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WCDMA Load Control
Algorithm and
Parameters
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Foreword
The WCDMA system is a self-interfering system, so the
capacity, coverage, and QoS are mutually affected
The target of load control is to maximize the system
capacity while ensuring coverage and QoS, and providedifferentiated services for users
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References
3GPP TS 25.133: Requirements for Support of Radio Resource
Management (FDD)
3GPP TS 25.215: Physical Layer - Measurements (FDD)
3GPP TS 25.304: UE Procedures in Idle Mode and Procedures
for Cell Reselection in Connected Mode
3GPP TS 25.321: Medium Access Control (MAC) Protocol
Specification
3GPP TS 25.331: Radio Resource Control (RRC)
3GPP TS 25.413: UTRAN Iu Interface RANAP Signaling
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Objectives
Upon completion of this course, you will be able to:
Outline the principle of load control
Describe the realization method of load control
Perform the parameter adjustment of load control
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Contents
1. Load Control Overview
2. Load Control Algorithms
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Contents
1. Load Control Overview
1.1 Load Control Algorithms Overview
1.2 Load Measurement
1.3 Priorities Involved in Load Control
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Load Definition
Load: the occupancy of capacity
Two kinds of capacity in WCDMA system:
Hard capacity:
Cell DL OVSF code
Iub transport resource
NodeB processing capability (NodeB credit)
Soft capacity: Cell power (UL and DL)
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Load Control Algorithms (Cont.)
Load Control AlgorithmResources
Power Code NodeB Credits Iub Bandwidth
PUC - - -IAC
CAC
LDB - - -
LDR
OLC - -
: not considered; : considered
Resources considered by different load control algorithms:
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Contents
1. Load Control Overview
1.1 Load Control Algorithms Overview
1.2 Load Measurement
1.3 Priorities Involved in Load Control
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Load Measurement
Load control function in the WCDMA system:
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Load Measurement Quantities
The major load-related measurement quantities are as follows:
Uplink Received Total Wideband Power (RTWP)
Downlink Transmitted Carrier Power (TCP)
Non-HSPA power: TCP excluding the power used for transmission
on HSPA channels
Provided Bit Rate (PBR) on HS-DSCH
PBR on E-DCH
Power Requirement for GBR (GBP) on HS-DSCH: minimum power
required to ensure the GBR on HS-DSCH
Received Scheduled E-DCH Power Share (RSEPS): power of the E-
DCH scheduling service
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Reporting Period
The NodeB periodically reports each measurement quantity to the
RNC.
The reporting period parameters for setting different measurement
quantities:
Measurement Reporting Period Parameter
RTWP ChoiceRprtUnitForUlBasicMeasTenMsecForUlBasicMeas
MinForUlBasicMeasChoiceRprtUnitForDlBasicMeasTenMsecForDlBasicMeasMinForDlBasicMeas
RSEPS
TCP
Non-HSDPA power
GBP ChoiceRprtUnitForHsdpaPwrMeasTenMsecForHsdpaPwrMeasMinForHsdpaPwrMeas
HS-DSCH PBR ChoiceRprtUnitForHsdpaRateMeasTenMsecForHsdpaPrvidRateMeasMinForHsdpaPrvidRateMeas
E-DCH PBR ChoiceRprtUnitForHsupaRateMeasTenMsecForHsupaPrvidRateMeasMinForHsupaPrvidRateMeas
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Contents
1. Load Control Overview
1.1 Load Control Algorithms Overview
1.2 Load Measurement
1.3 Priorities Involved in Load Control
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Priority
The QoS of the services or users with low priority will be
affected by the load control algorithms first
Three kinds of priorities involved in load control:
User priority
RAB integrated priority
User integrated priority
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User Priority
There are three levels of user priority:
gold (high priority), silver (middle priority) and copper (low
priority) users
User priority Gold Silver Copper
Uplink 384kbps 128kbps 64kbps
Downlink 384kbps 128kbps 64kbps
gold
user
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User Priority (Cont.)
The mapping relation between user priority and ARP isconfigured in RNC by SET UUSERPRIORITY
Typical relation between user priority and ARP:
ARP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
User
Priority Gold Silver Copper
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RAB Integrated Priority
RAB integrated priority is mainly used in load control
algorithms
RAB integrated priority are set according to :
ARP
Traffic Class
Traffic Handling Priority (THP, only for interactive services)
Carrier types: HSPA or DCH
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An Example for RAB Integrated Priority
Service
ID
ARP Traffic ClassBear
typeA 1 Interactive DCH
B 1 Interactive HSDPA
C 2 Conversational DCH
D 2 Background DCH
Services attribution in the cell
Based on ARP, HSPA priority is higher
Based on Traffic Class, HSPA priority is higher
Service
IDARP Traffic Class
Bear
type
B 1 Interactive HSDPA
A 1 Interactive DCH
C 2 Conversational DCH
D 2 Background DCH
Service
IDTraffic Class ARP
Bear
type
C Conversational 2 DCH
B Interactive 1 HSDPA
A Interactive 1 DCH
D Background 2 DCH
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User Integrated Priority
For single-RAB user, the user integrated priority is the
same as the RAB integrated priority
For multiple-RAB user, the user integrated priority is
based on the highest priority of RAB
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Parameters of Priority
PriorityReference
Parameter name: Integrate Priority Configured Reference
Recommended value: ARP
CarrierTypePriorInd
Parameter name: Indicator of Carrier Type Priority
Recommended value: NONE
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Contents
2. Load Control Algorithms
2.1 PUC (Potential User Control)
2.2 LDB (Intra-Frequency Load Balancing)
2.3 CAC (Call Admission Control)
2.4 IAC (Intelligent Access Control)
2.5 LDR (Load Reshuffling)
2.6 OLC (Overload Control)
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PUC Principle
The Potential User Control (PUC) algorithm only controls
the Inter-frequency cell reselection of the potential UE,
and prevents UE from camping on a heavily loaded cell
The PUC is valid only for inter-frequency cells, and ittakes effect only in the downlink
Potential UE:
UE in idle mode
UE in Cell-FACH, Cell-PCH and URA-PCH
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PUC Load Judgment
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PUC Load Judgment
For a cell not supporting DC-HSDPA, the RNC periodically
monitors the downlink load of the cell.
If the cell load is higher than the upper threshold
(SpucHeavy) plus the load level division hysteresis
(SpucHyst), the cell load is considered heavy.
If the cell load is lower than the lower threshold (SpucLight)
minus SpucHyst, the cell load is considered light.
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PUC Load Judgment
For a cell supporting DC-HSDPA, the RNC concurrentlymonitors the load state of each single cell and load state of the
cell group.
The determination of load state of a single cell is the same as that
of a cell not supporting DC-HSDPA
The determination of load state of the cell group is as follows:
If the load of the two cells is higher than their upper thresholds
(SpucHeavy) plus their load level division hystereses (SpucHyst), the load
of the cell group is considered heavy.
If the load of the two cells is lower than their lower thresholds (SpucLight)
minus their load level division hystereses (SpucHyst), the load of the cell
group is considered light.
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PUC Procedure
NodeB UE
Heavy?
Light?
Normal?
