2.6.10 3G Cell Reselection Signal Level Threshold
CELLFRC Modify:MOD
5.2 Dynamic Channel Configuration Control Parameters
The common configurable dynamic channel configuration parameters are listed here.
Table 5-2 List of dynamic channel configuration parameters N
o. Parameter
ID Parameter
Meaning Default Value Relevant
Command Level
1 Event4aThd Traffic upper threshold
2 Event4bThd Traffic lower threshold
D128, that is, 128 bytes
3 TimetoTrigg er4A
Time to trigger event 4A
D240, that is, 240 ms
D4000, that is, 4 s
D4000, that is, 4 s
D64 (64 kbit/s) Set or modify: SET DCCC
5.2.1 Traffic Upper Threshold
The premise for 4A event reporting is that the buffer traffic exceeds this threshold.
5.2.2 Traffic Lower Threshold
The premise for 4B event reporting is that the buffered traffic is lower than this threshold.
5.2.3 Time to Trigger Event 4A
When buffered traffic is greater than 4A threshold and remains there for a longer time than the delay trigger time, event 4A is reported.
5.2.4 Time to Trigger Event 4B
When buffered traffic is less than event 4B threshold and remains there for a longer time than the delay trigger time, event 4B is reported.
5.2.5 Pending Time after Trigger Event 4A
After a event 4A is reported, a timer is started. No more event 4A is reported before the timer expires.
5.2.6 Pending time after trigger Event 4B
After an event 4B is reported, a timer is started. No more event 4B is reported before the timer expires.
5.2.7 Uplink and Downlink DCCC Rate Thresholds
When the maximum uplink/downlink rates required by the BE service are not greater than the uplink/downlink DCCC rate thresholds, channel reconfiguration is not carried out for the uplink/
downlink services according to the traffic condition.
5.2.8 Uplink and Downlink Middle Rate Thresholds
These parameters are the uplink and downlink middle rate threshold when 3 rate adjusting in DCCC is used and the middle rate compute method is HAND_APPOINT.
5.2.9 Uplink and Downlink Rate Adjust Levels
These parameters are used to judge uplink and downlink 2 rates or 3 rates adjusting in DCCC.
5.2.10 Low activity bitrate threshold
When the PS BE service rate has reduced to the rate threshold of DCCC, but UE can not transfer to CELL_FACH state for some reasons (for example: PS_BE_STATE_TRANS_SWITCH is off; UE has CS service). The PS BE service rate is reduced to this rate when PS BE service satisfy the requirement of D2F.
5.2.1 Traffic Upper Threshold
The premise for 4A event reporting is that the buffer traffic exceeds this threshold.
Parameter ID
Event4aThd
Value Range
Enum (D16, D32, D64, D128, D256, D512, D1024, D2k, D3k, D4k, D6k, D8k, D12k, D16k, D24k, D32k, D48k, D64k, D96k, D128k, D192k, D256k, D384k, D512k, D768k)
Physical Value Range
Enum (16 ,32, 64, 128, 256, 512, 1024, 2k, 3k, 4k, 6k, 8k, 12k, 16k, 24k, 32k, 48k, 64k, 96k, 128k, 192k, 256k, 384k, 512k, 768k) bytes
Parameter Setting
The default value is D1024, that is 1024 bytes. The parameter is set separately in downlink and uplink.
Event 4A: The transmission channel traffic (which is the buffered traffic in DCCC) exceeds an absolute threshold. When this event occurs, data transmission is accelerated through the increase of channel transmission bandwidth.
The setting of the traffic upper threshold is used to check whether there are data to be transmitted.
Therefore, to meet the rapid requirement of user data transmission, we can configure the threshold of 4A to a low value; however, it should not be too low, so as to avoid triggering
unnecessary channel reconfiguration to increase the bandwidth while users do not have enough data to transmit.
Impact on the Network Performance
l The greater this parameter is set, the slower the user data transmission rate probably becomes.
l The smaller it is, the faster the user data transmission rate probably becomes. However, if the setting is too low, the channel bandwidth increases while it is unnecessary.
Relevant Commands
Set this parameter through ADD TYPRABDCCCMC, and modify it through MOD TYPRABDCCCMC, and query it through LST TYPRAB.
5.2.2 Traffic Lower Threshold
The premise for 4B event reporting is that the buffered traffic is lower than this threshold.
