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WCDMA Load Control Algorithm and Parameters
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The WCDMA system is a self-interfering system. As the load of the system increases,
the interference rises. A relatively high interference can affect the coverage and QoS
of established services. Therefore, the capacity, coverage, and QoS of the WCDMAsystem are mutually affected.
Through the control of key resources, such as power, downlink channelization codes,
channel elements (CEs), Iub transmission resources, which directly affect user
experience, load control aims to maximize the system capacity while ensuring
coverage and QoS.
In addition, load control provides differentiated services for users with different
priorities. For example, when the system resources are insufficient, procedures such
as direct admission, preemption, redirection can be performed to ensure the
successful access of emergency calls to the network.
Load control is implemented in the RNC through measurement reports from theNodeBs.
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WCDMA network load can be defined by four factors:
Power, includes DL transmitting power of cell and increased UL interference
(RTWP)
DL OVSF code of a cell.
DL and UL NodeB processing capability which is defined by NodeB credit.
Iub transmission bandwidth of a NodeB.
The power resource is related to the mobility, distribution of the UE and also effected
by the radio conditions. Therefore, for a fixed power resource, the numbers of service
can be supported is not a fix result. We believe the UL and DL power resources are
soft.
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In addition, functional load control algorithms vary depending on the load levels of the
cell, as shown in the following figure:
Start PUC: enable UEs in idle mode to camp on cells with light load
Start IAC: increase the access rate in cells with
heavy load by some actions while ensuring the QoS
Start LDR: check and relieve basic congestion in cells
NodeB TX
power (noise)
Cell load (number of subscribers)
Start OLC: check and relieve overload
congestion in cells
Icons for different load levels
Load control
is unneeded
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The load control functions, such as OLC and CAC, use load measurement values in
the uplink and the downlink. A common Load Measurement (LDM) function is used to
control load measurement in the uplink and the downlink separately.
Load measurement is implemented by the NodeB. The filtering of measurement
quantities is implemented by the NodeB and the RNC.
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The NodeB measures the major quantities related to load control. After layer 3
filtering, the measurement values are reported to the RNC.
The RNC performs smooth filtering on the measurement values reported from the
NodeB and then obtains the measurement values, which further serve as data input
for the load control algorithms.
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Layer 1 filtering is not standardized by protocols and it depends on vendor equipment.
Layer 3 filtering is standardized. The filtering effect is controlled by a higher layer. The
alpha filtering that applies to layer 3 filtering is calculated according to the followingformula:
Here:
Fn is the new post-filtering measurement value.
Fn-1 is the last post-filtering measurement value.
Mn is the new measurement value from the physical layer.
= (1/2)k/2, where k is specified by the UlBasicCommMeasFilterCoeff orDlBasicCommMeasFilterCoeffparameter.
Set the above parameters through SET ULDM.
PBR measurement does not use alpha filtering on the NodeB side.
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Set the above parameters through SET ULDM.
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LDM must apply different smooth filter coefficients and measurement periods to PUC,
CAC, LDR, and OLC so as to obtain appropriate filtered values.
The following table lists the smooth window length parameters for setting different
functions:
GBP measurements have the same smooth window length in all related functions.
The filter length for GBP measurement is specified by the HsdpaNeedPwrFilterLen
parameter.
The length of the PBR smooth filter window is specified by the
HsdpaPrvidBitRateFilterLen / HsupaPrvidBitRateFilterLen parameter.Set the
above parameters through SET ULDM.
Function Smooth Window Length Parameter
PUC PucAvgFilterLen
CACUlCacAvgFilterLen
DlCacAvgFilterLen
LDB LdbAvgFilterLen
LDR UlLdrAvgFilterLenDlLdrAvgFilterLen
OLC UlOlcAvgFilterLen
DlOlcAvgFilterLen
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User priority: mainly applying to provide different QoS for different users. Eg., setting
different GBR according to the user priority for BE service. No consideration about the
service.
RAB integrated priority: priority of a service, related to the service type, and the user
priority of the user.
User integrated priority: only used for multi-RAB user, it is a temporary priority of an
ongoing-service user.
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In CN HLR, operator can set ARP (Allocation Retention Priority ). During service
setup, CN sends ARP to RNC. Based on the mapping relation (configured in RNC),
RNC can identify the users priority, namely gold, silver or copper one.
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User priorities are adopted to provide differentiated services for users. For ease of
application, the RNC maps the 15 levels of Allocation/Retention Priority (ARP) that is
carried in the RAB ASSIGNMENT REQUEST message from the core network (CN)onto three user priorities, that is, gold (high priority), silver (medium priority), and
copper (low priority). The relation between user priority and ARP can be set through
SET UUSERPRIORITY command.
ARP 15 is always the lowest priority and is not configurable. It corresponds to lowest
user priority (copper user).
If ARP is not received in messages from the Iu interface, the user priority is regarded
as copper.
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The priority of a RAB is determined by its traffic class, ARP, and carrier type. Such a priority is
called RAB integrated priority. When resources are insufficient, services with the highest
integrated priority are preferentially processed. The values of RAB integrated priority are set according to the integrated priority configuration
reference parameter (PriorityReference):
If PriorityReference is set to Traffic Class, the integrated priority abides by the
following rules:
Traffic classes: conversational > streaming > interactive > background
Services of the same traffic class: priority based on ARP, that is, ARP1 >
ARP2 > ARP3 > ... > ARP14 > ARP15
Service of the same traffic class and ARP (only for interactive services):
priority based on Traffic Handling Priority (THP) that is carried in the RAB
ASSIGNMENT REQUEST message, that is, THP1 > THP2 > THP3 > ... >
THP14 > THP15
Services of the same traffic class, ARP and THP (only for interactive services):
High Speed Packet Access (HSPA) or Dedicated Channel (DCH) service
preferred depending on CarrierTypePriorInd.
If PriorityReference is set to ARP, the integrated priority abides by the following rules:
ARP: ARP1 > ARP2 > ARP3 > ... > ARP14 >ARP15
Services of the same ARP: priority based on traffic classes, that is,
conversational > streaming > interactive > background
Only for the interactive service of the same ARP value: priority based onTraffic Handling Priority (THP), that is, THP1 > THP2 > THP3 > ... > THP14 >
THP15
Services of the same ARP, traffic class and THP (only for interactive services):
HSPA or DCH service preferred depending on CarrierTypePriorInd.
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This example shows the RAB integrated priority calculation in 2 different conditions.
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A user may have multiple RABs, and the RABs may have different priorities. In this
case, the highest priority is taken as the priority of this user. Such a priority is called
user integrated priority. User integrated priority is used in user-specific load control.For example, the selection of R99 users during preemption, the selection of users
during inter-frequency load handover for LDR, and the selection of users during
switching of BE services to common channels are performed according to the user
integrated priority.
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Prior i tyReference
Content: Reference used to determine which priority is arranged first in the
priority sequence. If the ARP is preferably used, the priority sequence is gold >
silver > copper. If the ARPs are all the same, the TrafficClass is used and the
priority sequence is conversational > streaming > interactive > background.
