|
Feature Article*
Managing the Airspace
in Your Building, Part I
by Dr. Eric Reifsnider
Manager of Software and Technical Training
Wireless Valley Communications, Inc.
Networking Solutions
Create Management Challenges
As in-building wireless networks proliferate, so do the legal issues
surrounding their use. Businesses in multi-tenant office complexes
are becoming more aware of the advantages of wireless technology at an
executive level, setting the stage for tenants to expect a wireless
network in their office building or the ability to install their own
wireless network in their office space. As a result, today’s building
owners and managers require tools and methodology for investigating,
planning, and controlling radio transmissions in their buildings, as
well as tracking the location, status, and identity of installed radio
equipment.
Particular attention needs to be paid to unlicensed technologies, such
as IEEE 802.11 a/b/g wireless local area networks (WLANs). Wireless
carriers who provide cellular and PCS phone service over licensed
frequency bands have teams of trained professionals to thoroughly plan
and test their own networks for performance, and address all legal and
safety issues for their equipment. In contrast, the unlicensed network
equipment in a building (e.g., WLAN access points) are often deployed by
novice wireless network architects and are very poorly planned.
Hey – Keep It Down Up There, Would You Please?
Why worry? The main cause for concern is that in the “wild west” of
casual WLAN build-outs, tenants will contend with each other (and with
systems deployed by the building management) for use of the limited
number of available wireless channels. Interference among competing
transmitters can ruin the airwaves for everyone in the building,
degrading the performance of WLANs and other networks until they become
unusable. The fact that 802.11 b and g WLANs have only three
independent channels exacerbates the problem – four tenants in a
building, each having only one access point, are guaranteed to have an
interference problem.
An
analogy can be drawn between radio noise and physical noise.
Practically every office or personal lease has a clause with regard to
physical noise levels. This is to prevent tenants from disturbing other
tenants with loud music, noisy manufacturing equipment, crowds, etc. If
one tenant lets physical noise get out of control, the work of other
tenants can be seriously disrupted. The same is true in the context of
wireless networks. In both cases, building owners or property managers
can find themselves in the role of mediator.
Scoping Out the Situation
For physical noise, you can hear the problem yourself. Unfortunately,
radio noise and interference is not as easy to gauge. Radio site survey
testing equipment is required. By using test equipment specialized for
a given radio transmitter (e.g., testing software for 802.11b WLAN
client cards), or by using tunable power meters, or spectrum analyzers,
a technician can map the radio signal power received throughout a
building. Radio site surveys produce a received signal power map that
reveals areas where tenants are using WLANs and other networks, and also
reveals potentials for conflict among tenants. Disputes over
interference among networks of neighboring tenants can thus be
quantified via a radio site survey. Lease clauses that detail
permissible radio transmission power, or that forbid tenants from
deploying networks altogether, can refer to radio site surveys as
verification of compliance. A site survey can also detect violations of
legal signal power limits. Using the appropriate software, site surveys
can be performed in-house with a minimum of effort; site surveys are
also one of the most readily available wireless networking services for
outsourcing.
Avoiding Trouble
After a radio site survey has revealed and quantified wireless
interference and safety problems, a solution can be implemented via a
formal deployment plan. Planning a network carefully before deployment
begins is even better, although the current groundswell of WLAN
installations means that few buildings remain WLAN-free. Proper
deployment plans provide physical isolation among transmitters that
share the same channel (frequency), and minimize the overlap of their
coverage areas. A good deployment plan might involve lowering power
levels of needlessly strong transmitters so that neighbors experience
less interference. (To use our earlier analogy, this is
similar to turning down the volume on a stereo.) Directional antennas
can be used around the periphery of an office, pointing inwards, in
order to focus signals where they’re needed, and avoid spreading
interference into nearby offices. Channel usage can be
re-allocated so that neighbors can use different channels and avoid
interfering with each other's networks.
Building managers may decide to provide wireless networking coverage as
a service to tenants, and include lease clauses that prevent tenants
from implementing their own networks (similar to having lease clauses
that forbid other “improvements” without explicit authorization).
Becoming the sole WLAN provider in a building helps building owners and
managers to avert conflicts among tenants over use of a limited number
of channels. Fortunately, software tools are available that enable
technicians to plan optimal wireless network designs. Wireless network
planning can also be outsourced to engineering firms and system
integrators.
Keeping Tabs on the Situation
Once wireless networks have been deployed in a building, it’s essential
to track the identity and location of the radio equipment.
Troubleshooting is tremendously eased by having a map of where equipment
was installed (and often hidden for physical security), so that all
hardware with a known flaw can be located beforehand on the map, and so
that hardware can be tracked down and inspected in place. Asset
management and tracking is also essential for tax purposes (e.g.,
expense tracking and depreciation). Building owners and managers will
need to track their own equipment, and they will find it useful to
require similar documentation from tenants. Software solutions are
available for asset management, and some solutions are integrated with
network planning and site survey tools as a convenient all-in-one
package.
Conclusion
In-building wireless networks synergize the growth of businesses by
opening up data networks and making operations more efficient. However,
wireless transmissions further complicate a building management
situation that is already loaded with technical challenges. By using
appropriate testing, planning, and asset tracking of in-building
wireless networks, building owners can ensure that contracts are
satisfied and safety issues are addressed, and that tenants will extend
their leases.
________________________________________
About Wireless
Valley Communications, Inc. Wireless Valley is a pioneer of
site-specific network design and management software for all aspects of
campus and in-building networks. Over 300 companies and institutions
throughout the world are using Wireless Valley's products to sell,
design, bid, cost, measure, manage and maintain campus and in-building
networks, all within a seamless, easy to use software environment. For
more information please visit www.wirelessvalley.com, or call
512-821-1560.
*CRE Partners is not responsible for the content, validity,
technical accuracy or other claims or information contained in this
article. Feature Articles are often authored by outside sources
and do not necessarily reflect the views or opinions of CRE Partners.
Further, publication of articles in the CRE Partners Newsletter and/or
web site is not meant to represent, promote, or endorse any company,
brand, product or solution.
|
