Pilot Testing

Pilot Testing
Pilot testing involves installing a real version of the wireless LAN system that users actually
operate. This testing enables the evaluation of realistic utilization and long-term performance
issues. The results of this testing will also provide a blueprint for the installation of wireless
LANs in other common facilities.
The main attributes of pilot testing are as follows:
• Yields the most accurate (real) results because you’re using the actual hardware and software
under realistic conditions.
• Involves the purchase of applicable hardware and software.
• Depends on relatively firm requirements to minimize costly changes to the installed
system.
• Requires a live facility to install and use the system.
Consider using pilot testing for the following situations:
• When testing the design of a new product before going into mass production.
• When testing the system design of a wireless LAN solution prior to installing the system.
The implementation of a wireless LAN pilot test generally involves the installation of multiple
access points to cover the facility. Before installing the pilot system, perform an RF site survey
to determine the number and location of access points. In addition, the site survey will provide
information on the effects of multipath distortion and RF interference within the facility. This
data will provide a warning of issues that you may need to consider before installing wireless
LANs at other facilities.
To determine the number and location of access points, follow these steps:
1. Obtain a copy of the facility blueprint and verify its accuracy. Blueprints are often outdated
because changes, such as the removal of walls or new construction, are not always
made to the drawings. As a result, you should walk through the facility before running
tests to be sure the building is the same as in the drawing. If not, update the blueprints.
2. Mark user locations. On the blueprint, mark the location of users who will be operating
from a fixed location. Also outline potential user roaming areas within the building. In
some cases, the roaming area may be the entire facility; however, there may be some
areas where users will never roam.
3. Identify obstacles to the radio waves. Observe the construction of the facility, and mark
the location of obstacles that may cause a hindrance to radio wave propagation. For
instance, high metal racks typically found in warehouses offer a great deal of attenuation.
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4. Identify potential sources of RF interference. Discuss sources of interference with the
facility’s frequency manager, if one exists. If there’s doubt on the nature of potential
interference, use a spectrum analyzer to record RF transmissions that fall within the frequency
band in which your wireless LAN will operate. Be sure to outline on the blueprints
the areas that the sources of interference may affect.
5. Identify the preliminary locations of access points based on the vendor’s range specifications
and information gained from steps 2–4. Ensure that all stationary and roaming
users can maintain access to the wireless LAN via an access point. Mark the presumed
locations of access points on the blueprints.
6. Verify the location of access points. This is best done by setting up an access point at
each location identified in step 5 and testing the signal strength at all corresponding user
locations. If possible, be sure to use a device and radio that will be part of the eventual
system. This will provide the most accurate results because it will exhibit the same propagation
patterns as the eventual system. Most wireless LAN vendors have utilities that
run on the user device and record signal levels and packet transmission statistics. With
the appropriate tool loaded, walk with a portable computer and record the signal qualities
at all applicable locations. If the signal quality falls below suggested values supplied by
the vendor, then consider relocating the access point or adding more.