The Embedded SIM in IoT Applications

High-quality eSIM Controllers are key for Industrial Automation Environments and Connected Cars


Reliable machine-to-machine communication is a prerequisite for successful Internet of Things (IoT) applications. Whereas communication is always based on the secure identification of sender and recipient, connectivity requirements strongly vary depending on the safety and environmental features of the application. Cellular M2M communication for example makes a perfect match for connecting machines in areas that are remote and difficult to access with cabled connections. But they also apply to a large variety for mobile devices that send and receive data – ranging from mobile phones to connected cars.

To overcome the limitations of traditional, removable SIM (Subscriber Identity Module) cards as known from cellular communications, embedded SIMs (eSIM) bring a number of advantages for a smooth adoption of cellular connectivity in IoT devices and related services. To accelerate implementation of eSIMs, the industry is currently defining internationally applicable standards. However, as eSIMs are offered in different quality levels and form factors it is important to choose the right solution depending on the specific application.

Smart connectivity is at the heart of the IoT, where e.g. intelligent machines are capable of exchanging information during industrial production or connected cars send and receive updates on traffic or weather conditions.Wired communication provides broad bandwidth yet requires heavy invest in infrastructure (e.g installing glass fiber). Alternatively, the ubiquity of the cellular network and the ease of integrating cellular connectivity into devices make it possible to link remote production sites that would be otherwise difficult or expensive to connect. Given the surge of new IoT applications, initiatives to optimize the cellular network for machine-type communications such as LTE-M are therefore gaining momentum. Besides standardization, a significant number of Mobile Network Operators (MNOs) are enhancing their offering of M2M communication by making cellular connectivity even more appealing.

Eduardo Morral
Eduardo Andres Morral Fuentes, Product Marketing Manager M2M, Infineon Technologies AG

In order to address the challenges created by the SIM card in the M2M market, the eSIM or eUICC (embedded Universal Integrated Circuit Card) has been introduced and specified by the GSMA.The GSMA’s Embedded SIM specification provides a single, de-facto standard mechanism for the remote provisioning and management of M2M connections, allowing the “over the air” (OTA) provisioning of an initial operator subscription, and the subsequent change of subscription from one operator to another.

In essence, the eSIM provides the same functionality as traditional SIM cards but in contrast to the latter, it enables the change of operator profiles remotely at any time and comes in a miniaturized, solderable form factor. The concept of the eSIM is basically nothing new. In fact, eSIMs have already been used for M2M applications for several years and many eSIM vendors are providing solutions to manage subscriptions over the air. Infineon for example offers high-quality eSIM solutions since 2008.

 Advantages of eSIMs are an ideal choice for M2M applications because they are delivered sealed and can be soldered directly onto the circuit board of the device. This increases reliability in terms of reducing malfunction due to shocks, corrosion and other environmental factors. Additionally, the lifecycle of an eSIM with usually 10 years and more is longer than that of a standard form factor SIM. This means typically eSIMs do not need to be replaced during the device’s lifecycle.

Another important benefit of eSIMs is their physical security. Soldering the SIM directly onto the circuit of the device makes it nearly impossible for anyone tampering the device to remove the SIM for misuse.

Today eSIMs for M2M applications are typically available in a small surface mount MFF2 package (5.0 mm x 6.0 mm x 0.9 mm). The surface mount format provides the same electrical interface as the full size, 2FF and 3FF SIM cards, but is soldered to the circuit board as part of the manufacturing process. In M2M applications where there is no need to change the SIM card, this avoids the requirement for a connector, improving design, reliability and security.

Embedded SIM drives M2M market growth

Today still the majority of embedded systems (“things”) are offline, but by 2020, more than 30 billion items will be online, at least 12 billion of them over mobile networks, according to GSMA estimates, and the main growth will come from connected M2M devices. Mobile networks are being used to connect all sorts of devices: machines in factory automation, automated reading of utility meters, intelligent connectivity of cars and commercial vehicles, traffic lights, home security and assisted living.

For the industry, eSIM improves the implementation of cellular connectivity on industrial devices. It also helps to solve the challenge of managing those devices in the field: many M2M devices are remotely located and often hermetically sealed, while their after sale location is not known during production and their product life cycle often are quite long.

Besides the industrial automation there are a lot of other interesting examples to implement eSIM. One is the “cold chain” monitoring.  In this case eSIM is used to monitor temperature sensitive products throughout the complete logistics cycle. A special solution for container reader from Maersk controls position and temperature of 280 000 cooling containers worldwide via satellite.

Mobile network operator AT&T for example offers products, that check the level of liquids in tanks and inform the supplier if they decrease below a certain level. Lift supplier Otis on the other hand uses real-time-data exchange to define the right moment for maintenance.

In addition, eSIM is ideal to be integrated in products used for energy or smart meters. Related systems are used for remote monitoring of energy consumption/generation at residential customers, industries and power generation plants.

For industrial device manufacturers, eSIM increases design flexibility due to its small footprint. It also simplifies the manufacturing processes by enabling a single stock-keeping unit and facilitates global distribution. It simplifies the rollout for end customers (e.g. manufacturing plants), and since there is no need to separately purchase and distribute SIM cards for specific equipment, it helps reduce operational costs. Customers also have the possibility to change service provider at any time. Nevertheless, all these benefits might not be realized in industrial and automotive environments if the quality and the security of the eSIM doesn´t match the challenging requirements of the dedicated application.

