Choosing Between Cellular and WiFi for IoT Projects

Mar, 15 2024

You have a decision to make when you need to send or receive data from your IoT device: cellular or WiFi? For standalone devices you will need to choose between one of these protocols. Both have tradeoffs.

Cellular Connectivity

Strengths

If your device is in a remote location far away from WiFi, cellular is the obvious choice. However, cellular can also make sense even when in range of WiFi networks. Cellular connectivity leads to a really nice onboarding experience as your device will automatically connect to the network when your user turns it on. Cellular also allows your device to remain connected if the device is frequently on the move.

Tradeoffs

Typically cellular is going to be the more expensive option. Cellular modems are more expensive and as the manufacturer your are responsible for the cost of the data transmission. You will have to maintain SIM cards for each of your devices while considering carrier coverage and fees.

When to choose it

1. You are less cost sensitive
2. Your device has low bandwidth requirements
3. You want to streamline or entirely remove the user onboarding experience
4. The device is out of range of available WiFi networks
5. Your device is frequently on the move
6. You want to deploy many devices at once in one facility

WiFi Connectivity

Strengths

If you're building a device that remains in the user's home or in an office environment, typically you will have access to a strong WiFi network. WiFi would be the better option if your device needs to transfer large amounts of data such as audio or video. WiFi controllers have become such a commodity that you can add WiFi connectivity to your device for a very small additional cost compared to cellular.

Tradeoffs

Sometimes the user's WiFi connection can be interrupted causing your device to fall off the network, or the network settings might change leaving your device without a connection. You have to trust your user to maintain your device's connection to the WiFi network. The experience of connecting your device to the user's WiFi network will have to carefully considered.

When to choose it

1. You are cost constrained
2. Your device has high bandwidth requirements
3. You already have a user onboarding process - this can be extended to include WiFi provisioning
4. You make no re-occurring revenue from the user
5. Your device will always be within the range of WiFi or can tolerate intermittent connection
6. You trust your users to maintain the connectivity status of your device

Cost breakdown

Below are some very rough estimates of costs associated with cellular and WiFi devices. Most of these estimates are "worst case scenarios".