Cell TCP
RNC
Threshold
cell reselection
parameters
System
information
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PUC Procedure (Cont.)
Freq1
Freq2
System Info
SIB3,11
System Info
SIB3,11
System Info
SIB3,11
Heavy load
Light load Normal load
Idle state CCH state
Modify1.
Sintersearch2. Qoffset
Modify 1. Sintersearch
2. QoffsetStay
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Parameters of PUC
NBMLdcAlgoSwitch-PUC
Parameter name: Cell LDC algorithm switch for PUC
Recommended value: OFF
SpucHeavy Parameter name: Load level division threshold 1
Recommended value: 70, namely 70%
SpucLight
Parameter name: Load level division threshold 2
Recommended value: 45, namely 45%
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Parameters of PUC (Cont.)
SpucHyst
Parameter name: Load level division hysteresis
Recommended value: 5, namely 5%
PucPeriodTimerLen
Parameter name: PUC period timer length
Recommended value: 1800, namely 1800s
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Parameters of PUC (Cont.)
OffSinterLight
Parameter name: Sintersearch offset 1
Recommended value: -2, namely -4dB
OffSinterHeavy
Parameter name: Sintersearch offset 2
Recommended value: 2, namely 4dB
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Parameters of PUC (Cont.)
OffQoffset1Light(for RSCP)
Parameter name: Qoffset1 offset 1
Recommended value: -4, namely -4dB
OffQoffset1Heavy(for RSCP)
Parameter name: Qoffset1 offset 2
Recommended value: 4, namely 4dB
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Contents
2. Load Control Algorithms
2.1 PUC (Potential User Control)
2.2 LDB (Intra-Frequency Load Balancing)
2.3 CAC (Call Admission Control)
2.4 IAC (Intelligent Access Control)
2.5 LDR (Load Reshuffling)
2.6 OLC (Overload Control)
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LDB Principle
Intra-frequency Load Balancing (LDB) is performed to
adjust the coverage areas of cells by modifying PCPICH
power
LDB affect UEs in all states
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LDB Procedure
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Parameters of LDB
NBMLdcAlgoSwitch-INTRA_FREQUENCY_LDB
Parameter name: Cell LDC algorithm switch for LDB
Recommended value: OFF
IntraFreqLdbPeriodTimerLen
Parameter name: Intra-frequency LDB period timer length
Recommended value: 1800, namely 1800s
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Parameters of LDB (Cont.)
CellOverrunThd
Parameter name: Cell overload threshold
Recommended value: 90, namely 90%
CellUnderrunThd Parameter name: Cell underload threshold
Recommended value: 30, namely 30%
PCPICHPowerPace
Parameter name: Pilot power adjustment step
Recommended value: 2, namely 0.2dB
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Parameters of LDB (Cont.)
PCPICHPower
Parameter name: PCPICH transmit power
Recommended value: 330, namely 33dBm
MaxPCPICHPower Parameter name: Max transmit power of PCPICH
Recommended value: 346, namely 34.6dBm
MinPCPICHPower
Parameter name: Min transmit power of PCPICH
Recommended value: 313, namely 31.3dBm
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Contents
2. Load Control Algorithms
2.1 PUC (Potential User Control)
2.2 LDB (Intra-Frequency Load Balancing)
2.3 CAC (Call Admission Control)
2.4 IAC (Intelligent Access Control)
2.5 LDR (Load Reshuffling)
2.6 OLC (Overload Control)
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Contents
2. Load Control Algorithms
2.3 CAC (Call Admission Control)
2.3.1 CAC Overview
2.3.2 CAC Based on Code Resource
2.3.3 CAC Based on Power Resource
2.3.4 CAC Based on NodeB Credit Resource
2.3.5 CAC Based on Iub Resource
2.3.6 CAC Based on the Number of HSPA Users
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Why We Need CAC?
WCDMA is an interference limited system, after a new
service is admitted, the system load will be increased
If a cell is high loaded, a new service will affect the QoS
of ongoing user, even result in call drop
CAC is used to determine whether the system resources
are sufficient to accept a new user's access request or
not
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CAC Procedure
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CAC Algorithm Switches
Power CAC Uplink CAC algorithm switch: ALGORITHM_SECOND
Downlink CAC algorithm switch: ALGORITHM_FIRST
NodeB credit CAC
CAC algorithm switch: ON
Cell CAC algorithm switch-CRD_ADCTRL: ON
HSDPA user number CAC
Cell CAC algorithm switch-HSDPA_UU_ADCTRL: OFF
HSUPA user number CAC
Cell CAC algorithm switch-HSUPA_UU_ADCTRL: OFF
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Contents
2. Load Control Algorithms
2.3 CAC (Call Admission Control)
2.3.1 CAC Overview
2.3.2 CAC Based on Code Resource
2.3.3 CAC Based on Power Resource
2.3.4 CAC Based on NodeB Credit Resource
2.3.5 CAC Based on Iub Resource
2.3.6 CAC Based on the Number of HSPA Users
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CAC Based on Code Resource
Code resource CAC is involved in:
RRC connection setup
Handover
R99 services setup
RRC connection setup and handover have higher priority
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Parameter of CAC Based on Code
Resource
DlHoCeCodeResvSf
Parameter name: DL handover credit and code reserved SF
Recommended value: SF32
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Contents
2. Load Control Algorithms
2.3 CAC (Call Admission Control)
2.3.1 CAC Overview
2.3.2 CAC Based on Code Resource
2.3.3 CAC Based on Power Resource
2.3.4 CAC Based on NodeB Credit Resource
2.3.5 CAC Based on Iub Resource
2.3.6 CAC Based on the Number of HSPA Users
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CAC Based on Power Resource
Power resource CAC is involved in:
RRC connection setup
Handover
Services setup
RRC connection setup and handover have higher priority
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Power CAC ProcedureRequest initiation
Uplink call
admission decision
Admitted?
Downlink calladmission desicion
Admitted?
Request accepted Request rejected
No
No
Yes
Yes
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Power CAC Algorithms
Algorithm 1: based on UL/DL load measurement andload prediction (RTWP and TCP)
Algorithm 2: based on Equivalent Number of User (ENU)
Algorithm 3: loose call admission control algorithm
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Power CAC for RRC Connection Setup
For the RRC Connection Setup Request for the reason ofemergency call, detach, or registration: Direct Admission
For the RRC connection setup request for other reasons:
When power-based admission is based on power (algorithm 1 and
algorithm 3), the UL or DL OLC trigger threshold (UlOlcTrigThd orDlOlcTrigThd) is used for admission.
When power-based admission is based on the ENU (algorithm 2),
the admission decision is made as follows:
When UL_UU_OLCor DL_UU_OLCis set to 1, RRC connection setup
request is rejected when the cell is in the overload state. If the cell is not inthe overload state, the UL or DL OLC trigger threshold is used for power-
based admission.
When UL_UU_OLCor DL_UU_OLCis set to 0, the UL or DL OLC trigger
threshold is used for power-based admission.
