Embedded SIM for 5G Cellular Connectivity to IoT-M2M devices

IoT is the next development in modern life evolving through the present era of smartphones, tablets, and wearables. Connected cars, smart earphones, AI translators, personal assistance systems powered by augmented reality, vehicle tracking, AI-backed video surveillance, and many other embedded applications will become a part of our existence. These billions of “things” need internet connectivity and 5G technology will be a significant connectivity solution. Most of the IoT devices will rely on Machine-to-Machine (M2M) communication with no or little 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, eSIM cannot be swapped from one device to another. Instead, it is programmable and can be remotely provisioned. Embedded SIM is supposed to be used in IoT devices that will be using 5G networks, mainly for machine-to-machine communication. eSIM may almost replace traditional SIM cards in mobile phones and tablets as it is possible to change operator on eSIM by merely rewriting the integrated SIM to new software settings.

What is eSIM
eSIM is a global specification by GSMA, the global association of around 800 mobile operators worldwide. Unlike plastic SIM cards, eSIM is integrated into mobile and IoT devices, and, as such, cannot be removed from it. To switch from one operator to another, the end-user will simply need to update software settings over the air. In comparison to traditional SIM cards, integrated eSIM cards are much robust to extreme environments like temperature, humidity, water-resistance, vibrations, etc. and so are better suitable for internet connectivity in IoT devices. As a global specification, eSIM adheres to the same security specifications as conventional SIM cards.

Why eSIM
eSIM is specifically useful in the IoT scenario. This specification is a progressive development concurrent 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 – eSIM specification is deemed to be adopted globally. This will allow manufacturers to design and implement “Things” that could connect to internet infrastructure from anywhere and anytime. It will be possible for IoT devices to contract and provision instantly over the air (OTA) to any local communication service provider (CSP) whenever required. If an IoT or mobile device is deployed in a changeable location, it will be possible to instantly switch CSP to grant uninterrupted access of the internet to the device.
Flexibility – eSIM will allow end-users (consumers and enterprises) to instantly switch CSP or configure available services on a contract with current CSP anytime. This flexibility of instant configuration and provisioning will rest true power to the end-users and let IoT devices operate with full flexibility.
Universality – eSIM specification will let manufacturers integrate a single global eSIM to IoT and mobile devices. The eSIM must be operational all around the world irrespective of the device’s geographical location, its manufacturer, and the communication service provider (CSP). This will set a universal standard of cellular connectivity for both IoT and mobile devices.
Connectivity Bootstrapping – IoT devices are deployed on a large scale. The process of connecting new powered-on devices to internet infrastructure is called bootstrapping. Bootstrapping of millions of connected devices should be fully automated and standardized. With traditional SIMs, neither installation nor bootstrapping can be automated. eSIM solves this problem by eventually making the IoT devices born to be automatically connected, configured, managed, secured, and cloud-ready.
Device Bootstrapping – eSIM will be extremely useful in device management and security. These integrated SIMs could automatically connect to a secured network and let device self-manage by connecting to a server/cloud.
Robustness – In comparison to traditional SIM cards, eSIM is robust to extreme environmental factors like temperature, vibrations, and humidity. These can be integrated into very-compact devices without any issue of size or physical modeling of the device.

Disadvantages of eSIM
eSIM offers a lot of advantages in the case of IoT applications. However, there can be some disadvantages of eSIM, particularly in the case of consumer devices. eSIM, being integrated into the device itself, can cause some serious privacy issues when used in consumer mobile devices. The end-user is left with complete control of the device with the manufacturer and the service providers. Automatic configuration and updating can cause an infringement of privacy and security of the devices as well as users. The privacy and security of IoT devices with eSIM cannot be guaranteed until the specification is universally adopted all around the world.

eSIM application and use-case
Engineers can choose from a variety of technologies and protocols to enable M2M communication in an IoT device. An important factor in the selection of protocols and technologies is the range of communication. For example, a consumer device may only require connectivity within a few meters of an access point. In that case, Bluetooth or Wi-Fi is sufficient for the device to connect with internet infrastructure. Bluetooth can facilitate internet connectivity to a device within 10 to 100 meters of an access point, and Wi-Fi can facilitate internet connectivity within 32 meters of a router.

When an IoT device requires access beyond this range or the device is mobile, cellular connectivity is the only resort to guarantee internet access to an IoT/M2M device. The typical cell size of a mobile network is 16-30 Km, where the cellular network operates as a wide area network (WAN). It is seamless for a device to connect with a cellular network while migrating from one cell to another. It is even possible for mobile devices to connect with a network via satellites. Therefore, the cellular network ensures global connectivity to an IoT/M2M device.

Global connectivity, automatic bootstrapping, and over the air (OTA) provisioning are the key factors involved in the deployment of eSIM in IoT applications.

eSIM vs. SIM Cards vs. chip SIM
eSIM is the most preferred solution for internet access by IoT/M2M devices that need global access, robustness, and remote handling. It is important to understand how eSIM differs from SIM cards and even differ from embedded chip SIMs. At many times, embedded chip SIMs are mistaken for eSIM.

To connect with a carrier (mobile network operator/cellular service provider), a device needs SIM. SIM cards come in four form factors 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 are pluggable into mobile/IoT devices. As plastic SIM cards are removable, they are not physically robust and it is not possible to automate their subscription.

Chip SIM is not much different than a regular SIM card. Chip SIM is a regular SIM card that is vacuum-sealed in a case which can be soldered to a device to enable mobile connectivity. As the chip SIM is soldered to the circuit of a device, it is not manual to remove SIM from it. Due to the vacuum seal, SIM gets longer life and robustness against temperature, humidity, vibrations, and shocks. The chip SIM is available in the MFF2 form factor, which is four times smaller than Nano-SIM.

eSIM is a completely different SIM technology, which should not be mistaken for chip SIM. eSIM comes in all existing form factors – 2FF, 3FF, 4FF and MFF2. eSIM is integrated into the circuit of mobile/IoT devices. Another fundamental difference between eSIM and chip SIM cards is remote SIM provisioning. eSIM is essentially capable of remote SIM provisioning according to standard architecture specified by GSMA. For consumer and M2M applications, eSIM follow different architectures. Chip SIM is not capable of remote SIM provisioning.

Other SIM technologies are under development like nuSIM, iSIM, and soft SIM. However, these SIM technologies do not have as much acceptance as these technologies are uncertified and may have security threats. eSIM seems to be the only viable solution for global outdoor connectivity for IoT/M2M devices.

In the next article, we will discuss eSIM architecture for consumer and M2M solutions.