Installation guide

55
Wi-Fi Location-Based Services—Design and Deployment Considerations
OL-11612-01
Deployment Best Practices
Figure 34 Location-Aware AP Deployment
Access points are typically configured for primary channel operation on non-overlapping channels (that
is, channels 1, 6, and 11 in 2.4 GHz, for example), either statically or more commonly via the Cisco
Radio Resource Management (RRM) algorithm inherent in Cisco WLAN controllers. Controllers also
assign either the dynamic configuration channel set, the regulatory channel set, or all channels for
periodic noise, interference, and rogue off-channel scanning.
Further discussion of proper access point placement can be found in Cisco Wireless Location Appliance:
Deployment Guide at the following URL:
http://www.cisco.com/en/US/products/ps6386/prod_technical_reference09186a008059ce31.html.
Access Point Density Considerations
Access point density also has a significant effect on location tracking performance. Although there is no
single steadfast rule that yields the proper density for every situation, Cisco highly recommends to begin
with the signal threshold and placement suggestions from the previous sections coupled with an
inter-access point separation of 50 to 70 feet. In most cases, this approach yields an access point density
of approximately one location-aware access point every 2500 to 4900 square feet.
Deviations may occur because it is expected there are factors beyond the control of the designer (local
codes, customer safety, or aesthetic requirements, proximity to other equipment, unexpected density of
material, and so on) that may cause some variance in the actual deployment. Deviations such as this
should be the exception and not the rule.
Figure 35 is a representative illustration of how these concepts of access point placement and density
can serve as a starting point for a location-aware design. The environment in the figure consists of
drywall offices and cubicle office spaces, approximately 275 feet by 175 feet or 48,125 square feet. Both
the linear spacing as well as the square footage-based approaches of Access Point Density
Considerations, page 55 suggest approximately twenty location-aware access points as a starting point.
Incorporating the placement suggestions of Access Point Placement Considerations, page 54, it is
determined that a repeating triangular pattern fits the environment fairly well and meets the
recommended density requirement.