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WCDMA DCCC Algorithm and
Parameters
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Foreword
z Rate control triggers rate decrease, rate increase, or handover
according to the resource consumption conditions to ensure
the QoS, maintain system stability, and improve system capacity
z Rate control in the WCDMA system is applicable to the
following services:
Adaptive Multi Rate (AMR) services
Adaptive Multi Rate - Wideband (AMR-WB) services
Best Effort (BE) services
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References
z 3GPP TS 25.331: Radio Resource Control (RRC)
z 3GPP TS 25.413: UTRAN Iu interface RANAP signalling
z 3GPP TS 25.415: UTRAN Iu interface user plane protocols
z 3GPP TS 25.433: UTRAN Iub interface NBAP signalling
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Objectives
z Upon completion of this course, you will be able to:
Explain the principle of DCCC
Describe the realization method of DCCC
Perform the parameter adjustment of DCCC
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Contents
1. DCCC Overview
2. DCCC Based on Traffic Volume
3. DCCC Based on Throughput
4. DCCC Based on Link Stability
5. DCCC Based on Basic Congestion
6. UE State Transition
7. Always Online
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Contents
1. DCCC Overview
2. DCCC Based on Traffic Volume
3. DCCC Based on Throughput
4. DCCC Based on Link Stability
5. DCCC Based on Basic Congestion
6. UE State Transition
7. Always Online
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DCCC Description
z DCCC: Dynamic Channel Configuration Control
z DCCC allocates dynamically resources according to the service
request and system load. So, DCCC is an effective method to
increase the radio resource utilization efficiency
z The UL DCCC algorithm and the DL DCCC algorithm work
independently
z The DCCC function is controlled by the subparameter DRA_DCCC_SWITCH of the
parameter DraSwitch.
z The UL DCCC function is invalid for the BE service whose maximum UL rate is below or
equal to the UL rate threshold for DCCC specified by UlDcccRateThd. Thus, excessive
signaling procedures can be avoided. The DL rate is limited in the same way. The DL rate
threshold is specified by DlDcccRateThd.
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Parameters of DCCC
z DraSwitch-DRA_DCCC_SWITCH
Parameter name: Dynamic resource allocation switch for DCCC
function
Recommended value: ON
z UlDcccRateThd/DlDcccRateThd
Parameter name: Uplink/Downlink Bit Rate Threshold For DCCC
Recommended value: 64kbit/s, 64kbit/s
z DraSwitch-DRA_DCCC_SWITCH
Content: When the switch is on, the dynamic channel reconfiguration control
algorithm is used for the RNC.
Value range: OFF, ON
Physical value range: 0, 1
Set this parameter through SET CORRMALGOSWITCH.
z UlDcccRateThd/DlDcccRateThd
Content: For a BE service that has a low maximum rate, the DCCC algorithm is not
obviously effective yet it increases algorithm processing. Thus, the traffic-based
DCCC algorithm is applied to BE services whose maximum UL/DL rate is greater
than the threshold.
Value range: D8, D16, D32, D64, D128, D144, D256, D384
Physical value range: 8, 16, 32, 64, 128, 144, 256, 384
Physical unit: kbit/s
Set these parameters through SET DCCC.
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Contents
1. DCCC Overview
2. DCCC Based on Traffic Volume
3. DCCC Based on Throughput
4. DCCC Based on Link Stability
5. DCCC Based on Basic Congestion
6. UE State Transition
7. Always Online
z Rate adjustment based on traffic volume only applies to R99 BE services.
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Contents
2. DCCC Based on Traffic Volume
2.1 Traffic Volume Measurement and Event Reporting
2.2 Rate Adjustment Based on Traffic Volume
2.3 Signaling Procedure
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Traffic Volume Measurement Item
z In the uplink, the UE measures Dedicated Traffic Channel
(DTCH), (that is, buffer usage of RLC entities), to obtain the
uplink traffic volume
z In the downlink, the RNC measures the DTCH, (that is, buffer
usage of RLC entities), to obtain the downlink traffic volume
z The traffic volume is measured by the buffer usage of the RLC entity. The RNC increases or
decreases the rate of BE services based on the traffic volume to avoid excessively high or
low traffic volume.
z The traffic volume measurements defined in 3GPP TS 25.331 are applicable to only the UL.
For the DL, traffic volume measurements and associated rate adjustment are designed and
implemented by Huawei.
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Traffic Volume Measurement Event
z Event 4a:
Traffic volume is above a threshold for a period of time
z Event 4b:
Traffic volumes is below a threshold for a period of time
z In the UL, the UTRAN sends to the UE the absolute threshold, time to trigger event 4a or
4b, and pending time after trigger through a MEASUREMENT CONTROL message. The UE
sends a report on event 4a or 4b through a MEASUREMENT REPORT message.
z In the DL, measurement control is also performed through messages. The difference is that
all the interactions occur within the RNC in the DL.
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Event 4a
z Event 4a triggered by an increase in the transport channel
traffic volume:
z In the uplink:
When the traffic volume is higher than the value of Event4aThd for a period of
time defined by TimetoTrigger4A, the UE reports an event 4a. No more events 4a
are reported during the time defined by PendingTime4A.
z In the downlink:
When the traffic volume is higher than the value of Event4aThd for a period of
time defined by TimetoTrigger4A, the RNC reports internally an event 4a. No more
events 4a are reported during the time defined by PendingTime4A.
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Event 4b
z Event 4b triggered by a decrease in the transport channel traffic
volume:
z In the uplink:
When the traffic volume is lower than the value of Event4bThd for a period of time
defined by TimetoTrigger4B, the UE reports an event 4b. No more events 4b are
reported during the time defined by PendingTime4B.
z In the downlink:
When the traffic volume is lower than the value of Event4bThd for a period of time
defined by TimetoTrigger4B, the RNC reports internally an event 4b. No more
events 4b are reported during the time defined by PendingTime4B.
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Parameters of Traffic Volume
4000ms4000msPending time after trigger 4B PendingTime4B
2560ms2560msTime to trigger 4B TimetoTrigger4B
256bytes256bytesTraffic Measurement Event 4B
threshold Event4bThd
4000ms4000msPending time after trigger 4A PendingTime4A
240ms240msTime to trigger 4A TimetoTrigger4A
1024bytes1024bytesTraffic Measurement Event 4A
threshold Event4aThd
Recommended Value in DL
RecommendedValue in UL
Parameter NameParameter
z Recommended values of event 4a and event 4b:
z Rate adjustment based on traffic volume takes effect in the UL and DL separately.
Associated parameters are configured in the UL and DL separately.
z Set these parameters through ADD TYPRABDCCCMC/MOD TYPRABDCCCMC.
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Contents
2. Rate Reallocation Based on Traffic Volume
2.1 Traffic Volume Measurement and Event Reporting
2.2 Rate Adjustment Based on Traffic Volume
2.3 Signaling Procedure
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Rate Adjustment Strategy
z In Huawei implementation, two strategies are available for DCH
rate adjustment based on traffic volume:
RATE_UP_AND_DOWN_ON_DCH
RATE_UP_ONLY_ON_DCH
z DcccStg
Parameter name: DCCC strategy
Recommended value: RATE_UP_AND_DOWN_ON_DCH
z The RATE_UP_AND_DOWN_ON_DCH strategy means that the rate can be either
downsized or upsized. When the system resources in the network are insufficient, the
RATE_UP_AND_DOWN_ON_DCH strategy is recommended.
z The RATE_UP_ONLY_ON_DCH strategy means that the rate can only be upsized. When
the network resources are sufficient, the RATE_UP_ONLY_ON_DCH strategy is
recommended.
z DcccStg
Content: This parameter defines the strategy of adjusting the data rate of PS BE
services when the UE is in CELL_DCH state.
RATE_UP_AND_DOWN_ON_DCH: Data rate upsizing and rate downsizing are
allowed.
