[wiki:Internal Internal] -> Calibration

= !WiFi Card Calibration =

As the first important discovery in ORBIT testbed, some (if not most) !WiFi cards behaved strangely. Therefore, it is really important to identify those '''bad''' cards. The calibration procedure tries to find if the Tx power and RSSI measurement of the card in each 802.11 channel is ''regular''  or not.

For each card, the calibration has two experiments:
 1. Card-RX exp: A standard signaling generator will generator 500 802.11 beacons in 5 seconds, the card has to report its measured RSSIs.
 1. Card-TX exp: A VSA equipment will measure 500 beacons generated by the card

Those experiments are going to be repeated in each 802.11 a/b/g channel and with 4 different Tx power levels: 1, 10, 20, 100mW.

== Calibration Procedure ==
 1. Pick up one node from the grid and take it down from the shelf
 1. load baseline-calibration.ndz image to the node
 1. Connecting RF cable to one of the card
 1. ssh to console.grid
 1. ./caliber.pl [mac-addr]
 1. check the calibration_central database in idb1. 
 1. Do above procedures for another card

== Database Format ==

The database is named  “calibration_central”. It is now in idb1.
It has two tables:
 *  Rx_caliber: has all measurements by  Card-Tx experiment.
 *  Tx_caliber: has all measurements by  Card-Rx experiment.

=== Example table records ===
Rx_caliber

|| Card || Mac address || Date ||Time  || ESGTxPr || channel||RSSI ||
||3F:65:89:4E:2D:0C||	2006-07-07||	12:29:15||	10||	6||	45||
					
Tx_caliber

||Mac-address||	Date ||	Time|| !CardTxPr	|| channel||	VSAreading||
||3F:65:89:4E:2D:0C||	2006-07-07	||12:30:21 ||	100 ||	11 ||	65 ||


 
== For developers ==

 * [wiki:Internal/Mapping/Calibration/DesignSpec Design Specification for Calibration Experiment]
 * Flow Diagram of the Main Perl Script (Progress Chart)