The ubiquitous SIM card has played a fundamental role in mobile telecommunications for over three decades. It is recognised by end users and provides a secure means for authenticating devices onto networks, all inside a removable “Secure Element”, which is easily transferrable between mobile devices.
Although the role of the SIM itself is not changing, the global industry responsible with unifying the mobile ecosystem called GSMA, has defined a radical new way to load it into devices. Now the SIM may be securely downloaded into a ‘Secure Element’ that can be permanently embedded inside any type of device. To enable this into reality, an ecosystem of trusted platforms and players has been facilitated by the GSMA to create the eSIM solution. It offers an equivalent level of security and protection to that provided by the removable SIM card.
Definition
An embedded SIM, eSIM (also called as eUICC) is not a traditional SIM card, instead it is a chip-based SIM that is directly soldered into a device at point of manufacture. The SIM itself is embedded with a Subscription Manager (SM), which is used to securely package profiles that can be provisioned on the device’s eUICC (Universal Integrated Circuit Card). It is a programmable SIM that can be reprogrammed over the air (OTA). eSIM and eUICC together form the architecture which is securely downloaded in the device and is fixed in the device permanently providing the facility of changing the network operator at any instance without physically removing the SIM.
eSIM Logo
eSIM basically is not tied to a specific Mobile Network Operator (MNO). It is embedded directly in the mobile device and no physical swapping of SIM is required to change the operator. Users can switch between the operators remotely on one device and can have multiple network operator profiles installed on the device.
HOW eSIM WORKS
The principle behind eSIM is simple. The integrity of traditional SIM cards is safeguarded by using secure facilities for their manufacture, which includes loading of software and operator credentials. Operator logistics channels then distribute the SIM cards to the required endpoints, for example retail shops, retail partners or enterprise customers managing fleets of connected devices. eSIM extends the reach of the secure facilities from specific physical locations to any location where the device can be reached over the internet. Also, eSIM protocols provide security and integrity for data transfer. This, however, is only one part of the challenge. As well as being secure, the distribution channels for SIM cards also contain ‘business logic’ which is required by various service models. In some channels, that logic may even dictate who has control of device connections. Unfortunately, it is not practical to combine this logic into a single technical solution for eSIM. The GSMA has created solutions suited to different types of channels. Which resulted in having two different set of solutions for that, one for the consumer solution and the other for machine-to-machine (M2M) solution:
- Consumer solution:
For the direct to consumer (customer) channel, this solution is required where the end user (or consumer) has direct choice of the operator supplying connectivity. Consumer solutions require a high degree of end user interaction, with the principle that the end user is familiar with operating the end user interface on the device and actively choosing their preferred network connectivity provider. This offers customers flexibility of choosing the operators when in different geographical regions. The users or consumers can connect to the network available in that country or area by requesting and downloading the profile details. The Consumer solution also targets enterprises who use devices targeted to the consumer market. - M2M solution:
For the machine to machine to consumer/IoT channels, this solution serves the needs of business-to-business customers, specifically in the Internet of Things (IoT) market.
Machine-to-Machine (M2M) is a solution technology that enables machines/devices to communicate with each other without human intervention. This is possible because of several Artificial Intelligence algorithms and Machine Learning. The data that are fetched with the IoT devices are fetched and analysed with the pre-existing data models. After processing, these devices communicate within themselves and make their own autonomous decisions. IoT devices are generally connected through wireless mediums which are prone to any unexpected circumstances like unfavourable weather conditions, network unavailability etc. The incorporation of eSIM with M2M/IoT can help to eliminate these problems. As it will be pre embedded, there will be no dependencies on any environmental or other factors as well as no manual human interference.
TECHNICAL DESCRIPTION OF AN eSIMs SOLUTION
1 - The M2M Solution
The GSMA M2M solution was the first Remote SIM Provisioning solution developed. There were two reasons for this:
- The M2M solution is simpler as interaction of end user is not required, or desirable, in the business to business to consumer (B2B2C) segment, and
- The immediate commercial need was for technical solutions that supported B2B2C deployments alongside regulatory requirements for the launch of services such as eCall.
