When the test set receives SACCH data from the mobile station, results are reported to you in the SACCH Report window (Call Setup screen), and the Neighbour Cell Report window (Cell Info screen). The results are reported remotely with the CALL:MS:REPORTED commands. No mechanism is provided to turn off SACCH data reports.
The SACCH reports are delayed, they reflect what the mobile station is actually experiencing. It is possible for SACCH reported MS TX level results to be different than the cell power level due to limitations of the mobile station. The SACCH reported TCH timing advance should eventually match the value in the Timing Advance field once the mobile station has time to react.
SACCH data will report any time there is a downlink TCH and the mobile station is synchronized to the test set transmitting a valid SACCH on the uplink.
:NEW? and [:LAST?] Queries
:NEW? queries hang until a new SACCH message is received by the test set or until 10 seconds have elapsed at which point the test set times out. The mobile station issues data updates on the SACCH every 480 ms, (4 frames).
Measurements made during this four frame period are averaged and the result of these averaged measurements are reported by the mobile station during the next period. Measurements must be stable in order to give valid (stable) results for a :NEW? query. Therefore, it may take up to three SACCH reports before a reported value accurately reflects a change to any of its parameters. See Figure 1.
After changing measurement parameters, you must send three consecutive :NEW? queries to obtain stable, accurate results. By querying :NEW? three times the value becomes stable for the second query, and meaningful stable results are then reported for the third query. The results from the first two queries should not be used.
SACCH Report Measurement Cycle
If several SACCH reported values are needed from the same report, the first value needed should be queried three times (to receive a stable new report). Then the additional values should be immediately queried using the :LAST? query before the next report arrives or the measurement parameters are changed again.
The :LAST? query is not a hanging query; values are returned from the last SACCH report. As shown in the following program example (line 60), the :LAST? command is optional. If :NEW? is not used in the MS:REPORTED command, the :LAST value is automatically reported.
Programming Example
10 OUTPUT 714;"CALL:CELL:POW -83"
20 OUTPUT 714;"CALL:MS:TADV 11"
30 OUTPUT 714;"CALL:MS:TXL 11"
40 OUTPUT 714;"CALL:MS:REPORTED:TXL:NEW?;NEW?;NEW?" ! Query 3 times
50 ENTER 714;Ignore_result,Ignore_result,Valid_result ! Only use Valid_result
60 OUTPUT 714;"CALL:MS:REPORTED:RXL?;TADV?" ! Additional values
70 ENTER 714;Rceived_lvl,Timing_adv
80 END
