How to connect IoT devices to a network

Probably one of the biggest misconceptions about IoT is that it must be connected over the internet.

Despite the name “Internet” of Things, IoT can exist without a direct internet connection and there are many cases where WiFi and SIM cards aren’t the chosen connection methods or are only used for setup and configuration purposes. 

In spite of this, when it comes to smart consumer devices, a lot of manufacturers are opting to put their devices online.

Why?

Well, often it’s because companies want to meet user expectations and offer convenience.

What does that mean?

Modern consumers expect to have control over the devices within their digital world, and they want to take this digital universe with them everywhere. 

In the last two decades, we’ve seen the humble telephone transform into a mobile smart device that can be used to browse the internet, run software applications, make payments and monitor health vitals. All while on the go.   

If that weren’t enough, customers also expect these devices to be “plug-and-play,” with as little manual input as possible. Since internet-connected devices align with this expectation, they become a popular choice for companies wanting to offer their customers an intuitive and hassle-free experience.

Going online offers benefits to businesses too… 

In industry, hyper-connectivity enables remote monitoring, automation, the collection of actionable data from distributed sensors and predictive maintenance. With an internet connection, data can be transported to the cloud, making the possibilities for integration and analysis almost endless. 

How do you connect IoT devices to a network?

IoT devices can connect to a network using technologies such as Wi-Fi, Bluetooth, cellular networks, Ethernet and low-power wide-area networks (LPWAN) such as LoRaWAN.

The right connection depends on what the device needs to do. Factors such as range, power consumption, bandwidth, location, security and the amount of data being transmitted all affect which technology is most suitable.

For example, a smart device inside a building might use Wi-Fi or Bluetooth, while remote sensors used for agriculture or environmental monitoring may need a low-power connection capable of transmitting small amounts of data over much greater distances.

Once connected, IoT devices can exchange data with other devices, gateways, cloud platforms or edge systems, depending on how the wider Internet of Things (IoT) architecture has been designed.

IoT connectivity options at a glance

Cellular: How to Connect IoT with a SIM Card

Now that we’ve looked at some of the reasons why business owners and consumers tend to lean toward internet-connected devices, let’s explore our first connectivity type – cellular.

In order for cellular IoT to work, a SIM card is placed inside of an IoT device. This is normally housed within a designated slot or integrated into the device’s module or modem. This IoT SIM stores information including the device’s unique identifier, authentication keys, and other details required for network access.

Once the SIM card is in place, it allows the device to establish a secure connection with the cellular network, enabling communication with nearby cell towers. This then facilitates the transmission of data to and from the internet.

Communication Protocols

Here are some of the most common protocols that govern wireless cellular communication:

• LTE-M (Long-Term Evolution for Machines)

LTE-M is a low-power, wide-area (LPWA) cellular technology specifically designed for IoT devices. It is designed to offer efficient data transfer, extended battery life, and improved coverage when compared with traditional LTE networks.

LTE-M can be used for applications like asset tracking, smart meters, and wearables.

• NB-IoT (Narrowband Internet of Things)

NB-IoT is another LPWA cellular technology designed for low-power, wide-area communication. It tends to offer better coverage in challenging environments, with a focus on supporting a massive number of devices. This is why it is commonly used in smart city applications, smart agriculture, and industrial IoT.

• 4G LTE (Long-Term Evolution)

4G LTE, one of the more widely used cellular technologies, is designed to deliver high-speed data transfer, low latency, and reliable connectivity. While not designed explicitly for IoT, it remains a viable option for applications that require robust cellular connectivity.

• 5G IoT

With the advent of 5G technology, IoT devices can leverage even higher data speeds and, again, offer low latency while providing increased network capacity. 5G IoT is particularly beneficial for applications requiring real-time data processing, such as augmented reality (AR), virtual reality (VR), and advanced industrial automation.

• CAT-M1 (Category M1)

Lastly, we have CAT-M1. This is a cellular technology that falls under the LTE-M umbrella. Striking a balance between data rate, power consumption, and coverage, CAT-M1 is suitable for applications such as smart meters, healthcare devices, and asset tracking.

What Makes Cellular IoT a Desirable Choice?

There are a number of perks associated with the use of cellular connectivity. Here are some common advantages: 

Better Coverage in Remote Locations

As long as a robust signal is present, technologies such as NB-IoT and LTE-M can provide much better coverage than WiFi in remote settings or when tracking mobile devices, since they aren’t affected by obstructions and can transmit data over long distances. 