If the TrafficClass is preferably used, the priority sequence is conversational >
streaming > interactive > background. If the TrafficClass factors are all the
same, the ARP factor is used and the priority sequence is gold > silver >
copper.
Value range: ARP, TrafficClass
Physical value range: ARP, TrafficClass
CarrierTypePriorInd
Content: Decide which carrier is prior when ARP and TrafficClass are both
identical.
Value range: NONE, DCH, HSPA
Physical value range: NONE, DCH, HSPA
Set these parameters through SET UUSERPRIORITY.
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The Potential User Control (PUC) function controls the cell reselection of a UE that is
in idle mode, or in the CELL_FACH state, CELL_PCH state, or URA_PCH state and
prevents the UE from camping on a heavily loaded cell.
PUC procedure:
Adjust the parameters of the
current cell and neighboring cellsaccording to the load
YesNo
Update and broadcast the system
information of the current cell andneighboring cells
Periodically monitor the load of the
current cell and neighboring cells
Are these
parameters changed?
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The PUC function is enabled only when the PUC subparameter of the
NBMLdcAlgoSwitch parameter is set to 1. Set the NBMLdcAlgoSwitch parameter
through ADD UCELLALGOSWITCH/ MOD UCELLALGOSWITCH.
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The load state of a cell supporting DC-HSDPA is determined based on the following
table:Load of Single
Cell Load of Cell Group Load of Cell Supporting DC-HSDPA
Heavy Heavy, normal, or light Heavy
Heavy, normal, or
light
Heavy Heavy
Normal Normal, or light Normal
Normal, or light Normal Normal
Light Light Light
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Based on the cell load, the PUC works as follows:
If the cell load becomes heavy, the PUC modifies reselection parameters and
broadcasts them through system information. In this way, the PUC leads UEs
to the neighboring cells with light load.
If the cell load becomes normal, the PUC uses the reselection parameters
configured on the RNC LMT.
If the cell load becomes light, the PUC modifies cell reselection parameters
and broadcasts them through system information. In this way, the PUC leads
UEs to this cell.
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The variables related to cell selection and reselection are Qoffset1(s,n) (load level
offset), Qoffset2(s,n) (load level offset), and Sintersearch (start threshold for inter-
frequency cell reselection). The following table describes PUC-related variables and
their impacts on UEs:Item Description
Implementatio
n
The variables related to cell selection and reselection areQoffset1(s,n) (load level offset), Qoffset2(s,n) (load level
offset), and Sintersearch (start threshold for inter-frequency
cell reselection).
The NodeB periodically reports the transmit power of the cell,
and the PUC periodically triggers the following activities:
Assessing the cell load level based on the non-HSPA power
and HS-DSCH GBP
Setting Sintersearch, Qoffset1(s,n), and Qoffset2(s,n) based
on the cell load level
Updating the parameters in system information SIB3 andSIB11
Adjustment
Based on the characteristics of inter-frequency cell selection
and reselection, the UE makes the corresponding adjustments:
Sintersearch
- When this value is increased by the serving cell, the UE
starts inter-frequency cell reselection ahead of schedule.
- When this value is decreased by the serving cell, the UE
delays inter-frequency cell reselection.
Qoffset1(s,n): applies to R (reselection) rule with CPICH
RSCP- When this value is increased by the serving cell, the UE has
a lower probability of selecting a neighboring cell.
- When this value is decreased by the serving cell, the UE has
a higher probability of selecting a neighboring cell.
Qoffset2(s,n): applies to R (reselection) rule with CPICH
Ec/No
- When this value is increased by the serving cell, the UE has
a lower probability of selecting a neighboring cell.
- When this value is decreased by the serving cell, the UE has
a higher probability of selecting a neighboring cell.
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Depending on the load status of the serving cell, the cell reselection parameters are
adjusted up or down or kept unchanged. The setting of Sintersearch is related to the
serving cell:
Load State of the
Serving Cell Sintersearch
Change to
Sintersearch
Light S'intersearch = Sintersearch + OffSinterLight
Normal S'intersearch = Sintersearch
Heavy S'intersearch = Sintersearch + OffSinterHeavy
: indicates that the parameter value remains unchanged.: indicates that the parameter value increases.
: indicates that the parameter value decreases.
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The configurations of Qoffset1 and Qoffset are related to the load of the serving cell
and the load of the neighboring cells:
Load State
of the
Neighboring
Cells
Load State
of the
Serving
Cell
Q'offset1
Change
to
Q'offset1
Q'offset2
Change
to
Q'offset2
Light Light Q'offset1 = Qoffset1 Q'offset2 = Qoffset2
Light Normal Q'offset1 = Qoffset1 Q'offset2 = Qoffset2
Light HeavyQ'offset1 = Qoffset1
+ OffQoffset1Light
Q'offset2 = Qoffset2
+ OffQoffset2Light
Normal Light Q'offset1 = Qoffset1 Q'offset2 = Qoffset2
Normal Normal Q'offset1 = Qoffset1 Q'offset2 = Qoffset2
Normal Heavy
Q'offset1 = Qoffset1
+ OffQoffset1Light
Q'offset2 = Qoffset2
+ OffQoffset2Light
Heavy LightQ'offset1 = Qoffset1
+ OffQoffset1Heavy
Q'offset2 = Qoffset2
+ OffQoffset2Heavy
Heavy NormalQ'offset1 = Qoffset1
+ OffQoffset1Heavy
Q'offset2 = Qoffset2
+ OffQoffset2Heavy
Heavy Heavy Q'offset1 = Qoffset1 Q'offset2 = Qoffset2
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NBMLdcAlgoSwitch-PUC
Content: Potential user control algorithm. Based on the cell load, this algorithm
changes the selection/reselection parameters of a cell to lead the UE to a
lighter loaded cell.
Value range: OFF, ON
Physical value range: 0, 1
Set this parameter through ADD UCELLALGOSWITCH/ MOD
UCELLALGOSWITCH.
SpucHeavy/SpucLight
Content: It is used to decide whether the cell load level is Heavy or Light. It is
denoted by the ratio of NodeB TX power to the maximum TX power.
Value range: 0~100
Physical value range: 0~100; step: 1
Physical unit: %
Set this parameter through ADD UCELLPUC/ MOD UCELLPUC.
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SpucHyst
Content: Hysteresis used to determine the cell load level. It is denoted by the
ratio of NodeB TX power to the maximum TX power. It is used to avoid the
unnecessary ping-pong effect of a cell between two load levels due to tiny
load change.
Value range: 0~100
Physical value range: 0~100; step: 1
Physical unit: %
Set this parameter through ADD UCELLPUC/ MOD UCELLPUC.
PucPer iodTimerLen
Content: Identifying the potential user control period. When the cell load is
high, the cell selection and reselection can be periodically modified in order toenable users in unconnected mode to select other cells more easily, thus
reducing the local cell load.
