Which wireless communications option is best for your agricultural operation? Four major considerations for each connectivity option include:
- Range: How far away can end devices (the devices doing the sensing) be located from edge devices (the devices sending data to the cloud or network)? Is line of sight required?
- Bandwidth: How much data needs to be sent over the connection?
- Power: How much power does the solution require? Are batteries enough, or is solar power an option to power the devices?
- Cost: System price matters, especially when you’re scaling up a solution over a large operation.
Let’s walk through the options one by one. If you’re short on time, skip to the comparison table at the end for a brief overview of each connectivity option.
WiFi works across a few buildings, but expanding the range of your signal to fields and other areas of your operation costs more than it’s worth. A WiFi signal is attenuated (read: reduced) by walls, large devices, and bodies of water. That’s not ideal for an agricultural operation with large pieces of equipment, bodies of water, and miles of fields. And even without a lot of things in the way, WiFi range really isn’t that great. A general rule of thumb in home networking says that WiFi routers operating on the traditional 2.4 GHz band reach up to 150 feet (46 m) indoors and 300 feet (92 m) outdoors. Newer WiFi devices operating in the 5 Ghz range experience even more attenuation than traditional ones.
The one benefit of WiFi is that you can send a ton of data over the connection. After all, this is the same type of connectivity you’d use to stream Netflix or play video games. So, while you can send huge amounts of data, the range is too short to be valuable in a large agricultural operation, especially in a field or on a mobile machine.
WiFi hardware is also relatively power-hungry compared to other connectivity options designed for embedded devices. Connecting devices with WiFi also assumes that there is an uplink to the rest of the internet at the wireless access point your devices are connecting to.
Result: Short range, high bandwidth, draws a medium amount of power. Relatively inexpensive connectivity if you already have an internet connection.
Cellular devices share many of the benefits of WiFi, and can be more flexible. Depending on the network your cellular device connects to, they can have very high bandwidth.
Bandwidth for cell connections:
- 3G: 2 Mbps
- 4G: 200 Mbps
- 5G: 1+ Gbps
However, if each device has its own cellular connection, it will require its own subscription, and those subscriptions costs can add up. A cellular connection is also limited if your service provider doesn’t have a cell tower in range of the device you want to connect. This can be a big factor for farms or other rural locations, where cell service may be fine at the house, but could be non-existent a few miles down the road.
A cellular connection can connect to the cloud wherever there’s cellular coverage. However, the high bandwidth and easy cloud connectivity comes at a cost: power. Cellular connections require a lot of energy. If devices are battery-powered, they need a way to charge their batteries. If the device has access to line power, that’s not a problem. But for agricultural applications, remote is the norm, in which case a renewable source like solar power is a good option.
Result: Range dependent on cell signal, high bandwidth, draws a substantial amount of power and is relatively costly on a per unit basis.
Satellite uplink can be used in areas with no cellular coverage. Range is essentially a nonfactor, because satellite coverage is available nearly everywhere on planet Earth. A disadvantage of this type of connectivity is that it requires line-of-sight with one or more satellites, so it won’t work indoors or in areas with a cluttered or non-open sky (under trees or near large buildings).
Satellite hardware and data subscriptions both cost more than cellular, and satellite has significantly reduced bandwidth. Power consumption is typically substantial, requiring additional supplemental power. However, satellite options are getting more affordable as smaller, smarter satellites are taking to the sky.
Result: Maximum range, low bandwidth, draws a lot of power, and requires a clear sky to maintain connection. The most expensive option, today.
It’s in the name: LoRa technology has incredibly Long Range. LoRa signals can even get through substantial foliage like dense irrigated corn. In exchange for this far-reaching range, the LoRa connection has a modest bandwidth of 27 Kbps. For applications where you don’t need constant data transfer, sending a few small data packets per hour is more than sufficient. LoRa devices require a communications device like a LoRa to cellular Data Gateway to get data to the cloud.