This makes them ideal for applications where seamless connectivity is crucial across expansive areas or in challenging environments. 

Ease of Onboarding and Setup 

Another benefit of cellular connectivity for IoT is that devices can be provisioned on the network without the need for users to enter complex Wi-Fi passwords or go through the authentication process. This means that not only is the initial setup easier, but it also allows for more seamless transitions between locations without the need for extensive reconfiguration.

When we were working on Switchee back in 2015 (a smart home device for housing associations) a SIM card was used for this exact reason as it eliminated the need for manual WiFi setups.

Potential Security Benefits

For those who need to make security their highest priority, cellular can be a great option. 

Cellular networks include built-in authentication and encryption mechanisms, which can provide security advantages over poorly configured local WiFi networks. However, cellular connectivity isn't inherently risk-free, and devices still need appropriate security controls at the hardware, software and application layers.

Additionally, cellular security updates are managed by providers who tend to have specialised cybersecurity teams with a financial incentive to keep data safe. WiFi, on the other hand, requires the individual WiFi network owner to take proactive measures to prevent breaches and keep their connection secure.

Disadvantages of Cellular

Although cellular IoT does offer many benefits, there are some potential drawbacks to be considered. 

Elevated Cost

Firstly, cellular connectivity can be more costly per byte than WiFi. If your IoT devices generate a significant amount of data, especially in scenarios with frequent transmissions or large payloads, the costs can quickly add up and you need to decide who pays for that data and how. In this scenario, you might choose to look into transparent pricing models or think about bundling data costs into the overall product or service offering. 

You should also consider the possibility of significant roaming charges that may occur if you don’t use a specialised IoT SIM card for roaming. Although a simple consumer sim may appear to save you time and money, it can actually end up costing you if you deploy your IoT devices in multiple geographic locations with varying cellular networks.

Service Issues

Although technologies like NB-IoT and LTE-M can offer better coverage in remote settings compared to WiFi, this doesn’t guarantee flawless performance in every instance.

Challenges such as service gaps and signal fluctuations can still exist, particularly in areas with limited cellular coverage or complex signals. Having a backup plan or alternative communication method may be necessary to ensure continuous and reliable operation. This is a common practice and often, devices will offer dual options for connectivity, just as you get with mobile phones.

Problems with Device Tracking

Another common issue is that device location tracking using cellular networks may vary. 

Although cellular technologies have advanced, challenges in accurately pinpointing a device’s location can occur, especially in densely populated urban areas with numerous signal obstructions. This limitation can affect applications that rely heavily on precise location data, such as asset tracking or geofencing. 

Power Consumption

Lastly, although both can impact battery life significantly, generally speaking, cellular technologies tend to use slightly more power than WiFi. This is because cellular has to try to maintain a constant connection to the network which requires continuous communication with cell towers, leading to more frequent data exchanges and signalling activities. 

Cellular IoT Recap

Cellular connectivity is well suited to IoT devices that need to operate across large areas, move between locations or communicate without relying on a local WiFi network.

Technologies such as LTE-M and NB-IoT are designed specifically for IoT applications and can support devices such as smart meters, asset trackers and remote sensors. 4G and 5G may be more appropriate where higher data speeds or lower latency are required.

The main trade-offs are cost, power consumption and network availability. Cellular devices usually require a data plan and reliable coverage, so these factors need to be considered when designing and deploying the system.

Best suited to: remote monitoring, asset tracking, connected vehicles, smart infrastructure and mobile IoT devices.

WiFi: How to Connect IoT Wirelessly

Next up we have WiFi. When connecting IoT devices over WiFi, the wireless connection is facilitated by a wireless adapter within the IoT device. 

Once connected, the wireless adapter links with the router, serving as the conduit for the device’s data to traverse the internet via a wired connection. This link must comply with WiFi standards like WiFi 7 or 802.11ax (WiFi 6) in order to ensure compatibility among the IoT device, the wireless adapter’s chip, and the router.

What are WiFi 6 and WiFi 7?

You may already be very familiar with WiFi 6 and 7 but, if not, these two communication frameworks are simply standards for wireless communication. 

WiFi 6 (802.11ax) is widely used and offers faster speeds, improved efficiency and better performance in environments with many connected devices.

WiFi 7 (802.11be) is the newer generation, offering higher throughput, lower latency and improved capacity. For IoT applications, the right standard will depend on the device's bandwidth, power and infrastructure requirements.

