Chapter 2
GSM Call Mode Operation
GSM tests
4460 GSM System Option and 4468 EDGE System Option
Version 12.20
65
MS Report on BER test menu
The mobile sends a measurement report to the base station on a regular basis.
This measurement report contains the mobile’s estimation of
– the RF power level, at which it receives the base station
– the quality of the signals received from the base station.
For more details on the MS report, please check with section
“MS Report display”
.
Curr.
FER and RBER of the current test run (FER =
F
rame
E
ra-
sure
R
atio, the relation of the number of rejected speech
frames to all frames used for testing).
Please see section
“Statistical test evaluation”
for details.
Min.
Smallest FER and RBER of all test runs. Please see section
“Statistical test evaluation”
for details.
Avg.
Average FER and RBER of all test runs. Please see section
“Statistical test evaluation”
for details.
Max.
Largest FER and RBER of all test runs. Please see section
“Statistical test evaluation”
for details.
Round trip
delay
The round-trip delay is the number of TDMA frames
between the reception of the first burst of a particular
voice block at the mobile and the transmission of the first
burst of the same voice block on the uplink. According to
GSM/ETSI recommendations, the round-trip delay should
be less than 26 TDMA frames.
The round-trip delay is a measure of how fast the mobile
can receive, decode and encode data.
Notes:
– Using a full-rate TCH, a voice block is spread out on
eight TDMA frames. Consequently, the mobile has to
gather those eight TDMA frames in order to be able to
decode the initially sent voice block. After the voice
block has been decoded, the mobile must encode it
again and send it back to the 4400. Therefore, the
minimum round-trip delay will be 8 TDMA frames on a
full-rate TCH.
If there are SACCH frames or idle frames between the
single blocks, the typical round-trip delay is 9 or 13
frames.
– A round-trip delay of 26 TDMA frames equals roughly
120 ms.
– More details on speech frames and diagonal interleav-
ing can be found in section
“Voice coding”
.