How is the Paging Channel's Message Error Rate (MER) measured?
The Paging Channel MER test is used to evaluate how well the mobile station demodulates the paging channel in an AWGN (no fading or multipath) environment.
-
There are two types of Paging Channel MER tests specified in the EIA/TIA-98E standard:
3.3.1 demodulation of non-slotted mode paging channel
and
3.3.2 demodulation of slotted mode paging channel
. The test set only supports measuring MER for slotted mode paging channel.
-
The EIA/TIA-98E standard specifies two alternative methods for determining Paging Channel MER. The first method (as shown in
Paging Channel MER Calculation - Based on Message Counts
) involves counting the messages sent to the mobile and comparing that count against the number of messages the mobile receives. The second technique (as shown in
Paging Channel MER Calculation - Based on Test Time
) involves estimating the number of message sent to the mobile station (as opposed to counting them) and comparing the estimate against the number of messages the mobile received. The test set uses the first method for determining the Paging Channel MER. However, you can estimate the Paging Channel MER with the second method.
During the Paging Channel MER test (see
Paging Channel MER Procedures
), the test set continuously sends messages on the paging channel that are addressed to the recently registered mobile station and keeps a running count of the paging channel messages in the F-Paging Messages parameter (see
Paging Channel MER Results
). The mobile station records how many messages are received and keeps a running count of the received messages in the PAG_3 parameter of the mobile station's internal register. At the end of the test procedure, the test set retrieves the value of the mobile station's PAG_3 parameter and stores the value in the test set's MS PAG_3 parameter (see
Paging Channel MER Results
). The Slotted Paging Channel MER is then calculated based on the formula as shown in
Paging Channel MER Calculation - Based on Message Counts
Paging Channel MER Calculation - Based on Message Counts
Paging Channel MER Calculation - Based on Test Time
If the Paging MER is estimated based on the test time, it recommends to use script programming and need to:
1. set the Max Slot Cycle Index to 0 (see
Setting Cell Parameters
).
2. strictly follow the procedure (see
Paging Channel MER Procedures
).
Paging Channel MER Procedures
All parameters and results relating to the Paging Channel MER test are accessed from the
Paging MER
menu by pressing the
F6
(
Paging Channel MER
) on
Call Control 3 of 3
menu. For details on front panel operation, see
Measuring Paging Channel Message Error Rate (MER)
.
It's recommended that you follow the steps in the order described below to ensure valid results. If you vary the test procedure you may get the unexpected results.
-
Verify that the test set is configured to provide paging channels (see
Control Channel Configuration
)
-
Turn off the timer based registration (see
D. Registration Parameters
).
-
Set up the Paging Channel MER parameters (see
Paging Channel MER Parameters
for details).
It is recommended that you set up the parameters associated with the paging MER test prior to initiating the test procedure. The test set provides a warning message (
MER Proc Warning
) if key settings are changed during the test. However, the test set does not block the changes or cause the paging MER test procedure to be aborted.
-
Establish a call (see
How Do I Set Up a Call?
).
A call must be established prior to proceeding to the next step since starting the MER procedure requires the exchange of the signaling via the traffic/fundamental channel.
-
Start the MER Procedure (see
CALL:PAGing:MERRor:PROCedure:STARt
).
When the MER procedure is started, the test set will set its internal counters (the F-Paging Messages and the Paging MER Test Time) to their default values and set the PAG_3 parameter in the mobile station's register to zero via
Set Parameter Message
(STPM) (see
Messaging associated with Paging MER Test
). When the mobile station successfully responds to the STPM, the test set will update its internal MS PAG_3 parameter to zero. Now, the test set's internal counter (F-Paging Messages) are ready to increment for each message sent on the Paging Channel addressed to the currently registered mobile station. Also the test set's internal timer (Paging MER Test Time) starts counting.
-
Disconnect the call (see
How Do I End a Call?
).
This ensures counting the messages that the mobile station should demodulate since the mobile station does not listen to the paging channel when a call is established.
It's recommended that you wait for a few seconds (depending upon your mobile station design) before proceeding to the next step. This ensures that the mobile station is ready to monitor the paging channel.
-
Set Audit Order to On (see
CALL:CCHannel:AUDit:STATe
).
This causes the test set to start sending Audit Order (see
Messaging associated with Paging MER Test
) messages on the paging channel which do not require a Layer 2 acknowledgment.
The timer may not reflect the duration of the time when the mobile station is demodulating the paging channel if you did not end the call in step 6.
If a different mobile station registers when the Audit Order turns on, the test set will send the Audit Order messages to the newly registered mobile station but the F-Paging Messages counter does not reset. This may cause the invalid MER results.
-
Wait the desired time you'd like to have the MER test procedure run. The standard specifies "at least 2 minutes and until sufficient confidence is ensured".
-
Set Audit Order to Off. (see
CALL:CCHannel:AUDit:STATe
).
This causes the test set to stop sending Audit Order messages on the paging channel.
-
Establish a call (originating from the mobile station).
A call must be established prior to proceeding to the next step since stopping the MER procedure requires the exchange of the signaling via the traffic/fundamental channel.
It is recommended that you originate the call from the mobile station. This can avoid additional messages sent on the paging channel to result in the different MER results got from the message count based calculation and the timer based estimation or result in the mismatched paging message counting in the mobile station's register and the test set's counter due to mobile station missing the paging channel messages.
-
Stop the MER procedure (see
CALL:PAGing:MERRor:PROCedure:STOP
).
When the MER procedure is stopped, the test set internal message counters (F-Paging Messages) stop incrementing. Also the test set's internal timer (Paging MER Test Time) stops counting (no longer increments). The test set sends
Retrieve Parameters Messag
e (RTPM) (see
Messaging associated with Paging MER Test
) to the mobile station to retrieve the value of PAG_3 in the mobile station's internal register and updates its MS PAG_3 parameter based on the received
Parameters Response Message
(PRSM) (see
Messaging associated with Paging MER Test
) from the mobile station. The Slotted Paging Channel MER is then calculated based on the formula as shown in
Paging Channel MER Calculation - Based on Message Counts
-
Monitor the test results. All related results should be displayed on the Paging Channel Message Error Rate window (see
Paging Channel MER Results
).
-
(optional) Disconnect the call.
-
(optional) Clear the counters and results associated with Paging MER test (see
CALL:PAGing:MERRor:PROCedure:PARameter:CLEar
).
It does not clear the counters (such as PAG_3) in the mobile station's internal register.
-
Turn the timer based registration back to on (see
D. Registration Parameters
).
Messaging associated with Paging MER Test
Messages
|
Description
|
Retrieve Parameters Message (RTPM)
|
The test set sends this message to request the mobile station to report its current value for the PAG_3 parameter.
|
Parameters Response Message (PRSM)
|
The mobile station sends this message (in response to the RTPM) to report the values of its parameters and indicate parameters that are not supported.
|
Set Parameters Message (STPM)
|
The test set uses this message to set the mobile station's settable parameters (for example, PAG_3).
|
Mobile Station Reject Order
|
The mobile station shall send this message with REJECTED_PARAM_ID (for each PARAMETER_ID not set) if the mobile can not set the parameters specified by PARAMETER_ID fields in the STPM.
|
Audit Order (ORDM)
|
The test set will send the Audit Order messages addressed to the most recently registered mobile station when the Audit Order turns on. See
Paging Channel MER Procedures
.
|
Paging Channel MER Results
The following results are available on the Paging Channel Message Error Rate window when the Paging Channel MER procedure ends.
Key TIA/EIA-98-E Tests Using Paging MER