3 wcdma handover

WCDMA Handover Principle and relevant parametersWCDMA Handover Principle and Relevant Parameters
Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.
Foreword
It is decided by the characters of mobile system:
The mobility of UE
The mobile system is composed by cells which the coverage ability is limited.
Providing the continuous service in mobile system is the basic element in QoS.
Objectives
Upon completion of this course, you will be able to:
Know the basic definitions of Handover
The algorithms of handover decision
The handover flow
Contents
Contents
The Purpose of Handover
Providing the continuous service in mobile system is the basic element in QoS
The load balance: sharing the resource
The hierarchy divided by speed and service: high efficiency of using resource
Handover is a basic function of a cellular mobile network. The purpose of handover is to ensure that a UE in CELL_DCH state is served continuously when it moves.
The Basic Concepts of Handover
Active Set
Monitored Set
Detected set
CPICH
Active set : Cells, which belong to the active set. User information is sent from all these cells. In FDD, the cells in the active set are involved in soft handover. In TDD the active set always comprises one cell only. The UE shall only consider active set cells included in the variable CELL_INFO_LIST for measurement; i.e. active set cells not included in the CELL_INFO_LIST shall not be considered in any event evaluation and measurement reporting.
Monitored set :Cells, which are not included in the active set, but are included in the CELL_INFO_LIST belong to the monitored set.
Detected set : Cells detected by the UE, which are neither in the CELL_INFO_LIST nor in the active set belong to the detected set. Reporting of measurements of the detected set is only applicable to intra-frequency measurements made by UEs in CELL_DCH state.
RL: Radio link between NodeB and UE.
RLS: Radio link set. The RLs from same NodeB.
Combination way: For soft handover, the uplink signals are combined in RNC. The RNC will select one best signal to process. We call this selective combination. For softer handover, the uplink signals are combined in the RAKE receiver of NodeB. It is maximum ratio combination.
Soft handover gain: We have introduced in Coverage Planning.
CPICH: Common Pilot Channel. UE measure the signal strength of CPICH for handover decision.
The Categories of Handover
Soft handover (softer handover)
According to the properties of source cell and target cell:
Intra-frequency handover
Inter-frequency handover
Based on Coverage
Based on Noncoverage
The unique signaling of soft handover is Active Set Update, and the unique signaling of hard handover is Physical Channel Reconfiguration.
Soft handover include soft handover and softer handover. It is depended on if the two (or three) RLs belong to one NodeB.
The handover based on load is load control algorithm.
The handover based on mobility of UE is for HCS handover.
The handover based on service: for example, the handover between R99 and HSDPA.
The Characters of Different Handover
Comparison between soft handover and hard handover:
Item
Several
One
Can be happened in Intra-frequency cells or Inter-frequency cells
The maximum number of RL is 3. This value can be changed. But this function need the UE to support. Normally, the active set supported by UE is fixed 3 and can not be changed.
The Characters of Different Handover
Comparison between soft handover and softer handover :
Item
Signal combined in NodeB by maximum ratio combination
DL combination
Signal combined in UE by maximum ratio combination
Signal combined in UE by maximum ratio combination
During softer handover, the uplink signaling are combined in NodeB by maximum ratio combination, but during soft handover they are combined in RNC by selective combination
Compare to later one, the maximum ratio combination can get more gain. So the performance of maximum ratio combination is better
Since softer handover is completed in NodeB, it does not consume transport resource of Iub
Soft Handover
NodeB 2
NodeB 1
Cell A
Cell B
It is soft handover. During the handover, two radio links are connected with UE, and data in each RL are same. So the UE can combine the data in RAKE receiver. But the control part are different for downlink.
Softer Handover
Cell B
Cell A
It is softer handover. The cells in active set belong to one NodeB. The NodeB use the RAKE receiver to combine the data in HULP board. Then send the data to WFMR board in RNC.
Hard Handover
NodeB 2
NodeB 1
Cell A
Cell B
It is hard handover. The UE disconnect the original radio link, then connect to the target cell. It happened in intra-frequency, inter-frequency and inter-RAT.
Three Steps of Handover
The following figure shows handover procedure (measurement quality set to PCPICH Ec/No)
Decision
Execution
Measurement
In the measurement phase, the UE takes measurement according to the MEASUREMENT CONTROL message received from the RNC. The UE sends related measurement reports to the RNC according to the rules defined in the MEASUREMENT CONTROL message when the event triggering conditions are met.
After receiving the intra-frequency measurement report from the UE, the RNC decides whether to go to the execution phase, depending on the information in the report.
Contents
Contents
2.2 Measurement Phase
Measurement Control
MEASUREMENT CONTROL
If the UE setup a RRC connection or trigger the 1D event, the UTRAN will send the measurement control to UE. The measurement control include the algorithm of measurement and handover, for example, the intra-frequency handover criteria, and how to report.
The latter message includes the following measurement control information:
1. Measurement identity: A reference number that should be used by the UTRAN when setting up, modifying or releasing the measurement and by the UE in the measurement report.
2. Measurement command: One out of three different measurement commands.
-Setup: Setup a new measurement.
-Modify: Modify a previously defined measurement, e.g. to change the reporting criteria.
-Release: Stop a measurement and clear all information in the UE that are related to that measurement.
3. Measurement type: One of the types listed above describing what the UE shall measure. Presence or absence of the following control information depends on the measurement type.
4. Measurement objects: The objects the UE shall measure, and corresponding object information.
5. Measurement quantity: The quantity the UE shall measure. This also includes the filtering of the measurements.
6. Reporting quantities: The quantities the UE shall include in the report in addition to the quantities that are mandatory to report for the specific event.
7. Measurement reporting criteria: The triggering of the measurement report, e.g. periodical or event-triggered reporting.