Advantages of WiFi Connectivity for IoT

Let’s look at some of the benefits of using WiFi to connect IoT over the internet.

Cost-Effectiveness

First up is cost-effectiveness. When compared to cellular alternatives, WiFi can be a more purse-friendly option for stationary IoT devices. This is because, as you would imagine, leveraging existing networks eliminates the need for additional data plans. 

With that being said, it’s important to factor in the maintenance costs of WiFi which can rack up over time. For a modest home setup, it’s not normally too much of an issue; however for use in the workplace or in a home where there are plans to add additional IoT devices, WiFi upgrades and security measures may be required.

Efficient Data Transfer

WiFi excels in swift and substantial data transfers which is why it’s often chosen for high-performance applications that regularly demand quick and efficient data exchange.

This can give WiFi an advantage over cellular networks in terms of speed and reliability.

Lower Power Consumption

Lastly, when compared with SIM-based IoT, WiFi does tend to consume slightly less power which might be helpful in scenarios where prolonged device operation is key. 

In spite of this, most research suggests that power consumption, particularly when using battery-operated devices, is still a major concern with WiFi and therefore, energy-saving modes should be considered as part of the device design.

Drawbacks of WiFi Connectivity for IoT

As with all technology, there are some limitations. Here’s what you need to know… 

Security Levels May Vary

Although WiFi is widely used, its security for IoT devices is very much dependent on the user’s WiFi network. Even though there are ways of encrypting local WiFi networks, many consumers fail to protect their connections which puts them at risk. What’s more, in instances where IoT devices are connected to shared or public WiFi networks, these risks are heightened. Due to the inherent vulnerabilities of shared connections, there is a danger of exposing IoT devices to unauthorised access, data breaches, and malicious activities. For businesses using IoT, these are never things to take lightly. Therefore, to protect a business network, an up-to-date firewall is a must. 

Want to find out more about how to protect your network? Check out our article on preventing IoT Security issues. 

Onboarding and Setup Dependency

When it comes to onboarding and setup processes, WiFi not only requires access to the network with usernames and passwords but it may also have to rely on another connection like Bluetooth or a wired connection to facilitate the initial configuration. 

Even if just a minor drawback, these additional steps for setup can make IoT devices less convenient and less user-friendly, especially when compared to the straightforward nature of cellular setups.

Interruptions from Other Devices

One last thing to consider when connecting with WiFi is interruptions.

Unfortunately, the WiFi signal of IoT devices can be susceptible to interference from other devices on the network. This susceptibility can result in signal degradation or disruptions, impacting the reliability of data transmission and overall device performance. 

WiFi Recap

WiFi is a practical option for IoT devices operating within homes, offices, factories and other environments where a reliable wireless network is already available.

It can support relatively high data transfer speeds without requiring a separate cellular data plan, making it useful for connected devices that regularly transmit larger amounts of information.

However, range, interference, security and power consumption all need to be considered. WiFi is generally less suitable for devices that move between locations or remote sensors that need to operate on battery power for long periods.

Best suited to: smart buildings, connected appliances, cameras, industrial equipment and other stationary devices with reliable access to WiFi.

For devices that need to operate remotely or move between locations, cellular or satellite connectivity may be more appropriate.

Satellite Connectivity

Satellite connectivity allows IoT devices to transmit data in locations where cellular or fixed network infrastructure is unavailable.

This makes it particularly useful for devices operating in remote or difficult-to-reach environments, such as maritime operations, agriculture, logistics, environmental monitoring and infrastructure located far from populated areas.

Satellite IoT can provide much wider geographic coverage than terrestrial networks, but cost, power consumption, latency and the amount of data being transmitted all need to be considered.

Best suited to: remote assets, maritime applications, agriculture, environmental monitoring and infrastructure operating beyond reliable cellular coverage.

Exploring IoT Connectivity: Beyond the Internet Misnomer

As we mentioned at the start, IoT doesn’t have to communicate via the internet and at times, software developers, business owners and CTOs will decide to create local networks so devices can communicate and process data without requiring a constant connection to the internet.

Offline connections may also be used in scenarios where devices operate in isolated environments or where constant internet connectivity is unreliable or costly. In this case, a local communication approach, such as Zigbee or Bluetooth, might be chosen as an alternative. 

Bluetooth and Zigbee tend to work well in scenarios where short-range, low-power, and localised connectivity are prioritised. 

