Internet of Lawnmowers Last time I explored the concept of geofencing, and how low-power technologies are used both to create "virtual walls" and to create beacons. This time, I’m going to take a look at the individual technologies that Internet of Things (IoT) devices will use to communicate for the next several years.
Infrared beacons are positively old school. Your TV remote has used them forever. I remember building low-baud networking out of infrared diodes and photoreceptors when I was a kid. Today's DIT crowd has it easy.
Given that infrared beacons aren't particularly difficult, complex or easy to screw up, the part where the Universal Traffic Management Systems society of Japan thinks infrared beacons are the future of traffic management has me a little worried.
My wife has a recurring nightmare of cars as a hack target (or in this case, traffic control as an attack target) and here I understand why. An infrared virtual wall or infobeacon inside my home is one thing, but infrared is unregulated spectrum. Anyone can use devices here and there's a great big ball of fusion in the sky that spends a goodly percentage of each day flooding this spectrum with noise.
I'm not overly keen on living in a city where the road network cranks out infrared powerful enough to drown out the sun because, to my mind, Sol is plenty warm enough, thank you very much. For a more sane (and indoors!) use of infrared technology give this (PDF) a read.
Zigbee is a low-power mesh networking protocol that uses radio frequencies at 2.4GHz (worldwide), 915 MHz (Americas and Australia) and 868 MHz (Europe). Unfortunately, it's a protocol that raises the ugly spectre of IoT standards and how much (or little) vendors adhere to them.
PC World summed it up succinctly by saying: "Just because a product on the shelf has the ZigBee logo on the packaging doesn’t necessarily mean it is compatible with another product with that same logo.” Oops.
When it works, Zigbee is used to allow individual low-power devices to talk amongst themselves until one of them gets close enough to a home (or business) router that messages can be passed on to the network proper. From here, information from a device dozens of hops away from the router can reach the Internet.
When thinking about Zigbee, keep this mesh networking concept in mind. Now consider for a moment that there are people selling Zigbee gear that think it would be a good idea to have Zigbee home security systems, and have their Zigbee mesh talk to the internet. Admiral Adama disapproves.
Bluetooth has also moved into the ultra-low-power realm and with each new iteration is targeting IoT devices more and more. In addition to your standard Bluetooth beacons, Bluetooth has also decided that mesh networking is the future.
This time with IPv6 and vague handwaving about privacy. Because nothing says private like a house full of ultra-low-power Bluetooth powered toothbrushes, each with their own internet addressable IP address that can talk on a mesh network with your security system.
Getting away from creepy meshnets that can bounce signals around corners using the power of the hivemind we have 60GHz Wireless, complete with its own standards wars. The short version is that 60GHz is not going to penetrate walls. You can bounce the signal off walls if you know what you're doing, but it's really only any good when it's used at short range and with line-of-sight.
There are at least three competing wireless display technologies in this field. Intel's WiDi, The WiFi Alliance's WiGig Display Extention (PDF) and Silicon Image's WirelessHD (also known as UltraGig). For added fun and games, WiGig is also a 60GHz version of Wi-Fi and a wireless version of USB.
60GHz is considered an IoT technology mostly because it's hopeless over any distance greater than "from one end of the average conference room to the other". This makes it mostly useful for "things" that are in close physical proximity that need to talk really, really fast at one another.
If you need to talk even faster than 60Ghz can allow, you need to turn to Visible Light Networking (VLN). VLN has gotten up to 200Gbps, and comes with the usual useful benefits of interference from the sky fusion ball, lack of spectrum regulation and being utterly useless beyond the confines of a single room.
This actually makes VLN a great geofencing technology. You can blast out VLN at intensities and wattage powerful enough to light up a room and it can serve the purpose of lighting that room. It will also be pretty much useless outside of that room, as VLN doesn't survive bouncing off of walls quite so well as 60Ghz networking does. Beamforming visible light is bad for life forms with retinas.
And there you have it: the core communications technologies of the internet of things. ®