P B d Ad i i Al ith 1
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Power-Based Admission Algorithm 1
for RAB Setup
Power-based admission decision based on algorithm 1consists of uplink power-based admission decision and
downlink power-based admission decision procedures:
Uplink admission decision:
R99 cell
HSPA cell
Downlink admission decision:
R99 cell
HSPA cell
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Algorithm 1 - Uplink for R99 Cell
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Parameters of Power CAC
UlCCHLoadFactor
Parameter name: UL common channel load reserved
coefficient
Recommended value: 0, namely 0%
UlNonCtrlThdForHo/UlNonCtrlThdForAMR/UlNonCtrlThdF
orNonAMR/UlNonCtrlThdForOther
Parameter name: UL threshold of handover/Conv AMR/Conv
non_AMR/other service
Recommended value: 80%, 75%, 75%, 60%
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Algorithm 1 - Uplink for HSPA Cell
1. The RNC obtains the uplink RTWP of the cell andcalculates the current uplink load factor.
After the Received Scheduled E-DCH Power Share (RSEPS)
measurement is introduced, the UL RTWP is divided into
two parts:
Controllable part
Uncontrollable part
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Algorithm 1 - Uplink for HSPA Cell
2. The RNC calculates the uplink load increment ULbased on the service request using Ec/N0 of the GBR of
the service, neighboring interference factor, and AF of
the service
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Algorithm 1 - Uplink for HSPA Cell
3. The RNC determines whether to grant the UE admission:
1).
2).
3). 4).
5).
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Algorithm 1 - Uplink for HSPA Cell
3. The RNC determines whether to grant the UE admission: The RNC admits the HSUPA scheduling services in either of the
following cases:
Formula 1, 2, or 3 is fulfilled.
Formula 4 is fulfilled.
The RNC admits the HSUPA non-scheduling services in either of the
following cases:
Formula 1, 2, or 3 is fulfilled.
Formulas 4 and 5 are fulfilled.
The RNC admits the DCH services when formulas 4 and 5 are
fulfilled
If the access request is rejected, the RNC performs the next step
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Algorithm 1 - Uplink for HSPA Cell
4. The RNC checks whether the Control RTWP Anti-interference function switch (RsvdBit1subparameter of
the RsvdPara1parameter) is enabled. If it is enabled, the
RNC checks whether the uplink equivalent user load
proportion of the cell is lower than 40%. If it is lower
than 40%, the RNC accepts the access request.
Otherwise, the RNC rejects the access request.
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Parameters of Power CAC
UlHsDpcchRsvdFactor
Parameter name: UL HS-DPCCH reserve factor
Recommended value: 0, namely 0%
UlCellTotalThd
Parameter name: UL total power threshold
Recommended value: 83, namely 83%
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Parameters of Power CAC (Cont.)
HsupaLowPriorityUserPBRThd
HsupaEqualPriorityUserPBRThd
HsupaHighPriorityUserPBRThd
Parameter name: Low/Equal/High priority HSUPA user PBR
threshold
Recommended value: 100%, 100%, 100%
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Algorithm 1 - Downlink for R99 Cell
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Parameters of Power CAC (Cont.)
DlCCHLoadRsrvCoeff
Parameter name: DL common channel load reserved
coefficient
Recommended value: 0, namely 0%
DlHOThd/DlConvAMRThd/DlConvNonAMRThd/DlOtherTh
d
Parameter name: DL threshold of handover/Conv AMR/Conv
non_AMR/other service
Recommended value: 85%, 80%, 80%, 75%
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Algorithm 1 - Downlink for HSPA Cell
1. The RNC calculates the downlink power incrementPDLfor new service request
The power increment estimation for the DCH RAB in the
HSPA cell is similar to the DCH RAB in the R99 cell
The power increment estimation for HSDPA RAB PDLis
made on the basis of GBR, Ec/N0, non-orthogonal factor,
and so on
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Algorithm 1 - Downlink for HSPA Cell
2. The RNC determines whether to grant the UEadmission:
Admission Decision for DCH RAB in the Downlink:
1).
2).
3).
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Algorithm 1 - Downlink for HSPA Cell
2. The RNC determines whether to grant the UEadmission:
Admission Decision for DCH RAB in the Downlink:
If the current cell does not support DC-HSDPA, the RNC admits
the DCH RAB when either of the following conditions is met:
Condition A: Formulas 1 and 2 are fulfilled
Condition B: Formulas 1 and 3 are fulfilled
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Algorithm 1 - Downlink for HSPA Cell
2. The RNC determines whether to grant the UEadmission:
Admission Decision for HSDPA RAB in the Downlink:
1).
2).
3).
4).
5).
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Algorithm 1 - Downlink for HSPA Cell
2. The RNC determines whether to grant the UEadmission:
Admission Decision for HSDPA RAB in the Downlink:
If the current cell does not support DC-HSDPA, the RNC admits
the HSDPA RAB when any of the following conditions is met:
Condition C: Formula 1 (for streaming service) is fulfilled or Formula 2
(for BE service) is fulfilled
Condition D: Formulas 3 and 4 are fulfilled
Condition E: Formulas 3 and 5 are fulfilled
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Parameters of Power CAC (Cont.)
DlCellTotalThd
Parameter name: DL total power threshold
Recommended value: 90, namely 90%
DlHSUPARsvdFactor
Parameter name: DL HSUPA reserved factor
Recommended value: 0, namely 0%
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Parameters of Power CAC (Cont.)
HsdpaStrmPBRThd
Parameter name: HSDPA streaming PBR threshold
Recommended value: 70, namely 70%
HsdpaBePBRThd
Parameter name: HSDPA best effort PBR threshold
Recommended value: 30, namely 30%
Power-Based Admission Algorithm 2
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Power-Based Admission Algorithm 2
for RAB Setup
When the CAC function uses algorithm 2, the admissionof uplink/downlink power resources uses the algorithm
depending on the Equivalent Number of Users (ENU)
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Equivalent Number of Users
The 12.2 kbit/s AMR traffic is defined as one ENU. Thus,the 12.2 kbit/s AMR traffic can be used to calculate the
ENU of all other services. The calculation is related to the
following factors:
Cell type, such as urban or suburban
Traffic domain, CS or PS
Coding type, turbo code or 1/2, 1/3 convolutional code
Traffic QoS, that is, Block Error Rate (BLER)
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Power CAC Algorithm 2 Procedure
Get current total ENU
Admission request
Get the traffic characteristic, and
estimate the increment of ENU
Calculate the predicted ENU
admitted rejected
End of UL/DL CAC
Y NSmaller than
the threshold?
N
i
itotal ENUNENU
1
)(
newENU
newtotaltotal ENUNENUNENU )()1(
max/)1( ENUNENUENULoad total
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Parameters of Power CAC (Cont.)
