By Tom Condon, RPA, FMA
Published in the September 2009 issue of Today’s Facility Manager
Developments in wireless technologies continue to evolve as significantly as the facilities that use them do. Facility managers (fms) in all types of organizations are discovering ways that wireless systems can assist them in their work. Here’s a look at several interesting components of the current wireless market.
One of the most exciting new wireless technologies for facilities promises to reduce some of the many wires in building systems. The ZigBee wireless standard is similar to Bluetooth and designed for communication with sensors and control devices. Why do we need yet another wireless standard? Existing standards like Bluetooth and Wi-Fi have high data rates and work well for computers and phones, but these are not well suited to sensors and control devices, which only need to transmit small amounts of data and require much lower energy usage than other standards. The ZigBee standard addresses these needs and also provides the ability to relay messages from one device to another in a chain or a mesh architecture.
A mesh architecture greatly extends the total range of a system. In a chain configuration, devices (e.g., cell phones) communicate with a base antenna but not with each other. If a device is too far away from the base antenna, the two cannot communicate. With mesh, each device can communicate either with the antenna or with each other. If a device is too far from the antenna but there is a device within range that is close enough to the antenna, the signal can “hop” from one device to another until it reaches the base antenna. (More on mesh later.)
So what does this mean for fms? We’ll be seeing a host of wireless devices in facilities. In fact, many are already on the market, including wireless thermostats and light switches, self reading electric meters, and load management devices. Siemens is using ZigBee in its building automation system (BAS) offerings, and you can expect wireless BAS to be widely used in the near future.
For computer communications, the 802.11 Wireless LAN (Local Area Network) standard is still the norm, and it has continued to evolve. The next standard to emerge, 802.11n, is slated for confirmation this month following a five year saga that left many thinking it would never happen. This new standard has better security and has an upper limit of 600 Megabits per second (mbps) under certain circumstances; most users will see about 130 mbps or slightly less. Even at that speed, 802.11n is almost three times as fast as 802.11g’s 54 mbps and 11 times faster than 802.11b, the grandfather of WLANs. These speeds and the wide availability of inexpensive routers will make wireless a viable alternative to wired networks for many organizations. You can expect WLAN standards to continue to evolve, with new standards already in the works.
There are also changes occurring in the antennas and management systems that use WLAN standards like 802.11n. Most wireless devices communicate with simple wireless routers or access points. Most of these devices do little more than connect wireless users to the network. But a new technology from Trapeze Networks enables customers to use wireless signals to locate the position of any wireless computer or device within range of their WLAN. The Trapeze technology employs triangulation, a technique that measures signal strength from multiple antennas to determine distance from each and, therefore, the location of the computer or device. The system then knows where that computer or device is located and shows the location on a map of the facility accurate to one or two meters.
The system can also use location as a way to deny or permit access to a network. For example, if you want to allow people inside a certain area of your facility, you can set the system to allow some and to deny others.
The Trapeze technology can track computers, smart phones, active RFID tags, or any device that communicates via WLAN. Active RFID tags can be used to track items without built-in communications capabilities (e.g., expensive equipment). Some hospitals use Trapeze and the hockey puck-sized active RFID devices to track mobile equipment like x-ray machines and defibrillators.
Trapeze offers many capabilities in a single package: WLAN, asset tracking, voice service for VOIP-enabled phones, load balancing (the ability to shift loads between frequencies to take advantage of less used bands), and security that complies with Department of Defense standards for wireless security. These factors make a compelling case for a WLAN solution in many facilities.
Outside the facility, WiMax is a wireless technology used for wide outdoor areas like campuses or even entire cities. It is similar to the 802.11 technology used inside facilities, but it is much more powerful—with a range of up to 30 miles on fixed antennas and three to 10 miles when used in vehicles. With this range, fms can cover large campuses with wireless connectivity that normal 802.11 WLAN could never accomplish.
WiMax is also being used in mobile networks to connect emergency vehicles and has been used to provide live video and medical information from ambulances to doctors at hospitals so they can begin treatment en route.
Mesh networking is another technology useful in solving the problem of lack of infrastructure for wireless systems. This is the great irony of all wireless technology: ultimately, it is not truly wireless; at some point, it must connect to a hard-wired network. No matter how great the wireless, all those signals must be routed to and from a physical cable. And getting that cable installed can be costly and difficult. With conventional wireless technologies, each antenna must be connected to the hard-wired network. This means you still need a lot of cabling, conduit, and cost.
But in a mesh architecture, each antenna can receive and transmit signals. A signal can be relayed from one antenna to the next until that signal reaches a connection point to the wired network. This dramatically reduces the amount of cabling required, because it does not demand network cable at each antenna—only power, which is much easier to supply. And even if there are no power lines where you want to install mesh architecture, solar panels can provide enough power to keep the antenna working.
The capacity of mesh wireless technologies is also impressive. There is equipment that can handle huge areas and very high bandwidth data transmission. The company I work for installed Firetide systems to connect digital video across a campus area that spans more than 12 square miles, and the performance has been exceptional.
Mesh architecture is finding its way into other areas of wireless technology. The ZigBee standard supports mesh, and the Trapeze technology also has mesh capabilities.
Lastly, there is a wireless technology showing promise, but it is still in its early stages. Transmitting electrical power without wires has long been a dream, starting with Nikola Tesla’s experiments in the early 20th century. Tesla was able to send electricity through the air by converting it into electromagnetic waves, broadcasting from an antenna, and then converting it back to electricity at a receiving antenna. While this technology proved impractical on a large scale, the technique has started to find a place in small electronics.
A company called WildCharge has developed a “charging pad” that powers up the batteries in small electronic devices when those devices are placed on top of the pad. Electromagnetic waves are emitted by the pad, and a receiver in an equipped device converts the waves into electricity and charges the battery.
This technology is also starting to be used in a way that could mean the end to batteries in some small electronics. Researchers have discovered there are so many radio signals in the air that we live in a kind of an electromagnetic “soup.” The signals from WLANs, cell phones, televisions, and radios are a source of electromagnetic energy. A technique called energy harvesting converts those electromagnetic waves into electricity. While the amount of power is very small, it is also free and seems to be just about everywhere in populated areas.
Harvesting this energy could be a source of power for small electronic devices. Jennic, a manufacturer of wireless devices, has shown how ZigBee modules can be powered by energy harvested from the air. Because ZigBee devices use very little energy, they can function on the energy coursing through the air. The potential is incredible; imagine being able to install sensors in any location with absolutely no wires.
Wireless technologies are developing quickly, with increasing speeds, better security, and innovative new products that are making it easier to provide coverage for facilities. Who knows? Maybe someday we really will get rid of all those cables.
Condon, a Facility Technologist and former facility manager, is a contributing author for BOMI Institute’s revised Technologies in Facility Management textbook. He works for System Development Integration, a Chicago, IL-based firm committed to improving the performance, quality, and reliability of client business through technology.
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