8. Measurement Validity: Defines in which UE states the measurement is valid.
9. Measurement reporting mode: This specifies whether the UE shall transmit the measurement report using AM or UM RLC.
10. Additional measurement identities: A list of references to other measurements. When this measurement triggers a measurement report, the UE shall also include the reporting quantities for the measurements referenced by the additional measurement identities.
Measurement Control, normal case
MEASUREMENT REPORT
Measurement Report
The purpose of the measurement reporting procedure is to transfer measurement results from the UE to UTRAN.
Based on the algorithm in measurement control, the UE will measure the signal strength and check if it meet the requirement of all event. If it meet the requirement of any event, UE will send the measurement report to UTRAN to trigger the handover. The most important information in the measurement are the PSC and the CPICH Ec/No of the target cell, and the triggered event.
Contents
2.2 Measurement Phase
Measurement Model
A is measurement value at the physical layer
B is the measurement value after layer 1 filtering at physical layer. The value goes from the physical layer to high layer
C is measurement after processing in the layer3 filter
C’ is another measurement value
D is measurement report information sent on the radio interface or Iub interface
Layer 1
Measurement Quantity
For inter-RAT measurement ,GSM cell RSSI is used.
Measurement Quantity Configuration
The default value of this parameter is Ec/No
InterFreqMeasQuantity
The default value of this parameter is “Both”
MeasQuantityOf3A
The default value of this parameter is RSCP
IntraFreqMeasQuantity
Value range: CPICH_Ec/No, CPICH_RSCP .
The recommended value of this parameter is CPICH_EC/NO
Set this parameter through SET INTRAFREQHO, query it through LST INTRAFREQHO.
InterFreqMeasQuantity
Content: Measurement quantity used in coverage-based inter-frequency measurement .
The recommended value of this parameter is BOTH.
Set this parameter through SET INTERFREQHOCOV, query it through LST INTERFREQHOCOV.
MeasQuantityOf3A
Value range: CPICH_Ec/No, CPICH_RSCP.
Set this parameter through SET INTERRATHOCOV, query it through SET INTERRATHOCOV.
Layer 3 filtering
Mn is the latest measurement value from the physical layer.
a = 1/2(k/2) (k is set to Intra-freq meas L3 filter coeff)
Where:
The greater this parameter is ,the stronger the smoothing effect on the signal will be , and the stronger the fast fading resistance capability will be , but the weaker the tracing capability of the signal change will be.
When k = 0, that is, a is set to 1, no layer 3 filtering is performed.
Layer 3 filtering coefficient
The default value of this parameter is D3
InterFreqFilterCoef
InterRATFilterCoef
FilterCoef
Value range: 0~19.
Content: L3 filtering coefficient for intra-frequency measurement. The greater this parameter is, the greater the smoothing effect and the higher the anti fast fading capability, but the lower the signal change tracing capability.
The recommended value of this parameter is 3
InterFreqFilterCoef
Value range: 0~19.
InterRATFilterCoef
Value range: 0~19.
Set this parameter through SET INTERRATHOCOV, query it through LST INTERRATHOCOV.
Measurement Report Mode
Event to Periodic Report
According to the Measurement Control , UE will report the measurement results to UTRAN by event trigger report or periodic report.
If the UE report a measurement report triggered by Event ,the UE will wait for response from UTRAN, if there is no any response after a specific period, to avoid measurement report loss, the event reporting can be turned to periodical report.
Contents
Contents
Contents
Brief Introduction of Soft Handover
Characters of Soft Handover
During handover, UE has several RLs with different cells
The handover among different cells which are in same RLS can be softer handover
Signals from each RL will be combined in UL and DL.
Soft handover:
Softer handover
Brief Introduction of Soft Handover
Advantages
Disadvantages
it may cause side-effect
Advantages
Because of the signal combination, the combination gain can overcome some of the path loss
During the handover, UE has several RLs with the network, call drop caused by ping-pong handover can be avoided
Disadvantages
Soft handover will occupy more resource ,such as CE, Iub transmission, especially for the code resources for BE service
When the downlink power from different cells are not balanced, it will cause side-effect in downlink.
Measurement of Soft Handover
Event type
1A,1B,1C,1D
Normally, the soft handovers are triggered by 1A,1B,1C events in the Measurement report signaling, UTRAN will make decisions according to these events
1D event will trigger new measurement control.
Soft Handover Measurement Events
Event
Description
1A
The PCPICH quality of the cells in the monitored set enters the reporting range . This indicates that the quality of a cell is close to the quality of the best cell . A relative high combined gain can be achieved when the cell is added to the active set
1B
The PCPICH quality of the cells in the active set leaves the reporting range. This indicates that quality of a cell is much worse than the quality of the best cell. The cell should not stay in the active set
1C
A non-active PCPICH becomes better than an active PCPICH. This indicates that the quality of a cell is close to the quality of the best cell. In addition ,the number of cells in the active set has reached the maximum value. The cell replaces the worst cell in the active set ; thus achieving a higher combined gain
1D
Event of the change of the best cell
Actually ,we can consider Events are the suggestions from the UE:
1A means UE suggests to add a radio link,
1B means UE suggests to remove a radio link,
1C means UE suggests to exchange a radio link
The Trigger Algorithm of 1A Event
Event 1A is triggered on the basis of the following formula
Mnew is the measurement value of the cell in the reporting range
CIOnew is cell individual offset of the cell in the reporting range . It is set for the neighboring cell
W is the weight value
Mi is the measurement value of the cell in the active set
NA is the number of cells in the current active set
Mbest is the measurement value of the best cell in the active set
R1a is the reporting range or relative threshold of soft handover. The threshold parameters of CS and PS service are CS service 1A event relative threshold , PS service 1A event relative threshold respectively
H1a is 1A hysteresis , the hysteresis value of event 1A
Example of 1A Event
A: signal curve of the best cell in the active set
B: signal curve of a cell in the monitoring set
C: The 1A curve
Key parameters of 1A Event
INTRARELTHDFOR1ACS
The default value of this parameter is 6 ( 3dB )
INTRARELTHDFOR1APS
INTRARELTHDFOR1ACS
Value range: 0~14.5; step: 0.5
Content: The CS service relative threshold of the event 1A. It is easier to trigger event 1A if the value increases. It is harder to trigger event 1A if the value decreases.