UlTotalEqUserNum
Parameter name: UL total equivalent user number
Recommended value: 80
DlTotalEqUserNum
Parameter name: DL total equivalent user number
Recommended value: 80
Power-Based Admission Algorithm 3
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Power Based Admission Algorithm 3
for RAB Setup
Algorithm 3 is similar to algorithm 1. The difference isthat the estimated load increment in algorithm 3 is
always set to 0
In accordance with the current cell load (uplink load
factor and downlink TCP), the RNC determines whether
the cell load will exceed the threshold, with the
estimated load increment set to 0. If yes, the RNC rejects
the request. If not, the RNC accepts the request
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Contents
2. Load Control Algorithms
2.3 CAC (Call Admission Control)
2.3.1 CAC Overview
2.3.2 CAC Based on Code Resource
2.3.3 CAC Based on Power Resource
2.3.4 CAC Based on NodeB Credit Resource
2.3.5 CAC Based on Iub Resource
2.3.6 CAC Based on the Number of HSPA Users
C
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NodeB Credit
CE is used to measure the channel demodulationcapability of the NodeBs. On the RNC side, it is referred
to the NodeB credit. On the NodeB side, it is the Channel
Element (CE)
The resource of one equivalent 12.2 kbit/s AMR voice
service, including 3.4 kbit/s signaling on DCCH, is defined
as one CE
There are two kinds of CE, that is, uplink CE supportinguplink services and downlink CE supporting downlink
services. Therefore, one 12.2 kbit/s AMR voice service
consumes one uplink CE and one downlink CE
N d B C di CAC
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NodeB Credit CAC
NodeB credit CAC is involved in: RRC connection setup
Handover
Services setup
RRC connection setup and handover have higher priority
P t f N d B C dit CAC
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Parameter of NodeB Credit CAC
UlHoCeResvSf Parameter name: UL handover credit reserved SF
Recommended value: SF16
DlHoCeCodeResvSf
Parameter name: DL handover credit and code reserved SF
Recommended value: SF32
HsupaCeConsumeSelection
Parameter name: HSUPA Credit Consume Type
Recommended value: MBR
C t t
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Contents
2. Load Control Algorithms2.3 CAC (Call Admission Control)
2.3.1 CAC Overview
2.3.2 CAC Based on Code Resource
2.3.3 CAC Based on Power Resource
2.3.4 CAC Based on NodeB Credit Resource
2.3.5 CAC Based on Iub Resource
2.3.6 CAC Based on the Number of HSPA Users
I b R CAC
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Iub Resource CAC
Iub overbooking The Iub overbooking feature considers the statistic
multiplexing of service activities and multiple users
Through the admission of more users, Iub overbooking
increases the resource utilization on the Iub interface
I b R CAC (C t )
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Iub Resource CAC (Cont.)
Activity factor RT services, including conversational and streaming services,
are admitted at the Maximum Bit Rate (MBR):
Admission bandwidth = MBR x activity factor
NRT services, including interactive and background services,
are admitted at the GBR:
Admission bandwidth = GBR x activity factor
I b R CAC P d
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Iub Resource CAC Procedure
For handover of a user, the following requirements apply: Load of the path + Bandwidth required by the user < Total
configured bandwidth of the path
For a new user, the following requirements apply:
Load of the path + Bandwidth required by the user < Total
configured bandwidth of the path - Bandwidth reserved for
handover
For rate upsizing of a user, the following requirementsapply:
Load of the path + Bandwidth required by the user < Total
configured bandwidth of the path - Congestion threshold
P t f I b R CAC
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Parameters of Iub Resource CAC
FWDHORSVBW/BWDHORSVBW
Parameter name: Forward/Backward handover reserved bandwidth
Recommended value: 0, namely 0Kbit/s
FWDCONGBW/BWDCONGBW
Parameter name: Forward/Backward congestion threshold
Recommended value: 0, namely 0Kbit/s
FWDCONGCLRBW/BWDCONGCLRBW
Parameter name: Forward/Backward congestion clear threshold
Recommended value: 0, namely 0Kbit/s
C t t
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Contents
2. Load Control Algorithms2.3 CAC (Call Admission Control)
2.3.1 CAC Overview
2.3.2 CAC Based on Code Resource
2.3.3 CAC Based on Power Resource
2.3.4 CAC Based on NodeB Credit Resource
2.3.5 CAC Based on Iub Resource
2.3.6 CAC Based on the Number of HSPA Users
HSPA U N b CAC
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HSPA User Number CAC
HSPA user number CAC is involved in: Cell level
Maximum number of HSPA users in a cell
NodeB level
Maximum number of HSPA users in all the cells configured in one
NodeB
CAC f HSDPA U
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CAC of HSDPA Users
When HSDPA_UU_ADCTRLis set to 1, the HSDPA services have
to undergo admission decision based on the number of HSDPA
users.
When a new HSDPA service attempts to access the network,
the algorithm admits the service if the following conditions are
met:
The number of HSDPA users in the cell does not exceed the
maximum value specified by MaxHsdpaUserNum.
The number of HSDPA users in the NodeB does not exceed the
maximum value specified by NodeBHsdpaMaxUserNum.
Otherwise, the HSDPA service is degraded to R99 service to
retry admission.
CAC of HSUPA Users
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CAC of HSUPA Users
When HSUPA_UU_ADCTRLis set to 1, the HSUPA services have to
undergo admission decision based on the number of HSUPA users
When a new HSUPA service attempts to access the network, the
algorithm admits the service if the following conditions are met:
The number of the HSUPA users in the cell does not exceed the maximum
value specified by MaxHsupaUserNum.
The number of the HSUPA users in the NodeB does not exceed the
maximum value specified by NodeBHsupaMaxUserNum.
Otherwise, the HSUPA service is degraded to R99 service to retry
admission
Parameters of HSPA User Number
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CAC
MaxHsdpaUserNum Parameter name: Maximum HSDPA user number
Recommended value: 64
NodeBHsdpaMaxUserNum Parameter name: NodeB Max HSDPA User Number
Recommended value: 3840
Parameters of HSPA User Number
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CAC (Cont.)
MaxHsupaUserNum Parameter name: Maximum HSUPA user number
Recommended value: 20
NodeBHsupaMaxUserNum Parameter name: NodeB Max HSUPA User Number
Recommended value: 3840
Contents
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Contents
2. Load Control Algorithms2.1 PUC (Potential User Control)
2.2 LDB (Intra-Frequency Load Balancing)
2.3 CAC (Call Admission Control)
2.4 IAC (Intelligent Access Control)
2.5 LDR (Load Reshuffling)
2.6 OLC (Overload Control)
Why Do We Need IAC?
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Why Do We Need IAC?
The disadvantages of CAC: For PS NRT (Non-Real Time) services, CAC is not flexible
No consideration about the priority of different users
No consideration about Directed Retry after CAC rejection
Intelligent means the algorithm can increase admission
successful rate
IAC Procedure
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IAC Procedure
Contents
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Contents
2. Load Control Algorithms2.4 IAC (Intelligent Access Control)
2.4.1 IAC During RRC Connection Setup
2.4.2 Directed Retry Decision During RAB Procedure
2.4.3 Rate Negotiation at Admission Control
2.4.4 Admission Decision
2.4.5 Preemption
2.4.6 Queuing
2.4.7 Low-Rate Access of the PS BE Service
2.4.8 IAC for Emergency Calls
IAC RRC Connection Setup
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IAC - RRC Connection Setup
.
RRC Redirection based on
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Distance
Target service: UE-originating AMR services
RNC estimates the distance between the UE and the cell
center by considering the propagation delay
RNC determines whether to perform RRC redirectionbased on the estimation result
RRC Redirection for Service Steering
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RRC Redirection for Service Steering
Purpose: Enable the successful RRC connection setup by
selecting an appropriate cell for the UE based on the requested
service.
