IoT is the next development in modern life, evolving through the current era of smartphones, tablets and wearables. Connected cars, smart headphones, AI translators, augmented reality-powered personal assistance systems, vehicle tracking, AI-supported video surveillance, and many other embedded applications will become part of our existence. These billions of “things” need internet connectivity and 5G technology will be a significant connectivity solution. Most IoT devices will rely on machine-to-machine (M2M) communication, with little or no interaction with human users.
Embedded SIM (eSIM) or embedded universal integrated circuit card (eUICC) is a SIM (Subscriber Identity Module) card that is integrated into a device and cannot be removed from it. Unlike traditional SIM cards, the eSIM cannot be swapped from one device to another. Instead, it is programmable and can be provisioned remotely. The embedded SIM is intended for use in IoT devices that will use 5G networks, mainly for machine-to-machine communication. eSIM can almost replace traditional SIM cards in cell phones and tablets, as it is possible to change carriers on the eSIM by simply rewriting the built-in SIM to new software configurations.
What is eSIM
eSIM is a global specification from GSMA, the global association of around 800 mobile operators around the world. Unlike plastic SIM cards, eSIM is embedded in mobile and IoT devices and as such cannot be removed from them. To switch from one carrier to another, the end user will simply need to update the wireless software settings. Compared to traditional SIM cards, integrated eSIM cards are very robust to extreme environments such as temperature, humidity, water resistance, vibrations, etc. and are therefore best suited for internet connectivity on IoT devices. As a global specification, eSIM follows the same security specifications as conventional SIM cards.
Why eSIM
eSIM is specifically useful in the IoT scenario. This specification is a progressive development simultaneously with the application of 5G mobile networks for the Internet of Things, offering several advantages. Some of the key benefits of using eSIM/eUICC for IoT applications are as follows:
- Global connectivity – The eSIM specification is considered globally adopted. This will allow manufacturers to design and implement “things” that can connect to the Internet infrastructure from anywhere and at any time. It will be possible for IoT devices to contract and deliver instantly over the air (OTA) to any local communications service provider (CSP) whenever needed. If an IoT or mobile device is deployed in a changing location, it is possible to instantly change the CSP to grant uninterrupted Internet access to the device.
- Flexibility – The eSIM will allow end users (consumers and businesses) to instantly switch CSPs or configure services available under a contract with their current CSP at any time. This flexibility of instant configuration and provisioning will provide true power to end users and allow IoT devices to operate with complete flexibility.
- Universality – The eSIM specification will enable manufacturers to integrate a single global eSIM into IoT and mobile devices. The eSIM must be operational worldwide, regardless of the device's geographic location, manufacturer and communication service provider (CSP). This will establish a universal cellular connectivity standard for IoT and mobile devices.
- Connectivity bootstrap – IoT devices are deployed at scale. The process of connecting new devices connected to the Internet infrastructure is called bootstrapping. The startup of millions of connected devices must be fully automated and standardized. With traditional SIMs, neither installation nor initialization can be automated. eSIM solves this problem, eventually making IoT devices born to be automatically connected, configured, managed, secured and cloud-ready.
- Device initialization – eSIM will be extremely useful in device management and security. These integrated SIMs can automatically connect to a secure network and allow the device to self-manage by connecting to a server/cloud.
- Robustness – Compared to traditional SIM cards, the eSIM is robust to extreme environmental factors such as temperature, vibrations and humidity. They can be integrated into very compact devices without any size or physical modeling issues of the device.
Disadvantages of eSIM
eSIM offers many advantages in the case of IoT applications. However, there can be some disadvantages of eSIM, especially in the case of consumer devices. The eSIM, being integrated into the device itself, can cause serious privacy issues when used in consumer mobile devices. The end user remains in full control of the device with the manufacturer and service providers. Automatic configuration and updating may cause a violation of the privacy and security of devices as well as users. The privacy and security of IoT devices with eSIM cannot be guaranteed until the specification is universally adopted across the world.
eSIM application and use case
Engineers can choose from a variety of technologies and protocols to enable M2M communication on an IoT device. An important factor in selecting protocols and technologies is the communication range. For example, a consumer device may only require connectivity within a few meters of an access point. In this case, Bluetooth or Wi-Fi is sufficient for the device to connect to the internet infrastructure. Bluetooth can facilitate Internet connectivity to a device at a distance of 10 to 100 meters from an access point, and Wi-Fi can facilitate Internet connectivity at a distance of 32 meters from a router.
When an IoT device requires access beyond this range or the device is mobile, cellular connectivity is the only resource to guarantee Internet access for an IoT/M2M device. The typical cell size of a mobile network is 16 to 30 km, where the cellular network operates as a wide area network (WAN). It is easy for a device to connect to a cellular network while migrating from one cell to another. It is even possible for mobile devices to connect to a satellite network. Therefore, the cellular network guarantees global connectivity to an IoT/M2M device.
Global connectivity, auto-boot and over-the-air (OTA) provisioning are the key factors involved in deploying eSIM in IoT applications.
eSIM x SIM cards x SIM chip
eSIM is the preferred solution for Internet access by IoT/M2M devices that need global access, robustness and remote handling. It is important to understand how the eSIM differs from SIM cards and even SIMs with an embedded chip. SIMs with an embedded chip are often confused with eSIM.
To connect to an operator (mobile network operator/cellular service provider), a device needs a SIM. SIM cards come in four formats or sizes – 1FF, 2FF (Mini-SIM), 3FF (Micro-SIM) and 4FF (Nano-SIM). 1FF is now obsolete, while 2FF to 4FF still dominate plastic SIM cards in use. These SIM cards can be connected to mobile/IoT devices. As plastic SIM cards are removable, they are not physically robust and it is not possible to automate your subscription.
The SIM chip is not much different from a normal SIM card. SIM chip is a regular SIM card vacuum-sealed in a case that can be soldered to a device to enable mobile connectivity. Since the SIM chip is soldered to the circuitry of a device, it is not manual to remove the SIM from it. Due to vacuum sealing, the SIM gains greater useful life and robustness against temperature, humidity, vibrations and shocks. The SIM chip is available in the MFF2 format, which is four times smaller than the Nano-SIM.
eSIM is a completely different SIM technology, which should not be confused with SIM chip. The eSIM comes in all existing formats – 2FF, 3FF, 4FF and MFF2. The eSIM is integrated into the circuitry of mobile/IoT devices. Another key difference between eSIM and chip SIM cards is remote SIM provisioning. The eSIM is essentially capable of remote SIM provisioning in accordance with the standard architecture specified by the GSMA. For consumer and M2M applications, eSIM follows different architectures. SIM Chip is not capable of remote SIM provisioning.
Other SIM technologies are under development, such as nuSIM, iSIM and soft SIM. However, these SIM technologies do not have much acceptance, as these technologies are not certified and can present security threats. eSIM appears to be the only viable solution for global external connectivity for IoT/M2M devices.
In the next article, we will discuss the eSIM architecture for consumer and M2M solutions.
