Hardware-less SoftSIMs Are Here With the Help of Nordic’s Cellular Chip

May 16, 2023 by Jake Hertz

Nordic Semiconductor and IoT software company Onomondo have teamed up to eliminate traditional hardware-based SIM cards for 4G and 5G designs.

Ever since wireless devices reached the mainstream market in the 1990s, SIM cards have become an essential piece of hardware. In 2018, it was estimated that over 7.8 billion devices in the world relied on SIM cards—a number that, at the time, exceeded the human population!

Despite their traditional necessity, SIM cards represent yet another piece of hardware for devices, taking up space, resources, and power consumption. Recently, Nordic Semiconductor and IoT software company Onomondo challenged physical SIM cards with the release of the so-called world’s first software SIM solution.


SoftSIM will improve the power efficiency of Nordic’s hardware

Onomondo's SoftSIM will improve the power efficiency of Nordic’s hardware. Image courtesy of Nordic Semiconductor


In this article, we’ll review the traditional necessity of physical SIM cards and how Nordic’s collaboration with Onomondo may offset a future of completely software-based SIM cards.


The Traditional Necessity of SIM Cards

For devices to connect to GSM or CDMA cellular networks, a SIM card is a historically essential piece of hardware. A SIM card, or subscriber identity module card, facilitates the connection of a cellular device to a mobile network.

A SIM card contains code that uniquely identifies a mobile user to a cellular network. When the device turns on, the SIM card establishes a link between a physical device and the device owner’s cellular account, making it possible for the network to properly route calls and for cellular providers to accurately determine a user’s data consumption. 


The pinout and structure of a SIM card

The pinout and structure of a SIM card. Image courtesy of Research Gate


A SIM card generally consists of flash memory and a small MCU, which contains unique codes such as International Mobile Subscriber Identity (IMSI) and Integrated Circuit Card Identifier (ICCD) numbers. At boot-up, the network probes the cellular device for these two numbers and related authentication keys. If the response matches the cellular provider’s records, then the device will be granted access to the mobile network. These codes are used for identification purposes with a network and allow the network to verify and provide security to the phone’s user. 


Nordic and Onomondo Team Up on Software-based SIM

Recently, Nordic Semiconductor and Onomondo challenged the conventional notion of a hardware SIM card with a new software-based SIM solution. The solution consists of two main components: Onomondo’s SoftSIM technology and Nordic’s nRF9160 low-power SiP.

SoftSIM is a software-based, GSMA-compliant SIM solution that requires no unique or additional hardware to run. The solution downloads SIM information from the cloud and stores it on microcontrollers that already exist on cellular and IoT devices. By leveraging already-existing hardware on the device, Onomondo’s SoftSIM technology can be deployed entirely as software.

Now, Onomonodo has teamed up with Nordic Semiconductor to apply its SoftSIM technology to Nordic’s nRF9160 SiP. In this architecture, the SoftSIM information is downloaded from the cloud and stored on the nRF9160’s embedded Arm Cortex-M33 application processor, where it can be easily deployed and used. 


Application circuit of the nRF9160 SoC

Application circuit of the nRF9160 SoC. Image courtesy of Nordic Semiconductor


With this collaboration, Nordic hopes to provide its customers with an “out-of-the-box” solution for IoT and GNSS that shrinks down the BOM, makes designs cheaper, and decreases area requirements. Additionally, Nordic claims that SoftSIM will improve the power efficiency of its nRF9160 by an average of 40 uA compared to conventional SIM or eSIM solutions.