Value range: 6~86400
Physical value range: 6~86400; step: 1
Physical unit: s
Set this parameter through SET ULDCPERIOD.
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OffSinter ight
Content: Offset of Sintersearch when center cell load level is "Light.
Value range: -10~10
Physical value range: -10~10; step: 2
Physical unit: dB
OffSinterHeavy
Content: Offset of Sintersearch when center cell load level is Heavy.
Value range: -10~10
Physical value range: -10~10; step: 2
Physical unit: dB
Set these parameters through ADD UCELLPUC/ MOD UCELLPUC.
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OffQoffset1Light
Content: Offset of Qoffset1 when neighboring cell load is lighter than that of
the center cell.
Value range: -20~20
Physical value range: -20~20; step: 1
Physical unit: dB
OffSinterHeavy
Content: Offset of Qoffset1 when neighboring cell load is heavier than that of
the center cell.
Value range: -20~20
Physical value range: -20~20; step: 1 Physical unit: dB
Set these parameters through ADD UCELLPUC/ MOD UCELLPUC.
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OffQoffset2Light
Content: Offset of Qoffset2 when neighboring cell load is lighter than that of
the center cell.
Value range: -20~20
Physical value range: -20~20; step: 1
Physical unit: dB
OffQoffset2Heavy
Content: Offset of Qoffset2 when neighboring cell load is heavier than that of
the center cell.
Value range: -20~20
Physical value range: -20~20; step: 1 Physical unit: dB
Set these parameters through ADD UCELLPUC/ MOD UCELLPUC.
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Intra-frequency Load Balancing (LDB) is performed to adjust the coverage areas of
cells according to the measured values of cell load. The intra-frequency LDB function
is applicable only to the downlink.
LDB between intra-frequency cells is implemented by adjusting the transmit power of
the Primary Common Pilot Channel (PCPICH) according to the downlink load of the
associated cells. When the load of a cell increases, the cell reduces its coverage to
lighten its load. When the load of a cell decreases, the cell extends its coverage so
that some traffic is off-loaded from its neighboring cells to it.
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When the intra-frequency LDB function is active, that is, when the
INTRA_FREQUENCY_LDB subparameter of the NBMLdcAlgoSwitch parameter is
set to 1, the RNC checks the load of cells periodically and adjusts the transmit powerof the P-CPICH in the associated cells based on the cell load. Set the
NBMLdcAlgoSwitch parameter through ADD UCELLALGOSWITCH/ MOD
UCELLALGOSWITCH.
The intra-frequency LDB is described as follows:
If the downlink load of a cell is higher than the cell overload threshold
(CellOverrunThd), it is an indication that the cell is heavily overloaded. In this
case, the transmit power of the P-CPICH needs to be reduced step by step.
The step is specified by the PCPICHPowerPace parameter.
If the current transmit power is equal to the minimum transmit power of P-
CPICH (MinPCPICHPower), the current transmit power is not adjusted.
If the downlink load of a cell is lower than the cell underload threshold
(CellUnderrunThd), it is an indication that the cell has sufficient remaining
capacity for more load. In this case, the transmit power of the P-CPICH can be
increased step by step to help lighten the load of neighboring cells. The step is
specified by the PCPICHPowerPace parameter.
If the current transmit power is equal to the maximum transmit power of P-
CPICH (MaxPCPICHPower), the current transmit power is not adjusted.
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NBMLdcAlgoSwitch-INTRA_FREQUENCY_LDB
Content: Intra-frequency load balance algorithm. It is also named cell
breathing algorithm. Based on the cell load, this algorithm changes the pilot
power of the cell to control the load between intra-frequency cells.
Value range: OFF, ON
Physical value range: 0, 1
Set this parameter through ADD UCELLALGOSWITCH/ MOD
UCELLALGOSWITCH.
IntraFreqLdbPer iodTimerLen
Content: Identifying the period of the Intra-frequency load balance algorithm.
When the cell load is high, the cell PCPICH TX power can be periodically
reduced in order to enable users in connected mode to be switched over to
other cells more easily, thus reducing the local cell load.
Value range: 1~86400
Physical value range: 1~86400; step: 1
Physical unit: s
Set this parameter through SET ULDCPERIOD.
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CellOverrunThd
Content: If the cell downlink load exceeds this threshold, the algorithm will decrease the pilot
transmit power of the cell so as to increase the whole system's capacity. This parameter isbased on network planning. When the cell breathing algorithm is activated, if the value is too
small, the physical coverage of the cell is limited so as to avoid cell capacity waste. If the value
is too great, the physical coverage is expanded and interference over other cells is increased.
Value range: 0~100
Physical value range: 0~100; step: 1
Physical unit: %
Cel lUnderrunThd
Content: If the cell downlink load is lower than this threshold, the algorithm will increase the pilot
transmit power of the cell so as to share load of other cells. This parameter is based on network
planning. When the cell breathing algorithm is activated, if the value is too small, the physical
coverage of the cell is limited so as to avoid cell capacity waste. If the value is too great, thephysical coverage is expanded and interference over other cells is increased.
Value range: 0~100
Physical value range: 0~100; step: 1
Physical unit: %
PCPICHPowerPace
Content: Pilot power adjustment step increased or decreased in each increase of the cell
breathing algorithm or decrease of cell pilot. If the value is too great, the cell pilot may change
fiercely, which is easy to lead to user call drops. If the value is too small, the cell pilot may
change smoothly. However, the response speed of the cell breathing algorithm is decreased,
impacting the algorithm performance.
Value range: 0~100
Physical value range: 0~10; step: 0.1
Physical unit: dB
Set these parameters through ADD UCELLLDB/ MOD UCELLLDB.
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PCPICHPower
Content: TX power of the PCPICH in a cell.
Value range: -100~500
Physical value range: -10~50; step: 0.1
Physical unit: dBm
MaxPCPICHPower
Content: Maximum TX power of the PCPICH in a cell.
Value range: -100~500
Physical value range: -10~50; step: 0.1
Physical unit: dBm
MinPCPICHPower
Content: Minimum TX power of the PCPICH in a cell.
Value range: -100~500
Physical value range: -10~50; step: 0.1
Physical unit: dBm
Set these parameters through ADD UPCPICH/ MOD UPCPICHPWR.
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CAC is needed under such scenarios:
RRC connection setup request
RAB admission decision
Handover
Rate reconfiguration
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The admission decision is based on:
Available cell code resource
Available cell power resource
NodeB credits, which are used to measure the channel demodulation
capability of NodeBs
Available Iub transmission bandwidth
Number of HSDPA users (only for HSDPA services)
Number of HSUPA users (only for HSUPA services)
A call can be admitted only when all of these resources are available.
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Code and Iub resource-based admission control are mandatory and can not be disabled. Other
admission control strategies may be enabled/disabled through the RNC command:
The switch of power CAC can be set by ADD UCELLALGOSWITCH/ MODUCELLALGOSWITCH:
Uplink CAC algorithm switch (NBMUlCacAlgoSelSwitch) selects the algorithm
used for power admission in the uplink.
