GSM Frame Erasure Rate (FER) Measurement Description
Last updated: December 2, 2008
This section is only applicable to the lab applications and is not applicable to GPRS or EGPRS.
You can use the GSM Frame Erasure Rate (FER) measurement to verify the mobile station's reference sensitivity for control channels.
How is the FER Measurement Made?
The test set measures FER by sending a Layer 3 message that does not require a Layer 3 response from the mobile station. It does require acknowledgment in the form of an RR frame from the mobile station. When the test set does not receive the RR frame in acknowledgment, it retransmits the Layer 2 message. The test set counts the number of times it resends Layer 2 messages.
The test set uses an MM Information message with all the optional fields omitted for the Layer 3 message.
You can make the Frame Erasure Rate Measurement on a full-rate FACCH channel (FACCH/F) or a half-rate FACCH channel (FACCH/H).
Operating Considerations
The FER measurement can only be performed in Active Cell Operating Mode.
The connection type must be Auto.
FER Measurement Parameters
-
Samples to Test - The number of samples to be taken by the measurement.
-
Minimum Frame Interval (FACCH/F)- The minimum interval between FACCH frames (full rate) being sent to the mobile station.
-
Minimum Frame Interval (FACCH/H)- The minimum interval between FACCH frames (half rate) being sent to the mobile station.
-
Trigger Arm - (See
Trigger Arm (Single or Continuous) Description
.)
-
Measurement Timeout - (See
Measurement Timeouts
.)
FER Measurement Results
-
Integrity Indicator - (see
Integrity Indicator
)
-
Frames Sampled - The count of samples tested.
-
Frames Erased - The count of frames requiring retransmission by the test set.
-
Frame Erasure Rate - The ratio of Frames Erased to Frames Sampled.
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