RATE_UP_ONLY_ON_DCH: Only data rate upsizing is allowed. It means that the
state of UE transits from CELL_DCH to CELL_FACH when the 4b event is reported.
Value range: RATE_UP_AND_DOWN_ON_DCH, RATE_UP_ONLY_ON_DCH
Physical value range: RATE_UP_AND_DOWN_ON_DCH, RATE_UP_ONLY_ON_DCH
Set this parameter through SET DCCC.
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Rate Adjustment Strategy in UL
z Principles of RATE_UP_AND_DOWN_ON_DCH in UL:
Rate upsizing is performed if the RNC receives a report of event 4a
about the uplink traffic volume
Rate downsizing is performed if the RNC receives a report of event
4b about the uplink traffic volume
z After receiving a report on event 4a, the RNC triggers rate increase. After receiving a
report on event 4b, the RNC triggers rate decrease. The minimum value to which the rate
can be decreased is the UL rate threshold for DCCC (UlDcccRateThd). The maximum value
to which the rate can be increased is the MBR, which is Min{ the requested maximum bit
rate assigned by the CN, the maximum rate supported by UE capabilities}.
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Rate Adjustment Strategy in UL (Cont.)
z Principles of RATE_UP_ONLY_ON_DCH in UL:
Rate upsizing is performed if the RNC receives a report of event 4a
about the uplink traffic volume
Rate downsizing is prohibited. If a UE is in low activity, the state of
the UE is directly transited to CELL_FACH if the UE state transition
algorithm is enabled
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UL Rate Increase Procedure
z If the UL rate increase level is 2_Rates and the current rate is below
the UlDcccRateThd, the current rate is increased to the
UlDcccRateThd. If the current rate is above or equal to the
UlDcccRateThd and lower than the MBR, the current rate is increased
to the MBR
z If the UL rate increase level is 3_Rates and the current rate is below
the UlDcccRateThd, the rate is increased to the UlDcccRateThd. If the
current rate is equal to the UlDcccRateThd, the current rate is
increased to the UL middle rate threshold and then to the MBR. If the
current rate is lower than the MBR but higher than the
UlDcccRateThd, the current rate is increased to the MBR
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UL Rate Decrease Procedure
z If the UL rate decrease level is 2_Rates, the rate is decreased
directly to the UlDcccRateThd
z If the UL rate decrease level is 3_Rates and the current rate is
the MBR, the current rate is decreased to the UL middle rate
threshold and then to the UlDcccRateThd. If the current rate is
lower than the MBR but higher than the UlDcccRateThd, the
current rate is decreased to the UlDcccRateThd
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Example of UL Rate Adjustment
z Rate adjustment when the UL rate increase and decrease level
are 2_Rates:
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Example of UL Rate Adjustment (Cont.)
z Rate adjustment when the UL rate increase and decrease level
are 3_Rates:
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Parameters of Traffic Volume (Cont.)
z UlRateUpAdjLevel
Parameter name: Uplink Rate Increase Adjust Level
Recommended value: 3_Rates
z UlRateDnAdjLevel
Parameter name: Uplink Rate Decrease Adjust Level
Recommended value: 3_Rates
z UlRateUpAdjLevel
Content: This parameter determines whether the UL rate is raised to the maximum
rate in one step or two steps for BE service set up on DCH in uplink.
Value range: 2_Rates, 3_Rates
Physical value range: 2_Rates, 3_Rates
Set this parameter through SET DCCC.
z UlRateDnAdjLevel
Content: This parameter determines whether the UL rate is lowered to the
minimum rate in one step or two steps for BE service set up on DCH in uplink.
Value range: 2_Rates, 3_Rates
Physical value range: 2_Rates, 3_Rates
Set this parameter through SET DCCC.
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Parameters of Traffic Volume (Cont.)
z UlMidRateCalc
Parameter name: Uplink Mid Bit Rate Calculate Method
Recommended value: HAND_APPOINT
z UlMidRateThd
Parameter name: Uplink Mid Bit Rate Threshold
Recommended value: D128, namely 128kbit/s
z UlMidRateCalc
Content: This parameter determines whether automatic or manual mode is used
for 3-step adjustment of the uplink intermediate rate.
Value range: AUTO_CALC, HAND_APPOINT
Physical value range: AUTO_CALC, HAND_APPOINT
Set this parameter through SET DCCC.
z UlMidRateThd
Content: Threshold of the UL intermediate rate when the 3-step mode is used for
UL rate adjustment and the manual mode is used for UL intermediate rate
adjustment.
Value range: D16, D32, D64, D128, D144, D256, D384
Physical value range: 16, 32, 64, 128, 144, 256, 384
Physical unit: kbit/s
Set this parameter through SET DCCC.
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Rate Adjustment Strategy in DL
z Principles of RATE_UP_AND_DOWN_ON_DCH in DL:
Rate upsizing is performed if the RNC receives a report of event 4a
about the downlink traffic volume
Rate downsizing is performed if the RNC receives a report of event
4b about the downlink traffic volume
z After receiving a report on event 4a, the RNC triggers rate increase. After receiving a
report on event 4b, the RNC triggers rate decrease. The minimum value to which the rate
can be decreased is the DL rate threshold for DCCC (DlDcccRateThd). The maximum value
to which the rate can be increased is the MBR, which is Min{ the requested maximum bit
rate assigned by the CN, the maximum rate supported by UE capabilities}.
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Rate Adjustment Strategy in DL (Cont.)
z Principles of RATE_UP_ONLY_ON_DCH in DL:
Rate upsizing is performed if the RNC receives a report of event 4a
about the downlink traffic volume
Rate downsizing is prohibited. If a UE is in low activity, the state of
the UE is directly transited to CELL_FACH if the UE state transition
algorithm is enabled
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DL Rate Increase Procedure
z If the DL rate increase level is 2_Rates and the current rate is below
the DlDcccRateThd, the current rate is increased to the
DlDcccRateThd. If the current rate is above or equal to the
DlDcccRateThd and lower than the MBR, the current rate is increased
to the MBR
z If the DL rate increase level is 3_Rates and the current rate is below
the DlDcccRateThd, the rate is increased to the DlDcccRateThd. If the
current rate is equal to the DlDcccRateThd, the current rate is
increased to the DL middle rate threshold and then to the MBR. If the
current rate is lower than the MBR but higher than the
DlDcccRateThd, the current rate is increased to the MBR
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DL Rate Decrease Procedure
z If the DL rate decrease level is 2_Rates, the rate is decreased
directly to the DlDcccRateThd
z If the DL rate decrease level is 3_Rates and the current rate is
the MBR, the current rate is decreased to the DL middle rate
threshold and then to the DlDcccRateThd. If the current rate is
lower than the MBR but higher than the DlDcccRateThd, the
current rate is decreased to the DlDcccRateThd
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Parameters of Traffic Volume (Cont.)
z DlRateUpAdjLevel
Parameter name: Downlink Rate Increase Adjust Level
Recommended value: 3_Rates
z DlRateDnAdjLevel
Parameter name: Downlink Rate Decrease Adjust Level
Recommended value: 3_Rates
z DlRateUpAdjLevel
Content: This parameter determines whether the DL rate is raised to the maximum
rate in one step or two steps for BE service set up on DCH in downlink.
Value range: 2_Rates, 3_Rates
Physical value range: 2_Rates, 3_Rates
Set this parameter through SET DCCC.
z DlRateDnAdjLevel
Content: This parameter determines whether the DL rate is lowered to the
minimum rate in one step or two steps for BE service set up on DCH in downlink.
Value range: 2_Rates, 3_Rates
Physical value range: 2_Rates, 3_Rates
Set this parameter through SET DCCC.
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Parameters of Traffic Volume (Cont.)
z DlMidRateCalc
Parameter name: Downlink Mid Bit Rate Calculate Method
Recommended value: HAND_APPOINT
z DlMidRateThd
Parameter name: Downlink Mid Bit Rate Threshold
Recommended value: D128, namely 128kbit/s
z DlMidRateCalc
Content: This parameter determines whether automatic or manual mode is used
for 3-step adjustment of the downlink intermediate rate.