During the RRC connection setup, the RNC implements service
steering between inter-frequency or inter-RAT cells according
to the cause of RRC connection setup. In addition, the RNC
considers the load of the cell for access and the redirection
factors to control the degree of load balancing
Algorithm switch: DrSwitch-DR_ RRC_DRD_SWITCH
Triggering factor: RedirFactorOfNormor RedirFactorOfLDR
Target cell: RedirSwitch
Parameters of RRC Redirection
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Parameters of RRC Redirection
DrSwitch-DR_ RRC_DRD_SWITCH Parameter name: DRD switch for RRC connection
Recommended value: ON
RedirSwitch
Parameter name: Redirection Switch
Recommended value: OFF
RedirFactorOfNorm/RedirFactorOfLDR
Parameter name: Redirection Factor Of Normal/LDR
Recommended value: 0, 100
RRC DRD
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RRC DRD
Purpose: Instruct the UE to set up an RRC connection inan inter-frequency neighboring cell with better signal
quality
Algorithm switch: DrSwitch-DR_ RRC_DRD_SWITCH
Target cell: same-coverage inter-frequency neighboring
cells, which quality is large than threshold:
Parameters of RRC DRD
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Parameters of RRC DRD
DRDEcN0Threshhold Parameter name: Drd Ec/N0 threshold
Recommended value: -18, namely -18dB
RRC Redirection after DRD Failure
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RRC Redirection after DRD Failure
Algorithm switch: DrSwitch-DR_ RRC_DRD_SWITCH
ConnectFailRrcRedirSwitch
Target cell: inter-frequency neighboring cells or inter-RATneighboring cells
Parameters of IAC RRC
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Redirection
ConnectFailRrcRedirSwitch Parameter name: RRC redirect switch
Recommended value: Only_To_Inter_Frequency
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IAC - RAB DRD
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IAC - RAB DRD
Purpose
Select a suitable cell for a UE to access according to the HSPA+
technological satisfaction, service priority, and cell load
Scenario
RAB setup
RAB modification
DCCC channel reconfiguration
Non-periodic DRD:
Inter-frequency DRD Inter-RAT DRD.
Contents
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Contents
2. Load Control Algorithms
2.4 IAC (Intelligent Access Control)
2.4.1 IAC During RRC Connection Setup
2.4.2 Directed Retry Decision During RAB Procedure
2.4.3 Rate Negotiation at Admission Control
2.4.4 Admission Decision
2.4.5 Preemption
2.4.6 Queuing
2.4.7 Low-Rate Access of the PS BE Service
2.4.8 IAC for Emergency Calls
IAC - Rate Negotiation
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IAC Rate Negotiation
Rate negotiation includes: PS MBR negotiation
PS GBR negotiation
Initial rate negotiation
Target rate negotiation
PS MBR Negotiation
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PS MBR Negotiation
If the IE "Alternative RAB Parameter Values" is present inthe RANAP RAB ASSIGNMENT REQUEST or the
RELOCATION REQUEST message when a PS service is set
up, reconfigured, or handed over, then the RNC and the
CN negotiate the rate according to the UE capability to
obtain the MBR while ensuring a proper QoS
Parameters of PS MBR
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Negotiation PsSwitch-PS_STREAM_IU_QOS_NEG_SWITCH
Parameter name: PS rate negotiation switch for Streaming service
Recommended value: OFF
PsSwitch-PS_ BE_IU_QOS_NEG_SWITCH
Parameter name: PS rate negotiation switch for BE service
Recommended value: OFF
PsSwitch-PS_BE_STRICT_IU_QOS_NEG_SWITCH
Parameter name: PS rate negotiation switch for strict BE service
Recommended value: OFF
PS GBR Negotiation
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PS GBR Negotiation
During the setup, reconfiguration, or handover of a real-time PS service, if the RAB assignment message carries
multiple alternative GBRs and
PS_STREAM_IU_QOS_NEG_SWITCHsubparameter of the
PsSwitchparameter is set to 1, the RNC selects the
maximum rate as the GBR of this RAB and sends it to the
CN
Initial Rate Negotiation
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Initial Rate Negotiation
For a BE service in the PS domain, the RNC selects an initial rate to
allocate bandwidth for the service before the admission request based
on cell resources in the following cases:
A service is set up
The UE state changes from CELL_FACH to CELL_DCH
Purpose: Enable UE admission at an appropriate rate based on the
service requested by the UE and the signal quality of the cell
The negotiation is based on the cell load information, which includes:
Uplink and downlink radio bearer status of the cell
Minimum spreading factor (SF) supported
HSPA capability
Initial Rate Negotiation (Cont )
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Initial Rate Negotiation (Cont.)
DCCCSwitch
PS BE Initial Rate DynamicConfiguration Switch
Actual Initial Rate
ON ON
In the uplink, the initial rate is the smaller oneof the MBR and 384 kbit/s.In the downlink, the initial rate is dynamicallyset on the basis of Ec/N0.
ON OFF
In the uplink, the initial rate is the smaller oneof the MBR and the initial rate of the uplink BEservice (UlBeTraffInitBitrate).In the downlink, the initial rate is the smallerone of the MBR and the initial rate of the
downlink BE service (DlBeTraffInitBitrate)OFF - MBR
Initial rate definition for DCH services:
Parameters of Initial Rate Negotiation
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Parameters of Initial Rate Negotiation
DraSwitch-DRA_DCCC_SWITCH Parameter name: Dynamic resource allocation switch for
DCCC
Recommended value: ON
PsSwitch-PS_BE_INIT_RATE_DYNAMIC_CFG_SWITCH
Parameter name: PS rate negotiation switch for initial rate
reconfiguration
Recommended value: OFF
Parameters of Initial Rate Negotiation
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Parameters of Initial Rate Negotiation
EcN0EffectTime
Parameter name: Ec/N0 effective time
Recommended value: 30000, namely 30000ms
EcN0Ths
Parameter name: Ec/N0 threshold
Recommended value: 41, namely -4dB
DlBeTraffInitBitrate
Parameter name: DL BE traffic Initial bit rate
Recommended value: D64, namely 64kbit/s
Initial Rate Negotiation (Cont.)
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Initial Rate Negotiation (Cont.)
Initial rate of HSDPA services: GBR
Initial rate definition for HSPA services:
If the DRA_HSUPA_DCCC_SWITCHsubparameter of the
DraSwitchparameter is set to 1, the actual initial rate is the
initial rate of the HSUPA BE service (HsupaInitialRate).
If the DRA_HSUPA_DCCC_SWITCHsubparameter of the
DraSwitchparameter is set to 0, the actual initial rate is the
MBR.
