I haven't had much luck using the linear calibration model, so I use the point calibration model instead. I configure my wireless card to operate as an 802.11a client for one set of point calibrations throughout the facility, then I configure it to operate as an 802.11b/g client (only) for the second pass at the calibration process.
I don't stop calibrating the floor area until I have covered the floor area with data points from one corner of the floor to the other. I don't know if this is necessary given the paragraph above, but the data collected across the floor area appears as "complete" to a customer reviewing the RF calibration.
Recently I did a full calibration of a 34,000 square foot facility. The deployment consisted of 11 3500i series CleanAir access points. The time to calibrate from beginning to end was approximately 4 hours. Two hours to calibrate for the 5GHz frequency, and two hours to make a second pass to calibrate for the 2.4GHz frequency. Each point calibration location sampling took at least two minutes to complete.
Neither of the design/configuration guides tells you exactly what you're supposed to do with the laptop when you're using the point collection model, unless you're really supposed to pirouette while holding the laptop. I tried to follow this example for the first calibration I did - it just ended up making me dizzy. Now I stand in one place and change the laptop orientation while changing the direction I'm facing. I've found that if I hold the laptop in the same orientation the data point collection fails quite often.
I made a video showing all the stages of the calibration process to help explain how the process is done, and the method I've used for collecting data points.
There are several important bits of information spread throughout the WCS 7.0 Configuration Guide and the Wi-Fi Location-Based Services 4.1 Design Guide. I will list them below.
The Wi-Fi Location-Based Services 4.1 Design Guide states:
"Due to an open caveat1 concerning the use of dual-band calibration clients and performing a location calibration data collection on both bands simultaneously, it is recommended that calibration data collection be performed for each band individually at this time. When using a dual-band client, use either of the following alternatives:
1.Perform the calibration data collection using a single laptop equipped with a Cisco Aironet 802.11a/b/g Wireless CardBus Adapter (AIR-CB21AG) on each band individually. For example, proceed to disable the 5 GHz band and complete the data collection using the 2.4 GHz band only. Then, disable the 2.4 GHz band and enable the 5 GHz band, and proceed to repeat the data collection using the 5 GHz band only.
2.Perform the calibration using two people and two laptops. Each laptop should have a Cisco AIR-CB21AG and be associated to the infrastructure using a different band. The two calibration operators may operate independently; there is no need for them to visit each data point together. In this way, a complete calibration data collection can be performed across both bands in half the amount of time as option #1 above."
"Temporarily disable Dynamic Transmit Power Control (DTPC) prior to conducting calibration data collection. DTPC must be disabled separately for each band using either the controller GUI, the controller CLI or WCS for each controller whose registered access points are expected to participate in calibration data collection. After calibration data collection has been performed, DTPC should be re-enabled for normal production operation.
Ensure that the WLAN to which your calibration client will associate is configured to support Aironet Information Elements (Aironet IE). Doing so will enable the use of unicast radio resource measurement requests during calibration data collection for more efficient operation."
According to the WCS Configuration guide: "Only Intel and Cisco adapters have been tested. Make sure the Enable Cisco Compatible Extensions and Enable Radio Management Support are enabled in the Cisco Compatible Extension Options."
Also of note from the WCS Configuration guide: "The calibration status bar indicates data collection for the calibration as done, after roughly 50 distinct locations and 150 measurements have been gathered. For every location point saved in the calibration process, more than one data point is gathered. The progress of the calibration process is indicated by two status bars above the legend, one for 802.11b/g/n and one for 802.11a/n."