Value range: AUTO_CALC, HAND_APPOINT
Physical value range: AUTO_CALC, HAND_APPOINT
Set this parameter through SET DCCC.
z DlMidRateThd
Content: Threshold of the DL intermediate rate when the 3-step mode is used for
DL rate adjustment and the manual mode is used for DL intermediate rate
adjustment.
Value range: D16, D32, D64, D128, D144, D256, D384
Physical value range: 16, 32, 64, 128, 144, 256, 384
Physical unit: kbit/s
Set this parameter through SET DCCC.
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Contents
2. Rate Reallocation Based on Traffic Volume
2.1 Traffic Volume Measurement and Event Reporting
2.2 Rate Adjustment Based on Traffic Volume
2.3 Signaling Procedure
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Signaling Procedure
z Signaling procedure of UL rate upsizing based on traffic volume:
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Signaling Procedure (Cont.)
z Signaling procedure of UL rate downsizing based on traffic
volume:
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Signaling Procedure (Cont.)
z Signaling procedure of DL rate upsizing based on traffic volume:
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Signaling Procedure (Cont.)
z Signaling procedure of DL rate downsizing based on traffic
volume:
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Contents
1. DCCC Overview
2. DCCC Based on Traffic Volume
3. DCCC Based on Throughput
4. DCCC Based on Link Stability
5. DCCC Based on Basic Congestion
6. UE State Transition
7. Always Online
z Rate adjustment based on throughput applies to HSUPA and R99 BE services.
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Contents
3. DCCC Based on Throughput
3.1 Throughput Measurement and Event Reporting
3.2 Rate Adjustment Based on Throughput
3.3 Signaling Procedure
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Throughput Measurement Item
z In each measurement period, the MAC-d measures the traffic
volume of radio bearers (RBs). Then, it divides the measurement
result by the measurement period to obtain the throughput
To enable throughput-based rate adjustment on the DCH, set the
subparameter DRA_THROUGHPUT_DCCC_SWITCH of the
parameter DraSwitch to ON
To enable throughput-based rate adjustment for HSUPA, set the
subparameter DRA_HSUPA_DCCC_SWITCH of the parameter
DraSwitch to ON
z Throughput is the traffic volume in a measurement period. The RNC adjusts the rate of BE
services based on the throughput.
For HSUPA BE services, the RNC performs rate decrease or rate increase based on
the throughput.
For DCH BE services, the RNC performs rate decrease only when the throughput is
excessively high.
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Throughput Measurement Event
z Event 4a:
Throughput is above a threshold for a period of time
z Event 4b:
Throughput is below a threshold for a period of time
z For throughput-based rate adjustment on the E-DCH, both events 4a and 4b apply, that is,
both rate upsizing and downsizing are applicable for both uplink and downlink.
z For throughput-based rate adjustment on the DCH, only event 4b applies, that is, only rate
downsizing is applicable.
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Throughput Measurement Event (Cont.)
z Mechanism of measuring the throughput and reporting events
4a and 4b:
z The throughput measurement period can be specified by the parameter
E2FThrouMeasPeriod for services on the E-DCH and DchThrouMeasPeriod for services on
the DCH
z Assume that AvgThroughput represents the throughput of an RB during a measurement
period. Then:
If the AvgThroughput is above the threshold of event 4a for a period of time
specified by EdchTimetoTrigger4A and the current time is not in the pending time
after trigger, then event 4a is triggered. After event 4a is triggered, it cannot be
triggered any more in the period of time specified by EdchPendingTime4A.
If the AvgThroughput is below the threshold of event 4b for a period of time
specified by EdchTimetoTrigger4B or DchThrouTimetoTrigger4B and the current
time is not in the pending time after trigger, then event 4b is triggered. After event
4b is triggered, it cannot be triggered any more in the period of time specified by
EdchPendingTime4B or DchThrouPendingTime4B.
z The previous figure shows the mechanism of measuring the throughput and reporting
events 4a and 4b. In this example, the time to trigger event 4a or 4b is three consecutive
measurement periods, and the pending time after trigger is four consecutive measurement
periods.
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Rate Adjustment Set
z Compared with R99 service, HSUPA can support higher bit rate.
Usually there is big gap between maximum and minimum bit
rate. To utilize the rate adjustment effectively, some middle bit
rate levels and associated thresholds need to be added. We call
all the bit rates and thresholds as a Rate Adjustment Set, just
like {(Rmin, TRmin), (R1, TR1 ), , (Rmax,TRmax)}
z If the subscribed MBR is bigger than Rmin, the DCCC algorithm
is on. Otherwise, the DCCC algorithm will not work
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The mechanism of reporting events 4a and 4b about throughput is as follows:
z Assume that a set of adjustment rates and associated throughput thresholds is: {(R1, TR1), ... (Ri, TRi), ... (RN, TRN)}
For services on the E-DCH:
The first variable in each pair of parentheses represents the HSUPA adjustment rate specified by the EdchRateAdjustSet parameter.
The second variable in each pair of parentheses represents the throughput threshold corresponding to the adjustment rate.
TRi = Ri x (Threshold rate ratio). For different threshold rate ratios, see the following table.
RN represents the maximum adjustment rate specified by the EdchRateAdjustSet parameter.
Assume that RMaxRate represents the MBR assigned for a service through an RAB ASSIGNMENT REQUEST message. Then, TRMaxRate = RMaxRate x (Threshold rate ratio)MaxRate.
If Rt < RMaxRate Rt+1 (1 t N1), the set of HSUPA adjustment rates and associated throughput thresholds is: {(R1, TR1), ..., (Ri, TRi), ..., (Rt, TRt), ( RMaxRate, TRMaxRate)}.
If RMaxRate > RN, the set of HSUPA adjustment rates and associated throughput thresholds is: {(R1, TR1), ..., (Ri, TRi), ..., (RN, TRN), (RMaxRate, TRMaxRate)}.
For services on the DCH, the adjustment rate set is {rate threshold for DCCC, middle rate, maximum rate}.
The rate threshold for DCCC is specified by the UlDcccRateThd or DlDcccRateThd parameter.
The middle rate is determined by the UlMidRateCalc or DlMidRateCalcparameter and the UlMidRateThd or DlMidRateThd parameter.
The maximum rate is the MBR.
The throughput threshold is as follows: Rt = Rt x 90%.
70%2890 kbit/s, 5760kbit/s
75%384 kbit/s, 608kbit/s, 1450kbit/s, 2048kbit/s
80%128 kbit/s, 144kbit/s, 256kbit/s
90%8 kbit/s, 16 kbit/s, 32 kbit/s, 64 kbit/s
Threshold Rate RatioRate
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Threshold for Triggering Events 4a/4b
z In the aspect of DCCC for HSUPA service:
The threshold of 4a is the throughput threshold associated with
the current HSUPA adjustment rate, that is, TRt
TRt = Rt * (threshold rate ratio)t
The threshold of 4b is the throughput threshold associated with
the latest HSUPA adjustment rate, that is, TRt1
TRt1 = Rt1 * (threshold rate ratio)t1
z Here:
Rt is the current rate in the HSUPA rate adjustment set.
Rt-1 is the latest rate in the HSUPA rate adjustment set.
Threshold rate ratiot and threshold rate ratiot-1 are defined by the table of previous
page.
z If the current HSUPA adjustment rate is the minimum rate, the threshold of event 4b is the
threshold rate of E-DCH to FACH state transition (E2FThrouThd).
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Threshold for Triggering Events 4a/4b (Cont.)z In the aspect of DCCC for DCH service:
The threshold of 4b is the throughput threshold associated with
the latest DCH adjustment rate, that is, TRt1
TRt1 = Rt1 * (threshold rate ratio)t1
z Here:
Rt-1 is the latest rate in the DCH rate adjustment set.
Threshold rate ratiot-1 is set to 90%.
