Installation guide

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Wi-Fi Location-Based Services—Design and Deployment Considerations
OL-11612-01
Deployment Best Practices
When verifying whether RSSI cutoff thresholds have been met in production areas, use clients that are
identical to the production clients if at all possible. If this is not possible, keep in mind that mobile
devices with significantly higher default maximum transmitter output than devices regularly expected to
be tracked should have their output power adjusted downward. Using devices with higher output power
can lead to situations where the higher-powered test client was successfully detected by access points at
the recommended signal strength but the actual lower-powered production clients are not. This can lead
to degraded performance when using the lower-powered production clients.
Inspecting Location Quality
A new capability introduced with version 4.0 of WCS and 2.1 of the location appliance is Location
Inspection. Location inspection is the ability to directly validate the performance of the path loss models
you have created via the calibration process. Unlike the location planner or location readiness tools,
which are purely predictive in nature, when you inspect location quality, you are directly comparing
predicted locations to actual physical locations and graphically expressing the accuracy of the path loss
model. Using the calibration model and the location inspection tool, you can then quantify whether you
are achieving the 10 m/90 percent performance metric in the environment and if so, whether it has been
uniformly achieved throughout the area. Location inspection allows you to see the areas where the
location performance may be below the performance expectations as well as those where you are clearly
exceeding them.
Location inspection is accessible from the Monitor > Maps > RF Calibration Model > model name WCS
menu via the “Inspect Location Quality” hyperlink located next to the name of the floor where data
collection for the calibration model was performed, as shown in Figure 51.
Figure 51 Accessing Location Inspection
Location inspection uses the signal strength information recorded during data collection and the path
loss model to compute estimated location. It does this for each data collection point that was recorded.
These estimated locations are then compared against the actual location coordinates (also recorded
during data collection), and the results of the comparison are displayed in a graphical format indicating
the level of precision available throughout the environment for various selected accuracy levels (as
shown in Figure 52).