The ultimate guide to cellular IoT networks

IoT devices need connectivity to communicate with gateways, applications, servers, and cloud platforms. This sending and receiving of data between devices and the cloud is what makes the Internet of Things (IoT) possible.

For IoT projects, it’s important to prioritize connectivity early to avoid future headaches and remember that a proof-of-concept may fail when scaled globally.

Cellular IoT networks are a popular choice for connecting devices to the internet.

In short, cellular IoT uses the same cellular networks as smartphones to connect IoT devices to the internet.

But why is Cellular IoT popular and what are some common pitfalls you should look out for? We’ll cover those questions in detail.

What is IoT connectivity?

IoT is a broad field made up of various skill sets and industries. When building an IoT solution, you will need to consider a variety of options for each of the three layers of the IoT technology stack: Device, Connectivity, and Cloud.

For this article, we are focusing on the connectivity part of Iot.

IoT connectivity refers to the process of transferring data from IoT devices to the cloud. It involves using sensors on devices to measure various parameters in the environment. These sensors, managed by device software, capture data that is then transmitted via wired or wireless means, such as cellular, Wi-Fi, Bluetooth, satellite, or Ethernet, depending on the use case.

This connectivity layer bridges the device and cloud levels of the IoT technology stack, where data is stored, processed, and utilized in applications for value extraction.

Why is cellular good for IoT?

Cellular connectivity is popular in IoT applications for two simple reasons:

1. It’s global.
2. It’s standardized.

Cellular IoT is a natural choice for many use cases as it utilizes long-established global networks. Cellular networks reach most corners of the globe, and IoT has piggy-backed on that existing infrastructure.

The demand for global cellular connectivity has driven the development of global standards and means that there is international alignment on technologies.

Even though standards like 2G, 3G, 4G, 5G, NB-IoT, and LTE-M may seem like a complex myriad of acronyms, international organizational bodies like the 3rd Generation Partnership Project (3GPP) and the GSM Association (GSMA) keep everything in check.

Other connectivity technologies either miss the advantages of global standardization and/or are not deployed globally with the capability of interconnecting (e.g., SigFox, LoRa, Bluetooth, WiFi).

When is Cellular IoT the right choice?

What constitutes a prime use case for cellular in IoT is continually changing as cellular networks evolve.

For example, latency and high power usage are historically good reasons people might avoid cellular connectivity. But newer, low-latency technologies, new connectivity methods, and modern cellular devices have changed the game.

Examples of cellular IoT use cases:

1. Telematics and connected cars.
2. Fleet management.
3. Retail IoT.
4. Smart buildings.
5. Micromobility.
6. Smart meters.
7. Agricultural IoT.
8. Manufacturing.
9. Predictive analytics.
10. Logistics and transportation.
11. Wearable health devices.
12. Smart cities.

What are the types of cellular networks?

There are a range of cellular technologies available throughout the world. These are grouped into generations, of which there have been five. Here’s a brief overview of the cellular generations.

2G

Second Generation Cellular Networks:

• 2G is an abbreviation for second-generation cellular networks.
• 2G is GSM (Global System for Mobile Communications) based and supports phone calls and SMS.
• 2.5G employs GPRS and allows for data connections.
• 2.75G uses EDGE (Enhanced Data Rates for GSM Evolution) for faster data connections.
• Although 2G is still very useful for IoT applications, operators are currently sunsetting the technology in multiple regions.

3G

Third Generation Cellular Networks:

• 3G introduced the UMTS (Universal Mobile Telecommunications System), which includes faster data connection speeds than 2G thanks to new modulation schemes as well as improved handover with interconnected RNCs (Radio Network Controllers).
• 3.5G introduced HSDPA and HSUPA (High Downlink/Uplink Speed Packet Access) for faster data speeds.
• 3.75G goes even further with HSPA+ (Evolved High-Speed Packet Access +) and boosted data connection speeds yet again.

LTE

Long Term Evolution:

• Long Term Evolution, also known as 3.95G, is a technology that is based on GSM/EDGE and UMTS/HSPA.
• Despite being marketed as 4G, LTE is classified as 3G because it does not meet all of the 4G criteria. LTE+ or LTE Advanced, on the other hand, meet 4G requirements.

4G

Fourth Generation Cellular Networks:

• 4G was introduced to meet modern multimedia requirements for high uplink and downlink speeds (e.g. video streaming).
• Download speeds of up to 100 Mbps are expected on 4G networks.

5G

Fifth Generation Cellular Networks:

• 5G is the cutting-edge of cellular communication. It’s being rolled out globally and will provide high-speed bandwidths of up to 1Gbps.
• Aside from being fast, the technology also has low latency and can support large numbers of devices in small spaces (no more cellular outages at music festivals, for example).
• Both NB-IoT and LTE-M have their origins in the 4G LTE standard. However, the 3rd Generation Partnership Project (3GPP)—the organization responsible for 5G as well as the NB-IoT and LTE-M standards—has incorporated these technologies into the 5G standard.

What are the best cellular IoT networks?

Typical IoT solutions require low amounts of data and are power constrained. So high-speed 5G that is attractive for streaming Netflix on smartphones isn’t necessarily great for IoT applications.

Older technologies like 2G are still very useful for sending low amounts of data across large areas, but 2G and 3G networks are being shut down to make way for newer technologies built for IoT.