The recommended value of this parameter is 6 (3dB)
INTRARELTHDFOR1ACS
Content: The PS service relative threshold of the event 1A. It is easier to trigger event 1A if the value increases. It is harder to trigger event 1A if the value decreases.
Key parameters of 1A Event
HYSTFOR1A
The default value of this parameter is 0( 0dB )
TRIGTIME1A
The default value of this parameter is D320 ( 320ms )
HYSTFOR1A
Value range: 0~7.5dB; step: 0.5
Content: The hysteresis value of the event 1A. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.
The recommended value of this parameter is 0 ( 0dB )
TRIGTIME1A
Parameter name: 1A event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The trigger delay time of the event 1A. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.
The recommended value of this parameter is D320 ( 320ms )
The Trigger Algorithm of 1B Event
Event 1B is triggered on the basis of the following formula
Mold is the measurement value of the cell that becomes worse
CIOold is cell individual offset of the cell in the reporting range . It is set for the neighboring cell
W is the weight value
Mi is the measurement value of the cell in the active set
NA is the number of cells in the current active set
Mbest is the measurement value of the best cell in the active set
R1b is the reporting range or relative threshold of soft handover. The threshold parameters of CS and PS service are CS service 1B event relative threshold , PS service 1B event relative threshold respectively
H1b is 1B hysteresis , the hysteresis value of event 1B
Example of 1B Event
B: signal curve of a cell in the monitoring set
C: The 1B curve
Key parameters of 1B Event
INTRARELTHDFOR1BCS
INTRARELTHDFOR1BPS
INTRARELTHDFOR1BCS
Content: The CS service relative threshold of the event 1B. It is easier to trigger event 1B if the value decreases. It is harder to trigger event 1B if the value increases.
INTRARELTHDFOR1BCS
Content: The PS service relative threshold of the event 1B. It is easier to trigger event 1B if the value increases. It is harder to trigger event 1B if the value decreases.
HYSTFOR1B
TRIGTIME1B
HYSTFOR1B
Content: The hysteresis value of the event 1B. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.
TRIGTIME1B
Parameter name: 1B event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The trigger delay time of the event 1B. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.
The Trigger Algorithm of 1C Event
Event 1C is triggered on the basis of the following formula
Mnew is the measurement value of the cell in the reporting range
CIOnew is cell individual offset of the cell in the reporting range . It is set for the neighboring cell
M inAS is the measurement value of the worst cell in the active set
CIOInAS is cell individual offset of the worst cell in the active set
H1c is 1C hysteresis , the hysteresis value of event 1C
Example of 1C Event
B: signal curve of a cell in the active set
C: signal curve of the worst cell in the active set
D: signal curve of a cell in the monitoring set
E: The 1C curve
Key parameters of 1C Event
HYSTFOR1C
TRIGTIME1C
HYSTFOR1C
Content: The hysteresis value of the event 1C. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.
TRIGTIME1C
Parameter name: 1C event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The trigger delay time of the event 1C. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.
The Trigger Algorithm of 1D Event
Event 1D is triggered on the basis of the following formula
MNotBest is the measurement value of a cell that is not on the list of the best cells.
MBest is the measurement value of the best cell in the active set.
H1d is 1D hysteresis, the hysteresis value of event 1D.
Example of 1D Event
B: signal curve of a cell in the active set or monitoring set
C: Th1D curve
Key parameters of 1D Event
HYSTFOR1D
TRIGTIME1D
HYSTFOR1D
Content: The hysteresis value of the event 1D. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.
TRIGTIME1D
Parameter name: 1D event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The trigger delay time of the event 1D. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.
Other key parameters for SHO
Weight
SHOQualmin
The default value of this parameter is -24(-24 dB)
CELLINDIVIDALOFFSET
Weight
Parameter name: Weighted factor
Value range: 0~2
Content: This parameter is used to define the soft handover relative threshold based on the measured value of each cell in the active set. The greater this parameter is set, the higher the soft handover relative threshold. When this parameter is set as 0, the soft handover relative threshold is only for the best cell in the active set.
The recommended value of this parameter is 0.
SHOQualmin
Value range: -24~0;
The recommended value of this parameter is -24 (-24dB)
CELLINDIVIDALOFFSET
Value range: -10~10 dB;
Content: Offset of cell CPICH measurement value. The offset is added to the measurement quantity before the UE evaluates if an event has occurred. In handover algorithms, this parameter is used for moving the border of a cell.
Set this parameter through ADD INTRAFREQNCELL, query it through LST INTRAFREQNCELL.
Contents
Brief Introduction of Intra-Frequency Hard Handover
Characters of Intra-Frequency Hard Handover
During handover, UE has only one RL with one cell
Switch off the RL with the original cell, then setup the RL with target cell
The frequency of source cell and target cell are same
In some cases ,UE want to take soft handover according to the intra-frequency measurement, but RNC don’t allow the UE to take this soft handover cause there is no IUR interface between 2 RNCs or the service rate is higher than a threshold, then the UE has to ask for hard handover based on the measurement.
During the intra-frequency hard handover, the RNC will ask the UE to switch off the RL with the original cell and setup the RL with the target cell, so there is a gap during this procedure.
Intra-Frequency Handover is always triggered by 1D event.
Brief Introduction of Intra-Frequency Handover
Advantages
Enhance the usage efficiency of the OVSF code and hardware
Disadvantages
High call drop possibility because of the intra-frequency interference
Cause there is only 1 RL for the UE, OVSF code resources ,CE resources DL tx power resources and IUB resources can be saved
During the hard handover, the frequency of the original cell and target cell are the same, so when the UE want to setup the RL with the target cell, the original cell will cause DL interference to the UE.