Parameters of Initial Rate Negotiation
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a a ete s o t a ate egot at o
DraSwitch-DRA_HSUPA_DCCC_SWITCH
Parameter name: Dynamic resource allocation switch for
HSUPA DCCC
Recommended value: ON
HsupaInitialRate
Parameter name: Initial rate of HSUPA BE traffic
Recommended value: D256, namely 256kbit/s
Target Rate Negotiation
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Target Rate Negotiation
For a BE service in the PS domain, if the cell resource-
based admission at the initial rate fails, the RNC selects a
target rate to allocate bandwidth for the service based
on cell resource in following cases:
Service setup
Soft handover
DCCC rate upsizing
Contents
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Contents
2. Load Control Algorithms
2.4 IAC (Intelligent Access Control)
2.4.1 IAC During RRC Connection Setup
2.4.2 Directed Retry Decision During RAB Procedure
2.4.3 Rate Negotiation at Admission Control
2.4.4 Admission Decision
2.4.5 Preemption
2.4.6 Queuing2.4.7 Low-Rate Access of the PS BE Service
2.4.8 IAC for Emergency Calls
Admission Decision
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After rate negotiation, RNC makes admission decision.
The admission decision performed by CAC is based on
resources, such as code resources, power resources,
NodeB credits, and Iub resources
If the admission is successful, UE access is granted.
Otherwise, the RNC performs the next step
Contents
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2. Load Control Algorithms
2.4 IAC (Intelligent Access Control)
2.4.1 IAC During RRC Connection Setup
2.4.2 Directed Retry Decision During RAB Procedure
2.4.3 Rate Negotiation at Admission Control
2.4.4 Admission Decision
2.4.5 Preemption
2.4.6 Queuing2.4.7 Low-Rate Access of the PS BE Service
2.4.8 IAC for Emergency Calls
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Preemption Procedure
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p
1. The RNC selects the target cell for preemption
For non-DC-HSDPA services: the RNC selects a suitable cell
according to the settings of the DRD functions
For DC-HSDPA services: the RNC selects the two cells in the
DC-HSDPA cell group as the target cell
Preemption Procedure
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p
2. The RNC selects a service for preemption
3. The preemption algorithm determines the radio link
sets to be preempted
a. Selects SRNC users first. If no user under the SRNC is
available, the algorithm selects users under the DRNC.
b. Sorts the preemptable users by user integrated priority,
or sorts the preemptable RABs by RAB integrated priority.
c. Determines candidate users or RABs
Parameters of Preemption
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p
PreemptAlgoSwitch
Parameter name: Preempt algorithm switch
Recommended value: OFF
Contents
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2. Load Control Algorithms
2.4 IAC (Intelligent Access Control)
2.4.1 IAC During RRC Connection Setup
2.4.2 Directed Retry Decision During RAB Procedure
2.4.3 Rate Negotiation at Admission Control
2.4.4 Admission Decision
2.4.5 Preemption
2.4.6 Queuing
2.4.7 Low-Rate Access of the PS BE Service
2.4.8 IAC for Emergency Calls
IAC - Queuing
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g
For PS services, after preemption fails, the RNC performs
queuing if the following conditions are met:
The RNC receives a RAB ASSIGNMENT REQUEST message
indicating that queuing is supported
The queuing algorithm switch (QueueAlgoSwitch) is set to
ON
The queuing function is triggered by the heartbeat timer
that is set by the PollTimerLenparameter. Each time the
timer expires, the RNC selects the service that meets the
requirement to make an admission attempt
Parameters of Queuing
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g
QueueAlgoSwitch
Parameter name: Queue algorithm switch
Recommended value: OFF
MaxQueueTimeLen
Parameter name: Max queuing time length
Recommended value: 5, namely 5s
Contents
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2. Load Control Algorithms
2.4 IAC (Intelligent Access Control)
2.4.1 IAC During RRC Connection Setup
2.4.2 Directed Retry Decision During RAB Procedure
2.4.3 Rate Negotiation at Admission Control
2.4.4 Admission Decision
2.4.5 Preemption
2.4.6 Queuing
2.4.7 Low-Rate Access of the PS BE Service
2.4.8 IAC for Emergency Calls
IAC - Low-Rate Access of the PS BE
Service
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Service
Low-rate access means access from the DCH at 0 kbit/s,
FACH, or enhanced FACH (E-FACH)
Low-rate access is used in the following scenarios:
RAB setup
Hard handover or SRNS relocation
Parameters of Low-Rate Access of the
PS BE Service
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PS BE Service
PsSwitch-PS_BE_EXTRA_LOW_RATE_ACCESS_SWITCH
Parameter name: PS rate negotiation switch for low rate
access
Recommended value: OFF
ZeroRateUpFailToRelTimerLen
Parameter name: Release 0 kbit/s Timer length for failed to
rate up
Recommended value: 180, namely 180s
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2. Load Control Algorithms
2.4 IAC (Intelligent Access Control)
2.4.1 IAC During RRC Connection Setup
2.4.2 Directed Retry Decision During RAB Procedure
2.4.3 Rate Negotiation at Admission Control
2.4.4 Admission Decision
2.4.5 Preemption
2.4.6 Queuing
2.4.7 Low-Rate Access of the PS BE Service
2.4.8 IAC for Emergency Calls
IAC for Emergency Calls
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RRC connection setup process of emergency calls:
No admission on power resource
Admission is successful if the current remaining hard
resources are sufficient
If the hard resource admission failspreemption is
performed regardless of the preemption switch
RRC connection
setup request
Admission
algorithmPreemption DRD Redirection
RAB process
Fails
Succeeds
Fails Fails
Succeeds Succeeds
IAC for Emergency Calls (Cont.)
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RAB Admission of Emergency Calls :
For power resource admission:
When EMC_UU_ADCTRLis on, power admission fails if the
system is in overload. Otherwise, the admission succeeds
If the CAC algorithm switch is off, the emergency calls are directly
admitted
Admission is successful if the current remaining hard
resources are sufficient
IAC for Emergency Calls (Cont.)
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Preemption of Emergency Calls
If cell resource-based admission fails, preemption is
performed regardless of whether the preempt function is
enabled or not.
If EmcPreeRefVulnSwitchis set to ON, all non-emergency
users that have accessed the network can be preempted,
regardless of the preemption-prohibited attribute of the
users.
If EmcPreeRefVulnSwitchis set to OFF, only the non-
emergency users with preemption-allowed attribute can be
preempted.
