Location, Location, Location: IoT Design with LoRaWAN for Asset Tracking

If the first thing that comes to mind when I mention LoRaWAN is a temperature and humidity sensor, that is totally understandable. Those kinds of sensors were the initial “killer app” for LoRaWAN because the technology operated so well in environments and locations that were challenging for other connectivity technologies: restaurant kitchens, food logistics warehouses, remote farms, and so on. LoRaWAN’s ability to perform in very difficult RF settings with metallic surfaces and concrete walls made it ideal for restaurants and warehouses, where temperature and humidity readings are critical to food safety. And LoRaWAN’s ability to transfer data over very long distances without the need for traditional telecom infrastructure made it ideal for agricultural sensors in farms far from the nearest cell tower or Wi-Fi router. Plus its ultra-low power consumption also made it ideal for all of those different situations.

LoRaWAN initially gained traction in those important but niche use cases, but today it is being used for far more than just temp and moisture readings. LoRaWAN’s use has accelerated rapidly over the past couple of years, with growth projections of 40-50 percent annually according to the researchers at IoT Analytics. What is the main trend driving that growth? LoRaWAN’s even bigger killer app: asset tracking.

LoRaWAN has become the go-to technology for device, equipment, materials and product tracking in a long list of vertical industries. That includes equipment and vehicle tracking in industrial, agriculture and transportation; tracking and monitoring of medical devices and other equipment in hospitals and healthcare settings; merchandise tracking in retail; product tracking in supply chain logistics; and much more. 

Why is LoRaWAN seeing such strong adoption for asset tracking? The strengths that made it such a great fit right away for temperature and humidity monitoring turned out to also be perfectly aligned with the needs of asset tracking: reliable performance in challenging RF environments, the ability to transfer data over long distances even when telecom infrastructure is not nearby, and ultra-low power consumption. Asset tracking requires all three of these, and LoRaWAN (both in its current form and in the enhancements in the LoRaWAN roadmap) is proving to be more effective at checking all three of those boxes than other technologies.

As background for engineering teams that have not worked with LoRaWAN before, it provides secure, bi-directional data transfer and communications with IoT networks over very long distances – up to 10 miles – even in areas where telecommunications infrastructure does not exist. That range can be extended indefinitely with the addition of inexpensive LoRaWAN relays at 10 mile intervals. LoRa’s sub-GHz frequency radio waves (400- to 900-MHz) can communicate directly with devices that are out on the horizon but within its direct line of sight. And that range can be increased by simply increasing the height of the LoRaWAN device on a pole, rooftop or hilltop. I should note that the estimated 10 mile range (between relays) is often exceeded in real world implementations. I have seen projects achieve reliable signals of 2x or 3x that distance and one experiment I read about was able to send the signal hundreds of kilometers with specialized antennas. Given that asset tracking often involves the movement of objects in and through areas that are far from the nearest LTE or Wi-Fi signal, the range of LoRaWAN makes it very desirable for these use cases. This range solves one of the key challenges of asset tracking.

IoT LoRaWAN Device Working

Another asset tracking challenge that LoRaWAN solves is the complexity of the RF environment, particularly for indoor applications or for assets that move within and through facilities with a lot of metal, concrete and wireless interference. Other connectivity technologies can struggle in those environments, but LoRaWAN performs reliably in these scenarios. Its signal can penetrate stainless steel, heavy insulation, and concrete walls as well as perform well in environments with significant RF interference.

Battery efficiency is another challenge for asset tracking that LoRaWAN has strong advantages for. Technologies like LTE have serious drawbacks when it comes to battery life. In contrast, LoRaWAN sensors can operate for years without requiring a battery change. LoRaWAN nodes are also inexpensive compared to other technologies, which is particularly valuable for high-volume deployments of sensors for asset tracking use cases.

Engineering teams considering LoRaWAN for a project should be aware of its limitations as well. Its primary limitation is data throughput. It will not be well suited for high-data rate applications, but asset tracking use cases rarely require high data rates. Typically, asset tracking applications require the delivery of small packets of periodic or event driven data, so this limitation is not a factor for these design projects.

Engineering teams that are already using GPS technology for asset tracking should be aware that LoRaWAN can play a valuable role as a complementary technology. GPS typically uses LTE to transfer data, but that technology is battery intensive and expensive. Plus LTE infrastructure may not consistently be nearby for many asset tracking use cases. By using LoRaWAN for GPS data transmission, teams can increase battery life, lower costs and successfully transmit data even in locations where LTE towers are not available. There are also experiments underway to enable GPS data transfer with LoRaWAN in open ocean using LEO satellites, which would solve a major challenge for asset tracking. 

Another advantage of LoRaWAN that I should mention is the simplicity of deploying them in the field. Deploying devices with other connectivity technologies can sometimes be complex because of the RF expertise that is needed to optimize those networks of sensors. LoRaWAN simplifies that by using self-discovering technology in the nodes and gateways. To set up each segment of the network, a central gateway is placed in a location free of major physical obstructions, and then the stick-and-go sensors are attached to the assets to be tracked. When the gateway is turned on, the network self-discovers the sensors, and the network is off and running doing what it was designed to do. When assets move to a new location in range of a different gateway, the network re-discovered the LoRaWAN device so it can continue to be tracked. 

One of the major challenges of asset tracking is optimizing performance as the location of an asset changes, leading to a change in the RF dynamics. For example, if an asset moves behind an obstacle or if multiple assets are near each other, how does the network ensure that the connections remain strong? LoRaWAN automates these adjustments in real time using ADR (Adaptive Data Rate), which continuously makes frequency adjustments to automatically optimize the connection between sensors and LoRaWAN gateways. ADR monitors the signal-to-noise ratio and adjusts frequency to maintain a strong connection and optimize performance. This feature of LoRa is another reason why LoRaWAN is so compelling for asset tracking use cases. 

To support the accelerating adoption of LoRaWAN, there are now far more hardware solutions on the market than in the past. These modules, sensors and gateways simplify the process of integrating LoRaWAN into IoT devices and deploying asset tracking networks. LoRaWAN’s initial applications may have been in the food service world, but its strengths for asset tracking are making it a technology that more and more engineering teams are working with.

About the Author:

Senthooran Ragavan is the Senior Product Manager for IoT at Laird Connectivity, which provides a full range of modules, antennas and IoT devices that simplify the process of using embedded processing and wireless technology. In this role at the company, he oversees development of solutions utilizing low-power connectivity technologies such as LoRaWAN and he works with companies around the world for their wireless product development initiatives. He has 10 years of experience in the embedded engineering and wireless design industry. He earned his Bachelor of Engineering from University of Hertfordshire, and is pursuing a degree in Masters of Business Administration from the University of Essex.