Main System Elements for M2M Solution
Remote SIM Provisioning for M2M/IoT utilises a server-driven (push model) to provision and remotely manage operator Profiles. The solution is organised around 3 elements: the SM-DP (Subscription Manager - Data Preparation), the SM-SR (Subscription Manager - Secure Routing), and the eUICC (embedded Universal Integrated Circuit Card).
The diagram below is the high-level representation of the M2M main system elements. Beyond common SIM functions, such as SIM Toolkit and Bearer Independent Protocol (BIP) support, the M2M solution does not impose additional requirements on M2M devices to enable usage of eUICCs.
Machine-to-Machine (M2M) eSIM Architecture
- SM-DP:
The SM-DP (Subscription Manager - Data Preparation) is responsible for preparing, storing, and protecting operator Profiles (including the operator credentials). It also downloads and install Profiles onto the eUICC. - SM-SR:
The SM-SR (Subscription Manager - Secure Routing) is responsible for managing the status of Profiles on the eUICC (enable, disable, delete). It also secures the communications link between the eUICC and SM-DP for the delivery of operator Profiles. - eUICC:
The eUICC (embedded Universal Integrated Circuit Card) is a secure element that contains one or more subscription Profiles. Each Profile enables the eUICC to function in the same way as a removable SIM issued by the operator that created it. An eUICC may be built using any form factor from the traditional removable card to embedded formats soldered into devices.
2 - The Consumer Solution
The GSMA Consumer solution has been developed from the base provided by the M2M solution, with additional consideration of requirements for end user-managed devices. This solution is required to manage the use cases are more complex than the M2M solution. Consequentially, more features are required in the specification. In particular, the Consumer solution manages end user interaction via the mobile device end user interface, and also supports standalone and companion device types.
Main System Elements for Consumer Solution
Instead of server-driven provisioning such as the one present in M2M solution, the GSMA Remote SIM Provisioning Consumer solution follows a client driven (pull model), and it also enables control over remote provisioning and local management of operator Profiles by the end user of the device. The solution is organised around 4 elements: the SM-DP+ (Subscription Manager - Data Preparation +), the SM-DS (Subscription Manager - Discovery Server), the LPA (Local Profile Assistant) and the eUICC.
Remote SIM Provisioning for Consumer Architecture
- SM-DP+:
The SM-DP+ (Subscription Manager - Data Preparation +) is responsible for the creation, download, remote management (enable, disable, update, delete) and the protection of operator credentials (the Profile). It is given the + designation as it encapsulates the functions of both the SM-DP and the SM-SR of the M2M solution. - LPA:
The LPA (Local Profile Assistant) is a set of functions in the device responsible for providing the capability to download encrypted Profiles to the eUICC. It also presents the local management end user interface to the end user so they can manage the status of Profiles on the eUICC. The principal functions of the LPA may also be in built into the eUICC. - eUICC:
The eUICC in the Consumer solution serves the same high-level purpose as the eUICC in the M2M solution. But the implementation is different to support the end user interaction within the Consumer solution. - M-DS:
The SM-DS (Subscription Manager - Discovery Server) provides a means for an SM-DP+ to reach the eUICC without having to know which network the device is connected to. This feature is important as devices can be connected using different access networks with different addresses. The SM-DS overcomes this by allowing SM-DP+ to post alerts to a secure notice board and for devices to extract those alerts. It is used to notify the LPA when Profile data is available for download to the eUICC. Notifications are sent from the SM-DP+ to the SM-DS. The device LPA polls the SM-DS for notifications when required (supporting the “pull” model). Polling frequency is determined by the eUICC state and by end user actions.
METHOD OF SIMs PROVISIONING TO CONSUMER
1 - Physical SIM Cards
Normally, the traditional SIM card is owned and issued by a specific SIM operator company. The model diagram below illustrated the provisioning of SIM cards to a consumer by the operator.