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Parameters of Throughput
z DraSwitch-DRA_HSUPA_DCCC_SWITCH
Parameter name: Dynamic resource allocation switch for HSUPA
DCCC function
Recommended value: ON
z DraSwitch-DRA_THROUGHPUT_DCCC_SWITCH
Parameter name: Dynamic resource allocation switch for
throughput-based DCCC function
Recommended value: OFF
z DraSwitch-DRA_HSUPA_DCCC_SWITCH
Content: When the switch is on, the DCCC algorithm is used for HSUPA. The DCCC
switch must be also on before this switch takes effect.
Value range: OFF, ON
Physical value range: 0, 1
Set this parameter through SET CORRMALGOSWITCH.
z DraSwitch-DRA_THROUGHPUT_DCCC_SWITCH
Content: When the switch is on, the DCCC based on traffic statistics is supported
over the DCH.
Value range: OFF, ON
Physical value range: 0, 1
Set this parameter through SET CORRMALGOSWITCH.
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Parameters of Throughput (Cont.)
z E2FThrouMeasPeriod
Parameter name: E-DCH Throu Meas Period
Recommended value: 30, namely 300ms
z DchThrouMeasPeriod
Parameter name: DCH Throu Meas Period
Recommended value: 100, namely 1000ms
z E2FThrouMeasPeriod
Content: Period of E-DCH throughput ratio measurement. This parameter specifies
the period of E-DCH throughput ratio measurement. The throughput ratio over the
E-DCH is periodically measured to implement state transition from E-DCH to FACH
and DCCC algorithm on EDCH.
Value range: 1~10000
Physical value range: 10~100000; step: 10
Physical unit: ms
Set this parameter through SET UESTATETRANS.
z DchThrouMeasPeriod
Content: This parameter specifies the period of DCH throughput ratio
measurement. Macd performs statistic of traffic volume on DCH and reports 4B
events which are used for the rate decrease process of BE service set up on DCH.
Value range: 1~1000
Recommended value: 10~10000; step: 10
Physical unit: ms
Set this parameter through SET DCCC.
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Parameters of Throughput (Cont.)
16, 16Period Amount after trigger 4B on DCH
DchThrouPendingTime4B
2, 2Period Amount to trigger 4B on DCH
DchThrouTimetoTrigger4B
DCH
16, nonePeriod Amount after trigger 4B on EDCH
EdchPendingTime4B
2, nonePeriod Amount to trigger 4B on EDCH
EdchTimetoTrigger4B
16, nonePeriod Amount after trigger 4A on EDCH
EdchPendingTime4A
2, nonePeriod Amount to trigger 4A on EDCH
EdchTimetoTrigger4A
HSUPA
Recommended Value in UL/DL
Parameter NameParameterService Type
z Recommended values of event 4a and event 4b:
z For EDCH, rate adjustment based on throughput takes effect in the UL. So the associated
parameters are configured in the UL only.
z For DCH, rate adjustment based on throughput takes effect in the UL and DL separately.
So the associated parameters are configured in the UL and DL separately.
z Set these parameters through ADD TYPRABDCCCMC/MOD TYPRABDCCCMC.
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Parameters of Throughput (Cont.)
z EdchRateAdjustSet
Parameter name: HSUPA UpLink Rate Adjust Set
Recommended value:
RATE_8KBPS-0, RATE_16KBPS-0, RATE_32KBPS-0, RATE_64KBPS-0,
RATE_128KBPS-1, RATE_144KBPS-0, RATE_256KBPS-1, RATE_384KBPS-
0, RATE_608KBPS-1, RATE_1440KBPS-0, RATE_2048KBPS-0,
RATE_2880KBPS-0, RATE_5740KBPS-0
z EdchRateAdjustSet
Content: HSUPA UL rate adjustment set. It contains rates for rate adjustment and is
used in the HSUPA DCCC algorithm.
Value range: RATE_8KBPS, RATE_16KBPS, RATE_32KBPS, RATE_64KBPS,
RATE_128KBPS, RATE_144KBPS, RATE_256KBPS, RATE_384KBPS, RATE_608KBPS,
RATE_1440KBPS, RATE_2048KBPS, RATE_2880KBPS, RATE_5740KBPS
Physical value range: 8, 16, 32, 64, 128, 144, 256, 384, 608, 1440, 2048, 2880,
5740
Physical unit: kbit/s
Set this parameter through SET EDCHRATEADJUSTSET.
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Parameters of Throughput (Cont.)
z E2FThrouThd
Parameter name: E-DCH2F 4B Threshold
Recommended value: 8, namely 8kbit/s
z E2FThrouThd
Content: This parameter is used to check whether the UE in the low activity state.
If the UE is on the E-DCH channel, the low activity counter increases by 1 every
time throughput ratio event 4B is reported.
Value range: 0~384
Physical value range: 0~384; step: 1
Physical unit: kbit/s
Set this parameter through SET UESTATETRANS.
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Contents
3. DCCC Based on Throughput
3.1 Throughput Measurement and Event Reporting
3.2 Rate Adjustment Based on Throughput
3.3 Signaling Procedure
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Rate Adjustment Strategy
z In Huawei implementation, two strategies are available for
EDCH rate adjustment based on throughput:
RATE_UP_AND_DOWN_ON_EDCH
RATE_UP_ONLY_ON_EDCH
z For DCH rate adjustment based on throughput, only rate
downsizing is applicable
z The RATE_UP_AND_DOWN_ON_EDCH strategy means that the rate can be both
downsized and upsized. If the system resources in the network are insufficient, the
RATE_UP_AND_DOWN_ON_EDCH strategy is recommended.
z The RATE_UP_ONLY_ON_EDCH strategy means that the rate can only be upsized. When
the network resources are sufficient, the RATE_UP_ONLY_ON_EDCH strategy is
recommended.
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Parameters of Throughput (Cont.)
z HsupaDcccStg
Parameter name: HSUPA DCCC Strategy
Recommended value: RATE_UP_AND_DOWN_ON_EDCH
z HsupaDcccStg
Content: Strategy of the UE for rate adjustment over the EDCH.
RATE_UP_AND_DOWN_ON_EDCH indicates that the rate over the EDCH can be
raised or lowered. RATE_UP_ONLY_ON_EDCH indicates that the rate over the
EDCH can only be raised, which means that the UE can switch to the FACH state at
any rate.
Value range: RATE_UP_AND_DOWN_ON_EDCH, RATE_UP_ONLY_ON_EDCH
Physical value range: RATE_UP_AND_DOWN_ON_EDCH,
RATE_UP_ONLY_ON_EDCH
Set this parameter through SET DCCC.
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Rate Adjustment Procedure for EDCH
z Principles of RATE_UP_AND_DOWN_ON_EDCH:
After a report on event 4a is received, the rate is increased by one level,
that is, from Rt to Rt+1. If the current rate is the MBR, no action is required
After a report on event 4b is received, the rate is decreased to a rate that
is close to the corresponding throughput. If the reported throughput is TR
and TRi1 < TR < TRi, then the RB adjustment rate is Ri
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Rate Adjustment Procedure for EDCH (Cont.)z Principles of RATE_UP_ONLY_ON_EDCH:
After a report on event 4a is received, the rate is increased by one
level, that is, from Rt to Rt+1. If the current rate is the MBR, no
action is required
After a report on event 4b is received, rate decrease is not
performed. Instead, state transition is performed according to the
principles described in section 6 "UE State Transition"
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Rate Adjustment Procedure for DCH
z After a report on event 4b is received, the rate is decreased to a
rate that is close to the corresponding throughput. If the
reported throughput is TR and TRi1 < TR < TRi, then the RB
adjustment rate is Ri
z The above process applies to both uplink and downlink
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Contents
3. Rate Reallocation Based on Throughput
3.1 Throughput Measurement and Event Reporting
3.2 Rate Adjustment Based on Throughput
3.3 Signaling Procedure
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Signaling Procedure
z Signaling procedure of rate increase based on throughput:
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Signaling Procedure (Cont.)
z Signaling procedure of rate decrease based on throughput:
z Throughput-based rate adjustment on the DCH is implemented through the signaling on
the Uu and Iub interfaces.
z Only rate decrease can be implemented by this algorithm.
