsletter articles – eCall numbering challenge and eCall: getting ready for 2018 in 2015 and 2017, respectively.

When a crash takes place, a car fitted with an eCall device (an in-vehicle system) will automatically call the pan-European emergency number 112 and establish a voice connection towards the relevant PSAP. It is also possible to make an eCall manually by pressing a button in the vehicle. When the in-vehicle system in such a car is triggered, either automatically or manually, it tries to register on an available PLMN to establish an emergency call towards the relevant PSAP.

The eCall may be implemented in two different ways. The first is referred to as the 112-based eCall service where eCalls are directly routed to the PSAP. The 112-based eCall concept benefits from its direct prioritised emergency link to the appropriate PSAP through the existing 112 mechanisms. The 112 call over the mobile network is required to work in all European countries for free, even if no roaming agreement between the vehicle’s home network and the guest network is in place.

The second is referred to as third party service supported eCall systems (TPS eCall services) where the first part of the eCall is routed to a service centre of a car manufacturer and the second part is subsequently routed by the TPS service centre to the PSAP. Private eCall provision (i.e. TPS eCall services) is based on commercial agreements among the involved actors, including mobile operators and PSAPs. 112-based eCall is mandatory while the implementation of TPS eCall is optional.

As part of the network registration process, and before call set-up, the identity of the subscriber - the IMSI - is sent to the subscriber’s PLMN Home Location Register/Home Subscriber Server for authentication. Should the IMSI authentication fail for any reason then, subject to network operator and national regulatory policies, it may not be possible to establish a communication with the emergency services.

In order to provide with the above-mentioned eCall functionalities, the vehicles need facilities to communicate with the PSAP. This is carried out by means of mobile networks utilising physical SIM-cards or embedded SIMs. In order to provide the service, MSISDN and IMSI resources are needed.

ECC’s WG NaN provided guidance to administrations on the assignment and use of numbering resources for eCall and how to address concerns of PSAPs, original equipment manufacturers and operators regarding regulatory certainty on the use of numbers for eCall in a 2017 ECC Recommendation on numbering for eCall.

In December, WG NaN amended the foresaid ECC Recommendation with an Annex that provides a central reference point for all electronic communications network operators and service providers in Europe seeking information on numbering ranges used for eCall. The Annex will be updated periodically as required and published in the ECO Documentation Database (https://docdb.cept.org).

As already mentioned above, emergency calls from SIM-less devices are prohibited in several European countries so the eCall in-vehicle system should always have a SIM card.

To sum up

The policy situation regarding calls to emergency services from devices that are SIM-less has not been changed in the last 10 years. Future policy changes to permit SIM-less calls to emergency services remain uncertain as some CEPT countries face a high number of false calls or hoax calls. In the second-hand market for mobile handsets, it is well-known that the functionality of the handset is tested by making an emergency call. This practice is discouraged by regulators and is one of the main reasons for some countries blocking access to emergency services from SIM-less devices.

Network-provided location information is available to the emergency services in countries which permit calls to 112 from SIM-less devices.

According to the CJEU court ruling, where calls to emergency services from SIM-less devices are supported in a Member State of the EU, caller location information must also be provided to the emergency services with the call, if technically feasible. However, the EC’s opinion states that a Member State of the EU is, in principle, free to decide whether or not to permit calls to emergency services from devices that are SIM-less.

Currently available and potential future technical solutions for the provision of caller location information should be examined to determine if it would be feasible to improve the accuracy and reliability of caller location information for emergency calls from SIM-less devices and for emergency calls from devices in LSS for another reason.

Depending on the solution for PSAPs, receiving the IMEI and IMSI may also be useful if one of these parameters can be used to access the operator databases containing location information.

For emergency calls from SIM-less devices or from devices in LSS for another reason, handset-provided location information cannot currently be sent to the emergency services by SMS (as an MSISDN is required) or by HTTPS (as a data connection is required).