Parameter ID
Event4bThd
Value Range
Enum (D8, D16,D32, D64, D128,D256, D512, D1024, D2k, D3k, D4k, D6k, D8k, D12k, D16k, D24k, D32k, D48k, D64k, D96k, D128k, D192k, D256k, D384k, D512k)
Physical Value Range
Enum (8, 16,32, 64, 128,256, 512, 1024, 2k, 3k, 4k, 6k, 8k, 12k, 16k, 24k, 32k, 48k, 64k, 96k, 128k, 192k, 256k, 384k, 512k) bytes
Parameter Setting
The default value is D128, that is 128 bytes. The parameter is set separately in downlink and uplink.
Event 4B: The transmission channel traffic (which is the buffered traffic in DCCC) becomes lower than an absolute threshold. When this event occurs, the channel transmission bandwidth is reduced to avoid resource waste.
The 4B event is used to check whether the traffic becomes lighter. When the service transmission is about to finish, the traffic in the buffer decreases rapidly until it becomes zero. Therefore, event 4B threshold can be configured to a relatively small value. Furthermore, when the source rate of the service is relatively constant but very low, we can also configure an appropriate 4B threshold so that the low source rate can be detected and the channel bandwidth can be accordingly reduced. Tests on the FTP service and services with low source rates show that when the setting of the 4B threshold is slightly greater than the size of one transmission block, the detection required for bandwidth reduction for the two kinds of services above can be satisfied.
Impact on the Network Performance
A greater value of this parameter gets event 4B to be triggered more easily; however, the channel transmission bandwidth is reduced, which may influence the transmission speed of the user data.
Relevant Commands
Set this parameter through ADD TYPRABDCCCMC, modify it through MOD TYPRABDCCCMC, and query it through LST TYPRAB.
5.2.3 Time to Trigger Event 4A
When buffered traffic is greater than 4A threshold and remains there for a longer time than the delay trigger time, event 4A is reported.
Parameter ID
TimetoTrigger4A
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
TimetoTrigger4A is D240 by default, that is , 240 ms. The parameter is set separately in uplink and downlink.
Time to trigger for event 4A is to prevent frequent trigger caused by small fluctuation of the service traffic. It is only for the measurement report of the first trigger event.
Impact on the Network Performance
l A higher value of this parameter makes event 4A harder to be triggered. In such case it can prevent frequent adjustment of the BE service rate. However, too high value makes the system respond very slowly.
l A lower value of this parameter gets event 4A to be triggered more easily. However, small value may trigger events frequently under small fluctuation of the service traffic.
Relevant Commands
Set this parameter through ADD TYPRABDCCCMC, modify it through MOD TYPRABDCCCMC, and query it through LST TYPRAB.
5.2.4 Time to Trigger Event 4B
When buffered traffic is less than event 4B threshold and remains there for a longer time than the delay trigger time, event 4B is reported.
Parameter ID
TimetoTrigger4B
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
TimetoTrigger4B is D2560 by default, that is, 2.56 s. The parameter is set separately in uplink and downlink.
Time to trigger for event 4B is to prevent frequent trigger caused by small fluctuation of the service traffic. It is only for the measurement report of the first trigger event.
Impact on the Network Performance
l The higher the parameter is, the harder to trigger event 4B, in which case it can prevent frequent adjustment of the BE service rate. However, too high value makes the system respond very slowly.
l The lower the parameter is, the easier to trigger event 4B. However, small value may trigger events frequently under small fluctuation of the service traffic.
Relevant Commands
Set this parameter through ADD TYPRABDCCCMC, modify it through MOD TYPRABDCCCMC, and query it through LST TYPRAB.
5.2.5 Pending Time after Trigger Event 4A
After a event 4A is reported, a timer is started. No more event 4A is reported before the timer expires.
Parameter ID
PendingTime4A
Value Range
Enum (D250, D500, D1k, D2k, D4k, D8k, D16k)
Physical Value Range
Enum (250, 500, 1000, 2000, 4000, 8000, 16000) ms
Parameter Setting
The default value is D4000, that is, 4 s. The parameter is set separately in unlink and downlink.
The pending time after trigger for event 4A is the timer started after the event measurement report is triggered. It has two functions: The first is that within the pending time, no more measurement report is sent for the same measurement ID even the condition that triggers measurement report is met; the second is that when the pending timer expires, it judges whether the traffic is above the upper threshold or under the lower threshold. If yes, it restarts the Time to Trigger for event 4A timer and does not report event 4A any more unless the timer expires.
