Soracom iSIM for IoT Applications

An iSIM is an advanced connectivity solution embedded directly within an IoT device, similar to an eSIM but taking integration further. Unlike eSIMs, which are soldered onto a device's circuit board, iSIMs are built using a system-on-chip (SoC) architecture, combining the SIM functionality with the device’s onboard processor and modem.

This seamless integration results in an ultra-compact form factor, ideal for space-constrained applications like wearable tech.

By embedding SIM functions into the cellular modem, hardware developers can reduce the need for additional components, shrinking the SIM footprint from millimetres to a fraction of a millimetre. This not only optimises space but also enhances security, preventing physical SIM removal and enabling added layers of authentication.

iSIM-compatible modules offer significant advantages for IoT solutions, including:

• Cost savings: Fewer components reduce product costs and the bill of materials (BOM).
• Compact design: Eliminating a SIM holder allows for smaller end-product sizes.
• Simplified supply chain: No need to pre-purchase or stock SIMs, streamlining logistics.
• Extended device life: Supports low-power consumption, enabling devices to last longer in the field.
• Zero footprint: Minimal space requirement and lower power usage.
• Enhanced durability: High vibration tolerance and a wide operating temperature range.
• Strong security: Built-in encryption, authentication, and tamper resistance.

The main difference between eSIM and iSIM lies in their architecture. iSIM runs the SIM OS on a Secure Element embedded within the cellular IC (baseband modem), while eSIM operates on a secure chip physically soldered onto the PCB.

Advantages of iSIM vs eSIM:

• Integration: eSIM is a separate hardware component that adds costs related to manufacturing, procurement, and logistics, whereas iSIM is integrated directly into the modem, simplifying the design and reducing expenses.
• Procurement: eSIMs can be challenging to source, especially for smaller IoT projects, due to minimum order requirements from SIM vendors or network operators.

Both eSIM and iSIM are embedded, non-removable solutions. Soracom supports a unique profile management feature called Subscription Container on both formats, enabling versatile profile handling.

Looking ahead, iSIM adoption will drive significant change in the IoT industry by facilitating the GSMA’s IoT-specific remote SIM provisioning standard (SGP.32), known as IoT eUICC and IoT RSP, enhancing profile management for compact IoT devices.

iSIMs offer the same high level of security as eSIMs. Both iSIM and eSIM undergo the same rigorous evaluation processes and methodologies, ensuring comparable security standards. The iSIM’s integrated secure enclave adds robust protection, making it suitable for seamless, multi-national, and large-scale deployments.

iSIM is a fully standardised embedded solution, enabling interoperability across vendors and consistent adoption by IoT device makers. The GSMA has published approved iSIM specifications, integrating eUICC security while accounting for the unique characteristics of System-on-Chip (SoC) designs.