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Contents
1. DCCC Overview
2. DCCC Based on Traffic Volume
3. DCCC Based on Throughput
4. DCCC Based on Link Stability
5. DCCC Based on Basic Congestion
6. UE State Transition
7. Always Online
z Rate adjustment based on link stability only applies to R99 BE services.
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Contents
4. DCCC Based on Link Stability
4.1 Uplink Stability Measurement and Event Reporting
4.2 Downlink Stability Measurement and Event Reporting
4.3 Rate Adjustment Based on Uplink Stability
4.4 Rate Adjustment Based on Downlink Stability
4.5 Signaling Procedure
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Uplink Stability Measurement Item
z UL stability measurement involves two measurement items: UL
TX power of the UE and UL BLER
The UL TX power of the UE is measured on the Uu interface. If the
UL TX power reaches the maximum power, you can infer that the
radio link is unstable
The UL BLER is measured by the RNC. If the UL BLER is excessively
high, you can infer that the radio link is unstable
z Link stability is measured through the UE TX power or BLER in the UL. The RNC performs
rate decrease or rate increase for R99 BE services based on the link stability.
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Uplink Stability Measurement Event
z UL TX power of the UE:
Event 6A (6A1/6A2): The UE TX power is above a certain threshold for a
period of time
Event 6B (6B1/6B2): The UE TX power is below a certain threshold for a
period of time
Event 6D: The UE TX power is equal to the maximum allowed TX power
for a period of time
z UL BLER:
Event 5A: The number of error blocks during the sliding window is greater
than or equal to a predefined number
z After establishing an BE service, the RNC sends the following information specified by
switch setting to the UE through a MEASUREMENT CONTROL message:
Threshold of event 6A1, 6B1, 6A2, 6B2, or 6D for TX power.
Time to trigger event 6A1, 6B1, 6A2, 6B2, or 6D.
z Then, the UE measures the TX power in real time, filters the measurement results.
z Each time a measurement event is triggered, the UE sends a measurement event report to
the UTRAN through a MEASUREMENT REPORT message. Then, the UL stability function
performs corresponding control tasks according to the report.
z The UL stability control switch setting:
When BeUlEvTrigInd is set to SINGLE and BeUlQos6A1McSwitch is set to YES,
event 6A1 triggers UL stability control.
When BeUlEvTrigInd is set to SINGLE and BeUlQos5AMcSwitch is set to YES, event
5A triggers UL stability control.
When BeUlEvTrigInd is set to COMBINE, events 6A1 and 5A together trigger UL
stability control.
When BeUlQos6DMcSwitch is set to ON, event 6D triggers UL stability control.
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Parameters of Link Stability
z BeUlEvTrigInd
Parameter name: Indicator For BE Uplink QOS Event
Recommended value: SINGLE
z BeUlEvTrigInd
Content: For BE service, When the parameter is set to SINGLE, an UL event 6A1 or
5A can independently trigger the QOS enhancement action. The 6A1, 5A switch
settings decide whether to perform 6A1 or 5A measurement control. When the
parameter is set to COMBINE, only combined events 6A1+5A can trigger the QOS
enhancement action, and whether to perform 6A1 and 5A measurement is not
controlled by the 6A1 and 5A measurement switch.
Value range: SINGLE, COMBINE
Physical value range: SINGLE, COMBINE
Set this parameter through SET QOSACT.
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Parameters of Link Stability (Cont.)
z BeUlQos6A1McSwitch
Parameter name: Measurement Of 6A1 Switch
Recommended value: YES
z BeUlQos5AMcSwitch
Parameter name: Measurement Of 5A Switch
Recommended value: YES
z BeUlQos6DMcSwitch
Parameter name: Measurement Of 6D Switch
Recommended value: NO
z BeUlQos6A1McSwitch
Content: Event 6A1 measurement switch when BeUlEvTrigInd is set to SINGLE for
BE service. If this parameter is set to YES, event 6A1 measurement is delivered.
Value range: NO, YES
Physical value range: NO, YES
z BeUlQos5AMcSwitch
Content: Event 5A measurement switch when BeUlEvTrigInd is set to SINGLE for BE
service. If this parameter is set to YES, event 5A measurement is delivered.
Value range: NO, YES
Physical value range: NO, YES
z BeUlQos6DMcSwitch
Content: UL event 6D measurement switch for BE service. If this parameter is set to
YES, event 6D measurement is delivered.
Value range: NO, YES
Physical value range: NO, YES
z Set these parameters through SET QOSACT.
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Events 6A and 6B
z Events 6A1, 6A2, 6B1 and 6B2:
z As shown in the above figure, the maximum UL TX power for BE services is specified by
the parameter MaxUlTxPowerforInt or MaxUlTxPowerforBac. Delta_6a1, Delta_6b1,
Delta_6a2, and Delta_6b2 are relative thresholds, which are the differences between the
absolute thresholds of events 6A1, 6B1, 6A2, and 6B2 for TX power and the maximum UL
TX power of BE service. They are specified by the parameters UlThd6A1, UlThd6B1,
UlThd6A2, and UlThd6B2 respectively.
z The absolute thresholds are calculated according to the following formulas:
Threshold of event 6A1 for TX power = MaxUlTxPowerforInt/Bac UlThd6A1
Threshold of event 6B1 for TX power = MaxUlTxPowerforInt/Bac UlThd6B1
Threshold of event 6A2 for TX power = MaxUlTxPowerforInt/Bac UlThd6A2
Threshold of event 6B2 for TX power = MaxUlTxPowerforInt/Bac UlThd6B2
z If the UE TX power is above the threshold of event 6A1 for TX power for a period of time
specified by UlBeTrigTime6A1, event 6A1 is triggered.
z If the UE TX power is below the threshold of event 6B1 for TX power for a period of time
specified by UlBeTrigTime6B1, event 6B1 is triggered.
z If the UE TX power is above the threshold of event 6A2 for TX power for a period of time
specified by UlBeTrigTime6A2, event 6A2 is triggered.
z If the UE TX power is below the threshold of event 6B2 for TX power for a period of time
specified by UlBeTrigTime6B2, event 6B2 is triggered.
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Event 6D
z Event 6D:
z As shown in the above figure, the maximum UL TX power for BE services is specified by
the parameter MaxUlTxPowerforInt or MaxUlTxPowerforBac.
z If the UE TX power is equal to the maximum UL TX power for a period of time specified by
UlBeTrigTime6D, event 6D is triggered.
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Parameters of Link Stability (Cont.)
z MaxUlTxPowerforInt
Parameter name: Max UL TX power of interactive service
Recommended value: 24, namely 24dBm
z MaxUlTxPowerforBac
Parameter name: Max UL TX power of background service
Recommended value: 24, namely 24dBm
z MaxUlTxPowerforInt
Content: The maximum UL transmit power for the interactive service in a specific cell. It is
based on the UL coverage requirement of the interactive service designed by the network
planning. The larger the value of this parameter is, the wider the coverage of the
corresponding services will be. When the downlink coverage is exceeded, the uplink
coverage and downlink coverage of the service will become unbalanced. If the values of
these parameters are too small, the uplink coverage will probably be smaller than the
downlink coverage of the service.
Value range: -50~33
Physical value range: -50~33; step: 1
Physical unit: dBm
Set this parameter through ADD CELLCAC.
z MaxUlTxPowerforBac
Content: The maximum UL transmit power for background service in a specific cell. It is
based on the UL coverage requirement of the background service designed by the network
planning. The larger the value of this parameter is, the wider the coverage of the
corresponding services will be. When the downlink coverage is exceeded, the uplink
coverage and downlink coverage of the service will become unbalanced. If the values of
these parameters are too small, the uplink coverage will probably be smaller than the
downlink coverage of the service.
