Chapter 9 301
BERT
RF Loopback BER–Option 300
GSM Transmit Data
The minimum GSM transmit data requirements for the loopback test are a fully GSM-coded 26-channel
multiframe with either PN9 or PN15 in the payload. This is selected on the ESG by setting the timeslot
under test to normal and selecting the PN9 or PN15 multiframe PN pattern.
To meet the GSM standards requirements for full conformance, the adjacent timeslots should be loaded with
fully GSM-coded data. The ESG offers full flexibility of loading all timeslots.
Edge Frame Structure
52-frame PDCH multiframe structure.
Frames: 12 blocks of 4 frames, 2 idle frames, and 2 frames used for the PTCCH.
TS1-7 No SCH, but otherwise, don’t care
During TCH Synchronization
TSX 26-frame TCH Multiframe Structure
Frame 25 idle
Frame 12 don’t care
Other frames TCH
During Measurements
Timeslot under test 26-frame full-rate voice TCH Multiframe Structure
TCH
Frames 0-11, 13-24
Content determined by transmitted signal (looped by BTS except
for errored speech frames, i.e. speech frames with bad CRC)
Frames 12, 25 Don’t care
Tabl e 9-1 G SM R eceiv ed Dat a (C onti nu ed)
During BCH Synchronization
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