Reference Manual

Call Control
Precondition and Initiation
Channel combinations supported are defined in section Channel
Activation above.
This function is applicable for:
•
SAPI-0 on SDCCH and FACCH
•
SAPI-3 links on SDCCH, SACCH/T and SACCH/M
The function is initiated when the RBS receives a DATA REQUEST
from BSC.
Description
The following procedure is used by BSC to send a layer 3 message to
MS in acknowledged mode /GSM 08.58:3.5/. The message is sent
through the RBS on the layer 2 link (the RBS is not affected by the
message).
The function is initiated when a Data Request is received from BSC.
The message contains the complete layer 3 message to be sent in
acklowledged mode. The RBS sends the layer 3 message in accordance
with /GSM 08.58:3.5/ to the MS inside an I (information field)-frame.
Transparent transmission in acknowledge mode requires that multiframe
mode /GSM 08.58:3.1,3.2/ has been established. With multiframe mode
means that an answer is needed. In this case an RR-frame (receiver
ready) is sent back as a confirmation to the RBS.
The message is in this case sent from network (BSC) to MS. One
example when this is used is for sending of SMS-message to the mobile.
P003020A
RBS
BSCMS
I-frame
RR-frames
DATA REQ
Figure 130 Transparent message transmission
Transmission of SAPI-0 messages has higher priority than SAPI-3
messages. A separate queue for SAPI-3 messages (Short Message
Service) exists.
26.12 Transparent Message Reception
Purpose
To send transparent layer 3 information between MS and the network.
EN/LZT 720 0008 P2A
2001-11-28
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