Repeated SACCH Frame Erasure Rate (FER) Measurement Description
Last updated: December 3, 2008
This section is only applicable to the lab applications.
You can use the Repeated SACCH Frame Erasure Rate (FER) measurement to measure the Frame Erasure Rate on SACCH of a mobile that supports the Repeated SACCH function. See
Repeated SACCH
.
How is the SACCH FER Measurement Made?
The test set measures the Repeated SACCH FER by sending a Layer 3 message that does not require a Layer 3 response from the mobile station on the SACCH. If the mobile station fails to decode a SACCH block then it may request that the block be repeated by setting the SRR (SACCH Repetition Request) bit in the Layer 1 SACCH header on the uplink SACCH. If the MS fails to decode the repeated SACCH block and again sets the SRR bit then the test set counts that as a single Frame Erasure event and will not repeat the downlink SACCH block a second time. The two downlink SACCH blocks, the original and the repeat, are counted as a single sample and the failure of the MS to decode both of them is counted as a single failure.
The test set uses an MM Information message with all the optional fields omitted for the Layer 3 message.
Operating Considerations
The Repeated SACCH FER measurement can only be performed in Active Cell Operating Mode.
The connection type must be Auto and a speech call must be active before performing a Repeated SACCH FER measurement.
The Downlink Repeated SACCH must be set to
On Repeat Request
before performing a Repeated SACCH FER measurement. See
CALL:TCHannel:(SACCH|SACChannel):REPeat[:STATe]
.
Repeated SACCH FER Measurement Parameters
Repeated SACCH 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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