Network design forces integrators to choose between high performance and low power usage. "If you're looking for maximum performance, like with Wi-Fi 6 or 5G, you need constant, easy power, like a laptop or phone that's recharged every day or two," Ratliff says.
On the other hand, industrial project planners expect batteries powering IoT devices to last up to 10 years, according to Ratliff. "Most IoT command and control or monitoring devices are very low performance," he says. Water moisture sensors, for instance, may only send a few bytes per day over the network.
That's where the "LP" in LPWAN comes in. Popular network options are LoRaWAN (unlicensed spectrum) and Narrowband IoT (NB-IoT), which is licensed. NB-IoT ships in high volume in China, says Ratliff, "thanks to government-backed efforts for smart cities with huge node volume" that are less price sensitive. LoRaWAN devices, which all use chips from a single vendor, Semtech, are also popular in China from grass roots efforts where low cost is important; they have had considerable success in North America and Europe too. LoRaWAN devices offer battery life of 10 years for a single AA battery, making them a good choice for agricultural and industrial applications. Dozens of network providers offer private and public LoRaWAN support nationally, and many support global projects.
A good rule of thumb, says Ratliff, is the lower the performance, the cheaper the device and network.