Parameters of IAC for Emergency Calls
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EmcPreeRefVulnSwitch
Parameter name: Preemptvulnerability for Emergency call
switch
Recommended value: ON
NBMCacAlgoSwitch-EMC_UU_ADCTRL
Parameter name: Cell CAC algorithm switch for UU resource
of emergency call
Recommended value: ON
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2. Load Control Algorithms
2.1 PUC (Potential User Control)
2.2 LDB (Intra-Frequency Load Balancing)
2.3 CAC (Call Admission Control)
2.4 IAC (Intelligent Access Control)
2.5 LDR (Load Reshuffling)
2.6 OLC (Overload Control)
Contents
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2. Load Control Algorithms
2.5 LDR (Load Reshuffling)
2.5.1 Basic Congestion Triggering
2.5.2 LDR Procedure
2.5.3 LDR Actions
LCC (Load Congestion Control)
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Overload state: OLC
Load
THLDR
THOLC
100%
section A
section B
section C Normal state
Basic congestion state: LDR
LDR Principle
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Reason:
When the cell is in basic congestion state, new coming calls
could be easily rejected by system
Purpose:
Optimizing cell resource distribution
Decreasing load level, increasing admission successful rate
Triggering:
Power, code, Iub or NodeB credit
LDR Triggering - Power Resource
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Hysteresis time: 1000ms
UL/DL load
Cell in the basic congestionstate
Basic congestionrelieved
RNC periodic check
LDR trigger
threshold
LDR release
threshold
Time
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LDR Triggering - Code Resource
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Congestion control based on code resource can be
enabled through the CELL_CODE_LDRsubparameter of
the NBMLdcAlgoSwitchparameter
If the SF corresponding to the current remaining code of
the cell is larger than the value of CellLdrSfResThd, code
congestion is triggered and the related load reshuffling
actions are taken
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LDR Triggering - Iub Resource
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Congestion control based on Iub resource can be enabled
through the IUB_LDRsubparameter of the
NodeBLdcAlgoSwitchparameter
Iub congestion control in both the uplink and downlink is
NodeB-oriented. So for the basic congestion caused by
Iub resource, all UEs under the NodeB are the objects of
related LDR actions
Parameters of LDR (Cont.)
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NodeBLdcAlgoSwitch-IUB_LDR
Parameter name: NodeB LDC algorithm switch for LDR
Recommended value: OFF
LDR Triggering NodeB Credit
Resource
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esou ce
The basic congestion caused by NodeB credit resource is
of the following types:
Type A: Basic congestion at local cell level
Type B: Basic congestion at local cell group level (if any)
Type C: Basic congestion at NodeB level
Parameters of LDR (Cont.)
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Parameter Parameter name Recommended value
Type A:
CELL_CREDIT_LDRCell LDC algorithm switch for LDR OFF
Type A:
UlLdrCreditSfResThdUL LDR credit SF reserved threshold SF8
Type A:
DlLdrCreditSfResThd
DL LDR credit SF reserved threshold SF8
Type B:
LCG_CREDIT_LDR
NodeB LDC algorithm switch for
LDROFF
Type C:
NODEB_CREDIT_LDR
NodeB LDC algorithm switch for
LDROFF
Type B/C:
UlLdrCreditSfResThdUL LDR credit SF reserved threshold SF8
Type B/C:
DlLdrCreditSfResThdDL LDR credit SF reserved threshold SF8
Parameters of LDR (Cont.)
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If the congestion of all resources is triggered in a cell, the
congestion is relieved in order of resource priority for load
reshuffling as configured through the SET ULDCALGOPARA
command
Recommended setting is as follows:
The first priority for load reshuffling (LdrFirstPri) is set to IUBLDR
The second priority for load reshuffling (LdrSecondPri) is set to
CREDITLDR
The third priority for load reshuffling (LdrThirdPri) is set to
CODELDR
The fourth priority for load reshuffling (LdrFourthPri) is set to
UULDR
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2. Load Control Algorithms
2.5 LDR (Load Reshuffling)
2.5.1 Basic Congestion Triggering
2.5.2 LDR Procedure
2.5.3 LDR Actions
LDR Procedure
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The RNC periodically takes actions if the basic congestion
is detected:
Inter-frequency load handover
Code reshuffling
BE service rate reduction AMR rate reduction
Inter-RAT load handover in the CS domain
Inter-RAT load handover in the PS domain
QoS Renegotiation for Uncontrollable Real-Time Services
LDR Procedure
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LDR Actions Intended for Different
Resources
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When the basic congestion is triggered by different
resources, the congestion can be relieved in a order set
by running the SET ULDCALGOPARAcommand
LDR actions intended for different resource table (See the
notes)
Parameters of LDR (Cont.)
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LdrPeriodTimerLen
Parameter name: LDR period timer length
Recommended value: 10, namely 10s
GoldUserLoadControlSwitch
Parameter name: Gold user load control switch
Recommended value: OFF
Parameters of LDR (Cont.)
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DlLdrFirstActionto DlLdrTenthAction
Parameter name: DL LDR first action to DL LDR tenth action
Recommended value: CodeAdj, InterFreqLDHO, BERateRed
UlLdrFirstActionto UlLdrEighthAction
Parameter name: UL LDR first action to UL LDR eighth
action
Recommended value: InterFreqLDHO, BERateRed
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2. Load Control Algorithms
2.5 LDR (Load Reshuffling)
2.5.1 Basic Congestion Triggering
2.5.2 LDR Procedure
2.5.3 LDR Actions
LDR Actions - Inter-Frequency Load
Handover
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Inter-Frequency Load Handover
Based on Blind Handover
Based on Measurement
InterFreqLDHOMethodSelection
Parameter name: InterFreq Load Handover Method
Selection
Recommended value: BLINDHO
LDR Actions - Inter-Frequency Load
Handover
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Inter-Frequency Load Handover Based on Blind Handover
1. Check whether cells for inter-frequency blind handover are
available. If available, go to the next step. Otherwise, the action
fails
2. The algorithm selects the target cell according to the type of
resource that causes the basic congestion:
the basic congestion is caused by power resource
the basic congestion is caused by code resource
3. The algorithm selects the UEs to be handed over according tothe setting of InterFreqLdHoForbidenTC and NbmLdcUeSelSwitch
LDR Actions - Inter-Frequency Load
Handover
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Inter-Frequency Load Handover Based on Measurement: Only for
power congestion
1. The RNC selects the UE whose service types are not forbidden for LDR
handover by parameterInterFreqLdHoForbidenTC
2. The RNC selects the candidate cells
3. The RNC issues a measurement control message to the UE, requesting
the UE to measure the signal quality of all candidate cells
4. The UE measures the RSCP and Ec/No of the candidate cells and
periodically reports the measurement results to the RNC
5. Based on the received measurement results, the RNC selects the
candidate target cells
6. The RNC selects the cell with the highest priority from the candidate
target cells to perform inter-frequency hard handover
Parameters of LDR (Cont.)
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InterFreqLdHoForbidenTC
Parameter name: Forbidden Traffic Class for inter-freq HO
Recommended value: None
NbmLdcUeSelSwitch
Parameter name: Inter-freq Handover Select User algorithm
switch
Recommended value: NBM_LDC_MATCH_UE_ONLY
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Parameters of LDR (Cont.)
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UlInterFreqHoBWThd/DlInterFreqHoBWThd
Parameter name: UL/DL HO maximum bandwidth
Recommended value: 200000bit/s, 200000bit/s
LDR Actions - BE Rate Reduction
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Target RAB:
The RAB with the lowest integrated priority
The current rate is higher than GBR
Number:
UlLdrBERateReductionRabNum/DlLdrBERateReductionRabNum
The RNC sends a RADIO BEARER RECONFIGURATION
message to the UE
Parameters of LDR (Cont.)
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UlLdrBERateReductionRabNum/DlLdrBERateReductionRa
bNum
Parameter name: UL/DL LDR-BE rate reduction RAB number
Recommended value: 1, 1
LDR Actions - QoS Renegotiation
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QoS renegotiation function switch:
DRA_IU_QOS_RENEG_SWITCH
Target RAB:
The RAB with the lowest integrated priority
Number:
UlLdrPsRTQosRenegRabNum/DlLdrPsRTQosRenegRabNum
The RNC sends a RAB MODIFY REQUEST message to the
CN
Parameters of LDR (Cont.)