In (1), the end user sets up a contract with their chosen mobile network operator, and in return they receive a SIM card, which they can insert into their mobile device to enable it to connect to the operator’s network. This particular SIM card is marked with a red dot to indicate that the subscription credentials contained within it are issued and authenticated by that red mobile operator company.
Should the end user wish to change operator, they can set up a contract with the new operator (2), and in turn receives another different SIM card from that operator, this time marked with a blue dot indicating different subscription credentials from yet another blue mobile operator company.
It is obvious to note that even though the end user has this new SIM card in their possession, the mobile device is still connected to the first operator’s network. To change operators, the end user must physically swap the SIMs (3).
2 - Remote SIM
With Remote SIM (eSIM) Provisioning, there are no traditional SIM cards. Instead, there is an embedded SIM (called an eUICC), which may be soldered inside the mobile device, that can accommodate multiple SIM Profiles – each Profile comprising of the operator and subscriber data that would have otherwise been stored on a traditional SIM card (the red and blue dots in the previous diagram). An example for eSIM provisioning to end user is illustrated in the following figure, and the explanation follows.
Remote SIM Provisioning Operation – Operator Profile Installation
In (1), the end user sets up a contract with their chosen mobile network operator, and in the case of a Consumer solution, instead of receiving a SIM card, they will receive instructions on how to connect their device to the operator’s Remote SIM Provisioning system. In this example a QR (Quick Response) code is used. The QR code contains the address of the Remote SIM Provisioning system (SM-DP+ server within the GSMA specifications), which allows the device to connect to that system (2) and securely download a SIM Profile. Once the Profile is installed and activated, the device is able to connect to that operator’s network (3).
It should be noted that the use of QR codes is one way that the eSIM solution can be configured within a device, other alternatives include pre-configured devices, use of Subscription Manager - Discovery Server and companion devices.
Remote SIM Provisioning Operation – Operator Profile Selection
Should the end user wish to change operator, they can set up a contract with the new operator (4), and in turn receive a QR code from that operator while the first profile is still active. The device can scan the code to locate and download the new Profile, add it to the phone concurrently with previous profiles.
In (5) the end user is now able to switch among the Profiles, to connect their device to whichever operator’s network the end user selects (6).
What is an eSIM & How does it work?.
NOTE:
The Profile
A Profile comprises of the operator data related to a subscription, including the operator’s credentials and potentially operator or third-party SIM based applications. The secure element in the eSIM solution is called the eUICC, this can accommodate multiple Profiles. Profiles are remotely downloaded over-the-air into a eUICC. Although the eUICC is an integral part of the device, the Profile remains the property of the operator as it contains items “owned” by the operator (IMSI, ICCID, security algorithms, etc.) and is supplied under licence.
The content and structure for interoperable Profiles stored on eUICCs are similar to those installed on traditional SIMs. The interoperable description of these Profiles is defined by what is called the SIM Alliance.
APPLICATION AREAS OF AN eSIM
As we have already known, there exist two major solution uses of eSIM, typically for Consumers and Machines (M2M), both of which serving pull and push requests respectively. eSIM can be used in several areas for different purposes, which could increase both the outcome of performance and profits.
- Smart Agriculture:
The agriculture industry faces many challenges like scarcity of cultivable land, climate uncertainty, scarcity of water, improper use of fertilizers, uncertainty in availability of energy and price. To overcome these problems, precision agriculture methodology is adopted which is based on real time monitoring of crops and their predictive models through sensors. With these sensors, farmers can easily determine what kind of crops are to be cultivated at certain conditions. As sensors can also determine velocity of wind and its direction, temperature of the environment, solar radiation, amount of moisture in the soil etc. The IoT devices which contains these sensors can be connected with eSIM which will work on M2M model solution. - Smart Vehicles:
Physical SIM cards are already exists in some vehicles, especially cars. But there are limitations for using SIM cards in vehicles with respect to many things such as high and low temperatures, exposure to different whether conditions, corrosion issues, friction from engine and road conditions. One more limitation is they can connect to only one network at a time. eSIMs are now utilized in Automotive Industry Standard for commercial vehicles. This standard provides real time vehicle tracking, camera surveillance, emergency notification buttons, autodetect vehicle health and maintenance monitoring.
