WCDMA 3G ( Intra-Frequency ) Handover Principle and Parameters

WCDMA Handover Principle and Relevant Parameters

"Intra-Frequency Handover"

Why mobile system need handov

• LINK:-why handover is needed?

1.The mobility of UE

2.Load Balance

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.

Handover types supported by WCDMA-UMTS

HCS:WCDMA hierarchical cell structure

The Basic Concepts of Handover

1.     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. 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.

2.     Monitored set :Cells, which are not included in the active set, but are included in the CELL_INFO_LIST belong to the monitored set.

3.     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.

4.     RL: Radio link between NodeB and UE.

5.     RLS: Radio link set. The RLs from same NodeB.

6.     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.

7.     Soft handover gain: We have introduced in Coverage Planning.

8.     CPICH: Common Pilot Channel. UE measure the signal strength of CPICH for handover decision. 

WCDMA Handover types supported by UMTS can be classified as:

I.          Intra-frequency handover.

•  LINK:- What is Intra-frequency handover

II.          Inter-frequency handover.

• LINK:- What is Inter-frequency handover

III.          Inter-RAT handover.

• LINK:- 3G wcdmaI-RAT ( InterRat ) Handover

Classification:-

I.          Intra-Frequency Handover Includes:-

A.    Intra-Frequency Handover Overview

B.    Intra-Frequency Handover Procedure

C.    Signaling Procedures for Intra-Frequency Handover

Elaboration:-

A.    Intra-Frequency Handover Overview

The carrier frequencies of the current cell and target cell are the same

Intra-frequency handover consists of two types,

·       Intra-frequency soft handover:

-- more than one radio link are set up for the UE.

·       Intra-frequency hard handover:

-- only one radio link is set up for the UE.

Intra Frequence Handover

• LINK:- Hard handover and soft handover
• LINK:- 3g wcdma IRat frequency handover detailed topic

Intra-frequency soft handover is more commonly used than intra-frequency hard handover. Intra-frequency hard handover is used only in some special scenarios, for example, when there is no Iur interface between two RNCs.

Comparison between soft handover and hard handover:

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.

Intra-Frequency Soft Handover :

·       Soft Handover

·       Softer Handover

Intra-Frequency soft handover is a function in which the UE is connected to several cells at the same time. Addition or release of radio links are controlled by the ACTIVE SET UPDATE procedure.

Soft handover:-

A UE is in the overlapping cell coverage area of two sectors belonging to different base stations. The communications between UE and base station take place concurrently via two air interface channels from each base station separately.

Softer handover:-

A UE is in the overlapping cell coverage area of two adjacent sectors of a base station. The communications between UE and base station take place concurrently via two air interface channels, one for each sector separately.

Comparison between soft handover and softer handover

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 do not consume transport resource of Iub

Intra-Frequency Hard Handover :

l  No Iur interface

l  Iur interface is congested

l  High-speed Best Effort (BE) service Handover

l  Soft handover fails

Intra-frequency hard handover refers to a handover where all the old radio links are released before the new radio links are established. Compared with soft handover, intra-frequency hard handover uses fewer resources.The scenarios of intra-frequency hard handover are as follows:

The UE needs to perform the intra-frequency handover between two cells configured in different RNCs. No Iur interface is present between RNCs.The UE needs to perform the intra-frequency handover between two cells configured in different RNCs. The Iur interface is congested between RNCs.There is a high-speed Best Effort (BE) service.

Compared with soft handover, intra-frequency hard handover is used to save downlink bandwidth for a high-speed BE service.The intra-frequency soft handover fails and intra-frequency hard handover is allowed. When intra-frequency soft handover fails because of a congestion problem of the target cell, the RNC tries an intra-frequency hard handover with a lower service bit rate.

B.  Intra-Frequency Handover Procedure:-

·       Intra-frequency handover procedure is divided into three phases: handover measurement, handover decision, and handover execution.

·       After the UE transits to CELL_DCH state in connected mode during a call, the RNC sends a measurement control message to instruct the UE to take measurements and report the measurement event results.

·       Upon receiving an event report from the UE, the RNC makes a handover decision and performs the corresponding handover.

figure shows handover procedure

Intra-Frequency Handover Procedure Contents:-

       i.          Intra-Frequency Handover Measurement

     ii.          Intra-Frequency Handover Decision and Execution

   iii.          Neighboring Cell Combination Algorithm 

i.          Intra-Frequency Handover Measurement:-

MEASUREMENT CONTROL:-

MEASUREMENT CONTROL Intra-Frequency Handover Measurement

• LINK:- Diversity fading and interference in 3G Network

The measurement control message carries the following information:

-- Event trigger threshold

-- Hysteresis value

-- Event trigger delay time

-- Neighboring cell list

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 or quality 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 , the CPICH Ec/No of the target cell, and the triggered event.

MEASUREMENT REPORT Intra-Frequency Handover Measurement

--L3 Filtering for Intra-Frequency Handover

--The value after L3 filtering procedure is calculated according to following formula:

                                    Fn = (1 - α) x Fn-1 + α x Mn

Where:-

-- Fn is the new measurement value obtained after L3 filtering.

-- Fn-1 is the last measurement value obtained after L3 filtering.