Downlink CAC algorithm switch (NBMDlCacAlgoSelSwitch) selects the
algorithm used for power admission in the downlink.
The switch of NodeB credit CAC can be set by SET UCACALGOSWITCH and ADD
UCELLALGOSWITCH/ MOD UCELLALGOSWITCH:
CAC algorithm switch (CacSwitch) specifies whether to enable or disable the
NodeB level credit CAC algorithm.
Cell CAC algorithm switch (CRD_ADCTRL) specifies whether to enable or
disable the cell level credit CAC algorithm.
The switch of HSDPA user number CAC can be set by ADD UCELLALGOSWITCH/
MOD UCELLALGOSWITCH:
Cell CAC algorithm switch (HSDPA_UU_ADCTRL) specifies whether to
enable or disable the HSDPA user number admission control algorithm.
The switch of HSUPA user number CAC can be set by ADD UCELLALGOSWITCH/
MOD UCELLALGOSWITCH:
Cell CAC algorithm switch (HSUPA_UU_ADCTRL) specifies whether to
enable or disable the HSUPA user number admission control algorithm.
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When a new service attempts to access the network, code resource-based admission
is mandatory.
Code resourcebased admission is implemented as follows:
For RRC connection setup requests, the code resource-based admission is
successful if the current remaining code resource is sufficient for RRC
connection setup.
For handover services, the code resource-based admission is successful if the
current remaining code resource is sufficient for the service.
For other R99 services, the RNC has to ensure that the remaining code does
not exceed the DlHoCeCodeResvSfparameter after admission of the new
service.
For HSDPA services, the reserved codes are shared by all HSDPA services.Therefore, the code resource-based admission is not required.
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DlHoCeCodeResvSf
Content: Some cell resources can be reserved for handover UEs to guarantee
handover success rate and improve access priority of handover services. This
parameter defines the quantity of downlink code and CE resources reserved
for handover. SFOFF refers to that no resources is reserved. SF32 refers to
that a code resource with SF = 32 and its corresponding credit resource are
reserved. The backer position the value is in {SF4, SF8, SF16, SF32, SF64,
SF128, SF256, SFOFF}, the less code and credit resources reserved for
handover UEs. The possibility of rejecting handover UE admissions increases
and performance of UEs cannot be guaranteed. The more frontal position the
value is, the more the possibility of rejecting new UEs is and some idle
resources are wasted.
Value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF Physical value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF
Set this parameter through ADD UCELLCAC/ MOD UCELLCAC.
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The principles of NodeB credit-admission control are similar to those of power-based
admission control, that is, to check in the local cell, local cell group (if any), and
NodeB whether the remaining credit can support the requesting services.
The CE capabilities at the levels of local cell, local cell group, and NodeB are reported
to the RNC through the NBAP_AUDIT_RSP message over the Iub interface.
The CE capability of local cell level indicates the maximum capability in terms
of hardware that can be used in the local cell.
The CE capability of local cell group level indicates the capability obtained
after the license and hardware are taken into consideration.
The CE capability of NodeB level indicates the number of CEs allowed to use
as specified in the license.
For details about local cell, local cell group, and capacity consumption law,refer to the 3GPP TS 25.433.
According to the capacity consumption laws of common and dedicated channels, the
Controlling RNC (CRNC) debits the amount of the credit resource consumed from or
credits the amount to the Capacity Credit (CC) of the local cell (or local cell group, if
any) based on the SF. The specific scenarios are the addition, removal, and
reconfiguration of the common and dedicated channels.
If the UL CC and the DL CC are separate, they are maintained separately in
the local cell or local cell group.
If the UL CC and DL CC are not separate, only the total CC is maintained in
the local cell or local cell group.
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For the DCH service, the RNC uses the MBR to calculate the SF and searches the
following table for the number of consumed CEs.
Direction Rate
(kbit/s)
SF Number of CEs
Consumed
Corresponding Credits
Consumed
UL 3.4 256 1 2
13.6 64 1 2
8 64 1 2
16 64 1 2
32 32 1.5 3
64 16 3 6
128 8 5 10
144 8 5 10
256 4 10 20
384 4 10 20
DL 3.4 256 1 1
13.6 128 1 1
8 128 1 1
16 128 1 1
32 64 1 1
64 32 2 2
128 16 4 4
144 16 4 4
256 8 8 8
384 8 8 8
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For the HSUPA service,
If the NodeB reports through its private interface that the dynamic CE function
of the cell is enabled, the RNC uses the GBR to calculate the SF.
If the NodeB reports that the dynamic CE function is disabled, the RNC uses
the MBR to calculate the SF. If the NodeB does not report whether the dynamic CE function is enabled, the
RNC determines whether to use the GBR or MBR to calculate the spreading
factor, based on the value of HsupaCeConsumeSelection.
Direction Rate
(kbit/s)
SF Number of CEs
Consumed
Corresponding Credits
Consumed
UL 8 64 1 2
16 64 1 2
32 32 1 2
64 32 1 2
128 16 2 4
144 16 2 4
256 8 4 8
384 4 8 16
608 4 8 16
1450 2SF4 16 32
2048 2SF2 32 64
2890 2SF2 32 64
5760 2SF2+2SF4 48 96
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When a new service tries to access the network, the admission decision based on
NodeB credit is implemented as follows:
For an RRC connection setup request, the credit resource-based admission is
successful if the current remaining credit resources of the local cell, local cell
group (if any), and NodeB are sufficient for RRC connection setup.
For a handover service, the credit resource-based admission is successful if
the current remaining credit resources of the local cell, local cell group (if any),
and NodeB are sufficient for the service.
For other services, the RNC has to ensure that the remaining credit of the
local cell, local cell group (if any), and NodeB does not exceed the value of
UlHoCeResvSf(for the uplink) or DlHoCeCodeResvSf(for the downlink) after
admission of the new services.
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UlHoCeResvSf
Content: Uplink Credit Reserved by Spread Factor for HandOver. SFOFF means that none ofthem are reserved for handover. If the UL spare resource cant satisfy the reserved resourceafter the access of a new service, the service will be rejected. If the value is too high, the creditresource reserved for handover UEs will be less, leading to the increased possibility of rejectinghandover UE admissions, and performance of handover UEs cannot be guaranteed. If the valueis too low, the possibility of rejecting new UEs may increase and some idle resources arewasted.
Value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF
Physical value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF
Set this parameter through ADD UCELLCAC/ MOD UCELLCAC.
DlHoCeCodeResvSf
Content: Some cell resources can be reserved for handover UEs to guarantee handoversuccess rate and improve access priority of handover services. This parameter defines thequantity of downlink code and CE resources reserved for handover. SFOFF refers to that no
resources is reserved. SF32 refers to that a code resource with SF = 32 and its correspondingcredit resource are reserved. The backer position the value is in {SF4, SF8, SF16, SF32, SF64,SF128, SF256, SFOFF}, the less code and credit resources reserved for handover UEs. Thepossibility of rejecting handover UE admissions increases and performance of UEs cannot beguaranteed. The more frontal position the value is, the more the possibility of rejecting new UEsis and some idle resources are wasted.
