Installation guide

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Wi-Fi Location-Based Services—Design and Deployment Considerations
OL-11612-01
Deployment Best Practices
When you understand the procedure used by the location appliance to assign mobile devices to floors,
you can actively take steps to improve the location-aware designs to reduce the risk of floor misdetects.
For example, a situation to avoid is the placement of access points in such a fashion that access points
on floors directly above and below the mobile device are physically much closer than any access points
located on the same floor as the mobile device (Figure 41).
Note Note that this figure and the subsequent two are two-dimensional cross sections of a multi-story vertical
structure. The concepts discussed should be envisioned in three dimensions. In all cases, the layout of
access points on a floor should comply with the recommendations made in Access Point Placement
Considerations, page 54 and Access Point Density Considerations, page 55.
Figure 41 Non-Recommended Multi-Floor AP Placement for Location
Given the understanding of the mechanics of how a mobile device is assigned to a floor by the location
appliance, it is not difficult to visualize that better results can be had when you take steps to maximize
the signal strength of mobile devices to access points located on the same floor as opposed to those
access points on floors below and above.
Figure 42 illustrates one obvious method of obtaining an improvement in location performance over that
shown in Figure 41. In some cases, excessive co-channel interference may occur when access points are
directly “stacked” above one another. To resolve this, a compromise is typically reached between the two
approaches where the access point deployment is staggered to break up any vertical alignment and add
distance between access points located on different floors.