LoRa networks for transmitting sensor data
- By Matt Leonard
- Feb 09, 2018
If sensors are going to be useful they must connect to the internet. But wired hookups aren’t available everywhere and cellular connections can be expensive. That’s why IoT Dev Labs is setting up a LoRa-based wide-area network for sensors.
LoRa is a low-power wide area network “intended for wireless battery operated Things in a regional, national or global network,” according to the LoRa Alliance, a non-profit focused on deploying such networks. IoT Dev Labs is building the LoRa sensor network across the Washington, D.C.-Maryland-Virginia region to test it as an alternative to Wi-Fi or cellular.
In Washington, D.C., sensors are being placed on street lights to understand how carbon dioxide accumulates in an urban environment. In suburban environments, “we’re using [LoRa] as another type of interconnect … where you’re less likely to have Wi-Fi connection,” IoT Dev Labs CEO and chief engineer Greg Toth said.
Internet connectivity isn’t the only challenge in a sensor network; access to power must also be considered. Because LoRa draws less power than other communication networks, it makes using battery- or solar-powered sensors more feasible, he said.
The range of a LoRa varies based on the environment. A signal sent from a base station over a clear, flat space can travel tens of miles, but a heavily wooded area can cut that to less than a mile and an urban environment can reduce it to mere blocks.
“It very much depends on the specific environment,” Toth said.
LoRa also provides less bandwidth than is typically used by transmissions across an LTE network, but not much is needed to transfer data from environmental sensors. These sensors are sending a few bytes of data, and transmissions can be scheduled for specific times or when measurement thresholds are triggered, Toth explained.
The backend IoT Dev Labs set up to receive the data hosted on Amazon Web Services. This can be leveraged in a variety of ways depending on the user. IoT Dev Labs can use the data to ensure sensors and the network as a whole are operating correctly, Toth said.
So far two base stations have been set up: one in Rockville, Md., another in Ashburn, Va. A third is being deployed in downtown D.C. and a fourth is slated for Reston, Va. More locations are planned along Metro's Silver Line corridor in Virginia, Toth said.
Setting up a LoRa network is "similar to deployment of any kind of telecommunications equipment,” he told GCN. This means site surveys, network connectivity testing and ensuring proper security.
The network has been in test mode for about five months and has “dozens” of environmental sensors connected to it, but the goal is to open it up to other IoT projects. The company is also being open in its development so other cities and regions can build their own LoRa network, he said.
Matt Leonard is a former reporter for GCN.