LoRa connected devices shine in two ways: cost and power. Unlike cellular or satellite, LoRa connected devices are much more cost-effective in terms of hardware. Also, by using cheaper LoRa connections where you can, instead of using cloud-connected technology for each device, you’ll save quite a bundle on monthly subscriptions. In addition to cost-effectiveness, LoRa devices have very small power requirements. Battery-powered devices can last months or years in the field with no battery replacements.
Result: Long range, low bandwidth, ultra-low power. Priced to scale over multiple devices.
Sigfox is a proprietary network built for low-power, long-lasting devices. Sigfox technology takes the bandwidth-power relationship to the extreme. Transmitting at the lowest of the low of 100 bps allows Sigfox devices to have extraordinarily long battery life, up to 10 years. The rural range is advertised up to 40 km, which is the largest area covered out of all the connectivity options in this article. The cost per unit is relatively inexpensive. So if your use case will work with very small data packets in exchange for long battery life and long range, this might be a good option. Sigfox networks are strongest in Europe.
Like LoRa devices, Sigfox devices require a base station or communications device to relay data to the cloud.
Result: Long range, ultra-low bandwidth, low power. Priced to scale over multiple devices.
Zigbee technology is ultra-low power and low cost. Typical bandwidth is a respectable 250 Kbps. Zigbee devices communicate on the 2.4 GHz spectrum, the same frequency that most WiFi operates on. This means Zigbee devices experience interference from water, people, foliage, metal, and concrete. Coupled with its short range of 10 – 70 meters, the interference makes it essentially unusable for agricultural applications.
A key differentiator of Zigbee is its ability to create a mesh network. Like LoRa and Sigfox, Zigbee devices need a hub to transmit data to the cloud.
Result: Ultra-low range, low bandwidth, ultra-low power. Priced to scale for multiple devices.
Connectivity Platform from RealmFive
We believe in creating a Connectivity Platform that’s built for agriculture — which means optimizing products for remote applications. We’ve created a network to connect devices that couldn’t be connected before, because either there wasn’t a good signal, not enough power, or it was prohibitively expensive.
- Range: With modified LoRa technology called R5 Core, you get below-canopy connectivity through dense foliage. This exceptional range makes it possible to connect your entire operation to the cloud with minimal subscription costs.
- Bandwidth: RealmFive devices have a small data footprint. This lower bandwidth requirement makes it possible for lower power use and longer range.
- Power: This drop-in network doesn’t require line power: solar power or standard batteries — like AA or D cell — will keep your devices running through the season.
- Cost: The Connectivity Platform is priced to scale. Up to 50 sensing devices can connect over LoRa to a single Gateway Communications Device, which cuts down on per-unit data subscription costs.
Costs are quickly reducing per unit as the Internet of Things economy is driving economies of scale. For example, a 2017 Gartner report predicts that IOT devices will increase to 20 billion by 2020, up from the current total of 8 billion.
|Technology||Max bandwidth||Point-to-point||Ground-level range in crops||Power requirements||Pros||Cons|
|WiFi||300 Mbps||300 ft||N/A||medium||High bandwidth, low cost||Power footprint and range limits use for ag environments|
|Cellular||2-200 Mbps||20 miles||.25 to 1 miles||high||Average bandwidth, long range||Large power footprint, unit cost, subscription cost, coverage limitations|
|Satellite (bgan)||3-5 Mbps||N/A||N/A||ultra-high||Works everywhere in the world||Ultra-high power footprint, high subscription cost, susceptible to weather and foliage interference.|
|LoRa||27 Kbps||20 miles||.5 to 2 miles||ultra-low||Low power, long range, low cost, low subscription fees.||Low bandwidth limits use for video or imagery|
|Sigfox||100 or 600 bps||30 miles||N/A||ultra-low||Low cost, low power, no subscription||The lowest bandwidth|
|Zigbee||250 Kbps||150 ft||N/A||low||Low cost, low power, good bandwidth for IOT, no subscription||Poor range, unusable in foliage.|