Bluetooth is well suited to short-range connections between IoT devices and nearby smartphones, gateways or other equipment. It uses relatively little power, making it useful for wearables, sensors and devices that only need to exchange small amounts of data over short distances.

Its main limitation is range and bandwidth. Bluetooth generally isn't appropriate for devices that need to transmit large amounts of data or communicate directly over long distances without another device acting as a gateway.

Zigbee is a low-power wireless technology designed for short-range communication between connected devices. Unlike a simple point-to-point connection, Zigbee can create a mesh network where devices help pass data between one another.

This makes it useful for smart buildings, home automation and industrial environments where many sensors or devices need to communicate within the same area.

Like Bluetooth, Zigbee isn't designed for high-bandwidth or long-range data transfer. Depending on the application, a gateway may be used to connect the local Zigbee network to wider internet or cloud services.

Is it safe to put IoT devices online?

While it’s important to educate people about the security risks involved with internet-based IoT connections and data stored in the cloud, there is a lot of misinformation around it. Web security features are getting more advanced all of the time and, in some cases, web connectivity can be more secure than a local network. We’ve seen this evidenced in the form of E-commerce and banking portals. 

Internet and cloud connectivity can enable remote monitoring, centralised management and large-scale data analysis across distributed IoT devices. This can be particularly valuable when organisations need to combine information from devices operating across multiple locations.

However, not every IoT workload needs to be processed in the cloud. Edge computing can analyse data closer to where it is generated, which can reduce latency, limit unnecessary data transfer and allow systems to continue operating when connectivity is limited. Many IoT architectures therefore combine local, edge and cloud processing depending on the requirements of the system.

Onboarding Devices: Further Considerations 

When configuring and setting up IoT devices, choosing the right method for data transfer can sometimes be a challenge. If we use a SIM card or wired ethernet connection, configuration tends to be relatively straightforward because as soon as that sim-containing device is on or that cable is plugged in, you don’t need to do much else. However, not all options are quite so straightforward.

WiFi Network Configuration 

When an IoT device has a screen, such as a smart TV, the user can simply enter the WiFi network name and password when prompted. Yet, not all devices have screens and therefore must rely on mobile apps to act as controllers to enable setup. 

Devices like smart speakers, cameras and health devices can use the following methods for network configuration:

Bluetooth: Fortunately, Bluetooth is a relatively simple method for onboarding. Users can press a button on an IoT device and it will make itself known as a Bluetooth endpoint. For the user, this can feel quite seamless as the mobile app can automatically scan for matching Bluetooth signals and connect.

Once connected, the mobile app can present a user interface form displaying the wifi address and password. Once the details are entered, it tests the connection and sends this via Bluetooth to the device. The IoT device can then connect to the local wifi internet using these details. 

Device as a Wireless Router: Another option is for the device itself to present as a wireless access point (a bit like using a hotspot on a mobile phone).

In this scenario, the IoT device creates a temporary Wi-Fi network or hotspot to which other devices, such as a smartphone or tablet, can connect. This temporary network allows for the initial setup and configuration of the IoT device.

The mobile app instructs the user to connect to the device’s custom Wi-Fi network. Once connected, it presents a form for users to select their local Wi-Fi network thus providing internet access. 

It’s important to note that the custom WiFi network itself does not grant internet access; its sole purpose is to facilitate the connection between the mobile app and the device, much like the Bluetooth example.

After users input the details for their local Wi-Fi network with internet access, the process for storing and connecting to the internet remains consistent. At this stage, the IoT device concludes its role as a wireless access point, and it no longer appears as an available network for connection.

The Future of IoT Connectivity

As we continue to seek out new solutions for fast, convenient and secure IoT connections, who knows what lies ahead?

We’ve already seen building excitement around 6G, with its deployment expected as early as 2030. If we employ this next-generation cellular technology in conjunction with satellite, could this help us to meet the demands of our ever-expanding IoT networks? Or, will the quest for flawless IoT connectivity continue for many years to come…

Connecting devices is only part of an IoT system

Choosing how devices communicate is an important part of an IoT project, but connectivity is only one layer of the wider architecture.

You also need to consider how devices are managed, where data is processed and stored, how information is secured, and how insights are made available to users or other business systems.

In some applications, data may be sent to cloud platforms for processing and analysis. In others, edge computing can process information closer to where it is generated, reducing latency and allowing systems to respond more quickly.

These decisions need to be considered together. The best connectivity technology is ultimately the one that supports the requirements of the wider IoT system rather than simply offering the fastest or longest-range connection.

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