Key parameters of Intra-frequency Hard handover
BEBITRATETHD
The default value of this parameter is 384k
The Parameters about 1D Event
Time to trigger
Value range: 8k, 16k, 32k, 64k, 128k, 144k, 256k, 384k
Content: The bit rate threshold used to determine whether to perform soft handover for the Best Effort (BE) service on DCH. When the maximum bit rate of the BE service is lower than or equal to this threshold, the system will perform soft handover for this user to guarantee the service quality. If the maximum bit rate of the BE service is higher than the threshold, the system will perform intra-frequency hard handover for this user to avoid the too great effect of soft handover on the system capacity. .
The recommended value of this parameter is 384k.
Set this parameter through SET HOCOMM, query it through SET HOCOMM.
Contents
Brief Introduction of Inter-Frequency Handover
Characters of Inter-frequency Hard Handover
The frequency of original cell and source cell are different
There is only one RL for the UE
The compressed mode is needed
If the frequency of the original cell and target cell are different, the soft handover is impossible.
In a WCDMA FDD system, the UE in CELL_DCH state sends and receives signals continuously in uplink and downlink channels. If the UE in this case needs to measure the pilot signal strength of an inter-frequency WCDMA or GSM cell, and it has only mono-frequency receiver, the UE must use the compressed mode technique.
Compressed Mode
Measure the inter-frequency cell or Inter-RAT cell under FDD mode
Categories
In order to realize inter-frequency and inter-RAT measurement , WCDMA system introduces compressed mode .
In DL, during compressed mode ,UE receiver can test signal from other frequency. In order to avoid the effect cause by UE transmitter, compress mode is also used in UL.
The compressed mode includes two types, spreading factor reduction (SF/2) and high layer approaches. The usage of type of compressed mode is decided by the RNC automatically, according to spreading factor used in uplink or downlink.
Measurement of Inter-frequency Handover
Event type
Inter-frequency handover is also based on measurement. Similar with soft handover, measurement quantity include CPICH RSCP or Ec/No
UE can report the measurement result when event triggered ,then RNC performs handover decision. Or the UE periodically reports the inter-frequency measurement report, and the RNC decides the handover after evaluation.
Inter-frequency Handover Measurement Events
Event
Description
2D
When the current signal quality is lower than the preset threshold , the UTRAN enables the compressed mode and starts inter-frequency measurement
2F
When the current signal quality is higher than the preset threshold, the UTRAN disables the compressed mode and stops inter-frequency measurement
2B
When the current signal is lower than the preset threshold and the signal quality of an inter-frequency neighbouring cell is higher than the preset threshold , the UTRAN trigger an inter-frequency handover based on coverage
2C
The estimated quality of a inter-frequency neighbor cell is higher than the preset threshold
During the movement, UE can detect the severing cell signal is getting worse, then the UE will report a 2D event to trigger compress mode, and then the UE can measure the signals of inter-frequency neighbors. During the measurement period, if the serving cell signal recovers, UE will report a 2F event to stop compress mode, that is to stop the inter-frequency measurement.
During the compress mode ,UE can measure the inter-frequency cell signal, and 2B and 2C event may be triggered.
Event 2D is triggered on the basis of the following formula
QUsed is the measured quality of the cell that uses the current frequency.
TUsed2d is the absolute quality threshold of the cell that uses the current frequency. Based on the service type (CS or PS) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured as Inter-freq CS measure start Ec/No THD, Inter-freq PS measure start Ec/No THD, Inter-freq CS measure start RSCP THD, Inter-freq PS measure start RSCP THD respectively.
H2d is the event 2D hysteresis value 2D hysteresis.
After the conditions of Event 2D are fulfilled and maintained until the 2D event trigger delay time is reached, the UE reports the Event 2D measurement report message.
Key parameters of of 2D Event
InterFreqCSThd2DEcN0
The default value of this parameter is -14 dB
InterFreqPSThd2DEcN0
InterFreqCSThd2DEcN0
Value range: -24~0dB;
Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
The recommended value of this parameter is -14dB
InterFreqPSThd2DEcN0
Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
Key parameters of of 2D Event
InterFreqCSThd2DRSCP
The default value of this parameter is -95 dBm
InterFreqPSThd2DRSCP
InterFreqCSThd2DRSCP
Value range: -115~-25dBm;
Content: For CS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
Content: For PS domain services, whenRSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
Key parameters of 2D Event
HYSTFOR2D
TRIGTIME2D
HYSTFOR2D
Value range: 0 to 14.5 dB, step: 0.5
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2D might not be triggered in time.
TRIGTIME2D
Parameter name: 2D event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2D to measurement signal change.
The Trigger Algorithm of 2F Event
Event 2F is triggered on the basis of the following formula
TUsed2F is the absolute quality threshold of the cell that uses the current frequency. Based on the service type (CS or PS) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured as Inter-freq CS measure start Ec/No THD, Inter-freq PS measure start Ec/No THD, Inter-freq CS measure start RSCP THD, Inter-freq PS measure start RSCP THD respectively.
H2F is the event 2F hysteresis value 2F hysteresis.
After the conditions of Event 2F are fulfilled and maintained until the 2F event trigger delay time is reached, the UE reports the Event 2F measurement report message.
Key parameters of 2F Event
InterFreqCSThd2FEcN0
InterFreqPSThd2FEcN0
InterFreqCSThd2FEcN0
Value range: -24~-0dB;
Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter. .
InterFreqPSThd2FEcN0
Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.
InterFreqCSThd2FRSCP
InterFreqPSThd2FRSCP
InterFreqCSThd2FRSCP
Content: For CS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter. .
The recommended value of this parameter is -92dBm
InterFreqPSThd2FRSCP
Value range: -115~-25dB;
Content: For PS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.
HYSTFOR2F
TRIGTIME2F
HYSTFOR2F
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2F might not be triggered in time.