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DraSwitch-DRA_IU_QOS_RENEG_SWITCH
Parameter name: Dynamic resource allocation switch for IU
QoS RENEQ
Recommended value: OFF
UlLdrPsRTQosRenegRabNum/DlLdrPsRTQosRenegRabNu
m
Parameter name: UL/DL LDR un-ctrl RT Qos re-nego RAB
num
Recommended value: 1, 1
LDR Actions - Inter-RAT Handover
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Target user:
The user with the lowest integrated priority
Service handover indicator:
HO_TO_GSM_SHOULD_BE_PERFORM
HO_TO_GSM_SHOULD_NOT_BE_PERFORM
WCDMA cell
GSM cell
Parameters of LDR (Cont.)
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Parameter Parameter nameRecommended
value
UlCSInterRatShouldBeHOUeNum UL CS should be HO user number 3
DlCSInterRatShouldBeHOUeNum DL CS should be HO user number 3
UlCSInterRatShouldNotHOUeNumUL CS should not be HO user
number3
DlCSInterRatShouldNotHOUeNumDL CS should not be HO user
number3
UlPSInterRatShouldBeHOUeNum UL PS should be HO user number 1
DlPSInterRatShouldBeHOUeNum DL PS should be HO user number 1
UlPSInterRatShouldNotHOUeNumUL PS should not be HO usernumber
1
DlPSInterRatShouldNotHOUeNumDL PS should not be HO usernumber
1
LDR Actions - AMR Rate Reduction
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Target RAB:
The RAB with the lowest integrated priority
Number:
UlLdrAMRRateReductionRabNum/DlLdrAMRRateReductionRabNum
In downlink:
The RNC sends the Rate Control Request message through the Iu
interface to the CN
In uplink:
The RNC sends the TFC CONTROL command to the UE
Parameters of LDR (Cont.)
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UlLdrAMRRateReductionRabNum/DlLdrAMRRateReductio
nRabNum
Parameter name: UL/DL LDR-AMR rate reduction RAB
number
Recommended value: 1, 1
LDR Actions - Code Reshuffling
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Parameters of LDR (Cont.)
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CellLdrSfResThd
Parameter name: Cell LDR SF reserved threshold
Recommended value: SF8
MaxUserNumCodeAdj
Parameter name: Max user number of code adjust
Recommended value: 1
LdrCodePriUseInd
Parameter name: LDR code priority indicator
Recommended value: FALSE
Contents
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2. Load Control Algorithms
2.1 PUC (Potential User Control)
2.2 LDB (Intra-Frequency Load Balancing)
2.3 CAC (Call Admission Control)
2.4 IAC (Intelligent Access Control)
2.5 LDR (Load Reshuffling)
2.6 OLC (Overload Control)
Contents
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2. Load Control Algorithms
2.6 OLC (Overload Control)
2.6.1 Overload Triggering
2.6.2 General OLC Procedure
2.6.3 OLC Actions
OLC Principle
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Reason:
In overload congestion state, the system is not stable
Purpose:
Ensuring the system stability and making the system back to
the normal state as soon as possible
Triggering:
Power resource and interference
OLC Load Judgment
/ l d
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State transition hysteresis threshold
UL/DL load
Cell in overloadOverload released
RNC periodic check
OLC trigger
threshold
OLC release
threshold
time
Parameters of OLC
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NBMLdcAlgoSwitch-UL_UU_OLC/DL_UU_OLC
Parameter name: Cell LDC algorithm switch for OLC
Recommended value: OFF, OFF
UlOlcTrigThd/DlOlcTrigThd
Parameter name: UL/DL OLC trigger threshold Recommended value: 95%, 95%
UlOlcRelThd/DlOlcRelThd
Parameter name: UL/DL OLC release threshold
Recommended value: 85%, 85%
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2. Load Control Algorithms
2.6 OLC (Overload Control)
2.6.1 Overload Triggering
2.6.2 General OLC Procedure
2.6.3 OLC Actions
OLC Procedure
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Parameters of OLC (Cont.)
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OlcPeriodTimerLen
Parameter name: OLC period timer length
Recommended value: 3000, namely 3000ms
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2. Load Control Algorithms
2.6 OLC (Overload Control)
2.6.1 Overload Triggering
2.6.2 General OLC Procedure
2.6.3 OLC Actions
OLC Actions - Performing TF Control of
BE ServicesOLC l ith f TF t l i th d li k
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OLC algorithm for TF control in the downlink:
Select RABs with the lowest integrated priority
The RNC sends the TF control indication message to the MAC
The MAC restricts the TFC selection: TFmax(N+1) = TFmax(N) x
Ratelimitcoeff
OLC algorithm for TF control in the uplink:
Select RABs with the lowest integrated priority
the RNC sends a TRANSPORT FORMAT COMBINATION CONTROL
message to the UE
The UE restricts the TFC selection
Example of TF Control
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Parameters of OLC (Cont.)
DlD R t Thd
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DlDcccRateThd
Parameter name: Downlink Bit Rate Threshold For DCCC
Recommended value: D64, namely 64Kbit/s
DlOlcFTFRstrctRabNum
Parameter name: DL OLC fast TF restrict RAB number
Recommended value: 3
DlOlcFTFRstrctTimes
Parameter name: DL OLC fast TF restrict times
Recommended value: 3, namely 3 times
Parameters of OLC (Cont.)
i i
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RateRstrctTimerLen/RateRecoverTimerLen
Parameter name: DL TF rate restrict/recover timer length
Recommended value: 3000ms, 5000ms
RateRstrctCoef/RecoverCoef
Parameter name: DL TF rate restrict/recover coefficient
Recommended value: 68%, 130%
Parameters of OLC (Cont.)
UlD R t Thd
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UlDcccRateThd
Parameter name: Uplink Bit Rate Threshold For DCCC
Recommended value: D64, namely 64Kbit/s
UlOlcFTFRstrctRabNum
Parameter name: UL OLC fast TF restrict RAB number
Recommended value: 3
UlOlcFTFRstrctTimes
Parameter name: UL OLC fast TF restrict times
Recommended value: 3, namely 3 times
OLC Actions - Switching BE Services
to Common Channels
T t
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Target user:
Select users with the lowest integrated priority
The users with the DCH or HSPA BE services in PS domain
Execution:
The RNC sends RB Reconfiguration message to UE
The UE makes a response by RB Reconfiguration Complete
Parameters of OLC (Cont.)
T C hU N
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TransCchUserNum
Parameter name: Transfer Common Channel User number
Recommended value: 1
OLC Actions - Adjusting the Maximum
FACH TX Power
T t FACH h l
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Target FACH channel:
During an OLC period, the OLC can adjust the power of only
one FACH. If multiple FACHs meet the conditions, the OLC
adjusts them one by one in different OLC periods
Execution:
The cell adjusts the maximum FACH TX power:
arg maxt etP P Delta
Parameters of OLC (Cont.)
M F hP
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C