Today, connected cars are the major place holders of eSIM’s. Connectivity in vehicles emerged with emergency calling systems. And now it supports a lot of applications like analytic based solution such as in controlling temperature inside car, fuel alerts, alternative route navigations, vehicle tracking assistance, security alarm, geofence, speed alert, driving information etc.
Users can now simultaneously use voice and data services, allowing one user to do something online while second user initiates a call to someone. eSIM have its own unique identity for individual vehicles which helps them to encrypt communication and ensure security in global connectivity for smart vehicle systems. - Asset Tracking and Tracing:
Many heavy machinery manufacturers, construction equipment manufacturers or vehicles manufacturers are connected with other assets globally. The manufacturers have to perform global operations and distribute their products to geographically dispersed areas anywhere around the world. If traditional provisioning is done for their shipment on cellular networks, it can create a lot of business challenges such as: Unknown Asset Destination, Complex Logistical Processes, and Regulatory Compliance.
With eSIM solution, global manufacturers can use single integrated module to all connected devices without keeping in mind where they are to be deployed. Once that device reaches its destination, according to the carrier profile of that location, it can be provisioned. If the device moves to a new destination, it can again be re-provisioned using specific locations profile. - Energy Management:
One of the applications of IoT in energy management is Smart Metering. Smart metering enables remote reading of electricity, gas, water meters etc. Smart meters can reduce operational cost and automate service and network maintenance. The data collected from these smart meters are periodically collected and sent to the IoT cloud platform using standardized protocols.
BENEFITS OF USING eSIM
The change from the Removable SIM to an eSIM provides benefits for many players:
- For everyone:
eSIM provides an equivalent level of security as the removable SIM card. This is vital as it is the subscription credentials stored on the SIM card that enable secure and private access to mobile networks. It also supports the integrity of the billing process, especially in roaming scenarios. - For the End-user Device:
eSIM enables simplified management of subscriptions and connections. End users will no longer have to manage several SIM cards. Instead, they have to only manage the profiles. - For Organisations:
eSIM enables remote management of subscriptions. This is a significant benefit where devices are not managed by the end user or are not readily accessible, for example due to operational scale, making individual device management cost prohibitive. - For Distributors:
Simplified logistics are possible, customisation for specific operators or regions would be reduced. - For Mobile Network Operators:
Operators will have simpler means to expand their businesses into emerging markets, for example, automotive, wearables and consumer electronics. SIM card distribution costs will be eliminated, and eSIMs will enable new distribution models for devices and for marketing of subscriptions. - Device Manufacturers:
They can exploit the reduced space within their products to make smaller devices. Their products could also be made more tolerant to environmental factors such as dampness, temperature, and vibration as they can be hermetically (completely airtight) sealed. Manufacturers can also leverage eSIMs to optimise supply chain processes.
In theory, eSIMs offer end users the ability to swap between mobile operators without having to physically remove and replace the SIM, enabling more flexibility, more choice, reduced costs and faster deployments.
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REFERENCES
- eSIM on IoT : An Innovative Approach Towards Connectivity, INTERNATIONAL JOURNAL OF ENGINEERING RESEARCH & TECHNOLOGY (IJERT) ICSITS – 2020 (Volume 8 – Issue 05). https://www.ijert.org/esim-on-iot-an-innovative-approach-towards-connectivity. Retrieved on 7th April, 2023.
- eSIM Whitepaper: The what and how of Remote SIM Provisioning. March 2018. https://www.gsma.com/esim/wp-content/uploads/2018/12/esim-whitepaper.pdf Retrieved on 8th April, 2023.
- eSIMs – The connectivity future? February, 2022. https://techinformed.com/esims-the-connectivity-future/ Retrieved on 6th April, 2023.