TRIGTIME2F
Parameter name: 2F event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2F to measurement signal change.
The Trigger Algorithm of 2B Event
Event 2B is triggered on the basis of the following formula
, and
QNoused is the measured quality of the cell that uses other frequency.
TNoused2b is the absolute quality threshold of the cell that uses other frequency. Based on the service type (CS or PS) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured as Inter-freq CS target frequency trigger Ec/No THD, Inter-freq PS target frequency trigger Ec/No THD, Inter-freq CS target frequency trigger RSCP THD, And Inter-freq PS target frequency trigger RSCP THD respectively.
TUsed2d is the absolute quality threshold of the cell that uses the current frequency. Based on the service type (CS or PS) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured as Inter-freq CS measure start Ec/No THD, Inter-freq PS measure start Ec/No THD, Inter-freq CS measure start RSCP THD, Inter-freq PS measure start RSCP THD respectively.
H2b is the event 2B hysteresis value 2B hysteresis.
InterFreqCovHOCSThdEcN0
InterFreqCovHOPSThdEcN0
InterFreqCovHOCSThdEcN0
Content: For CS domain services,
- If the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the target frequency being higher than this threshold is necessary to the triggering of the event 2B.
- If the value of [Inter-frequency measure report mode] is PERIODICAL_REPORTING, this parameter is used to evaluate inter-frequency handovers at the RNC.
InterFreqCovHOPSThdEcN0
Content: - If the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the target frequency being higher than this threshold is necessary to the triggering of the event 2B.
- If the value of [Inter-frequency measure report mode] is PERIODICAL_REPORTING, this parameter is used to evaluate inter-frequency handovers at the RNC.
InterFreqCovHOCSThdRSCP
InterFreqCovHOPSThdRSCP
InterFreqCovHOCSThdRSCP
Content: For CS domain services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
Content: For PS domain services, whenRSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
IFHOUsedFreqCSThdEcN0
The default value of this parameter is -12dB
IFHOUsedFreqPSThdEcN0
IFHOUsedFreqCSThdEcN0
Value range: -24~0 dB
Content: For CS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .
The recommended value of this parameter is -12 dB
IFHOUsedFreqPSThdEcN0
Value range: -24~0 dB
Content: For PS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .
The recommended value of this parameter is -12 dB
IFHOUsedFreqCSThdRSCP
The default value of this parameter is -92dBm
IFHOUsedFreqPSThdRSCP
IFHOUsedFreqCSThdRSCP
Value range: -115~-25 dBm
Content: For CS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .
The recommended value of this parameter is -92 dBm
IFHOUsedFreqPSThdRSCP
Value range: -115~-25 dBm
Content: For PS domain services, if the value of [Inter-frequency measure report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 2B. The quality of the used frequency being lower than this threshold is necessary to the triggering of the event 2B .
The recommended value of this parameter is -92 dBm
HYSTFOR2B
TRIGTIME2B
HYSTFOR2B
The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2B might not be triggered in time.
TRIGTIME2B
Parameter name: 2B event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2B to measurement signal change.
The recommended value of this parameter is D0 (0ms )
Event 2C is triggered on the basis of the following formula
QNoused is the measured quality of the cell that uses other frequency.
TNoused is the absolute quality threshold of the cell that uses other frequency. Inter-freq measure target frequency trigger Ec/No THD.
H2c is the event 2C hysteresis value 2C hysteresis.
Key parameters of 2C Event
InterFreqNCovHOThdEcN0
Hystfor2C
TrigTime2C
The default value of this parameter is D640 (640ms)
InterFreqNCovHOThdEcN0
Content: This parameter is used to set measurement control on the event 2C. The event 2C is triggered when the signal quality of the target frequency is above this threshold .
Set this parameter through SET INTERFREQHONCOV, query it through LST INTERFREQHONCOV.
Hystfor2C
Value range: 0 to 14.5dB, step: 0.5 ;
Content: The event 2C is applied to non-coverage-based inter-frequency hard handover scenarios where inter-frequency measurement needs to be started. The event 2C is reported when the estimated quality of a non-used frequency is above a certain threshold. For details about the event 2C, refer to the 3GPP TS 25.331. The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2C might not be triggered in time .
TrigTime2C
Parameter name: 2C event trigger delay time
Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms;
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2C to measurement signal change.
The recommended value of this parameter is D640 (640ms)
Contents
Brief Introduction of Inter-RAT Handover
Characters of Inter-RAT Handover
Based on handover directions, inter-RAT handover is of two types:
UMTS->GSM handover
GSM->UMTS handover
Inter-RAT handover refers to the handover between different systems, such as UMTS and GSM, which use different radio access technologies (RAT).
Based on handover directions, inter-RAT handover is of two types:
UMTS->GSM handover (mainly described in this lecture)
GSM->UMTS handover
UMTS->GSM coverage-based handover
The coverage of UMTS is discontinuous at the very beginning. On the border, if the signal quality of UMTS rather than GSM is poor and if all services of the UE are supported by GSM, UMTS->GSM coverage-based handover is triggered.
UMTS->GSM load-based handover
If the load of UMTS rather than GSM is heavy and all services of the UE are supported by GSM, UMTS->GSM load-based handover is triggered.
UMTS->GSM service-based handover
Based on layered services, traffic of different classes is handed over to different systems. For example, when an Adaptive Multi Rate (AMR) speech service is requested, this call could be handed over to GSM.
Brief Introduction of Inter-RAT Handover
Advantages
For coverage, it can solve the problems from one system to another system
For capacity, it can enhance the utilizing efficiency of old equipments(2G->3G)
Disadvantages
The flow is complicated, and it demands higher compatibility for equipments
Demands more complicated UE
UMTS->GSM coverage-based handover
The CPICH Ec/N0 or CPICH RSCP of the UMTS cell to which the UE connects is lower than the corresponding threshold. In addition, there is a GSM cell whose GSM carrier RSSI is higher than the preset threshold.
