eSIM revolution is a win for service providers and users

When buying a new gadget, many people marvel over the new hardware and software that become more sophisticated from year to year, and the solutions that offer improved utility or have not even existed before. However, few of them consider the fact that often it is not just the device itself that required serious development effort, but its operation also necessitated deep-cutting changes in the underlying infrastructure.

Master Developer - Product Owner

Master Developer - Product Owner

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An excellent example is the devices aimed at Multi-SIM use, including, for example, one of the most popular smartwatches, the Apple Watch. Mobile networks had to be prepared to properly support this device and its peers. Fortunately, the IMS subsystem used by several mobile telephony service providers lays down an excellent foundation for such use, and by building on this subsystem, Ericsson was able to prepare the networks for the support of Apple Watch and other Multi-SIM devices. The company’s solution has been actively used in many countries for more than a year.


It is no news for most people that the above mentioned smartwatch uses an eSIM, which means that you do not need to insert the usual physical SIM card into it as it has been replaced by an embedded SIM, and access to the mobile network is activated for the device as necessary by the service provider. The eSIM technology has a lot of potential benefits, and not just for the Apple Watch and other smartwatches of its ilk: the broadest possible support for eSIM devices is important for the service providers too, because according to the estimations of GSMA, there will be more than two billion devices equipped with this technology will be in use by 2025.

One of the most evident benefits of this technology is that before going on a trip it is enough to download a new eSIM to the device in order to use local service packages and tariffs, furthermore, notebooks that increasingly require an online connection around the clock offer eSIMs a great future where users can do without sharing their phones or resorting to hotspots. But this technology can also come in handy when the coverage provided by the user’s own service provider is weak: in such a case, a new eSIM offered as an insurance policy can enable the device to simply switch to a different network.

Temporary eSIMs can be deployed as part of marketing campaigns, and they can be completely customized, even with exclusive product trials – according to a study made by Ericsson, no less than 82 percent of the smartphone users showed interest in them. The technology can also be employed at large-scale events, for example, in VIP participant plans: in such cases, the user can receive exclusive content through a dedicated eSIM connection, and the service provider can collect valuable information and even get a new sales channel. In the poll, 53 percent of the interviewed persons showed interest in options of this kind, and almost half of them are willing to pay for them. Furthermore, service providers can create trial versions of their plans that can be tested for a few days with an eSIM, and if the customer is satisfied, the trial plan can be finalized with a click, which appealed to more than 82 percent of the users.

This Ericsson technology allowed for the automated, dynamic management of distributed eSIMs. The company’s solution consists of an Ericsson Secure Entitlement Server (SES) and an eSIM manager with a GSMA certificate that are used by the company to offer automated end-to-end services from device and subscription orchestration through user authentication to eSIM onboarding tasks. In this way, it is not just the users’ lives that the technology makes easier, but it can also reduce the operating costs of network operators.


The Multi-SIM concept may sound familiar: this solution supports the use of a single mobile subscription with multiple SIM cards (either physical cards or eSIMs), granting access to multiple devices associated with the same call number, or allowing multiple devices to use the same mobile data plan and data limit without connecting to a Wi-Fi hotspot. As part of this solution, service providers clone unique contract identifiers that personify customers towards the mobile network, allowing the service to be shared between those devices.

Speaking of Multi-SIM, it is also worth mentioning Multi-Persona which takes flexible management of devices, phone numbers and subscriptions to the next level, allowing users to assign multiple call numbers to a single device. The concept resembles closely the already popular Dual-SIM solutions, but at the same time there absolutely no reason to stop after two subscriptions as up to ten virtual SIM cards or “personas” can be assigned to a single smartphone while having a single physical card or even an eSIM in the device. This, however, requires that the device properly supports the solution.

The technology offers a lot of options: in addition to the ability to manage business and personal subscriptions from a single device, it may also open the door to setting up temporary call numbers. The two solutions, jointly named Smart Calling, can be even combined, which means that all call numbers and subscriptions are accessible from all the devices of the subscriber - from smartphones through tablets to smart watches, such as the previously mentioned Apple Watch. Obviously, the above technologies are supported by the mobile networks, but the infrastructure might require some upgrades, at least on the software side.


The services are enabled by the backend, the IMS (IP Multimedia Subsystem). The IMS, as indicated by its name, converts the entire mobile network traffic to IP communication while maintaining telecom-level quality; among other things, the latter allows for making VoLTE and VoWiFi voice calls.

Fortunately, in order to make Smart Calling services available in mobile networks there was no need for changes in the hardware, the radio network remained unaffected, but the logic running on the central application servers had to be updated so that it would handle call redirection properly, regardless of whether multiple devices were called from a single number or several numbers were assigned to a single devices.

To accomplish this upgrade, the IMS must be flexible; similar functions on systems communicating with, among other things, difficult-to-access binary protocols known from 3G networks would be extremely difficult or impossible to implement. However, as adoption of 4G/LTE spread and as a result most of the mobile service providers have already switched to the IMS that operated behind the wired lines, these upgrades were quickly greenlighted.

The supplementary call management technology developed by Ericsson is natively supported by the IMS service layers, and it has been used in production environments by several operators in a number of countries for more than a year. The solution supports each of the above technologies, which means that through Multi-SIM, in addition to a smartphone, you can also link an Apple Watch equipped with an eSIM, or any other device with a conventional SIM card, to the same call number and mobile internet plan. In the same way, Multi-Persona is always ready for action so that the technology can be used to link multiple subscriptions to a single device. The technology developed by Ericsson even allows for combining them, provided that the service provider consents to it.

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