Introduction
The Packet Control Acknowledgment message is sent from the mobile station to the network on the PACCH. The format in which this message can be sent is either a RLC/MAC control block that uses the PACCH block format or as four identical access bursts that uses the PACCH uplink short acknowledgment block format. The access bursts format can be either 8-bit or 11-bit. The PACCH block formats defined in 3GPP TS 44.004 are shown below:
If the Packet Control Acknowledgment message is sent in response to a Packet Polling request message, the TYPE_OF_ACK parameter in the System Information (SI) messages indicate whether the Packet Control Acknowledgment message is formatted either as a normal RLC/MAC control block or as four access bursts. Otherwise, the CONTROL_ACK_TYPE parameter in the SI messages indicate the format of the Packet Control Acknowledgment message.
Configuring the Test Set
The test set provides two options for the type of bursts used to carry control acknowledgments from the mobile station to the test set.
Any delay between the last signaling from the mobile station to the network and the control acknowledgment allows a change in the timing advance required. Since access bursts are shorter than normal bursts, they are less likely to collide with subsequent timeslots when the base station redetermines the required timing advance.
For the procedure to manually configure the type of bursts to carry control acknowledgments, see
How Do I Configure the Type of Bursts used to Carry the Packet Control Acknowledgments?
.
The command to set the Control Acknowledgment Type is
CALL[:CELL]:PCAType
.
The command to set the Access Burst Type is
CALL[:CELL]:(PBCCH|PBCChannel):PRACh:LENGth
. The setting for Access Burst Type parameter is
Note: In half-rate Dual Transfer Mode the value of the Control Acknowledgment Type is ignored and Normal Bursts are used.
How Do I Configure the Type of Bursts used to Carry the Packet Control Acknowledgments?
This procedure details how to configure the type of bursts used to carry the control acknowledgment messages sent from the mobile station to the test set. The Packet Control Acknowledgment Type parameter can only be configured when the Operating Mode is set to Cell Off.
-
Press
CALL SETUP
.
-
Press
Operating Mode
(
F1
), and select Cell Off.
-
Press
Cell Info
(
F6
).
-
Press
Cell Operation
(
F1
). This brings up the
Cell Operation
menu.
-
Use the knob to scroll down and highlight
Packet Control Ack Type
.
-
Select the type of bursts you wish to carry the control acknowledgments. If you set the Packet Control Ack Type to
Four Access Bursts
, also set the access burst type (8-bit or 11-bit). The
PRACH Length
parameter is used to set the access burst type.
-
Press
Close Menu
(
F6
).
-
Press
Return
(
F6
).
-
Press
Operating Mode
(
F1
), and select an Active Cell operating mode.
-
Be sure to set the Operating Mode to an Active Cell Operating Mode or a Test Mode Operating Mode.
Impact on Other Measurements
If four access bursts are used to carry the control acknowledgments, then the increased use of access bursts may cause GPRS measurements to run more slowly since these bursts are skipped by the measurement.
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