As IoT expands to include many applications across geographies and industries, there’s a need for new types of connectivity. That’s because IoT sensors have different requirements than consumer devices like smartphones do. They may be deployed in rural or remote areas or need to connect while traveling across a continent. And many IoT sensors are designed to send small packets of data from time to time, without needing a constant connection to the network. For these IoT sensors in the field, saving power to maximize battery life is a higher priority than staying online 24/7.
LPWAN: A Perfect Fit for IoT
LPWAN stands for low-power wide-area network, a technology developed for large-scale IoT deployments. This type of networking emerged around 2010 with the advent of Sigfox and LoRa, followed by NB-IoT. While they differ substantially from each other, the technologies all fall under the LPWAN heading because they share a few essential characteristics—among them low cost, minimal power consumption, and the ability to achieve long-range communications.
What are the benefits of LPWAN?
Let’s take a closer look at the benefits of LPWAN, specifically for large-scale IoT deployments.
Low power consumption
Compared to other cellular technologies, LPWAN uses far less power and runs on inexpensive batteries that can last for a decade or more. This longevity is advantageous for IoT deployments in remote areas or sensors that are difficult to access, such as agricultural sensors or smart meters.
Compared to 3G and 4G, LPWAN technology is a low-cost solution that can enable IoT deployments at scale. If a city wants to install wireless sensors in trash containers, that project is feasible with LPWAN—where it wouldn’t be with a more expensive technology.
Operates on unlicensed radio spectrum
Some LPWAN technologies (such as LoRaWAN and Sigfox) operate on the unlicensed spectrum, cutting out ongoing connectivity costs. However, since interference can be an issue with a growing number of connected devices in many areas of the world, some operators choose to pay for connectivity on a licensed radio spectrum.
Because they operate at lower data rates, LPWAN signals can travel up to 40 km in rural areas and 1–5 km in urban environments. By comparison, 4G wavelengths have a range of about 16 km.
Limited infrastructure needs
Overall, LPWAN infrastructure requirements fit neatly between those of Wi-Fi and cellular technologies. LPWANs require more infrastructure than Wi-Fi, but offer more benefits. And they need less infrastructure than cellular to keep devices connected—but LPWAN connectivity isn’t as ubiquitous as standard cellular. For certain use cases, LPWAN technology provides an ideal solution.
How does LPWAN work?
LPWAN connectivity uses less power because devices are designed for fewer check-ins with the server. This arrangement doesn’t fit every use case, but for many IoT deployments—such as those in smart cities—reporting from the field only at scheduled intervals is a far more efficient use of power than maintaining a constant connection.
Narrow bandwidth and advanced signal processing
Some types of LPWAN technology utilize narrow bandwidth transmissions, while others encode signals in ways that maximize potential range. For example, LoRaWAN uses chirp spread spectrum (CSS), a method that utilizes wideband linear frequency modulated chirp pulses to encode data.
Greater latency equates a wider range
LPWAN technologies tend to transmit data at much slower rates than other cellular technologies such as 3G. But in wireless networking, it’s often true that the slower the data transmission, the greater distance it can travel.
What are some of the leading LPWAN technologies?
There’s a lot of diversity within the LPWAN category, which encompasses both cellular and non-cellular technologies. Sigfox emerged as the first LPWAN, but cellular options such as NB-IoT and LTE Cat-M1 are quickly gaining popularity among IoT leaders.
Designed for IoT devices with low bandwidth needs, NB-IoT operates in very narrow bandwidth at 180 kHz, a typically unused portion of the LTE spectrum. With upload speeds around 66K, it’s best suited for simple IoT devices that require small, intermittent data transmissions where latency doesn’t matter. NB-IoT offers long-range support and strong signal penetration, so it’s good for indoor, outdoor, and underground deployments.
Another cellular LPWAN technology, LTE Cat-M1 can support higher bandwidth than NB-IoT, with upload and download speeds in the neighborhood of 1Mbps. Many operators are migrating 2G and 3G devices to LTE Cat-M1 as those other cellular technologies come to an end.
A French company that built the first LPWAN in 2009, Sigfox continues to operate its proprietary network in many countries around the world. Like NB-IoT, it uses a narrow band and works best for very small bandwidth applications where energy savings is a paramount concern.
Developed on the heels of Sigfox, LoRa is based on chirp spread spectrum (CSS) technology and uses unlicensed radio frequency bands to enable long-range transmissions. Also a proprietary technology, the LoRaWAN network can transmit larger data loads than Sigfox, and its modulation scheme consumes more bandwidth—meaning it can enable more devices to transmit data simultaneously.
What are some ideal use cases for LPWAN?
IoT designers across many sectors are finding LPWAN an ideal choice for their deployments. Most IoT devices don’t need constant connectivity and the bandwidth to transmit large data packets. For most deployments of simple sensors spread across a geographical area, LPWAN is a clear solution. Let’s take a closer look at some examples of use cases in various industries:
Smart metering is an excellent use case for LPWAN technology. A utility company places thousands (or millions) of these meters across their service area. The sensors only need to report back periodically to guide billing information, the data load is small, and long battery life is essential to the financial feasibility of the deployment.
Wearable health devices
Like smart meters, telehealth monitoring devices typically send small packets of patient data (such as a glucometer that collects blood sugar readings). The data is collected and sent periodically to a management system that the patient and/or healthcare provider can access. Long battery life is a key feature for wearable health monitors, as it ensures greater convenience for the patient and fewer interruptions in data collection.
Agricultural IoT devices such as livestock trackers and soil moisture sensors are typically deployed across large, rural areas. These devices collect small amounts of information and don’t require a constant connection to the network—they just need to check in periodically to deliver data to a management system. LPWAN is an ideal solution for this category of IoT devices because it offers the needed long-range, low-power solution.
For companies renting bikes, scooters, and other short-range vehicles in urban areas, LPWAN connectivity provides energy-efficient, low-cost asset tracking. Sensors deliver data periodically and can be programmed to trigger an alert if someone moves the vehicle outside a designated geographic area.
Many companies are installing IoT sensors on vehicles and shipping containers—and again, LPWAN technologies fit the bill for these use cases. Asset trackers typically only need to check in periodically or trigger an alert if something is amiss, and long battery life is essential to success.
LPWAN is the Future
In 2018, LPWAN was deemed the fastest growing IoT technology on the market, with 1.1 billion connections expected by 2023. LPWAN technologies enable businesses and governments to collect new streams of important data—data that can save lives, increase efficiencies, and save energy. Ultimately, these low power, wide area network technologies are key to achieving the promise of an IoT connected world.