Wireless mesh networks are significant to a smoothly operating smart city, according to Phil Beecher, President and CEO of Wi-SUN Alliance, in a recent podcast episode of IoT Unplugged, season 3.
The technologies supporting smart cities are vast, as Beecher highlighted in this conversation, most of which are wireless technologies to facilitate connecting devices without having to run cables. “In dense urban environments there’s often a problem with connectivity, either from technologies like cellular or LPWAN,” explained Beecher, “Where devices are buried in these urban canyons of glass or concrete and steel.”
Wireless mesh network technologies work by combining a Wi-Fi router with one or more mesh satellites to expand the coverage of one network. “If you don’t have a direct connection between every device and the base station, you can hop through other devices in the network,” said Beecher. “That’s where mesh comes into it.”
In the example of a street lighting installation, Beecher said: “You have multiple street lights that are maybe 10, 20 metres apart. If a street light is trying to communicate to the back haul network and it can’t get the direct connection, it can talk to its neighbour, which is the next three lines along. That works very well as it extends the range of the network and it means you have less interference between devices.”
The sheer scale of devices working across a smart city, from street lights to parking meters can run the risk of interference as all of these devices are trying to communicate. Another challenging scenario is if a storm occurs and a neighbourhood goes “dark,” meaning the devices lose power, Beecher explained that wireless mesh networks ensure there is still communication going on. “With a wireless mesh network, smart meters have got a little bit of battery power left and they send a ‘last gasp’ message to indicate they’ve lost power. Then the utility can collect these messages and work out where the faults are.”
Beecher advised that for cities who are unsure how to proceed with their communications build future proofing into their networks. “In the utility industry in the US they’ve been doing this for a long time and are very aware of their requirements for the future,” he said. “An example of this is National Grid in Massachusetts who are rolling out four million electric meters onto the network, and are then planning on installing gas meters on the same networks and methane detectors so that they can check for gas leaks. That improves the safety.”
In closing comments, Beecher said: “I would say when you’re looking for a solution, look for something that is standards based, is interoperable and has a way of protecting your investment into the future.”
If you’d like to hear more from Phil on the subject of smart city developments and wireless mesh networks, you can listen to the podcast episode here.
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