Reference Manual

Call Control
• Set Dedicated Resource Channel state = Activate.
Description
In order to activate a channel between MS and RBS, the RBS receives
an idle traffic channel from BSC in a Channel_Activation message.
This message contains the reason for the activation (immediate
assignment, normal assignment, asynchronous handover, multislot
configuration), the identification of the channel to be used (channel no.)
and a complete description of the channel (full/half rate, speech/data,
coding/rate adaption, hopping sequence, encryption key, and so forth).
If the activation of the channel is successful, the RBS answer is
Channel_Activation_Acknowledgement. Otherwise, if the channel for
some reason cannot activate, the answer is a
Channel_Activation_Negative_Acknowledgement.
P003011A
RBS BSC
CHAN ACTIV ACK
CHAN ACTIV
OR
CHAN ACTIV NCK
MS
Figure 83 Channel activation message
20.3 Adaptive Frame Alignment
Purpose
To ensure that the burst received in the RBS from an MS is in time
alignment.
Precondition and initiation
See Channel Activation above.
Description
This function ensures that the burst received in the RBS from an active
MS at different distances from the RBS, is in time alignment. To
ensure this, the RBS must inform the MS at which instant the MS shall
start sending its bursts. /GSM 05.10:5/
Example
An MS is very close to an RBS. It is allocated on TS3 and only using
this time slot for the call. During the call, the MS moves away from the
RBS causing the information sent from the RBS to arrive at the MS
194 (421)
EN/LZT 720 0008 R1A
2001-06-26
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