Value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF
Physical value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF
Set this parameter through ADD UCELLCAC/ MOD UCELLCAC.
HsupaCeConsumeSelect ion
Content: When the dynamic CE algorithm on NodeB is applied, the CE consumption of HSUPAUE is based on the GBR. When the dynamic CE algorithm on NodeB is not applied, the CEconsumption of HSUPA UE is based on the MBR. If the CE consumption of HSUPA UE is
based on the GBR, the CE LDR will not select HSUPA users to do data rate reduction. If the CEconsumption of HSUPA UE is based on the MBR,the CE LDR will select HSUPA users to dodata rate reduction on condition that the HSUPA DCCC switch is ON.
Value range: MBR, GBR
Physical value range: MBR, GBR
Set this parameter through ADD UNODEBALGOPARA/ MOD UNODEBALGOPARA.
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The Universal Mobile Telecommunications System (UMTS) supports four traffic
classes: conversational, streaming, interactive, and background. The transmission
rate varies with the traffic class as follows:
For Circuit Switched (CS) conversational services, the channel transmits
voice signals at a certain rate (for example, 12.2 kbit/s) during a conversation
and only transmits Silence Descriptors (SIDs) at intervals when there is no
conversation.
For Packet Switched (PS) interactive and background services, such as web
browsing, there is data transmitted during data downloading. After a web
page has been downloaded, and when the user is reading the page, however,
there is very little data to transfer.
If the Radio Network Controller (RNC) allocates the maximum bandwidth to the
subscriber when a service is established, a large proportion of the Iub transmissionbandwidth is unused. For example, downloading a 50 KB page takes only about one
second, but reading this page needs dozens of seconds. Thus, over 90% of the Iub
transmission bandwidth is not used.
To save the Iub transmission bandwidth for operator use, Huawei provides the Iub
overbooking function, which applies an admission control mechanism to access the
service. Services are admitted according to the different activity factors. PS
interactive and background services can be admitted according to the Guaranteed Bit
Rate (GBR). In this way, the maximum number of users with the minimum number of
activity request to use voice and PS Best Effort (BE) services can access the network,
thus achieving a better utilization of transmission bandwidth.
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For BE services, the GBR can be set by running the SET UUSERGBR command.
Activity factors can be configured for different types of service by running the ADD
TRMFACTOR/ MOD TRMFACTOR command.
Default settings of activity factors for typical types of service:
Type of Service Default Activity Factor (%)
SRB 15/15 (DL/UL)
AMR voice 70/70 (DL/UL)
R99 CS streaming 100/100 (DL/UL)
R99 PS conversational 70/70 (DL/UL)
R99 PS streaming 100/100 (DL/UL)
R99 PS interactive 100/100 (DL/UL)
R99 PS background 100/100 (DL/UL)
HSPA SRB 50/50 (DL/UL)
HSPA voice 70/70 (DL/UL)
HSPA conversational 70/70 (DL/UL)
HSPA streaming 100/100 (DL/UL)
HSPA interactive 100/100 (DL/UL)
HSPA background 100/100 (DL/UL)
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The parameters of threshold should satisfy with: Bandwidth reserved for handover Congestion threshold Congestion resolving threshold.
The congestion threshold and the congestion resolving threshold are used to prevent
the ping-pong effect.
Based on the preceding requirement, the user priorities are as follows:
User requesting handover > New user > User requesting rate upsizing
The congestion thresholds are FWDCONGBWand BWDCONGBW, and the
congestion resolving thresholds are FWDCONGCLRBWand BWDCONGCLRBW.
The parameters that are used to reserve bandwidth for handover are as follows:
FWDHORSVBW
BWDHORSVBW
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The admission procedure is as follows:
The new user attempts to be admitted to available bandwidth 1 on the primary path.
If the user succeeds in applying for the resources on the primary path, the user is
admitted to the primary path.
If the user fails to apply for the resources on the primary path, the user then attempts
to be admitted to available bandwidth 2 on the secondary path. If the user succeeds in applying for the resources on the secondary path, the user is
admitted to the secondary path. If the user fails, the bandwidth admission request of
the user is rejected.
Admission procedure for handover of a user:
Admission procedure for a new user:
Admission procedure for rate upsizing of a user:
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FWDHORSVBW/BWDHORSVBW
Content: Reserved forward/backward bandwidth for handover user .
Value range: 0~320000
Physical value range:0~320000; step: 1
Physical unit: Kbit/s
FWDCONGBW/BWDCONGBW
Content: If the available forward/backward bandwidth is less than or equal to
this value, the forward/backward congestion alarm is emitted.
Value range: 0~320000
Physical value range:0~320000; step: 1
Physical unit: Kbit/s FWDCONGCLRBW/BWDCONGCLRBW
Content: If the available forward/backward bandwidth is greater than this value,
the forward/backward congestion alarm is cleared.
Value range: 0~320000
Physical value range:0~320000; step: 1
Physical unit: Kbit/s
Set these parameters through ADD AAL2PATH/ MOD AAL2PATH (for ATM
networking) and ADD IPPATH/ MOD IPPATH (for IP networking).
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MaxHsdpaUserNum
Content: Maximum number of users supported by the HSDPA channel. The
user in this parameter refers to the user with services on the HSDPA channel,
regardless of the number of RABs carried on the HSDPA channel. Maximum
HSDPA user number cannot exceed the HSDPA capability of the NodeB
product, In practice, the value can be set based on the cell type and the
richness of the available HSDPA power and code resources. If the value is too
low, the cell HSDPA capacity may be reduces, leading to waste in HSDPA
resources. If the value is too high, HSDPA services may be congested.
Value range: 0~100
Physical value range: 0~100; step: 1
Set this parameter through ADD UCELLCAC/ MOD UCELLCAC.
NodeBHsdpaMaxUserNum
Content: Maximum number of HSDPA users of the NodeB.
Value range: 0~3840
Physical value range: 0~3840; step: 1
Set this parameter through ADD UNODEBALGOPARA/ MOD
UNODEBALGOPARA.
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MaxHsupaUserNum
Content: Maximum number of users supported by the HSUPA channel. The
user in this parameter refers to the user with services on the HSUPA channel,
regardless of the number of RABs carried on the HSUPA channel. Maximum
HSUPA user number cannot exceed the HSUPA capability of the NodeB
product, In practice, the value can be set based on the cell type and the
richness of the available HSUPA power and code resources. If the value is too
low, the cell HSDPA capacity may be reduces, leading to waste in HSUPA
resources. If the value is too high, HSUPA services may be congested.
Value range: 0~100
Physical value range: 0~100; step: 1
Set this parameter through ADD UCELLCAC/ MOD UCELLCAC.
NodeBHsupaMaxUserNum
Content: Maximum number of HSUPA users of the NodeB.