Value range: -50~33
Physical value range: -50~33; step: 1
Physical unit: dBm
Set this parameter through ADD CELLCAC.
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Parameters of Link Stability (Cont.)
z UlThd6A1/UlThd6B1/UlThd6A2/UlThd6B2
Parameter name:
Uplink Event 6A1/6B1/6A2/6B2 Relative Threshold
Recommended value:
None, none, none, none
z UlThd6A1/UlThd6B1/UlThd6A2/UlThd6B2
Content: Measurement reporting threshold for triggering event 6A1/6B1/6A2/6B2/6D.
Value range: 0~82
Physical value range: 0~82; step: 1
Physical unit: dB
Set these parameters through ADD TYPRABQUALITYMEAS.
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Parameters of Link Stability (Cont.)
z UlBeTrigTime6A1/UlBeTrigTime6B1/UlBeTrigTime6A2
/UlBeTrigTime6B2/UlBeTrigTime6D
Parameter name:
BE Trigger Time 6A1/6B1/6A2/6B2/6D
Recommended value:
640ms, 2560ms, 1280ms, 1280ms, 240ms
z UlBeTrigTime6A1/UlBeTrigTime6B1/UlBeTrigTime6A2/UlBeTrigTime6B2/UlBeTrigTime6D
Content: Duration when the measured value of BE keeps fulfilling the 6A1/6B1/6A2/6B2/6D measurement condition before the event 6A1/6B1/6A2/6B2/6D is triggered. The trigger time is used to prevent the sudden change of the measured value for being reported. The longer the trigger time is, the greater the effect of ignoring sudden changes is. Yet the response to changes of the measured value becomes slower.
Value range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000
Physical value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000
Physical unit: ms
Set these parameters through SET QUALITYMEAS/ADD CELLQUALITYMEAS.
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Event 5A
z Event 5A:
z The UL BLER measurement may trigger event 5A. The RNC defines a sliding window of a
certain length through the parameter StaBlkNum5A. Each time the RNC receives a data
block, it compares the number of error blocks in the sliding window with the threshold of
event 5A specified by the parameter Thd5A. If the number of error blocks is above or
equal to the threshold of event 5A, event 5A is triggered. Then, the RNC can trigger again
event 5A only after the number of received error blocks reaches HangBlockNum5A, to
avoid excessive reporting of event 5A.
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Parameters of Link Stability (Cont.)
z StaBlkNum5A
Parameter name: Statistic Block Number For 5A Event
Recommended value: 500
z Thd5A
Parameter name: Event 5A Threshold
Recommended value: 280
z HangBlockNum5A
Parameter name: Interval Block Number
Recommended value: 512
z StaBlkNum5A
Content: When a DCH is set up, the UE starts counting the number of faulty CRCs
within a specified sliding window. If the number of faulty CRCs exceeds the
specified threshold, event 5A is triggered. The length of the sliding window is
specified by this parameter.
Value range: 1~512
Physical value range: 1~512; step: 1
z Thd5A
Content: When a DCH is set up, the UE starts counting the number of faulty CRCs
within a specified sliding window. If the number of faulty CRCs exceeds this
parameter, event 5A is triggered.
Value range: 1~512
Physical value range: 1~512; step: 1
z HangBlockNum5A
Content: When event 5A is triggered, a pending timer is started, during which
event 5A will not be reported before the specified number is reached. This
parameter can control the frequency for reporting event 5A.
Value range: 1~512
Physical value range: 1~512; step: 1
z Set these parameters through ADD TYPRABQUALITYMEAS.
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Contents
4. DCCC Based on Link Stability
4.1 Uplink Stability Measurement and Event Reporting
4.2 Downlink Stability Measurement and Event Reporting
4.3 Rate Adjustment Based on Uplink Stability
4.4 Rate Adjustment Based on Downlink Stability
4.5 Signaling Procedure
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Downlink Stability Measurement Item
z DL stability measurement involves two measurement items: TCP and
RLC PDU retransmission rate
The TX power in the pilot field of the DPCCH is measured on the NodeB
side. When the TX power is above the threshold of event Ea, you can infer
that the radio link is unstable
Whether the RLC PDU retransmission rate needs to be measured can be
specified by the parameter SrncBeDlRlcQosSwitch. The RLC PDU
retransmission rate is reported by event A. When the RLC PDU
retransmission rate is above the threshold of event A, you can infer that
the radio link is unstable
z Link stability is measured through the TCP or RLC PDU retransmission rate in the DL. The
RNC performs rate decrease or rate increase for R99 BE services based on the link stability.
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Downlink Stability Measurement Event
z DL TX power in the pilot field of the DPCCH:
Event E (Ea/Eb): is used to check whether the DL power is
excessively high, and trigger a DL rate decrease
Event F (Fa/Fb): is used to check whether the DL power is
excessively low, and trigger a DL rate increase
z DL RLC PDU retransmission rate:
Event A: The PDU retransmission rate during the sliding window is
above the predefined threshold
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Event E
z Event E has two measurement thresholds, that is, E threshold 1 and E
threshold 2:
Event Ea means that the TX power is above E threshold 1
Event Eb means that the TX power is below E threshold 2
z For different services, there are different thresholds for event Ea/Eb.
The E threshold of event Ea/Eb is obtained from the relative threshold
and calculated according to the following formula:
E threshold = Maximum DL power Relative threshold + PO3
z Here:
Maximum DL power is specified by the RlMaxDlPwr parameter, that is, the
maximum DL RL TX power of DPDCHs.
Relative threshold is the relative threshold of event Ea or Eb, which is specified by
the ThdEa or ThdEb parameter respectively.
PO3 is the offset from the TX power of the DPCCH pilot field to the TX power of
DPDCHs.
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Event E (Cont.)
z Event E reporting mechanism:
PowerT1: measurement hysteresis time
Measurementthreshold 1
Measurementthreshold 2
T1
T1
T1
Ea Eb EaPeriodic reporting
Time
z As shown in the previous figure:
If the TX power of the pilot field of DPCCH is above threshold 1 for a period of
time specified by the DlBeTrigTimeE parameter, event Ea is triggered. Then, the
NodeB periodically reports the measurement results of TX power to the RNC.
The NodeB reporting period is specified by the ChoiceRptUnitForBeE,
TenMsecForBeE, or MinForBeE parameter.
If the TX power of the pilot field of DPCCH is below threshold 2 for a period of
time, event Eb is triggered. For BE services, this period is set to 640 ms. Then, the
NodeB stops reporting the measurement results of TX power.
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Parameters of Link Stability (Cont.)
z RlMaxDlPwr
Parameter name: RL Max DL TX power
Recommended value: refer to Power Control course
z ThdEa/ThdEb
Parameter name: Event Ea/Eb Relative Threshold
Recommended value: None, none
z PO3
Parameter name: The power offsets of pilot fields of the DPCCH reference
to the power of DPDCHs
Recommended value: refer to Power Control course (3dB)
z ThdEa
Content: If DL code TX power is higher than the Ea absolute threshold, event Ea is
triggered. This event triggers DL QoS operation. This parameter specifies a relative
threshold.
Value range: 0~56
Physical value range: 0~28, step: 0.5
Physical unit: dB
z ThdEb
Content: If DL code TX power is lower than the Eb absolute threshold, event Eb is
triggered. When this event report is received, DL QoS operation is stopped. This
parameter specifies a relative threshold.
Value range: 0~56
Physical value range: 0~28, step: 0.5
Physical unit: dB
z Set these parameters through ADD TYPRABQUALITYMEAS.
