Call Control
38.3.13 LAPDm
The LAPDm (Link Access Procedure on the Dm-channel) function
denotes the overall functionality included in the LAPDm protocol and
the radio link layer management procedures.
The function is active and available for all traffic functions using the
radio link layer. LAPDm conforms to /GSM:04.06/.
LAPDm supports two modes of operation:
• Unacknowledged
• Acknowledged
Both SAPI-0 and SAPI-3 are supported, establishment of SAPI-3
requires that SAPI-0 is established.
SAPI-0
SAPI-0 is used for Call control, Mobility management and Radio
resource management signalling.
The following channels are supported:
BCCH + CCCH Downlink. Unacknowledged mode is
supported
SDCCH Acknowledged and unacknowledged
modes are supported
FACCH Acknowledged and unacknowledged
modes are supported
SACCH/C Unacknowledged mode is supported
SACCH/T Unacknowledged mode is supported
SAPI-3
SAPI-3 is used for Short message service point-to-point. The following
channels are supported:
SDCCH Acknowledged mode is supported
SACCH/T Acknowledged mode is supported
38.4 Operational Conditions
38.4.1 Channel Activation
The maximum delay from reception of a CHANNEL_ACTIVATION
command, until the
CHANNEL_ACTIVATION_ACKNOWLEDGEMENT or
CHANNEL_ACTIVATION_NEGATIVE_ACKNOWLEDGEMENT is
sent, is 25 ms.
EN/LZT 123 2697 R5A
1998-08-13
251 (306)
© Ericsson Radio Systems AB
— All Rights Reserved —
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