Value range: 0~3840
Physical value range: 0~3840; step: 1
Set this parameter through ADD UNODEBALGOPARA/ MOD
UNODEBALGOPARA.
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The purpose of Intelligent Access Control (IAC) is to increase the access success rate,
that is, RRC connection success rate and RAB setup success rate.
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There are two types of IAC, IAC for RRC connection processing and IAC for RAB
processing:
IAC for RRC connection processing is used to select a suitable cell for a UE to
access through redirection and RRC DRD. It also implements load balancing
and service steering
IAC for RAB processing is used to select a suitable cell for a UE to access
through DRD and CAC. It also implements load balancing and service steering.
Preemption, queuing, and low-rate access are used to further improve the
RAB setup success rate
IAC procedure supported by services:
Service
Type
Low-
Rate
Access
Rate Negotiation
Preemption Queuing
DRD
MBR
Negotiation
GBR
Negotiation
InitialRate
Negotiation
TargetRate
Negotiation
Inter-
Frequency
Inter-RAT
DCH
HSUPA
HSDPA
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As shown in the previous figure, the procedure of service access includes the
procedures for RRC connection setup and RAB setup. The successful setup of the
RRC connection is one of the prerequisites for the RAB setup.
During the RRC connection processing, the RNC performs the following steps:
1. Performs the RRC redirection based on distance (only for UE-originating
AMR services). If the RNC decides UE access from another cell, it sends anRRC connection reject message to the UE; otherwise, the RNC performs the
next step.
2. Performs RRC redirection for service steering.
3. If the RNC decides UE access from the current cell, it then makes a
resource-based admission decision. If the resource-based admission fails, the
RNC performs directed retry decision (DRD) and redirection.
If the RNC decides UE access from the current cell, it then makes a resource-
based admission decision. If the resource-based admission fails, the RNC
performs directed retry decision (DRD) and redirection.
If the RNC decides UE access from another cell, it then sends an RRC
connection reject message to the UE. The message carries the information
about the cell and instructs the UE to set up an RRC connection to the cell.
During the RAB processing, the RNC performs the following steps:
1. Performs inter-frequency DRD to select a suitable cell for service steering or
load balancing.
2. Performs rate negotiation according to the service requested by the UE.
3. Makes cell resource-based admission decision. If the admission is successful,
UE access is granted. Otherwise, the RNC performs the next step.
4. Selects a suitable cell, according to the inter-frequency DRD algorithm, fromthe cells where no admission attempt has been made, and then goes to 2. If
the attempt fails, the RNC performs the next step.
5. Selects a suitable cell, according to the inter-RAT DRD algorithm. If the inter-
RAT admission is successful, UE access is granted in the inter-RAT cell. If
the inter-RAT DRD fails or is not supported, the RNC performs the next step.
6. Makes a preemption attempt. If the preemption is successful, UE access is
granted. If the preemption fails or is not supported, the RNC performs the next
step.
7. Makes a queuing attempt. If the queuing is successful, UE access is granted.
If the queuing fails or is not supported, the RNC performs the next step.
8. Performs low-rate access. If the low-rate access is admitted, UE access is
granted. If the low-rate access is unsuccessful, the RNC performs the next
step.
9. Rejects UE access.
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IAC RRC Connection Setup
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Before a new service is admitted to the network, an RRC connection must be set up.
After receiving an RRC CONNECTION REQUEST message from the UE, the RNC
performs the RRC redirection based on distance (only for UE-originating AMR
services). For details, see section 5.2.2 "RRC Redirection based on Distance". If the
RNC decides UE access from another cell, it sends an RRC connection reject
message to the UE; otherwise, the RNC performs the next step. Then, the RNC uses the RRC redirection algorithm for service steering to decide
whether the UE may access the network from the current cell:
If the UE can access the network from the current cell according to the
decision result, the RNC uses the CAC algorithm to decide whether an RRC
connection can be set up between the UE and the current cell.
If the RRC connection can be set up between the UE and the current
cell, the RNC sends an RRC CONNECTION SETUP message to the
UE.
If the RRC connection cannot be set up between the UE and thecurrent cell, the RNC attempts to select a cell for RRC connection
setup through RRC DRD. If the RRC DRD fails, RRC redirection will be
performed.
If the UE needs to access the network from another cell according to the
decision result, the RNC sends an RRC CONNECTION REJECT message to
the UE. The message carries the information about this cell.
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In actual situations, a UE may receive signals from a distant cell and subsequently access thecell. However, the cells that are adjacent to this cell are not configured as its neighboring cells.
If the UE moves out of this cell, call drops may occur. To solve this problem, RRC redirectionbased on distance is introduced.
The procedure of RRC redirection based on distance is as follows:
1. Upon receiving an RRC CONNECTION REQUEST message from the UE, the RNCdetermines whether the requested service is the UE-originating AMR service. If yes, the RNCperforms the next step. If no, the RNC does not perform RRC redirection based on distance,and handles the RRC connection setup request of the UE in the current cell.
2. The RNC obtains the propagation delay from the NodeB and compares it with DelayThs.
If the propagation delay is greater than DelayThs, the RNC performs the next step.
If the propagation delay is equal to or smaller than DelayThs, the RNC does notperform RRC redirection based on distance, and handles the RRC connection setuprequest of the UE in the current cell.
3. The RNC checks the load status of the current cell and determines whether to perform RRCredirection based on distance by considering the load status.
If the cell is in the normal state, the RNC generates a random value ranging from 0 to 1and compares the value with the parameter RedirFactorOfNorm. If the random value isequal to or smaller than the parameter, the RNC performs the next step. Otherwise,the RNC does not perform RRC redirection based on distance, and handles the RRCconnection setup request of the UE in the current cell..
If the cell is in the basic congestion state or is overloaded, the RNC generates arandom value ranging from 0 to 1 and compares the value with the parameterRedirFactorOfLDR. If the random value is equal to or smaller than the parameter, theRNC performs the next step. Otherwise, the RNC does not perform RRC redirectionbased on distance, and handles the RRC connection setup request of the UE in the
current cell. 4. The RNC sends the UE an RRC CONNECTION REJECT message containing information
on the neighboring GSM cells of the current cell.
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The procedure of RRC redirection for service steering is as follows:
1. The RNC obtains the information about the service requested by the UE and the
capability of the UE.
If the DR_ RRC_DRD_SWITCH is set to 1, the RNC determines the service
type requested by the UE. If the RNC succeeds in determining the service
type requested by the UE and the switch of RRC direction for service steering
(RedirSwitch) is set to ONLY_TO_INTER_FREQUENCY or
ONLY_TO_INTER_RAT, the RNC performs the next step. Otherwise, the
RNC handles the RRC connection setup request of the UE in the current cell.
If the DR_ RRC_DRD_SWITCH is set to 0, the RNC handles the RRC
connection setup request of the UE in the current cell.
2. Based on the cell load and the redirection factors, the RNC decides whether to
perform RRC redirection for service steering.
