Installation guide

61
Wi-Fi Location-Based Services—Design and Deployment Considerations
OL-11612-01
Deployment Best Practices
Additional information regarding deployment guidelines and best practices can be found in the Cisco
Wireless Location Appliance: Deployment Guide at the following URL:
http://www.cisco.com/en/US/products/ps6386/prod_technical_reference09186a008059ce31.html.
Avoiding Location Display Jitter with Location Smoothing
In release 4.0 of WCS and release 2.1 of the location appliance, Location Smoothing was introduced to
enable the network administrator to compensate for cases of location instability sometimes seen with
clients that are not actually experiencing any change in movement. This observed instability can be
because of a variety of factors, including the following:
• Variances in client transmit power resulting in detected RSSI changes
• Environmental changes including changes in obstructions resulting in variations in attenuation and
multi-path
• Changes in client orientation including in-place rotation, especially with clients possessing
embedded antennas in components such as laptop screens
Location smoothing allows you to apply a damping factor to the displayed location when changes are
observed between the recorded (previous) position of a client and a new position that is based on RSSI
information received from WLCs. Smoothing factors are set in Location > Location Server >
Administration > Location Parameters via the Smooth Location Positions parameter, as shown in
Figure 40.
Figure 40 Configuring Location Smoothing
The various smoothing factor options impact the displayed location position by assigning different
weights to the latest reported position (that is, the new position) of the device versus its last recorded
position (the previous position). These weights are assigned as shown in Table 2.
Table 2 Smoothing Factor Weight Assignments
Smooth Location Positions
Value
Weight Assigned to Previous
Position
Weight Assigned to New
Position
Off (no smoothing) 0% 100%
Less smoothing 25% 75%
Average smoothing 50% 50%