What is eSIM, Embedded SIM, iSIM? Status of eSIM functionality in South Africa.

So many terms, and often some confusion around these terms within the Telecoms industry.
These terms can refer to the physical form of the SIM (form factor) or a set of SIM capabilities.

What is the Difference between eSIM Embedded SIM and iSIM in IoT deployments?

What is a SIM?

A SIM (Subscriber Identity Module), also called a Universal Integrated Circuit Card or UICC, stores information that uniquely identifies a cellular subscription.  It holds the credentials and security keys necessary to identify a subscriber. That identity comes in the form of a so-called IMSI number, or International Mobile Subscriber Identity, which is unique for every user or device on or off the network. SIMs also run an application that passes that identity information to an onboard cellular modem. The modem in turn conducts the actual attachment operation to the network. The application that the SIM card runs, by the way, is also referred to as UICC; the acronym is often used synonymously with the card or chip itself.

The rightmost Embedded and Integrated ones look a little different – that’s because these are chips soldered directly onto your electronic circuit board that makes up your device, vs. the bigger versions you insert manually into a slot. This smaller form factor was needed for our ever-shrinking consumer and IoT devices. You could say it is “embedded” into a bigger circuit board.

[Embedded SIM formats can be supplied by us for most local and global roaming mobile networks that we support.]

So if the MFF2 form factor is “embedded”, is this tiny SIM what we call an “eSIM”? Unfortunately, not always. Some do call it that, but it’s imprecise. While the “e” in eSIM does stand for embedded (you will also find the reading “electronic SIM” out there), what is meant with eSIM is really a different “kind” of embedded – not the hardware kind.

What is an eSIM?

In simple terms, an eSIM is a SIM that can load new carrier profiles digitally, over the air, which means you no longer need to physically swap SIM cards in your devices.

In more technical terms, an eSIM is any piece of hardware that runs an application called eUICC, which has storage to hold multiple SIM profiles at the same time (but only one can be active), and can be provisioned remotely, over the air (OTA).

An eSIM doesn’t need to come along only in the form of any of the known form factors (2FF, 3FF, 4FF, MFF2) – anyone can design their own hardware chip, as long as it runs an application that conforms to the eUICC standard

What is an iSIM? 

The next revolution in the eSIM world wil be the iSIM (aka integrated SIM), a SIM that integrates directly into the device's processor.

In essence, the iSIM enables devices to connect to a cellular network without needing a physical SIM card or soldered eSIM in a printed circuit board. 

Instead of using a separate physical SIM card, the iSIM technology embeds the SIM features directly into the device's hardware, allowing it to connect to the cellular network. Remote SIM provisioning (RSP) consists of loading and activating an MNO profile in an eUICC via over-the-air (OTA) download or other (manual) means.

The iSIM offers two key features: 

- It saves space by eliminating the need for a separate component.

- It requires significantly less power than eSIMs, making, for example, massive IoT use cases more operational.

What is the difference between eSIM and iSIM? (Source: u-Blox)

In short, the iSIM is a SIM OS running on a Secure Element embedded inside the cellular IC, whereas the eSIM is a Secure Element running the SIM OS soldered onto a PCB.

The advantages of the iSIM vs eSIM are less obvious. The eSIM is a hardware component that needs to be purchased, profiled (if eUICC capability and RSP are unavailable), and soldered onto the board. This creates a cost factor impacting hardware manufacturing, procurement, and logistics. Moreover, purchasing eSIMs is not as easy as purchasing plastic SIMs. Small IoT customers with low volumes are often unable to meet the minimum order quantities imposed by MNOs or SIM vendors.

The adoption of the iSIM will revolutionize the IoT market by pushing the adoption of the GSMA IoT-tailored remote SIM provisioning standard. Why? Because in cellular IoT applications, iSIM solutions only make sense if they feature ieUICC capability and support a remote SIM provisioning system tailored to the needs of network-constrained IoT devices.

Remote SIM Provisioning evolution and alternatives

This begs two questions: Why is remote SIM provisioning used in the consumer market, but not massively adopted in cellular IoT? And is the RSP the only method to switch between different networks?

Today there are two approaches to handle multiple MNO profiles in a single UICC, but by end 2024/2025 a third option will be available.

These three options are:

1. Proprietary Multi-IMSI solutions: 

Typically, M(V)NO non-standard approaches that only work in a closed environment.

2. Existing GSMA-compliant RSP solutions:

M2M (GSMA SGP.01/.02): targeting M2M devices and applicable to non-end-user interactive environments. Here, profiles are pushed from the MNO.

Consumer (GSMA SGP.21/.22): Targeting Consumer devices (e.g., smartphones, tablets, wearables). In this case, profiles are pulled by the user (often using a QR code).

3. The new, emerging GSMA RSP standard (SGP.31/.32):

This is specific to IoT applications and for network and UI constrained devices.

Adoption by MNOs and the wider ecosystem such as hardware providers is unlikely before 2025+.

Once the “IoT” SGP.31/.32 standard (based on the “old” Consumer eSIM standard) displaces the existing M2M standard, large-scale deployment of eSIM/iSIM in IoT deployments will become practically possible. 

Status of eSIM functionality in South Africa
Networks in South Africa (Vodacom, MTN, Telkom) only support eSIMs installed in a set list of consumer devices. These eSIMs can be managed on SIMcontrol.
They need to be programmed/activated manually on the device (not Over The Air), typically by using an app or scanning a QR code. The devices need to be on the list of allowed eSIM devices for each network. It is not currently possible to activate eSIMs on many IoT devices remotely. This will be possible once the new SGP.31/.32 standard is adopted. So for IoT devices, no local remote eSIM activation support is available yet on South African networks.

For consumer devices (with manual UI-based activation), the following eSIM supply is available from SIMcontrol:

Vodacom: Prepaid, Business Flexi or Top-Up Contract SIMs.
MTN: Contact Us

Article: eSIM support in South Africa — A sad affair of limited options

Multi-IMSI SIM

Multi-IMSI is a concept developed to overcome the single profile limitation set by UICC. The Multi-IMSI packages multiple MNO profiles (IMSI) in a single SIM card. The MNO profiles are managed by an applet running on the SIM

The applet allows remote management and control of the MNO profiles (add/remove/provision). These are typically user for roaming between mobile networks.

Please contact us for eSIM, embedded SIM or Multi-IMSI SIM options for IoT deployments. 

tags: eSIM, e-SIM, chip SIM, embedded SIM, multi-IMSI, eSIM Vodacom , eSIM MTN, eSIM South Africa, eSIM IoT, eUICC
Sources: Wikipedia, MyBroadband, Twillio, uBlox.