Deploying APs for Location Aware Services

Deploying APs for location tracking requires additional consideration above the standard AP deployment guidelines for coverage and capacity. The following are best practices for AP deployment:

• Minimum Received RSS. No less than three APs should be detecting and reporting the RSS of any client station. Only RSS reading stronger than -75 dBm are used by the Location Engine.
• Use the same AP model for the entire floor plan, so that the RSS readings in that area will have less variation.
• Design your floor plan with the APs installed at the corners of the floor plan, along the perimeter of the location area. (An area is considered a closed polygon.) Do not cluster APs in the center of the location area. The following illustration shows a recommended AP placement.
  

  
• The maximum distance between APs depends on environmental factors such as the presence of walls and structures, but as rule of thumb, in a location aware deployment, place the APs 10 to 20 meters apart.
• Install APs at the same height on the wall, and do not install APs behind walls or ceilings.
• Install APs away from metal structures like poles or racks, because metal can affect the radiated pattern.
• When location accuracy is paramount, augment your in-service deployment with Guardian APs. Guardian APs scan multiple channels where in-service APs operate on a single channel. Therefore, Guardian APs are capable of registering readings from more clients than in-service APs. Guardian APs also increase the number of triangulation points. The Guardian mitigates the problem of non-probing clients and is capable of sensing a client based on the data packets. For more information, see Configuring an AP as a Guardian.