March 3, 2005
Laptops, Treos and phones! (Oh my!)
By TROY THRUN
"Wireless" is perhaps the most overused techno-word today. Simply defined, wireless is a way to communicate without wires.
In today's labs, research staff use a number of wireless devices including local area network systems, personal digital assistants (such as Blackberrys and Treos), maintenance radios, cellular phones, cordless phones, Bluetooth devices and cordless headsets. The problem is that most people don't understand the differences between all of these devices and their effect on the infrastructure costs of a new lab.
Most labs today are being outfitted with conduit and data connections to provide coverage for wireless local area networks (WLAN), either now or in the future. A number of new laboratories in Seattle are in high-rise buildings, for which the city may soon mandate the installation of radio antenna systems to assist firefighters. Does this mean that we need to plan to install two separate wireless systems? Wireless is wireless, isn't it?
The surprising answer is that different devices can require different infrastructure, so two or more wireless systems may be required.
One subtle difference between a WLAN, a cellular phone and a fire-department handheld radio is the frequency band on which these signals are carried.
Each frequency band requires a different infrastructure to properly support the devices that operate in that band. You may ask "Why can't we run our WLAN over the same cables and antennas as our cellular phones and fire department radios?"
The reason is fundamental to wireless communications design: signals of different frequencies require specific handling of antenna configurations. The required characteristics vary enough between "radio" and "WLAN" to make a combined antenna system unworkable in most cases.
Due to the potential mayhem surrounding this issue, the Federal Communications Commission has defined certain devices to reside within certain frequency bands to help avoid interference problems. Poor antenna design, reconfigured office space and other devices at the same frequency are the most common roots to interruptions.
Let's look at two antenna systems that capture wireless signals needed in today's labs.
Wireless local area networks
Unlike commercial office tenants or college campus planners, biotech researchers are not jumping onto the wireless network bandwagon so quickly.
Laboratories have slightly different requirements from typical offices, so full-building wireless coverage is not usually needed. Unplanned interruptions of signal, limited bandwidth, slow data transfer and security of information are major concerns for lab clients.
The need to have a reliable, secure line far outweighs the need to be mobile inside the individual lab and support spaces. Therefore, data outlets located in the benches are still the choice of most research firms.
Increasingly, however, many labs include small breakout spaces where researchers can meet and informally collaborate. Having technology in place to travel wirelessly in these spaces is becoming more desirable.
In response, engineers are now designing antennas called wireless access points (WAPs) into public spaces such as corridors, small meeting rooms, cafeterias and lounges. The WAPs receive signals from laptops with wireless network cards. The antennas are powered to accommodate approximately 25 individual "data sessions" at one time. Adjacent WAPs are tuned to different frequency channels. As users move from one coverage zone to another, they unknowingly change frequency channels but maintain connection.
Internal re-radiating systems
The "wireless" technology of internal re-radiating systems (IRS), more aptly termed "radio technology," has been around for decades but is becoming more prevalent in many research facilities.
How do IRS systems differ from a WLAN in labs? While WLAN coverage is typically only desired in public spaces, the equipment used by the IRS is required building-wide. Also, the type of devices are different, one example being non-PCS-type cellular phones.
Distributed antenna systems (DAS) are one component of IRS that receives the signals within the space before re-routing to a roof-mounted antenna. Leaky coax is another way to gain extra signal bars to your cellular phone in a building. As the name suggests, the coaxial cable itself is the antenna and it "leaks" a signal along the entire length. A number of building-wide IRS systems will include a combination of both media to cover the building cost-effectively.
The IRS system, whether DAS or leaky coax, is entirely different from the WLAN. The antennas are different, the components are different and, in most cases, they are required building-wide.
The city of Seattle is currently considering adopting a rule that would mandate the installation of internal reradiating systems in high-rises and low-rise metal buildings. The rule not only mandates the use but specifies how the system will be tested to ensure such coverage. The testing requires that you have radio coverage in 95 percent of the building.
The University of Washington Bioengineering and Genome Sciences Building, currently under construction, is an example of a lab building that incorporates both WLAN and IRS systems.
You might wonder why labs are changing to require IRS components. First, there are more devices that require IRS systems. Second, construction methods can block those signals.
For example, low-E (low emissivity) glass is gaining popularity in projects seeking LEED certification. This high-efficiency glass creates energy savings on the HVAC systems, but the metallic coating blocks radio waves from entering or leaving the building. The U.S. Green Building Council is in the process of creating a new LEED standard specifically for lab buildings that will continue to fuel the increased use of low-E glass. Look for IRS systems to become installed more frequently because of these issues.
As the use of technology in buildings continues to grow, research facilities looking to cure a variety of diseases are not immune to this phenomenon. With laboratories becoming more collaborative and sustainable, an increasing number of separate "wireless" systems are filling the airwaves and fueling new scientific breakthroughs.
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