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Parameters of Link Stability (Cont.)
z DlBeTrigTimeE
Parameter name: BE Trigger Time Of Event E
Recommended value: 64, namely 640ms
z ChoiceRptUnitForBeE
Parameter name: BE Reporting Period Unit For Event E
Recommended value: TEN_MSEC
z TenMsecForBeE
Parameter name: BE Event E Reporting Period In 10ms
Recommended value: 480, namely 4800ms
z DlBeTrigTimeE
Content: Duration from when the BE TX power is beyond the threshold Ea to when the
event Ea is triggered or from when the BE TX power is below the threshold Eb to when the
event Eb is triggered. This parameter is used to avoid faulty reporting due to instability of
power.
Value range: 1~6000
Physical value range: 10~60000; step: 10
Physical unit: ms
z ChoiceRptUnitForBeE
Content: This parameter specifies the reporting period of the event E of the BE service. The
unit of the reporting period can be 10 ms or minute.
Value range: TEN_MSEC, MIN
Physical value range: TEN_MSEC, MIN
z TenMsecForBeE
Content: This parameter is valid when the corresponding parameter related to the reporting
period unit for the event E of BE service is set to TEN_MSEC. The DL code TX power is
reported periodically after the event Ea is reported. This parameter specifies the reporting
period. If the parameter is set to A, the reporting period is A x 10 ms.
Value range: 1~6000
Physical value range: 10~60000; step: 10
Physical unit: ms
z Set these parameters through ADD CELLQUALITYMEAS/SET QUALITYMEAS.
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Event F
z Event F has two measurement thresholds, that is, F threshold 1 and F
threshold 2:
Event Fa means that the TX power is below F threshold 1
Event Fb means that the TX power is above F threshold 2
z The F threshold is related to the current rate and the target rate of rate
increase (triggered by event 4a). The F threshold is calculated according
to the following formula:
F threshold = Pmax p Pmargin Ea relative threshold + PO3
z Here:
Pmax is the maximum DL TX power corresponding to the target rate.
p is the power difference between current rate and target rate which is calculated in RNC through the parameters acquired by the simulation and field test
results.
Pmargin is the event F reporting power margin and determined by the parameter
BePwrMargin for a single service or by the parameter CombPwrMargin for
combined services.
Ea relative threshold is used to avoid repeated triggering of event Ea after a rate
increase.
PO3 is the offset from the TX power in the pilot field of the DPCCH to the TX
power of the DPDCHs.
z In RAN 11.0, the thresholds of events Fa and Fb are the same. The threshold of event F
cannot be above the threshold of event Ea. Otherwise, the threshold of event F is set to
the threshold of event Ea.
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Event F (Cont.)
z Event F reporting mechanism:
z As shown in the previous figure:
When the TX power of the pilot field of DPCCH is below threshold 1 for a period
of time specified by the DlBeTrigTimeF parameter, event Fa is triggered. Then, the
NodeB periodically reports the measurement results of TX power to the RNC.
The NodeB reporting period is specified by the ChoiceRptUnitForBeF,
TenMsecForBeF, or MinForBeF parameter.
When the TX power of the pilot field of the DPCCH is above threshold 2 for 640
ms, event Fb is triggered. Then, the NodeB stops reporting the measurement
results of TX power.
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Parameters of Link Stability (Cont.)
z Pmax
Parameter name: the maximum DL TX power corresponding to the
target rate
Recommended value: refer to Power Control course
z BePwrMargin/CombPwrMargin
Parameter name: BE/Comb Event F Reporting Power Margin
Recommended value: 1dB, 2dB
z BePwrMargin
Content: The ralative power margin of single BE traffic, used to calculate the
triggering threshold of event F, can avoid the fluctuation of traffic rate in case the
power becomes restricted after rate is increased.
Value range: 0~100
Physical value range: 0~10, step: 0.1
Physical unit: dB
z CombPwrMargin
Content: The ralative power margin of combined traffics, used to calculate the
triggering threshold of event F, can avoid the fluctuation of traffic rate in case the
power becomes restricted after rate is increased.
Value range: 0~100
Physical value range: 0~10, step: 0.1
Physical unit: dB
z Set these parameters through ADD CELLDCCC/SET DCCC.
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Parameters of Link Stability (Cont.)
z DlBeTrigTimeF
Parameter name: BE Trigger Time Of Event F
Recommended value: 64, namely 640ms
z ChoiceRptUnitForBeF
Parameter name: BE Reporting Period Unit For Event F
Recommended value: TEN_MSEC
z TenMsecForBeF
Parameter name: BE Event F Reporting Period In 10ms
Recommended value: 480, namely 4800ms
z DlBeTrigTimeF
Content: Duration from when the BE TX power is below the threshold Fa to when the
event Fa is triggered or from when the BE TX power is beyond the threshold Fb to when
the event Fb is triggered. This parameter is used to avoid faulty reporting due to instability
of power.
Value range: 1~6000
Physical value range: 10~60000; step: 10
Physical unit: ms
z ChoiceRptUnitForBeF
Content: This parameter specifies the reporting period of the event F of the BE service. The
unit of the reporting period can be 10 ms or minute.
Value range: TEN_MSEC, MIN
Physical value range: TEN_MSEC, MIN
z TenMsecForBeF
Content: This parameter is valid when the corresponding parameter related to the reporting
period unit for the event F of BE service is set to TEN_MSEC. The DL code TX power is
reported periodically after the event Fa is reported. This parameter specifies the reporting
period. If the parameter is set to A, the reporting period is A x 10 ms.
Value range: 1~6000
Physical value range: 10~60000; step: 10
Physical unit: ms
z Set these parameters through ADD CELLQUALITYMEAS/SET QUALITYMEAS.
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Event A
z Event A reporting mechanism:
z The DL RLC PDU retransmission rate is calculated according to the ACK or NACK feedback
information.
z The RLC PDU retransmission rate is reported to layer 3 from layer 2.
z The procedure for measuring the RLC PDU retransmission rate is as follows:
Set up a sliding window for calculating the RLC PDU retransmission rate
periodically according to the period of monitoring the retransmission rate specified
by the parameter MoniterPrd.
Check whether the RLC PDU retransmission rate is above the threshold of event A
specified by the parameter EventAThred. If it is above the threshold for a period of
time, that is, MoniterPrd x TimeToTiggerA, event A is triggered and the RLC PDU
retransmission rate is reported.
In the period of time (MoniterPrd x PendingTimeA) after event A is reported, the
RLC PDU retransmission rate is not calculated any more. If a report on event Ea is
already received before a report on event A is received, the system may reduce the
DL rate.
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Parameters of Link Stability (Cont.)
z SrncBeDlRlcQosSwitch
Parameter name: Srnc Parameter for BE Downlink RLC QOS
Recommended value: YES
z MoniterPrd
Parameter name: re-TX monitor period
Recommended value: 1000, namely 1000ms
z SrncBeDlRlcQosSwitch
Content: When the parameter is set to YES, QoS control for DL BE services is based
on the TCP and RLC retransmission. When the parameter is set to NO, QoS control
for DL BE services is based on the TCP. In both situations, QoS control is not
performed across the Iur interface.
Value range: NO, YES
Physical value range: NO, YES
Set this parameter through SET QOSACT.
z MoniterPrd
Content: This parameter specifies a sampling period of retransmission ratio
monitoring after the RLC entity is established or reconfigured.
Value range: 40~60000
Physical value range: 40~60000; step: 1
Physical unit: ms
Set this parameter through ADD TYPRABRLC.
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Parameters of Link Stability (Cont.)
z EventAThred
Parameter name: Event A threshold
Recommended value: 160, namely 16%
z TimeToTiggerA
Parameter name: Event A time to trigger
Recommended value: 2
z PendingTimeA
Parameter name: Event A pending time after trigger
Recommended value: 1
z EventAThred
Content: This parameter specifies the threshold of event A, that is, the upper limit
of RLC retransmission ratio.
Value range: 0~1000
Physical value range: 0~100; step: 0.1
Physical unit: %
z TimeToTiggerA
Content: This parameter specifies the number of consecutive periods during which
the percentage of retransmitted PDUs is higher than the threshold of event A
before event A is triggered.