UMTS->GSM load-based handover
The load of the UMTS cell to which the UE connects is higher than the threshold.
UMTS->GSM service-based handover
When a service is established, the Core Network (CN) requests a handover of the service to GSM.
Measurement of Inter-RAT Handover
BOTH is valid when the Inter-RAT measurement chooses PERIODICAL_REPORTING Mode.
Inter-RAT Handover Measurement Events
Event
Description
2D
When the signal quality of the currently used frequency is lower than the preset threshold, the RNC enables the compressed mode and starts inter-RAT measurement.
2F
When the signal quality of the currently used frequency is higher than the preset threshold, the RNC disables the compressed mode and stops inter-RAT measurement.
3A
When the signal quality of the currently used UMTS frequency is lower than the preset threshold while the signal quality of any other system is higher than the preset threshold, the RNC triggers UMTS->GSM handover based on coverage.
3C
When the signal quality of any other system is higher than the preset threshold, the RNC triggers UMTS->GSM handover based on load or service.
2D Event: initiate GSM measurement
2F Event: stop GSM measurement
3A Event: based on coverage
3C Event: based on non-coverage
Event 2D is triggered on the basis of the following formula:
QUsed is the measurement value of the cell at the currently used frequency.
TUsed2d is the absolute quality threshold of the cell at the currently used frequency. Based on CS or PS services, CPICH Ec/No, or RSCP measurement quantity, it can be Inter-RAT CS measure start Ec/No THD, Inter-RAT PS measure start Ec/No THD, Inter-RAT CS measure start RSCP THD, or Inter-RAT PS measure start RSCP THD.
H2d is 2D hysteresis, the hysteresis value of event 2D.
When the conditions for event 2D are met and maintained in time-to-trigger specified in 2D event trigger delay time, the UE sends the measurement report of Event 2D.
Key Parameters of 2D Event
INTERRATCSTHD2DECNO
The default value of this parameter is -14 ( -14 dB )
INTERRATPSTHD2DECNO
INTERRATCSTHD2DECNO
Value range: -24~0
Physical unit: dB
Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to activate compressed mode and start inter-RAT measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
The recommended value of this parameter is -14 ( -14 dB ).
INTERRATPSTHD2DECNO
Value range: -24~0
Physical unit: dB
Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to activate compressed mode and start inter-RAT measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
INTERRATCSTHD2DRSCP
The default value of this parameter is -100 ( -100 dBm )
INTERRATPSTHD2DRSCP
The default value of this parameter is -110 (-110 dBm )
INTERRATCSTHD2DRSCP
Value range: -115~-25
Physical unit: dBm
Content: For CS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to activate compressed mode and start inter-RAT measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
INTERRATPSTHD2DRSCP
Physical unit: dBm
Content: For PS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to activate compressed mode and start inter-RAT measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter.
HYSTFOR2D
The default value of this parameter is 4 ( 2 dB )
TRIGTIME2D
The default value of this parameter is D320 (320 ms )
HYSTFOR2D
Value range: 0~29
Physical unit: dB
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2D might not be triggered in time.
The recommended value of this parameter is 4 ( 2 dB ).
TRIGTIME2D
Parameter name: 2D event trigger delay time[ms]
Value range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000
Physical value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000
Physical unit: ms
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2D to measurement signal change.
The recommended value of this parameter is D320 ( 320ms ).
Event 2F is triggered on the basis of the following formula:
TUsed2f is the absolute quality threshold of the cell at the currently used frequency. Based on CS or PS services, CPICH Ec/No, or RSCP measurement quantity, it can be Inter-RAT CS measure start Ec/No THD, Inter-RAT PS measure start Ec/No THD, Inter-RAT CS measure start RSCP THD, or Inter-RAT PS measure start RSCP THD.
H2f is 2F hysteresis, the hysteresis value of event 2F.
When the conditions for event 2F are met and maintained in time-to-trigger specified in 2F event trigger delay time, the UE sends the measurement report of Event 2F.
Key Parameters of 2F Event
INTERRATCSTHD2FECNO
INTERRATPSTHD2FECNO
INTERRATCSTHD2FECNO
Value range: -24~0
Physical unit: dB
Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.
INTERRATPSTHD2FECNO
Value range: -24~0
Physical unit: dB
Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.
INTERRATCSTHD2FRSCP
INTERRATPSTHD2FRSCP
INTERRATCSTHD2FRSCP
Physical unit: dBm
Content: For CS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.
The recommended value of this parameter is -97 ( -97 dBm ).
INTERRATPSTHD2FRSCP
Physical unit: dBm
Content: For PS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-RAT measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter.
HYSTFOR2F
TRIGTIME2F
The default value of this parameter is D1280 (1280 ms )
HYSTFOR2F
Value range: 0~29
Physical unit: dB
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 2F might not be triggered in time.
TRIGTIME2F
Parameter name: 2F event trigger delay time[ms]
Physical unit: ms
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 2F to measurement signal change.
The Trigger Algorithm of 3A Event
Event 3A is triggered on the basis of the following formula:
TUsed is the absolute quality threshold of the cell at the currently used frequency. Based on CS or PS services, CPICH Ec/No, or RSCP measurement quantity, it can be Inter-RAT CS Used frequency trigger Ec/No THD, Inter-RAT PS Used frequency trigger Ec/No THD, Inter-RAT CS Used frequency trigger RSCP THD, or Inter-RAT PS Used frequency trigger RSCP THD.
MOtherRat is the measurement value of the cell (in another RAT) in the reporting range.
CIOOtherRat is cell individual offset, the offset value of the cell (in another RAT) in the reporting range.
TOtherRat is the absolute inter-RAT handover threshold. Based on CS or PS services, it can be Inter-RAT CS handover decision THD or Inter-RAT PS handover decision THD.
H3a is 3A hysteresis, the hysteresis value of event 3A.
