WILLTEK 4400 Mobile Phone Tester Series, Руководство пользователя

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Chapter 2 GSM Call Mode Operation
GSM basics
4460 GSM System Option and 4468 EDGE System Option Version 12.20
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MS power classes
The power classes of the mobiles vary between the GSM bands. The codes stand
for different RF power levels in different GSM bands. The table below gives a
short overview.
Coding of RX Qual
Based on the number of bits corrected by its own channel decoder, the mobile
estimates the BER. The parameter reported back by the mobile in its MS report
is coded as follows:
NOTE
When you perform RX tests, just compare the error ratios of bits of classes Ia
and II when the connection is disturbed or at low signal levels. You will find
that the error ratios for class Ia bits are whole orders less than for class II bits.
NOTE
A similar technique is used for coding the signaling bits; something called ‘fire
coding’ in GSM terms. There, however, are no less significant bits. So all sig-
naling bits are protected by convolutional coding.
Power Class
Code 1 2 3 4 5
GSM 900 43
dBm 39
dBm 37
dBm 33
dBm 29
dBm
PCN/GSM 1800 30
dBm 24
dBm 36
dBm
PCS/GSM 1900 30
dBm 24
dBm 33
dBm
RX Qual BER in %
0 < 0.2
1 0.2...0.4