If the cell is in the normal state, the RNC generates a random number
between 0 and 1 and compares it with the corresponding unconditional
redirection factor (RedirFactorOfNorm). If the random number is smaller than
this factor, the RNC performs the next step. Otherwise, the RNC handles the
RRC connection setup request of the UE in the current cell.
If the cell is in the basic congestion or overload state, the RNC generates a
random number between 0 and 1 and compares it with the value of
RedirFactorOfLDR. If the random number is smaller than this factor, the
RNC performs the next step. Otherwise, the RNC handles the RRC
connection setup request of the UE in the current cell.
3. Based on the setting of RedirSwitch, the RNC takes the corresponding actions:
If RedirSwitch is set to ONLY_TO_INTER_FREQUENCY, the RNC sends an
RRC CONNECTION REJECT message to the UE, redirecting the UE to the
destination frequency carried in the message.
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DrSwitch -DR_ RRC_DRD_SWITCH
Content: When the switch is on, DRD and redirection is performed for RRC connection if retry is
required. Value range: OFF, ON
Physical value range: 0, 1
Set this parameter through SET UCORRMALGOSWITCH.
RedirSwitch
Content: This parameter specifies whether the RRC redirection algorithm is valid for the
specified traffic type. The algorithm is valid only when the RRC redirection switch is enabled
and when this parameter is set to ONLY_TO_INTER_FREQUENCY or
ONLY_TO_INTER_FREQUENCY. Value OFF indicates that RRC redirection is not allowed.
Value ONLY_TO_INTER_FREQUENCY indicates that only the RRC redirection to an inter-
frequency neighboring cell is allowed. Value ONLY_TO_INTER_RAT indicates that only the
RRC redirection to an inter-RAT neighboring cell is allowed.
Value range: OFF, ONLY_TO_INTER_FREQUENCY, ONLY_TO_INTER_RAT
Set this parameter through SET UREDIRECTION/ ADD UCELLREDIRECTION.
RedirFactorOfNorm/RedirFactorOfLDR
Content: When the load of the serving cell is within the normal range, a UE may be redirected to
another cell according to the traffic type. This parameter specifies the possibility of redirecting
the UE to another cell. When this parameter is set to 0, the RRC redirection is not performed if
the load of the serving cell is within the normal range. When the UL load state or DL load state
of the serving cell is LDR or OLC, a UE may be redirected to another cell according to the traffic
type. This parameter specifies the possibility of redirecting the UE to another cell. When this
parameter is set to 0, the RRC redirection is not performed if the load state on the serving cell is
LDR or OLC. LDR indicates basic congestion. OLC indicates overload congestion.
Value range: 0~100 Physical value range: 0~1; step: 0.01
Physical unit: %
Set these parameters through SET UREDIRECTION/ ADD UCELLREDIRECTION.
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The RNC performs the following steps:
1. The RNC selects the same-coverage inter-frequency neighboring cells of the
current cell. These neighboring cells are suitable for blind handovers
2. The RNC generates a list of candidate DRD-supportive inter-frequency cells. The
candidate cell must meet the quality requirements of DRD:
(CPICH_EcNo)RACH > DRD_EcNOnbcell
Here:
(CPICH_EcNo)RACHis the cached CPICH Ec/N0 value included in the RACH
measurement report. Note that this value is of the current cell
DRD_EcNOnbcell is the DRD threshold (DRDEcN0Threshhold) of the
neighboring cell
3. The RNC selects a target cell from the candidate cells for UE access. If thecandidate cell list is empty, the RRC DRD fails. The RNC performs RRC redirection.
If the candidate cell list contains more than one cell, the UE tries a cell randomly.
If the admission is successful, the RNC continues the RRC connection setup
procedure
If the admission to a cell fails, the UE tries admission to another cell in the
candidate cell list until an admission is successful or all admission attempts
fail
If all the admission attempts fail, then
The RNC makes an RRC redirection decision when the switch of RRCredirection after DRD failure (ConnectFailRrcRedirSwitch) is set to
ON
The RRC connection setup fails when the switch of RRC redirection
after DRD failure (ConnectFailRrcRedirSwitch) is set to OFF
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DRDEcN0Threshhold
Content: This parameter is used as the DRD Ec/No threshold of whether to
perform the blind handover. If the Ec/No measured value of the current cell is
greater than this parameter of the inter-frequency neighboring cell, this
neighboring cell can be selected to be the candidate DRD cell.
Value range: -24~0
Physical value range: -24~0; step: 1
Physical unit: dB
Set this parameter through ADD UINTERFREQNCELL/ MOD
UINTERFREQNCELL.
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When the RRC DRD fails, the RNC performs RRC redirection if the DR_RRC_DRD_SWITCH subparameter of the DrSwitch parameter is set to 1 and the
switch of RRC redirection after DRD failure (ConnectFailRrcRedirSwitch ) is set toOnly_To_Inter_Frequency orAllowed_To_Inter_RAT. The purpose of RRCredirection after DRD failure is to instruct the UE to set up RRC connection in aninter-frequency or an inter-RAT neighboring cell.
The procedure of RRC redirection after DRD failure is performed in the followingsteps:
1. The RNC selects all inter-frequency cells of the current cell.
2. The RNC selects candidate cells. The candidate cells are the cells selected in step1 but exclude the cells that have carried out inter-frequency RRC DRD attempts.
3. The RNC selects a target cell from the candidate cells for UE access.
If more than one candidate cell is available, the RNC selects a cell randomlyand redirects the UE to the cell.
If the admission is successful, the RNC continues the RRC connection setupprocedure.
If the admission attempt fails, the UE tries admission to another cell in thecandidate cell list.
If no candidate cell is available, or all the admission attempts fail:
If ConnectFailRrcRedirSwitch is set to Only_To_Inter_Frequency,the RRC connection setup fails.
If ConnectFailRrcRedirSwitch is set to Allowed_To_Inter_RAT,then:
a. If a neighboring GSM cell is configured, the RNC redirects theUE to that GSM cell.
b. If no neighboring GSM cell is configured, the RRC connectionsetup fails.
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DRDEcN0Threshhold
Content: This parameter specifies the RRC redirection strategy. OFF: RRC
redirection is not allowed. Only_To_Inter_Frequency: Only RRC redirection to
inter-frequency cells is allowed. Allowed_To_Inter_RAT: RRC redirection to
inter-frequency cells and redirection to inter-RAT cells are both allowed.
Value range: OFF, Only_To_Inter_Frequency, Allowed_To_Inter_RAT
Physical value range: OFF, Only_To_Inter_Frequency,
Allowed_To_Inter_RAT
Set this parameter through SET UDRD.
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During the RAB processing, non-periodic DRD is used to select a suitable cell for a
UE to access according to the HSPA+ technological satisfaction, service priority, and
cell load. Non-periodic DRD is performed during RAB setup, RAB modification, orDCCC channel reconfiguration.