Impact on the Network Performance
l The greater the parameter is, the harder to trigger event 4A again. Large value prevents frequent adjustment of the BE service rate. But too large value can make the system respond very slowly.
l The lower the parameter is, the easier to trigger event again. But too low value may result in frequent triggers under small fluctuation of the traffic.
Relevant Commands
Set this parameter through ADD TYPRABDCCCMC, modify it through MOD TYPRABDCCCMC, and query it through LST TYPRAB.
5.2.6 Pending time after trigger Event 4B
After an event 4B is reported, a timer is started. No more event 4B is reported before the timer expires.
Parameter ID
PendingTime4B
Value Range
Enum (D250, D500, D1k, D2k, D4k, D8k, D16k)
Physical Value Range
Enum (250, 500, 1000, 2000, 4000, 8000, 16000) ms
Parameter Setting
The default value is D4000, that is 4 s. The parameter is set separately in unlink and downlink.
The pending time after trigger for event 4B is the timer started after the event measurement report is triggered. It has two functions: The first is that within the pending time, no more measurement report is sent for the same measurement ID even the condition that triggers measurement report is met; the second is that when the pending timer expires, it judges whether the traffic is above the upper threshold or under the lower threshold. If yes, it restarts the Time to Trigger for event 4b timer and does not report event 4B any more unless the timer expires.
Impact on the Network Performance
l The greater the parameter is, the harder to trigger event 4B again. Large value prevents frequent adjustment of the BE service rate. But too large value can make the system respond very slowly.
l The lower the parameter is, the easier to trigger event again. But too low value may result in frequent trigger under small fluctuation of the traffic.
Relevant Commands
Set this parameter through ADD TYPRABDCCCMC, modify it through MOD TYPRABDCCCMC, and query it through LST TYPRAB.
5.2.7 Uplink and Downlink DCCC Rate Thresholds
When the maximum uplink/downlink rates required by the BE service are not greater than the uplink/downlink DCCC rate thresholds, channel reconfiguration is not carried out for the uplink/
downlink services according to the traffic condition.
Parameter ID
UlDcccRateThd DlDcccRateThd
Value Range
Enum(D8, D16, D32, D64, D128, D144, D256, D384)
Physical Value Range
Enum (8, 16, 32, 64, 128, 144, 256, 384) kbit/s
Parameter Setting
The default values are both D64, that is, 64 kbit/s.
Impact on the Network Performance
The greater these parameter are, the more difficult the adjustment of the channel bandwidth becomes.
Relevant Commands
The RNC-oriented parameters: set them through SET DCCC, and query them through LST DCCC.
5.2.8 Uplink and Downlink Middle Rate Thresholds
These parameters are the uplink and downlink middle rate threshold when 3 rate adjusting in DCCC is used and the middle rate compute method is HAND_APPOINT.
Parameter ID
UlMidRateThd DlMidRateThd
Value Range
Enum(D16, D32, D64, D128, D144, D256, D384)
Physical Value Range
Enum (16, 32, 64, 128, 144, 256, 384) kbit/s
Parameter Setting
The default values are both D128, that is 128 kbit/s.
Impact on the Network Performance
None.
Relevant Commands
The RNC-oriented parameters: set them through SET DCCC and query them through LST DCCC.
5.2.9 Uplink and Downlink Rate Adjust Levels
These parameters are used to judge uplink and downlink 2 rates or 3 rates adjusting in DCCC.
Parameter ID
UlRateAdjLevel DlRateAdjLevel
Value Range
Enum(2_Rates, 3_Rates)
Physical Value Range
None.
Parameter Setting
The default values are both 2_Rates.
Impact on the Network Performance
None.
Relevant Commands
The RNC-oriented parameters: set them through SET DCCC and query them through LST DCCC.
5.2.10 Low activity bitrate threshold
When the PS BE service rate has reduced to the rate threshold of DCCC, but UE can not transfer to CELL_FACH state for some reasons (for example: PS_BE_STATE_TRANS_SWITCH is off; UE has CS service). The PS BE service rate is reduced to this rate when PS BE service satisfy the requirement of D2F.
Parameter ID
LittleRateThd
Value Range
D8 ～ D384
Physical Value Range
8 kbit/s ～ 384 kbit/s
Parameter Setting
The default value is 64 kbit/s.
Impact on the Network Performance
None.
Relevant Commands
The RNC-oriented parameter: set it through SET DCCC and query it through LST DCCC.