When the conditions for event 3A are met and maintained in time-to-trigger specified in 3A event trigger delay time, the UE sends the measurement report of event 3A.
Key Parameters of 3A Event
IRHOUSEDFREQCSTHDECNO
IRHOUSEDFREQPSTHDECNO
IRHOUSEDFREQCSTHDECNO
Parameter name: Inter-RAT CS Used frequency trigger Ec/No THD [dB]
Value range: -24~0
Physical unit: dB
Content: For CS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT CS handover decision THD] is reached.
IRHOUSEDFREQPSTHDECNO
Parameter name: Inter-RAT PS Used frequency trigger Ec/No THD [dB]
Value range: -24~0
Physical unit: dB
Content: For PS domain services, when Ec/No is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT PS handover decision THD] is reached.
IRHOUSEDFREQCSTHDRSCP
IRHOUSEDFREQPSTHDRSCP
Parameter name: Inter-RAT CS Used frequency trigger RSCP THD [dBm]
Physical unit: dBm
Content: For CS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT CS handover decision THD] is reached.
Parameter name: Inter-RAT PS Used frequency trigger RSCP THD [dBm]
Physical unit: dBm
Content: For PS domain services, when RSCP is used as the measurement quantity for inter-RAT measurement and the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set measurement control on the event 3A. The event 3A is triggered, when the quality of the currently used UTRAN frequency is below this threshold and the [Inter-RAT PS handover decision THD] is reached.
INTERRATCOVHOCSTHD
The default value of this parameter is 16 ( -95 dBm )
INTERRATCOVHOPSTHD
INTERRATCOVHOCSTHD
Value range: 0~63
Physical value range: -110~-48 (The value 1 corresponds to the physical value -110, 2 to -109, ..., 63 to -48.)
Physical unit: dBm
Content: For CS domain services,
- If the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 3A. The event 3A is triggered, when the quality of the cell with the target frequency is higher than this threshold and the threshold of the used frequency quality of the corresponding measurement quantity is reached.
- If the value of [Inter-RAT report mode] is PERIODICAL_REPORTING, this parameter is used to evaluate coverage-based inter-RAT handovers at the RNC.
Note that the value 0 means the physical value is smaller than -110 dBm.
The recommended value of this parameter is 16 ( -95 dBm ).
INTERRATCOVHOPSTHD
Value range: 0~63
Physical value range: -110~-48 (The value 1 corresponds to the physical value -110, 2 to -109, ..., 63 to -48.)
Physical unit: dBm
Content: For PS domain services,
- If the value of [Inter-RAT report mode] is EVENT_TRIGGER, this parameter is used to set the measurement control on the event 3A. The event 3A is triggered, when the quality of the cell with the target frequency is higher than this threshold and the threshold of the used frequency quality of the corresponding measurement quantity is reached.
- If the value of [Inter-RAT report mode] is PERIODICAL_REPORTING, this parameter is used to evaluate coverage-based inter-RAT handovers at the RNC.
Note that the value 0 means the physical value is smaller than -110 dBm.
The recommended value of this parameter is 16 (-95 dBm ).
HYSTFOR3A
TRIGTIME3A
The default value of this parameter is D0 ( 0 ms )
HYSTFOR3A
Value range: 0~15
Physical unit: dB
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer the decision mistakes. In this case, however, the event 3A might not be triggered in time.
TRIGTIME3A
Parameter name: 3A event trigger delay time[ms]
Physical unit: ms
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 3A to measurement signal change.
CELLINDIVIDALOFFSET
CELLINDIVIDALOFFSET
Value range: -50~50
Physical unit: dB
Content: This parameter is used in inter-RAT handover decision. The larger the parameter, the higher the handover priority of the GSM cell. The smaller the parameter, the lower the handover priority of the GSM cell.
Set this parameter through ADD GSMNCELL, query it through LST GSMNCELL.
Event 3C is triggered on the basis of the following formula:
MOtherRat is the measurement value of the cell (in another RAT) in the reporting range.
CIOOtherRat is cell individual offset, the offset value of the cell (in another RAT) in the reporting range.
TOtherRat is the absolute inter-RAT handover threshold. Based on CS or PS services, it can be Inter-RAT CS handover decision THD or Inter-RAT PS handover decision THD.
H3c is 3C hysteresis, the hysteresis value of event 3C.
When the conditions for event 3C are met and the delay requirement specified by the 3C event trigger delay time parameter can be satisfied, the UE sends the measurement report of event 3C.
Key Parameters of 3C Event
INTERRATNCOVHOCSTHD
INTERRATNCOVHOPSTHD
The default value of this parameter is 21 (-90 dBm )
INTERRATNCOVHOCSTHD
Value range: 0 to 63
Physical value range: -110 to -48 (The value 1 corresponds to the physical value -110, 2 to -109, ..., 63 to -48)
Physical unit: dB
Content: This parameter is used to set measurement control on the event 3C. The event 3C is triggered when the quality of the target frequency is higher than this threshold. Note that the value 0 means the physical value is smaller than -110 dBm.
Set this parameter through SET INTERRATHONCOV, query it through LST INTERRATHONCOV.
INTERRATNCOVHOPSTHD
Physical value range: -110 to -48 (The value 1 corresponds to the physical value -110, 2 to -109, ..., 63 to -48)
Physical unit: dB
Content: The event 3C is triggered when the quality of the target frequency is higher than this threshold. Note that the value 0 means the physical value is smaller than -110 dBm.
HYSTFOR3C
TRIGTIME3C
The default value of this parameter is D640 ( 650 ms )
HYSTFOR3C
Value range: 0~15
Physical unit: dB
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the less the ping-pong effect and the fewer decision mistakes. In this case, however, the event 3C might not be triggered in time.
TRIGTIME3C
Parameter name: 3C event trigger delay time[ms]
Physical unit: ms
Content: The value of this parameter is relevant to the slow fading characteristic. The larger the value of this parameter, the lower the incorrect decision probability, but the slower the response of the event 3C to measurement signal change.
PENALTYTIMEFORINTERRATHO
The default value of this parameter is 30 ( 30 s )
INTERRATHOATTEMPTS
The default value of this parameter is 16
PENALTYTIMEFORINTERRATHO
Physical unit: s
Content: An inter-RAT handover to a GSM cell may fail due to the heavy load of the GSM cell. Therefore, in the period of time specified by this parameter, inter-RAT handover requests are not sent to the GSM cell.
The recommended value of this parameter is 30 ( 30 s ).
INTERRATHOATTEMPTS
Physical unit: times
Content: This parameter specifies the maximum number of attempts for the RNC to perform inter-RAT handovers after a non-coverage-based inter-RAT handover failure. For later handover attempts, target cells must be selected. Ensure that the target cells have not been tried but satisfy the handover conditions. No matter the inter-RAT handover failure penalty timer expires or not.
The recommended value of this parameter is 16.
INTERRATMEASTIME
The default value of this parameter is 60 ( 60 s )
INTERRATMEASTIME
Physical unit: s
Content: After inter-RAT measurement starts, if no inter-RAT handover is performed when this timer expires, the inter-RAT measurement is stopped. In addition, the compressed mode is deactivated, if any. The value 0 indicates the timer is not to be enabled.
The recommended value of this parameter is 60 ( 60 S ).
Contents
Blind Handover Measurement
Blind handover means UE can directly handover to the neighboring cell without measuring it.
If the serving frequency signal is getting worse quickly, but UE can not trigger a inter-frequency measurement and hard handover in time, blind handover might be used to save the call.
In Huawei implementation, blind handover can be triggered by intra-frequency measurement event 1F.
Where:
MOld is the measurement value of the cell signal that becomes worse
T1f is the absolute threshold of event 1F.
H1f is the hysteresis value of event 1F.
For different intra-frequency measurement quantity, the threshold T1f are set to 1F Event Absolute EcNo Threshold, 1F Event Absolute RSCP Threshold respectively.
Absolute Threshold T1f
Reporting event 1F
1F Trigger Delay Time
If the signal quality of a cell in the active set is worse than T1f - H1f /2 , and last for a certain time 1F Event Trigger Delay Time, then UE reports event 1F.
Key Parameters of Event 1F
INTRAABLTHDFOR1FECNO
The recommended value is -24 dB
INTRAABLTHDFOR1FRSCP
The recommended value is -115 dBm
INTRAABLTHDFOR1FECNO
Value range: -24 to 0
Physical value range: -24 to 0 dB. Step: 1
Content: The absolute EcNo threshold of the event 1F.It is easier to trigger event 1F if the value increases. It is harder to trigger event 1F if the value decreases.
Recommended value: -24
Value range: -115 to 25
Physical value range: -115 to 25 dB. Step: 1
Content: The absolute RSCP threshold of the event 1F.It is easier to trigger event 1F if the value increases. It is harder to trigger event 1F if the value decreases.
The recommended value is -115 dBm
For RNC level, set these two parameter through SET INTRAFREQHO, query them through LST INTRAFREQHO, and modify them through SET INTRAFREQHO
For cell level, set these two parameter through ADD CELLINTRAFREQHO, query them through LST CELLINTRAFREQHO, and modify them through MOD CELLINTRAFREQHO.
Key Parameters of Event 1F
HYSTFOR1F
TRIGTIME1F
The recommended value is D640, namely 640 ms
HYSTFOR1F
Physical value range: 0 to 7.5 dB. Step: 0.5
Content: The hysteresis value of the event 1F. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the less ping-pong effect and misjudgement can be caused. However, in this case, the event cannot be triggered in time.
Recommended value: 8
Parameter name: 1F event trigger delay time
Physical value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
Content: The trigger delay time of the event 1F. This parameter value is related to the slow fading characteristic. The greater this parameter is set, the smaller the misjudgement probability, but the lower the response speed of the event to the measured signal changes.
Recommended value: D640
For RNC level, set these two parameter through SET INTRAFREQHO, query them through LST INTRAFREQHO, and modify them through SET INTRAFREQHO
For cell level, set these two parameter through ADD CELLINTRAFREQHO, query them through LST CELLINTRAFREQHO, and modify them through MOD CELLINTRAFREQHO.
Blind Handover Decision
After receiving event 1F of best cell from UE, the RNC would check if blind handover neighbor is configured for the cell.
If multiple blind handover neighbors are configured, the RNC would perform blind handover to the target cell with the highest priority
When we configure the inter-frequency neighbor cell or GSM neighbor cell, two parameters of blind handover is included: Blind Handover Flag and Blind Handover Priority.
Key Parameters of Blind Handover
BLINDHOFLAG
BLINDHOPRIO
The value is set according to actual situation.
BLINDHOFLAG
Value range: FALSE, TRUE
Content: This parameter indicates whether the neighboring cell is the target cell for blind handovers. If the value is TRUE, blind handovers can be performed to the neighboring cell.
Default value: FALSE
Parameter name: Blind handover Priority
Content: The value 0 indicates the highest priority, and 30 the lowest. A neighboring cell of a cell must have a unique priority.
It is suggested 0 to 15 assigned to the neighboring cells superposed to the cell specified by [CELLID]. The success rate of handovers to these cells can be guaranteed.
Neighboring cells with priorities from 16 to 30 can be performed with blind handovers, but the handovers may fail.
Recommended value (default value): none
Set these two parameter through ADD INTERFREQNCELL or ADD GSMNCELL, query them through LST INTERFREQNCELL or LST GSMNCELL, and modify them through MOD INTERFREQNCELL or MOD GSMNCELL.
Thank you
Measure the CPICH Ec/N0 of the serving cell and
its neighboring cells as well as the relative time
difference between the cells

3 wcdma handover

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