STMicroelectronics has released the ST4SIM-300, which, according to the company, is the first embedded SIM (eSIM) device that complies with the new GSMA eSIM IoT Technical Specification (SGP.32).
Building upon prior eSIM standards, the new IoT protocols within the SGP.32 specification allow system operators to remotely program device subscriber identities over the air (OTA) to ensure device connectivity across global networks.
The new ST4SIM-300 eSIM
ST designed the ST4SIM-300 for small IoT devices like asset trackers, utility meters, and portable healthcare devices. In addition to its interoperability across global 4G and 5G networks, the new eSIM is also well suited for lower data rate applications that use narrow-band IoT (NB-IoT) or other bandwidth-constrained networks.
The new eSIM and associated IoT protocols are designed to simplify a system operator’s management of a fleet of connected devices. It is a plug-and-play solution that even smaller integrators can implement.
The First eSIM for SGP.32
The ST4SIM-300M (datasheet linked) is fully compliant for remote SIM provisioning per GSMA eSIM IoT standards. This means it is compatible with 2G, 3G, 4G (LTE), CDMA, NB-IoT, and CAT–M networks. For OTA updates, the small, 8-pin chip communicates with the device modem via an ISO/IEC 7816 protocol (I/O, RST, CLK) to relay the new subscriber ID to the eSIM. For WLCSP package options, ST offers an embedded secure element (eSE) for secure storage and cryptographic services. In addition to PCB mountable DFN and WLCSP packages, the ST4SIM-300M eSIM is also available in traditional SIM card plugin configurations.
The IoT-compliant ST4SIM-300 enables the remote swapping of devices from one cellular network operator to another without the need to physically access them.
Updating the ST4SIM-300 eSIM profile
To do this, the device fleet manager requests profiles from the new mobile network operator (MNO). The MNO delivers the new profiles to its subscription manager data preparation plus (SM-DP+). The IoT device operator then sends a “Download” command to the eSIM IoT remote manager (eIM) that allows the device to download the new profiles from the MNO’s SM-DP+ server to the IoT profile assistant (IPA). The new subscriber ID is then relayed to the ST4SIM-300 via the device modem.
Overview of the eSIM architecture.
The GSMA IoT protocols govern all interactions between the IoT device manager and the MNOs, enabling seamless coordination among network participants, including device managers and network operators.
What Is an Embedded Subscriber Identity Module (SIM)?
For cellular networks, a subscriber identity module (SIM) card is a small removable card that gives a device (traditionally a phone) a unique numerical identifier within the network. An embedded SIM (eSIM) is a small integrated circuit embedded into a phone, meter, or other IoT device during the manufacturing process that serves the same purpose as the traditional SIM card.
The evolution of SIM and eSIM
Some of the benefits of an eSIM are lighter, more compact devices. eSIMs are also more reliable in remote and potentially harsh industrial environments.
eSIM IoT Standards (SGP.32)
In 2013, the Global System for Mobile Communications (GSMA) established remote eSIM provisioning standards for automotive OEMs and machine-to-machine (M2M) service providers. In 2016, the M2M standard was followed by standards for consumer smartphones. In July 2023, the GSMA released the eSIM IoT Technical Specification (SGP.32) to ease the adoption of remote SIM provisioning for connected device system integrators.
The recent IoT standard introduces powerful configuration capabilities that allow device OEMs to manage their own device subscriber identities rather than the telecom operator. With eSIM IoT protocols, a device can be easily OTA configured for operation in any cellular network worldwide.
For example, asset trackers monitoring global shipments can pass from one cellular network to the next without physical access to the device, ensuring continuous connectivity as a shipment transits the globe.
ST believes its eSIM can help secure asset tracking and data handling from billions of devices in cities, smart homes, and industrial applications.
All images used courtesy of STMicroelectronics.
