These efforts, however, don’t represent LPWAN and specifically LoRa in the real world—and just think about the power consumption involved! With greater distance, you need more and more power, which means batteries last for shorter amounts of time. In more normal settings, there are several variables (some of which network designers and users don’t have any control over) that determine how far apart gateways need to be to optimize both power and range to achieve maximum battery life:
- How powerful the gateway is
- How powerful the antenna on is on the sensors, and what type of antenna it is
- The physical terrain (both natural and manmade)
- The ambient noise of other wireless networks and devices in the area
- How big a battery and what battery type, which impacts device size. Most batteries in LPWAN devices are lithium ion, which last longer for the types of applications being measured by the IoT devices
- What is being measured, how often it is being measured, and how long it takes to measure. Applications that require more real-time measurements, such as GPS location, for example, take longer to measure and are measured more frequently, and that drains the battery more quickly. If those types of measurements are required, the gateways need to be close together
In general, what emerges in just about every real-world LPWAN deployment is the classic tradeoff between power and range. There are two traditional ways companies try to overcome these tradeoffs: build the highest power gateway possible or use more gateways so they are closer together. Both come with issues of their own, such as cost and backhaul constraints.
There’s a third approach, however, that comes closer to solving the power vs. range conundrum: densifying the network through meshed gateways. While adding more gateways would traditionally mean individually connecting each gateway to the network, driving up costs, by interconnecting the gateways via a WiFi mesh, only one gateway connects to the Internet, delivering a more cost-effective solution.
While a denser network means more capex for gateways, the real cost is the ongoing operational cost of the gateway—getting it connected to the internet the first time with cables running up to a location high on a building or tower. Doing that for every gateway is an expensive proposition and you still have ongoing network maintenance for each gateway. By meshing the gateways, that happens once, not for every gateway, allowing users to densify networks at a much lower operational cost.
The net-net: Achieving super-long distances with LPWAN may make for stellar headlines, but doesn’t help much in real-world implementations. There’s a sweet spot that balances the number of gateways, the distance between them, and the power required for the applications being used. Longview’s meshed gateway networking technology creates operational savings AND battery savings, making big tradeoffs a thing of the past.