What are eSIMS and how are they used?

01-08-2020 | By Robin Mitchell

eSIMS provide future designs with plenty of opportunities, especially those in the IoT industry. But what exactly is an eSIM, and why are they going to help future IoT systems such as global asset tracking?

What is an eSIM?

An eSIM is an embedded SIM card that, unlike a traditional SIM card, is only the chip part of a SIM. These are embedded directly into designs and allow for on-the-fly reprogramming. This reprogramming can be done in a multitude of different ways, including NFC, phone call, or programming jig. Once programmed, the device using the eSIM can connect to a network, and operate as if it was connected to a physical SIM card. As such, an eSIM eschews the necessity to switch physical SIM cards or phones when you want to change carriers. 

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What advantages do eSIMs provide?

The first and most obvious advantage is that the size of an eSIM is incredibly small when compared to a traditional SIM card. This means that devices can be made to be significantly smaller while also removing the need for delicate mechanical connectors. The reduction in size and parts also means that the overall weight is also reducing, making it ideal for low-profile applications such as asset tracking stickers and remote Internet of Things (IoT) devices. The ability for an eSIM to be reprogrammed also provides the opportunity for a device to reprogram its ID when crossing country borders, thereby allowing it to choose different network operators that provide the lowest cost. Costs of eSIMs can be further reduced when directly integrated into a system-on-a-chip (SoC) which not only reduces the size of the PCB but also incorporates all needed system components into a single package.

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What disadvantages do eSIMs provide?

eSIMs are not without their disadvantages, but most of these mainly affect user devices such as smartphones. The first is that some eSIM manufacturers may choose to lock their eSIMs meaning they cannot be reprogrammed. From there, a manufacturer could then decide to use that eSIM in specific phones meaning that customers cannot change network and thus secure a better deal with a competing network operator. The second issue with eSIMs is that they cannot be removed easily (if at all), and thus are highly dependent on being reprogrammable should a change in network provider be required. This is easily done with traditional SIM cards which slide out of their mechanical fixing, but an eSIM is either soldered in place or integrated into an SoC. The third issue with eSIMs is that they cannot be removed, and thus may always try to stay connected to a network. This leads to making devices far easier to track as devices with SIM cards removed cannot be tracked via cellular triangulation.

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How will eSIM help the IoT industry?

One of the most significant changes that will happen by the end of the decade is the shift from local Internet systems utilising physical connections to Internet Service Providers (ISPs) to cellular based internet services. The use of 4G is a good demonstration of how internet demand on mobile devices has changed the direction of technology. 3G was designed to allow mobile users to access emails as well as perform basic web surfing, but 4G allows for HD video streaming, online gaming, and even access to cloud resources (the author of this article utilises 4G broadband being out in the country where landline internet is still only 4mbps). 

However, the rise of IoT, and the importance of global asset tracking, has helped shape how 5G will operate. High speeds and low latency make 5G the go-to network for any application especially those that require remote mobile IoT devices. For example, food containers that are shipped from one country to another may need to track data including temperature, humidity, and volatile organic compounds to determine how fresh the food is, and if it was exposed to harsh environments that may affect the shelf life. The use of asset tracking IoT devices, combined with eSIMs, allow for a device to be attached to the container and roam from country to country while still having a network connection. But the use of eSIM technology goes far beyond IoT asset tracking; even self-driving cars will benefit from eSIMs. For the past decade, designers in the automotive industry have argued about what network cars of the future will utilise. Some have suggested that cars can use Wi-Fi between other nearby cars for communication while others advocate for Bluetooth. However, as 5G begins to be rolled out it is becoming quickly apparent that cars of the future will utilise 5G. From obtaining the latest road traffic data to remote AI processing, 5G offers cars a whole range of possibilities, and eSIMs allow for cars to be integrated with cellular capabilities without the need for a SIM cardholder.

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Conclusion - How Embedded SIM Cards are Poised to Revolutionise the World

eSIMs are an emerging technology that is still yet to be established. However, while they may be a new concept, their importance will quickly rise as IoT devices and 5G become more established. The use of eSIMs will help to make devices smaller thereby making them cheaper, while also helping the industry develop next-gen tech.


By Robin Mitchell

Robin Mitchell is an electronic engineer who has been involved in electronics since the age of 13. After completing a BEng at the University of Warwick, Robin moved into the field of online content creation, developing articles, news pieces, and projects aimed at professionals and makers alike. Currently, Robin runs a small electronics business, MitchElectronics, which produces educational kits and resources.