LTE-M and NB-IoT are built for IoT

LTE-M and NB-IoT are Low Power Wide Area Networks (LPWAN) optimized for cellular IoT use cases. They offer IoT solutions features that dramatically reduce power consumption, offer better coverage across wider areas, and the ability to make smaller devices.

Long Term Evolution for Machines (LTE-M) is a shortened term for eMTC LPWA (enhanced machine type communication low power wide area) technology. LTE-M uses existing LTE technology and is currently a more robust choice than NB-IoT, which stands for NarrowBand-Internet of Things, which isn’t good for devices that are mobile or require support for SMS services (e.g. to over-the-air update eSIMs).

LTE Cat 1 bis is globally available

The problem with LTE-M and NB-IoT is that they have been deployed unevenly and neither are globally available. A ready-made alternative for these two LPWAN cellular networks is LTE Cat 1 bis.

LTE Cat 1 bis is an evolution of LTE Cat 1 where only one antenna is needed on devices without losing any of the main capabilities from the Cat 1 standard. LTE Cat 1 bis works everywhere there’s a 4G/LTE network available, enjoys the same bandwidth, and allows roaming.

How do Cellular IoT networks work?

The device transmits to a base station (aka cell tower). Base stations are the antennas you can typically see around the city on rooftops.

Groups of base stations are called radio access networks (RANs). As a part of the telecommunication network, the RAN sits between the device and the core network.

You could say RANs link users or devices to their operator, and the operator’s core network is the gateway to external networks, such as other core networks or the cloud (think Azure IoT Hub, AWS IoT Core, IBM Watson IoT, and the soon-to-be-depreciated Google Cloud IoT Core), and is also how operators connect to one another.

What are MNOs and MVNOs?

So, who is running this cellular network show?

Mobile Network Operators (MNOs) own the radio spectrum used by the RANs. Verizon, AT&T, Telefonica, Vodafone, China Mobile, and Telenor are examples of MNOs.

Apart from their retail business, MNOs also lease access to their infrastructure to Mobile Virtual Network Operators (MVNOs). This arrangement isn’t just for some extra revenue; it’s also required by law in most countries (e.g. Competition policy in telecommunications: The case of Denmark (PDF)). Many MVNOs are merely resellers of SIM cards who use roaming agreements and don’t have any technical access to RANs.

To differentiate, sometimes you’ll hear an operator call themselves a “full MVNO”, which means they run the entire network technology stack. A few MVNOs, like Onomondo, have fully integrated their core network with local RANs (this is very rare and no-one has as many full-core integrations as Onomondo). The way Onomondo accesses base stations is the same way an MNO attaches to their base stations (which is standardized by GSMA).

The other “full MVNOs” that we know of generally only do this with one MNO partner, e.g., Deutsche Telekom. This integration gives them full access to data on the integration and devices on their network, but not for other RANs in the world not operated by e.g. Deutsche Telekom.

What is the cellular core network?

Now let’s drill a little bit into the cellular (aka mobile) core network.

To keep it simple, you could say the main parts of the cellular network core are the HLR/HSS and the GGSN/PGW.

Every mobile network has a server that stores SIM information, such as location and authentication keys. The Home Location Register (HLR) or Home Subscriber Server (HSS) is the database of all the operator’s SIM cards.

The gateway GPRS support node (GGSN) and Packet data network GateWay (PGW) are where all the data a device tries to transmit goes through.

The core interfaces with other operators and the cloud, for example. You can also control what’s happening in the core with APIs or apps (e.g., with connectivity management platforms) and proactively access information via Webhooks.

What is roaming?

When using your IoT SIM outside of its home network, some of the data handling responsibility is handed over to the network you’re visiting. This is called the visited network or foreign network. In short, you’re roaming when you go outside of your home network.

As a basic example, if you take a UK SIM card to the US, you can’t see BBC online anymore because a local network has given you a local IP.

It’s fine to roam on an iPad or a phone; you can get an SMS, make a call, and access the internet. But with IoT, there are some limitations that can make a big difference in global deployments.

When roaming, your home network doesn’t know what you are doing in real-time.

The separation of responsibilities between your home and visited network is a problem for IoT – businesses often suffer from network debugging delays (days or weeks) because of a “not my customer” attitude.

Another issue is the lack of financial control and forecasting, as roaming typically means you get zero real-time insights as billing and reports come on the back of usage.

Onomondo has full-core integration with 680+ networks

We’ve shifted many of the SIM functionalities to our core network and we’ve integrated it with over 590+ operators globally. This has enabled us to offer unique benefits to our customers.

Reduce data consumption and increase energy efficiency – No-code cloud connectors move SDK logic from devices to our network. Our core network controls data security and data steering, and your device consumes less data and power.

Troubleshoot faster – Network transparency saves precious development and testing time. Onomondo shows you everything in real-time, globally; from what’s going on when a device tries to attach (signaling, authentication, etc.) to what’s happening once it has attached.

Less SIM management – Manage SIM networks and endpoints within a unified cellular IoT connectivity platform. Our automated price scaling and always active SIMs let you focus on improving products and rather than managing costs.

Rapid technological advancements create uncertainty for IoT developers when selecting hardware and connectivity providers for solutions that are expected to last three, five, or even ten years. Understanding cellular IoT and how to prepare for the future is critical for IoT deployments.