Global IoT Roaming on Cellular LTE-M and NB-IoT Networks

March 19 2023

Our mission is to help businesses connect, protect, and derive more value from their assets. As a leading global innovator, developer, and supplier of IoT solutions, we drive continuous innovation to enable our partners to deploy confidently at scale worldwide.

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We’re excited to report our next-gen IoT asset tracking devices support automatic roaming between LTE-M and NB-IoT networks with minimal delay and marginal impact on battery life or performance.

Automatic roaming between Cellular LPWAN networks enables new low-power, indoor/outdoor global asset tracking applications in connected packaging, parts and inventory management, supply chain management, shipping and logistics, and more!


The Challenges of Roaming on LTE-M / NB-IoT


We launched our first LTE-M (Cat-M1) / NB-IoT asset tracking device in early 2018. Since then, we have seen both 4G/5G network coverage and low-power modem technology mature significantly.

Our legacy range of LTE-M/NB-IoT devices needed to be provisioned for use on either LTE-M or NB-IoT networks.

Due to the infancy of these networks, even simply connecting to an NB-IoT network proved difficult in some regions. (We have since simplified connecting to NB-IoT with our wired provisioning tool and updated firmware.)

Our own testing, as well as partner deployments, proved roaming across LTE-M and NB-IoT networks was achievable with a roaming SIM and the correct APN settings. However, to connect to a roaming network, the device had to scan through all enabled network bands to confirm a home network could not be found, which was an extremely power-intensive process.

On NB-IoT networks, for example, it took 2 minutes and 45 seconds to scan each band, totaling to 44 minutes of scan time with 16 bands enabled. That’s more than 200x the energy of a standard upload on a home network! This high latency and power usage was just not practical, specifically for battery-powered devices where long battery life is imperative.

Seamless roaming across LTE-M/NB-IoT networks


As of March 2023, there are now 170 Mobile IoT networks deployed globally as well as more international roaming agreements between major network operators.

Due to greater network coverage, new low-power modem technology, roaming agreements, and our own firmware smarts, our latest range of LTE-M/NB-IoT asset tracking devices support automatic roaming between LTE-M and NB-IoT networks with minimal delay and marginal impact on battery life or performance.

A new integrated modem on our devices supports both LTE-M and NB-IoT and can operate globally, removing any need for regional variants. Cell scan energy has also more than halved, so not only does it not take as long to scan NB-IoT bands, it also takes less energy!

It now takes 1 minute and 45 seconds to scan through all 16 NB-IoT bands – That is less than the time it took to scan one band previously! In addition, the modem remembers the last network it connected to, so the next time it tries to connect to the same network, it takes a matter of seconds.

Real-World Results

The Power Profile below compares the Oyster2, our best-selling battery-powered GPS asset tracker with the next-generation Oyster3, connecting to Vodafone’s NB-IoT network in Australia with a roaming SIM.

Power Profile: Digital Matter Legacy and Next-Gen Oyster on NB-IoT

Power Profile
Red – Oyster2 (2019)
Green – Oyster3 (2021)

We can see the Oyster2 takes 14x longer to complete an upload and uses 25 times the energy when connecting to Vodafone’s NB-IoT network with only one band enabled.

Roaming Across Europe

The Yabby Edge, our battery-powered indoor/outdoor battery-powered asset tracker featuring GNSS, Wi-Fi MAC Address Scanning, and cell tower location, was put to the test in Europe using a 1nce roaming SIM card.

The Yabby Edge successfully traveled through 5 countries across 9 different networks with minimal delay and marginal impact on battery life or performance.

Data on Map
Yabby Edge Trip Data (2021)

Average network registration sat around 5 – 20 seconds when searching for a new roaming network, and 1-2 seconds when re-joining the same network. This translates to an average margin of 250 – 1000 % energy saving on re-joins!

There were extremes of about 120 seconds when roaming over from Cat-M1 (LTE-M) to NB-IoT for the first time when the network string was not configured – a scenario which would have resulted in a failed registration attempt after a significantly longer period on the previous generation of devices.

Country Operator Technology


Belgacom/Proximus Cat-M1
Mobistar/Orange Cat-M1



S.F.R Cat-M1
Bouygues Telecom Cat-M1
Orange Cat-M1
Italy Vodafone NB-IoT
Luxembourg P+T/Post LUXGSM Cat-M1


Swisscom Cat-M1
TDC Sunrise Cat-M1


EU to US Roaming

The Yabby Edge also connected seamlessly between the EU and the US on the same roaming SIM, successfully connecting to the AT&T and T-Mobile LTE-M networks in the United States. Registration delays across continents were comparable to roaming into a neighboring EU country and achieved without any band restrictions being required!

Data on Map
Yabby Edge point-based tracking data (2021)


Country Operator Technology


Belgacom/Proximus Cat-M1
Mobistar/Orange Cat-M1


AT&T Cat-M1
T-Mobile Cat-M1


New Applications in Cellular IoT Asset Tracking


Combining indoor/outdoor asset management, ‘deploy-once battery life’, and automatic roaming across LTE-M and NB-IoT networks enables exciting new use cases in connected packaging, global supply chain management, parts and inventory management, shipping and logistics, and more.

Global Supply Chain Management – Parts and Inventory

Manage critical supply chain assets, parts, and inventory as they travel indoors to outdoors, regionally, or globally with near-real-time location and movement history, movement and impact alerts, sensor monitoring, and more to enhance traceability and transparency. Provision devices to report more frequently when supply chain assets are on the move and conserve data and power usage when stationary.

Connected Packaging

Add indoor/outdoor asset trackers to high-value and/or returnable packaging to monitor location, delivery routes, handling, and arrival. Integrate with third-party Bluetooth® sensors to capture other key package conditions such as temperature, moisture, shock, vibration, and much more.

Rental Vehicles and Equipment

Manage and protect rental equipment across locations with your own wire-free, indoor/outdoor asset tracking system designed to improve productivity and churn rates. Track run-hours to bill customers based on usage. Receive alerts if equipment is used outside of agreed-upon hours or locations.


Digital Matter’s Cellular IoT Roaming Devices



Oyster Edge
Yabby Edge



For more information on our LTE-M/NB-IoT asset tracking solutions, contact us today!

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