I’m pretty much done with my introduction series on eSIM Remote Service Provisioing now but there is one important topic still missing that should be mentioned shortly: Downloading virtual SIM cards into an eSIM is not only interesting for consumer devices such as smartphones, tablets, watches, etc. but equally, if not even more, to embedded devices in cars and industrial applications where the device does not directly interact with a user. While the same principles are used for downloading virtual SIMs to such devices, the way this is done is slightly different from what I discussed so far for consumer devices.
Let’s quickly recap how a virtual SIM is downloaded to a consumer device. In the first step the user gets a 2D bar code that includes information from where the virtual SIM card it represents can be downloaded. The user scans the bar code with the camera of the device with a provisioning app that then initiates the virtual SIM card (the profile) download.
In the M2M (Machine 2 Machine) world this process won’t work in many cases. Let’s take a car with a built-in LTE modem as an example that the owner has bought with a ‘connectivity’ pack for a monthly fee from the car manufacturer. In this example it is not the owner of the car but the manufacturer of the car who takes care of the LTE connectivity and, as a consequence, of the subscription. Also the car is sold in many different countries so it’s not good enough to put a physical SIM card into the LTE modem at the time the car is built. Also, the car might be sold to an owner living in a different country after a while or the car manufacturer wants to switch to a different mobile network operator in a country after a while for competitive reasons. In both cases the SIM card has to be replaced, i.e. the virtual SIM card (the profile) in the eSIM in the LTE modem has to be replaced with a new virtual SIM card. Obviously this should all be transparent to the owner of the car. Also, unlike smartphones, tablets, etc., cars usually don’t have a camera built in that can be used to scan a bar code.
Bootstrapping
In summary the major difference between M2M and consumer devices is that the user of the device (e.g. an LTE modem in a car) is not part of the provisioning process. In addition, there is usually also no Internet connectivity while the LTE modem does not yet have a valid virtual SIM card. As a consequence the process for downloading a virtual SIM to an M2M device without user interaction is as follows:
While an eSIM in a consumer device is delivered ’empty’, i.e. there is no virtual SIM (profile) downloaded yet, an eSIM in an M2M device always has a bootstrap profile that allows the modem to connect to ‘the network’ and reach a discovery server and an SM-DP (not the missing ‘+’) from which the profile that has been activated for the M2M device (e.g. by the car manufacturer) can be downloaded. Once another profile is downloaded it can be activated and used. This way, no interaction with the user is necessary, everything is managed in the background. If the car is sold to another person in the same or a different country the car manufacturer can then deactivate the virtual SIM card. Once the new user has decided that he wants to use the connectivity, the car manufacturer can activate a new virtual SIM card from the same or a different network operator and make it available for download. For the details of how this is done in practice have a look at GSMA SGP.02. Note that this is a different spec from SGP.22 which covers the consumer use case with user interaction.