Quality and reliability are key

Historically, SIM cards have been used for consumer devices which means that in many cases they aren’t optimized to work under difficult and rough industrial environments. The promise of highly automated and optimized industrial processes using IoT technologies won’t hold true if a tiny but essential component like the SIM can’t cope with the quality challenges of industrial environments.

Vendors offer eSIM in different quality levels and form factors. Before making a design decision, it is important for industrial device manufacturers, together with the eSIM providers, to look into three main aspects that will affect the reliability of the eSIM: technology, application and environmental conditions.

Silicon technologies might react differently to similar operational conditions. For example, some technologies might have higher failure rates at higher temperatures and others at lower temperatures. In order to understand the effects of technology, device manufacturers must work together with the eSIM provider to make sure they are choosing the adequate one. They should also verify that the provider has the right measures in place to guarantee the promised quality such as advance testing, tightened process controls and quality gates as well as advance mechanisms to protect memory against excessive stress.The application, also known as mission profile, defines how the eSIM will be used, and has a significant influence on the overall failure rate of the eSIM. The mission profile involves understanding the active operational time, the frequency of updates and the size of memory used.

Environmental conditions are normally determined by variables such as moisture, humidity, corrosion, and mechanical and electromagnetic shocks. Yet, the most influential variable is the operational temperature. The temperature ranges from -25 to 85°C of a traditional SIM card is unlikely to fit the job. Therefore, eSIM solutions are needed, specified for a temperature range of -40°C to 105°C.

Security controller optimized for M2M applications

Infineon has developed an extensive family of industrial-grade security controllers ideal for the operation in difficult environmental and usage conditions, enabling secure and reliable cellular connectivity for industrial M2M applications.

The SLM family includes 16-bit and 32-bit security controllers optimized for industrial M2M applications.

The 16-bit SLM76 controller is optimized to address the needs of a large number of M2M applications, providing an extended temperature range from -40 to 105°C, a very robust E²PROM cell concept, leading up to 500k cycles per page, high resistance to harsh environmental conditions such as vibration or humidity, achieving 10 years of lifetime and 10 years’ data retention and low failure rates. The SLM76 devices are available in optimized packages, i.e. a tiny standard MFF2 packageor dedicated M2M chip card module.

SLM 97 is Infineon’s high-performance 32-bit product generation for industrial M2M applications. It offers extended temperature range, up to 1MByte SOLID FLASH memory, 32k Byte RAM, a set of hardware crypto-coprocessors and is Common Criteria EAL 5+ High certified. The SLM 97 product family fully complies with the eUICC specifications according to ETSI and GSMA.

To further improve security of connected industrial devices, the eSIM can be combined with the OPTIGA Trust authentication chips. The OPTIGA Trust E for example features an I2C interface as well as an extended temperature range (-40 to +85 °C) and has been designed to protect high-value investment goods.

Automotive is leading the way

M2M offers enormous opportunities for the automotive industry. The term “connected car” covers such diverse applications as engine management, remote vehicle monitoring, assumption of control if the driver loses consciousness, and automatic placing of an emergency call in the event of an accident.

Drivers for eSIM in cars are emergency call systems as well as connected car services.

The European Commission for example has selected the eUICC format for its in-vehicle emergency call service (eCall) which will be mandatory for new cars in the European Union from 2018 onwards. In the event of an accident where the driver loses consciousness for example, the car places an emergency call.

But integrated cellular connectivity also enables high-end connected car services such real-time traffic information, internet connectivity and remote assistance (examples: BMW Connected Drive, Audi Connect, Mercedes Me Connect).

The various opportunities for connected vehicles also present the automotive industry with particular challenges. While the service life of computers and mobile devices is targeted to a few years and new features can be implemented in the next generation of products, automotive manufacturers must think further ahead and assume a product life cycle of up to 15 years.

In a connected car, the eSIM is the linking element between the automotive and the telecommunication worlds. While automakers have a strong focus on meeting the highest quality levels, mobile network operators focus on protecting their security credentials against theft and cloning. In addition, the remote management capabilities of the eSIM allow automakers to reduce logistic complexity and easily deploy new services for their customers during the vehicle’s lifetime for example by using Software-over-the-air (SOTA) updates.

Again and especially here, quality and reliability of the cellular communication are key. Infineon answers all these challenging requirements with the SLI 76/97 product families. The SLI families offer 16-bit (SLI76) and 32-bit (SLI97) security controllers optimized for automotive M2M applications. In addition to the SLM features, SLI fulfills highest automotive standards: the eSIM products provide extended quality targets, PPAP documentation and are qualified according to AEC-Q100. The SLI 97 provides a set of hardware crypto-coprocessors supporting all relevant crypto schemes and Common Criteria EAL 5+ High certification, making it a perfect solution for secure car connectivity.


The IoT with its plethora of new devices and solutions requires flexible and reliable solutions for M2M communication. Cellular based solutions provide a secure and cost-efficient alternative to wired applications, especially with regard to communication with machines in remote areas or for mobile applications such as ‘connected cars’. Infineon has been supplying SIM chips for more than twenty years and developed a broad range of specialized eSIM products. Benefitting from a deep cross-market system understanding and security expertise, high-quality solutions for cellular M2M communications can be provided.