The main concept of the Internet of Things (IoT) is to connect different devices, sensors (the things), and even systems together so they can send and receive data to communicate with each other.
So, how we connect these different things is often the most important discussion in designing an IoT system. Wi-Fi is one of the most popular connectivity options in IoT, especially for relatively smaller implementations like a smart home. However, Wi-Fi has two notable weaknesses: first that it consumes a relatively high amount of power, and second, is the relatively limited range.
With that being said, below we will discuss some connectivity alternatives to Wi-Fi for IoT implementations.
Bandwidth VS Range VS Power Consumption
In choosing between the different IoT connectivity options, there are three key factors to consider:
- Bandwidth: the amount of data that can be sent/received within the IoT system, would also include data transfer speed
- Range: how far the devices/things can be separated from each other
- Power consumption: since IoT devices typically operate on battery power, then low power consumption is always preferred
Wi-Fi, for example, has a relatively small range, medium power consumption, and high bandwidth. If, for example, you are looking for more range, then you should look for another alternative.
In turn, these three factors would affect how we can design the IoT system while considering:
- The purpose/objective of the IoT application
- The minimum performance requirement of the application to achieve the objective(s)
- The planned physical locations of the embedded devices and sensors, and how far they are separated from each other.
Another factor that is often considered is that different connectivity options have different levels of tolerance to coexist in environments with other wireless connections. Below, we will discuss the available alternatives and review them based on these considerations.
Alternatives to Wi-Fi for IoT
1. Cellular/Satellite Connection
In IoT, cellular connectivity is most commonly referred to as “M2M”, or Machine-to-Machine, and it is the same cellular connection we use on our smartphones/tablets. Cellular data connectivity enables communication from a device to the next broadcast tower/antenna, typically in around 10 to 15 miles of range.
Key Characteristics:
- Cellular connectivity has the highest range compared to other connectivity options
- Reliable and stable connection (cellular connection is available everywhere with very rare downtime)
- Universal compatibility, you only need a SIM card/eSIM, and you are good to go
- It doesn’t involve direct communication between devices but has to go through satellite (might translate into latency issues)
- Highest power consumption compared to other alternatives
- You are tied to a monthly data plan, which can be expensive
If you are looking for the best coverage range and/or if you want to scale your IoT system, then cellular M2M connectivity is your best bet. If you plan to choose a cellular IoT connectivity, then choosing the right vendor is very important. Truphone, for example, offers global IoT connectivity solutions where you can connect different devices in more than 100 countries.
2. LPWAN
Stands for Low Power Wide Area Network, LPWAN is a relatively new wireless protocol that, as the name suggests, allows low power consumption while covering a wide area. It’s relatively similar to a cellular connection, but with much lower power consumption. However, as a trade-off, it can only deliver low amount of data.
There are now various types of LPWAN connections built for different purposes, like NB-IoT (NarrowBand IoT), LTE-M (a modified LTE connection with low power consumption), and LoRa.
LPWANs, in most cases, can connect almost all types of devices/sensors and enable data sharing with each other and with the cloud. However, the key weakness is that it cannot send a large amount of data at a time.
LPWAN is a great choice for IoT implementations that only require a small amount of data to be transmitted (i.e. between a thermostat and a smart refrigerator.)
3. Zigbee
Zigbee is a popular IoT connectivity option that operates with a mesh networking principle: the interconnected devices work together to send data to a target device/sensor, like in a ‘mesh’. Zigbee is specifically designed for IoT and can connect up to 65,000 devices in its mesh.
Amazon Echo and other Alexa devices, for example, support Zigbee, as well as various other smart home products.
Key characteristics:
- One of, if not the best mesh networking implementations
- Doesn’t need a central hub to operate (lower overall cost)
- Secure and reliable
- Has relatively short-range, devices can only be separated around 30-50 feet from each other
- Relatively slow in data transmission (only around 250 kbps), so only suitable for low data transfer
4. Bluetooth
Most of us are familiar with Bluetooth since we have it on our smartphones. Bluetooth is a wireless protocol designed for data transmission in short distances.
In the past, Bluetooth used to be a major battery-drainer in older smartphones, but with today’s Bluetooth Low Energy technology, Bluetooth now consumes fairly low power. Bluetooth can transfer data with a fairly decent bandwidth (2Mbps) but most can only cover a very low range of below 30ft (10m).
So, Bluetooth is a great choice if you are looking to transfer information between IoT devices that are near each other in medium to low bandwidth situations.
5. Z-Wave
Z-Wave is a radio-frequency (RF) based connection, much like Zigbee. However, unlike Zigbee, Z-Wave typically requires the need for a central hub device (which can add to latency and limit range). Z-Wave is also a bit slower than Zigbee but it has a longer range (more than 30+ feet).
Z-Wave operates on the 908 MHz band, which allows the increased range while also enabling reduced interference. Z-Wave is more reliable than Zigbee with a longer range, but at the moment it supports fewer devices than Zigbee. This is because Silicon Labs (Z-Wave’s owner) has to certify devices that can use it, so adoption is a little bit slower.
End Words
In most cases, cellular (M2M) IoT connectivity is the best alternative to Wi-Fi for IoT. Cellular IoT plans are now more affordable, and you also get reliable connectivity that is very easy to scale up on a global scale. Truphone, for example, offers an affordable, reliable IoT plan with coverage in more than 100 countries.
About Author: Mike Khorev is an SEO expert and marketing consultant.
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