Ericsson RBS 2106 Reference Manual page 289

SID frames (including comfort noise parameters) are scheduled in
TDMA frames according to /GSM:05:08:8.3/. When a SID frame is
stolen for signalling (FACCH) purposes, the scheduling in TDMA
frames will instead be according to /GSM:06.31:5.1.2/, /
GSM:06.41:5.1.2/ or /GSM:06.81:5.1.2/.
The output power is turned off during periods of silence, except in the
following cases:
•
•
•
•
DTX Handling Non-transparent Data
To detect idle data transmission in the downlink direction, the E1-bits
of a complete RLP frame received from the RTC, are analysed /
GSM:08.20:4.2/. This frame is not transmitted on the air interface.
When idle data transmission is detected, an L2 (Layer 2 protocol) fill
frame /GSM:04.06:5.4.2.3/ is transmitted (on FACCH) in the SID
positions of the TDMA frame according to /GSM:05:08:8:3/.
The output power is turned off during periods of idle data transmission,
as described in the section DTX handling speech above.
30.2.2 DTX Uplink
The DTXu indicator (of element Channel Mode) in the
CHANNEL_ACTIVATION or MODE_MODIFY messages from the
BCS is ignored, since the RBS is always prepared to handle uplink
DTX.
The uplink DTX function is supported for the following services:
•
•
•
•
•
Data frames (transparent and non-transparent) are passed transparently
from the MS to the RTC without consideration to DTX.
To detect if a speech frame (received from MS) contains speech or
comfort noise parameters, RBS analyses the SID code word /
GSM:06.12:5.2/, /GSM:06.62:5.3/or /GSM:06.22:5.3/. An indication of
comfort noise parameters (SID flag), is sent in the full rateRTH-
SPEECH-IND/RTH-E-SPEECH-IND or half rate RTH-SPEECH-IND
frames to the RTC.
Full Rate
EN/LZT 720 0008 P2A
2001-11-28
Transmission of SID frames (comfort noise parameters)
Transmission of signalling (FACCH)
Transmission on a C0 carrier (dummy bursts)
Transmission on a transmitter configured for filling (dummy
bursts)
TCH speech, full rate (GSM speech alg. version 1)
TCH speech, full rate (Speech full rate version 2)
TCH speech, half rate (GSM speech alg. version 1)
TCH speech, full rate (GSM speech alg. version 1) bidirectional
TCH speech, full rate (Speech full rate version 2) bidirectional
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Discontinuous Transmission
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