Value range: 1~100
Physical value range: 1~100; step: 1
z PendingTimeA
Content: This parameter specifies the number of pending periods after event A is
triggered. During the pending time, no event related to retransmission ratio is
reported.
Value range: 0~1000
Physical value range: 0~1000; step: 1
z Set these parameters through ADD TYPRABRLC.
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Contents
4. DCCC Based on Link Stability
4.1 Uplink Stability Measurement and Event Reporting
4.2 Downlink Stability Measurement and Event Reporting
4.3 Rate Adjustment Based on Uplink Stability
4.4 Rate Adjustment Based on Downlink Stability
4.5 Signaling Procedure
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Rate Decrease in UL
z For rate decrease based on uplink stability, only the 3-Rates
decrease applies:
If the current rate is MBR, the rate is downsized to the value of
Uplink mid bit rate threshold
If the current rate is higher than Uplink full coverage bit rate and
lower than MBR, the rate is downsized to the value of Uplink full
coverage bit rate
z The Uplink mid bit rate threshold parameter is the same as that described in Rate
Adjustment Based on Traffic Volume.
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Rate Decrease in UL (Cont.)
z Rate decrease based on uplink stability in the case of 3-Rates
adjustment:
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Parameters of Link Stability (Cont.)
z UlFullCvrRate
Parameter name: Uplink Full Coverage Bit Rate
Recommended value: D64, namely 64kbit/s
z UlFullCvrRate
Content: Maximum UL rate when coverage of the entire cell is ensured under
certain load. For a BE service that has a low maximum rate, the DCCC algorithm is
not obviously effective yet it increases algorithm processing. Thus, the coverage-
based DCCC algorithm is applied to BE services whose maximum UL rate is greater
than the threshold.
Value range: D8, D16, D32, D64, D128, D144, D256, D384
Physical value range: 8, 16, 32, 64, 128, 144, 256, 384
Physical unit: kbit/s
Set this parameter through ADD CELLDCCC/SET DCCC.
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Rate Increase in UL
z Rate increase procedure based on uplink stability:
z Before rate increase, the RNC checks whether the current power is sufficient. If the power
is sufficient, rate increase is triggered by event 4a.
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Rate Increase in UL (Cont.)
z If the RNC receives a report on event 6B2 but does not receive
any report on event 6A2, the channel power is sufficient. In this
case, rate increase based on traffic volume can be triggered by
event 4a
z If the RNC receives a report on event 6A2, no rate increase
based on traffic volume can be triggered by event 4a
z If the RNC receives a report on event 6B1, rate decrease is
stopped and no rate increase can be triggered
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Contents
4. DCCC Based on Link Stability
4.1 Uplink Stability Measurement and Event Reporting
4.2 Downlink Stability Measurement and Event Reporting
4.3 Rate Adjustment Based on Uplink Stability
4.4 Rate Adjustment Based on Downlink Stability
4.5 Signaling Procedure
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Rate Decrease in DL
z For rate decrease based on downlink stability, only the 3-Rates
decrease applies:
If the current rate is MBR, the rate is downsized to the value of
Downlink mid bit rate threshold
If the current rate is higher than Downlink full coverage bit rate
and lower than MBR, the rate is downsized to the value of
Downlink full coverage bit rate
z The Downlink mid bit rate threshold parameter is the same as that described in Rate
Adjustment Based on Traffic Volume.
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Rate Decrease in DL (Cont.)
z Rate decrease based on downlink stability in the case of 3-Rates
adjustment:
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Parameters of Link Stability (Cont.)
z DlFullCvrRate
Parameter name: Downlink Full Coverage Bit Rate
Recommended value: D64, namely 64kbit/s
z DlFullCvrRate
Content: Maximum DL rate during network planning when coverage of the entire
cell is ensured. When the DL TCP is limited, the current rate is reduced to the full
coverage rate if the current rate is greater than the full coverage rate. For a BE
service that has a low maximum rate, the DCCC algorithm is not obviously effective
yet it increases algorithm processing. Thus, the DCCC algorithm is applied to BE
services whose maximum DL rate is greater than the threshold.
Value range: D8, D16, D32, D64, D128, D144, D256, D384
Physical value range: 8, 16, 32, 64, 128, 144, 256, 384
Physical unit: kbit/s
Set this parameter through ADD CELLDCCC/SET DCCC.
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Rate Increase in DL
z Rate increase procedure based on downlink stability:
z Before rate increase, the RNC checks whether the current power is sufficient. If the power
is sufficient, rate increase is triggered by event 4a.
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Rate Increase in DL (Cont.)
z If event Fa is reported, you can infer that the DL channel power
is sufficient. If event 4a is also reported, a rate increase can be
triggered
z If event Fb is reported, you can infer that the DL channel power
is insufficient. In this case, no rate increase can be triggered
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Contents
4. DCCC Based on Link Stability
4.1 Uplink Stability Measurement and Event Reporting
4.2 Downlink Stability Measurement and Event Reporting
4.3 Rate Adjustment Based on Uplink Stability
4.4 Rate Adjustment Based on Downlink Stability
4.5 Signaling Procedure
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Signaling Procedure
z Signaling procedure of rate decrease based on downlink
stability:
z For detailed information about the signaling procedure of rate increase, see Signaling
Procedure of Rate Adjustment Based on Traffic Volume.
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Contents
1. DCCC Overview
2. DCCC Based on Traffic Volume
3. DCCC Based on Throughput
4. DCCC Based on Link Stability
5. DCCC Based on Basic Congestion
6. UE State Transition
7. Always Online
z When the cell enters the basic congestion state, the RNC decreases the rate of BE services,
and the maximum target rate is the GBR for a BE RAB. When the cell exits from the basic
congestion state, the LDR function does not perform any task on the UEs in the cell. The
system decreases or increases service rates through the DCCC function.
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Contents
5. DCCC Based on Basic Congestion
5.1 Rate Adjustment Based on Uplink Congestion
5.2 Rate Adjustment Based on Downlink Congestion
5.3 Rate Increase Failure and Penalty
5.4 Signaling Procedure
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Rate Adjustment Based on Uplink Congestionz When LDR triggers BE service rate decrease, the selected RAB
rate is decreased to the target rate. The target rates for rate
adjustment are different for DCH RAB and HSUPA RAB:
If the selected RAB is a DCH RAB, the rate adjustment level can
only be 3_Rates:
If the current rate is equal to the MBR, it is decreased to the UL middle
rate threshold
If the current rate is higher than the GBR but lower than the MBR, it is
decreased to the GBR
z The UL mid bit rate threshold parameter is the same as that described in Rate Adjustment
Based on Traffic Volume.
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Rate Adjustment Based on Uplink Congestion (Cont.)
If the selected RAB is an HSUPA RAB, a rate is selected from the
HSUPA UL rate adjustment set as the target rate for rate decrease:
The target rate must be smaller than but the closest to the current rate.
Meanwhile it must be greater than or equal to the GBR
z The HSUPA UL rate adjustment set is the same as that described in Rate Adjustment Based
on Throughput.
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Rate Adjustment Based on Uplink Congestion (Cont.)
z The previous figure shows an example of UL BE rate decrease and increase in the case that
the RAB is a DCH RAB.
In this example, a rate decrease is triggered by UL basic congestion, and a rate
increase is triggered when basic congestion is relieved. In addition, the current UL
rate can be the initial rate, middle rate, or MBR.
When the current UL rate is the MBR, it is decreased to the middle rate if a UL
basic congestion report is received, and then decreased to the GBR if a second UL
basic congestion report is received.
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Contents
5. DCCC Based on Basic Congestion
5.1 Rate Adjustment Based on Uplink Congestion
5.2 Rate Adjustment Based on Downlink Congestion
5.3 Rate Increase Failure and Penalty
5.4 Signaling Procedure
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Rate Adjustment Based on Downlink Congestionz When a cell is in the basic congestion state in the downlink, the
rate of the selected RAB is decrease to the GBR if a BE rate
decrease is triggered. The rate decrease level can only be
3_Rates: