2.6.10 3G Cell Reselection Signal Level Threshold
CELLDCCC Query: LST
5.4 State Transfer Parameters
The common configurable state transfer parameters are listed here.
Table 5-4 List of state transfer parameters
No. Paramet
180 s Set or Modify: SET UESTATETRANS
5.4.1 DCH to FACH State Transition Timer
This parameter detects whether the users in CELL_DCH are stably in low activity to determine whether there is a need for state transition from CELL_DCH to CELL_FACH.
5.4.2 DCH to FACH / FACH to PCH State Transition Traffic 4B Threshold
It helps to judge whether a user is in low activity state. When a user in CELL_DCH state reports 4B traffic event every time, 1 is added to the low activity detection timer. When a user in CELL_FACH state reports 4B traffic event every time, 1 is added to the low activity detection timer when the 4B traffic is 0.
5.4.3 FACH to PCH State Transition Timer
This parameter detects whether the users in CELL_FACH are stably in low activity to determine whether there is a need for state transition from CELL_FACH to CELL_PCH.
5.4.4 Cell ReSelection Timer
This parameter and CellReSelectCounter jointly detect the status of the UE that frequently performs cell reselection to determine the need for state transition from CELL_FACH to URA_PCH.
5.4.5 FACH to DCH Traffic Report Threshold
This parameter defines the upper threshold of 4A traffic in the CELL_FACH state to trigger state transition from FACH to DCH.
5.4.6 FACH to DCH Traffic Time to trigger
For UEs in the CELL_FACH state, after the traffic exceeds the report threshold and the duration exceeds the time length specified by this parameter, the event 4A report is triggered, causing state transition to the CELL_DCH state.
5.4.1 DCH to FACH State Transition Timer
This parameter detects whether the users in CELL_DCH are stably in low activity to determine whether there is a need for state transition from CELL_DCH to CELL_FACH.
Parameter ID
DtoFStateTransTimer
Value Range
1 to 65535
Physical Value Range
1 s to 65535 s
Parameter Setting
The default value is 180, that is, 180 s.
Configuration of the parameter shall be based on the BE service model. The system judges whether the users have no data to send for a long time and uses this as condition for state transition to low activity. Whether the user has data to send can be reflected from the RLC buffered traffic:
If the user has no data to send, the RLC buffered traffic is zero. The traffic event 4B can be configured to detect low activity.
Within the transition timer period, if there are consecutive event 4B reports and the buffered service data is detected to be zero and the number of event 4B reports meets preset condition when the timer expires, it can be said that the service is in low activity.
Impact on the Network Performance
If the parameter value is too low, it would be hard to judge that the user is in relatively stable low activity status. Too large value may waste specific channel resources.
Relevant Commands
RNC-oriented parameter: set it through SET UESTATETRANS, and query it through LST UESTATETRANS .
5.4.2 DCH to FACH / FACH to PCH State Transition Traffic 4B Threshold
It helps to judge whether a user is in low activity state. When a user in CELL_DCH state reports 4B traffic event every time, 1 is added to the low activity detection timer. When a user in CELL_FACH state reports 4B traffic event every time, 1 is added to the low activity detection timer when the 4B traffic is 0.
Parameter ID
D2F2PTvmThd
Value Range
D8–D768K
Physical Value Range
8–768K bytes
Parameter Setting
The default value is D64, that is, 64 bytes.
Impact on the Network Performance
None.
Relevant Commands
RNC–oriented parameter: set it through SET UESTATETRANS, and query it through LST UESTATETRANS.
5.4.3 FACH to PCH State Transition Timer
This parameter detects whether the users in CELL_FACH are stably in low activity to determine whether there is a need for state transition from CELL_FACH to CELL_PCH.
Parameter ID
FtoPStateTransTimer
Value Range
1 to 65535
Physical Value Range
1 s to 65535 s
Parameter Setting
The default value is 180, that is, 180 s.
The principle of state transition from CELL_FACH to CELL_PCH is similar to the above-mentioned state transition from DCH to FACH. But because CELL_PCH does not support service data transmission, zero traffic event is used to determine the need for transition from FACH to PCH.
Impact on the Network Performance
If the parameter value is too low, it would be hard to judge that the user is in relatively stable low activity status. Too large value may waste FACH channel resources.
Relevant Commands
RNC-oriented parameter: set it through SET UESTATETRANS, and query it through LST UESTATETRANS .
5.4.4 Cell ReSelection Timer
This parameter and CellReSelectCounter jointly detect the status of the UE that frequently performs cell reselection to determine the need for state transition from CELL_FACH to URA_PCH.
Parameter ID
CellReSelectTimer
Value Range
1 to 65535
Physical Value Range
1 s to 65535 s
Parameter Setting
The default value is 180, that is, 180 s.
Impact on the Network Performance
When the parameter value is too low, it would be hard to judge that the users are in relatively stable low activity. Too large value may waste specific channel resources.
Relevant Commands
RNC-oriented parameter: set it through SET UESTATETRANS, and query it through LST UESTATETRANS .
5.4.5 FACH to DCH Traffic Report Threshold
This parameter defines the upper threshold of 4A traffic in the CELL_FACH state to trigger state transition from FACH to DCH.
Parameter ID
FtoDTvmThd
Value Range
Enum (D0, D4, D8, D16, D32, D64, D128, D256, D512, D1024, D2k, D4k, D8k, D16k, D32k, D64k, D128k, D512k, D1024k )
Physical Value Range
Enum ( 0, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2k, 4k, 8k, 16k, 32k, 64k, 128k, 512k, 1024k ) bytes
Parameter Setting
The default value is D1024, that is 1024 bytes.
This threshold is set to check whether there is data to be transmitted so that the UE moves to the CELL_DCH substate. To avoid common channel congestion, this parameter should not be set too high.
Impact on the Network Performance
The greater this parameter is, the more difficultly state transition occurs. However, if the setting is too low, it results in waste of the dedicated channel resources.
Relevant Commands
RNC-oriented parameter: set it through SET UESTATETRANS, and query it through LST UESTATETRANS .
5.4.6 FACH to DCH Traffic Time to trigger
For UEs in the CELL_FACH state, after the traffic exceeds the report threshold and the duration exceeds the time length specified by this parameter, the event 4A report is triggered, causing state transition to the CELL_DCH state.
Parameter ID
FtoDTvmTimeToTrig
Value Range
Enum (D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000)
Physical Value Range
Enum (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ) ms
Parameter Setting
The default value is D240, that is 240 ms.
This parameter prevents unnecessary triggering of traffic event due to traffic fluctuation. Too large value may delay report of event 4A and result in congestion of the common channel.
Impact on the Network Performance
The greater this parameter is, the more difficultly state transition occurs; the lower it is, the more easily UE enters the CELL_DCH state, but the more serious influence the traffic fluctuation brings.
Relevant Commands
RNC-oriented parameter: set it through SET UESTATETRANS, and query it through LST UESTATETRANS .
5.5 PS Inactive
The common configurable PS inactive parameters are listed here.
Table 5-5 List of PS inactive parameters
No. Paramet
5.5.1 Interactive Service T1
When no data to transfer during this timer for PS interactive user, then PDCP requests RRC layer to release this connection.
5.5.2 Interactive Service T2
If T1 is overtime, PDCP layer requires RRC layer to release this service and triggers T2. If this connection could not be released till T2 timer expires, PDCP layer applies to release this connection again.
5.5.3 Background Service T1
When no data to transfer during this timer for PS background user, PDCP requires RRC layer to release this connection.
5.5.4 Background Service T1
If T1 is overtime, PDCP layer requires RRC layer to release this service and triggers T2. If this connection could not be released till T2 timer expires, PDCP layer applies to release this connection again.
5.5.5 IMS Service T1
When no data to transfer during this timer for PS IMS users, PDCP requires RRC layer to release this connection.
5.5.6 IMS Service T2
If T1 is overtime, PDCP layer requires RRC layer to release this service and triggers T2, If this connection could not be released till T2 timer expires, PDCP layer applies to release this connection again.
5.5.1 Interactive Service T1
When no data to transfer during this timer for PS interactive user, then PDCP requests RRC layer to release this connection.
Parameter ID
PSINACTTMRFORINT
Value Range
0 to 14,400
Physical Value Range
0 s to 14,400 s
Parameter Setting
The default value is 20, that is, 20 s.
Impact on the Network Performance
The higher this parameter is, the more resource be occupied when no data to transfer; the lower it is, the more singling transfers when data transfer is unstable.
Relevant Commands
RNC-oriented parameter: set it through SET PSINACTTIMER, and query it through LST PSINACTTIMER.
5.5.2 Interactive Service T2
If T1 is overtime, PDCP layer requires RRC layer to release this service and triggers T2. If this connection could not be released till T2 timer expires, PDCP layer applies to release this connection again.
Parameter ID
PROTECTTMRFORINT
Value Range
0 to 60
Physical Value Range
0 s to 60 s
Parameter Setting
The default value is 20 s.
Impact on the Network Performance
l The greater this parameter is, the longer resource occupation time is if the resource could not be released after T1 is overtime.
l The lower it is, the more signaling overhead there is if the connection could not be released due to some special reasons.
Relevant Commands
RNC-oriented parameter: set it through SET PSINACTTIMER, and query it through LST PSINACTTIMER.
5.5.3 Background Service T1
When no data to transfer during this timer for PS background user, PDCP requires RRC layer to release this connection.
Parameter ID
PSINACTTMRFORBAC
Value Range
0 to 14,400
Physical Value Range
0 s to 14,400 s
Parameter Setting
The default value is 20, that is, 20 s.
Impact on the Network Performance
l The greater this parameter is, the more resource is occupied when no data to transfer.
l The lower it is, the more singling transfer there is when data transfer is unstable.
Relevant Commands
RNC-oriented parameter: set it through SET PSINACTTIMER, and query it through LST PSINACTTIMER.
5.5.4 Background Service T1
If T1 is overtime, PDCP layer requires RRC layer to release this service and triggers T2. If this connection could not be released till T2 timer expires, PDCP layer applies to release this connection again.
Parameter ID
PROTECTTMRFORBAC
Value Range
0 to 60
Physical Value Range
0 s to 60 s
Parameter Setting
The default value is 20 s.
Impact on the Network Performance
l The greater this parameter is, the longer resource occupation time it takes if the resource could not be released after T1 is overtime
l The lower it is, the more signaling overhead there is if the connection could not be release due to some special reasons.
Relevant Commands
RNC-oriented parameter: set it through SET PSINACTTIMER, and query it through LST PSINACTTIMER.
5.5.5 IMS Service T1
When no data to transfer during this timer for PS IMS users, PDCP requires RRC layer to release this connection.
Parameter ID
PSINACTTMRFORIMS
Value Range
0 to 14,400
Physical Value Range
0 s to 14,400 s
Parameter Setting
The default value is 20, that is, 20 s.
Impact on the Network Performance
l The greater this parameter is, the more resource is occupied when no data to transfer.
l The lower it is, the more singling transfer there is when data transfer is unstable.
Relevant Commands
RNC-oriented parameter: set it through SET PSINACTTIMER, and query it through LST PSINACTTIMER.
5.5.6 IMS Service T2
If T1 is overtime, PDCP layer requires RRC layer to release this service and triggers T2, If this connection could not be released till T2 timer expires, PDCP layer applies to release this connection again.
Parameter ID
PROTECTTMRFORIMS
Value Range
0 to 60
Physical Value Range
0 s to 60 s
Parameter Setting
The default value is 20 s.
Impact on the Network Performance
l The greater this parameter is, the longer resource occupation time it takes if the resource could not be released after T1 is overtime.
l The lower it is, the more signaling overhead there is if the connection could not be release due to some special reasons.
Relevant Commands
RNC-oriented parameter: set it through SET PSINACTTIMER, and query it through LST PSINACTTIMER.