By using inter-frequency DRD, the RNC selects the qualified candidate cells by
considering HSPA+ technological satisfaction, cell service priority, and cell load. Then,
the RNC sequences the candidate cells according to the priority. According to the
sequence from the highest to the lowest, the UE tries accessing the cells until it is
admitted or it fails to access any cell.
If the UE fails to access any cell in the case of inter-frequency DRD, inter-RAT DRD
will be triggered.
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MBR: Maximum Bit Rate
GBR: Guaranteed Bit Rate
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N-89
For the PS streaming service, when PS_STREAM_IU_QOS_NEG_SWITCH
subparameter of the PsSwitch parameter is set to 1, the Iu QoS negotiation function
is enabled for MBR negotiation.
For the PS BE service:
When both PS_BE_IU_QOS_NEG_SWITCH and
PS_BE_STRICT_IU_QOS_NEG_SWITCH subparameters of the PsSwitch
parameter are set to 1, the Iu QoS negotiation function is enabled, and the
RNC determines the MBR of Iu QoS negotiation based on the information
about UE capability, cell capability and rate requested by the CNother settings.
When PS_BE_IU_QOS_NEG_SWITCH is set to 1 and
PS_BE_STRICT_IU_QOS_NEG_SWITCH is set to 0, the Iu QoS negotiation
function is enabled, and the RNC determines the MBR of Iu QoS negotiation
based on the maximum rate supported by the UE rather than the cell capabilityand other settings.
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PsSwitch-PS_STREAM_IU_QOS_NEG_SWITCH
Content: When the switch is on, the Iu QoS Negotiation function is applied to the PS
STREAM service if Alternative RAB Parameter Values IE is present in the RANAPRAB ASSIGNMENT REQUEST or RELOCATION REQUEST message.
Value range: OFF, ON
Physical value range: 0, 1
PsSw itch -PS_ BE_IU_QOS_NEG_SWITCH
Content: When the switch is on, the Iu QoS Negotiation function is applied to the PS
BE service if Alternative RAB Parameter Values IE is present in the RANAP RAB
ASSIGNMENT REQUEST or RELOCATION REQUEST message.
Value range: OFF, ON
Physical value range: 0, 1
PsSwitch-PS_BE_STRICT_IU_QOS_NEG_SWITCH
Content: When the switch is on, the strict Iu QoS Negotiation function is applied to the
PS BE service, RNC select Iu max bit rate based on UE capacity, cell capacity, max
bitrate and alternative RAB parameter values in RANAP RAB ASSIGNMENT
REQUEST or RELOCATION REQUEST message. When the switch is off, the loose Iu
QoS Negotiation function is applied to the PS BE service, RNC select Iu max bit rate
based on UE capacity, max bitrate and alternative RAB parameter values in RANAP
RAB ASSIGNMENT REQUEST or RELOCATION REQUEST message, not consider
cell capacity, this can avoid Iu QoS Renegotiation between different cell. The switch is
valid when PS_BE_IU_QOS_NEG_SWITCH is set to ON.
Value range: OFF, ON
Physical value range: 0, 1
Set these parameters through SET UCORRMALGOSWITCH.
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As described in the table, when the two switches are ON, the initial rate is
dynamically set on the basis of Ec/No in the downlink. The specific method is as
follows:
When receiving an RRC connection setup request, the RNC starts the timer
EcN0EffectTime.
Before the timer expires, the RNC dynamically sets the initial rate based on
the P-CPICH Ec/N0 carried in the RRC CONNECTION REQUEST message:
If the cell Ec/N0 reported from the UE is above the Ec/N0 threshold
(EcN0Ths), the RNC sets the actual initial rate to the smaller one of
the MBR and 384 kbit/s. Note that if the UE is in the soft handover state,
the RNC sets the actual initial rate to the smaller one of the MBR and
384 kbit/s when any of the cells in the active set meets the threshold.
If the cell Ec/N0 is below or equal to the Ec/N0 threshold (EcN0Ths) or
the RRC CONNECTION REQUEST message does not carry the
information about Ec/N0, the RNC sets the actual initial rate to the
smaller one of the MBR and the initial rate of the downlink BE service
(DlBeTraffInitBitrate).
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PsSwit ch -PS_STREAM_IU_QOS_NEG_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
PsSwitch-PS_BE_INIT_RATE_DYNAMIC_CFG_SWITCH
Content: When the switch is on, the initial rate of the service should be
dynamically configured according to the value of Ec/No reported by the UE
when the PS BE service is established.
Value range: OFF, ON
Physical value range: 0, 1
Set these parameters through SET UCORRMALGOSWITCH.
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EcN0EffectTime
Content: This parameter specifies the time duration when the reported Ec/No
is valid. The reported Ec/No is valid for the period (starting from the time whenthe RRC connection request is initiated) specified by this parameter.
Value range: 0~65535
Physical value range: 0~65535; step: 1
Physical unit: ms
Set this parameter through ADD UCELLFRC/ SET UFRC.
EcN0Ths
Content: This parameter specifies the threshold for determining the signalquality in a cell. If the reported Ec/No exceeds the value of this parameter, youcan infer that the signal quality in the cell is good and a high code rate can be
set for initial access. Value range: 0~49
Physical value range: -24.5~0 (0: -24.5, 1: -24 49: 0) Physical unit: dB
Set this parameter through ADD UCELLFRC/ SET UFRC.
DlBeTraffIni tBitrate
Content: DL BE traffic Initial bit rate. When DCCC function is enabled, thedownlink initial bit rate will be set to this value if the downlink max bit rate ishigher than the initial bit rate.
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 SET UFRC.
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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 UCORRMALGOSWITCH.
HsupaInit ialRate
Content: HSUPA BE traffic Initial bit rate. When DCCC algorithm switch and
HSUPA DCCC algorithm switch are enabled, the uplink initial bit rate will be
set to this value if the uplink max bit rate is higher than the initial bit rate.
Value range: D8, D16, D32, D64, D128, D144, D256, D384, D608, D1440,
D2048, D2880, D5740
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 UFRC.
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If the cell has sufficient code and CE resources, the RNC sets the candidate target
rate to the one that matches the cell resource surplus. Then, the RNC sets the target
rate to the greater one of the candidate target rate and the GBR.
In the case of soft handover, the actual target rate is the candidate target rate set by
the RNC.
In the case of DCCC rate upsizing, if the rate upsizing fails, the target rate is the
greater one of the candidate target rate and the pre-upsizing DCCC rate.
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Preemption and queuing guarantee the success in the access of a higher-priority user
by forcibly releasing the resources of a lower-priority user.
Preemption and queuing are applicable to the following scenarios:
Setup or modification of a service
Hard handover or SRNS relocation
UE state transition from CELL_FACH to CELL_DCH
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The following table describes the selection of the target cell for preemption or queuing:
DRDSwitch for
Service
Steering
Power-BasedDRD Switch
for Load
Balancing
Code-BasedDRD Switch
for Load
Balancing
Target Cell for Preemption or Queuing
ON
ON - The cell with the lightest load among the cells
with the highest service priority.- ON