-- Mn is the latest measurement value obtained from the physical layer.

-- α = 1/2(k/2) (k is set to Intra-freq meas L3 filter coeff)

When α is set to 1, that is, k = 0, no L3 filtering is performed.

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

Key parameters of Intra-frequency Measurement

·       Intra-freq Measure Quantity

ü  Parameter ID: IntraFreqMeasQuantity 

ü  The default value of this parameter is CPICH_Ec/No

·       Intra-freq meas L3 filter coeff

ü  Parameter ID: FilterCoef

ü  The default value of this parameter is 3

     The measurement quantity of intra-frequency handover can be Common Pilot Channel (CPICH) Ec/No or CPICH Received Signal Code Power (RSCP). It can be used in all the measurement events of intra-frequency handover

·       Intra-freq Measure Quantity

ü  Parameter ID: IntraFreqMeasQuantity

ü  Value range: CPICH_Ec/No, CPICH_RSCP

ü  Content: This parameter specifies the measurement quantity used in intra-frequency measurement.

ü  The default value of this parameter is CPICH_Ec/No

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

Before judging a measurement event and sending the measurement report, the UE performs L3 filtering for the measurement value.

·       Intra-freq meas L3 filter coeff

ü  Parameter ID: FilterCoef

ü  Value range: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19

ü  Content: This parameter specifies the intra-frequency measurement L3 filter coefficient. The greater this value is set, the greater the smoothing effect and the higher the anti-fast fading capability are, but the lower the signal change tracing capability is.

ü  The default value of this parameter is 3

Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

MEASUREMENT EVENTS

If the signal quality of a cell that is not in the active set is higher than Th1A for a period of time specified by 1A event trigger delay time (that is, Time to trigger in the figure), the UE reports event 1A

1A EVENT

1A EVENT

Where:-

A: signal curve of the best cell in the active set  

B: signal curve of a cell in the monitoring set

C: Th1A curve

Parameters of Intra-Frequency Handover

l  CS non VP service 1A event relative THD
ü  Parameter ID: IntraRelThdFor1ACSNVP
ü  The default value of this parameter is 6 ( 3dB )
l  VP service 1A event relative THD
ü  Parameter ID: IntraRelThdFor1ACSVP
ü  The default value of this parameter is 6 ( 3dB )
l  PS service 1A event relative threshold
ü  Parameter ID: IntraRelThdFor1APS 
ü  The default value of this parameter is 6 ( 3dB )
l  CS non VP service 1A event relative THD
ü  Parameter ID: IntraRelThdFor1ACSNVP
ü  Value range: 0~14.5; step: 0.5
ü  Content: This parameter specifies the relative threshold of event 1A for the CS non-VP service. The larger the parameter value is, the more easily event 1A is triggered..
ü  The default value of this parameter is 6 (3dB)
ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .
l  VP service 1A event relative THD
ü  Parameter ID: IntraRelThdFor1ACSVP
ü  Value range: 0~14.5; step: 0.5
ü  Content: This parameter specifies the relative threshold of event 1A for the VP service. The larger the parameter value is, the more easily event 1A is triggered..
ü  The default value of this parameter is 6 (3dB)
ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .
l  PS service 1A event relative THD
ü  Parameter ID: IntraRelThdFor1APS
ü  Value range: 0~14.5; step: 0.5
ü  Content: This parameter specifies the PS service relative threshold of event 1A. The smaller the parameter value is, the more easily event 1A is triggered.
ü  The default value of this parameter is 6 (3dB)
ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .
l  Cell oriented Cell Individual Offset
ü  Parameter ID: CIO
ü  The default value of this parameter is 0 (0dB )
l  Neighboring cell oriented CIO
ü  Parameter ID: CIOOffset 
ü  The default value of this parameter is 0 (0dB )
l  Cell oriented Cell Individual Offset
ü  Parameter ID: CIO
ü  Value range: -10 to +10
ü  Content: This parameter is used together with Neighboring cell oriented CIO. The sum of the two parameter values is added to the measurement quantity before the UE evaluates whether an event occurred. In handover algorithms, this parameter is used for moving the border of a cell.  
ü  The default value of this parameter is 0 ( 0dB )
ü  Set this parameter through ADD CELLSETUP/MOD CELLSETUP
l  Neighboring cell oriented CIO
ü  Parameter ID: CIOOffset
ü  Value range: -10 to +10
ü  Content: This parameter is used together with Cell oriented Cell Individual Offset. The sum of the two parameter values is added to the measurement quantity before the UE evaluates whether an event has occurred. In handover algorithms, this parameter is used for moving the border of 2 neighbors.
ü  The default value of this parameter is 0 ( 0dB )
ü  Set this parameter through ADD INTRAFREQNCELL/MOD INTRAFREQNCELL
l  1A hysteresis
ü  Parameter ID: Hystfor1A
ü  The default value of this parameter is 0 (0dB )
l  1A event trigger delay time
ü  Parameter ID: TrigTime1A
ü  The default value of this parameter is D320 ( 320ms )
l  Weighted factor
ü  Parameter ID: Weight
ü  The default value of this parameter is 0
l  1A hysteresis
ü  Parameter ID: Hystfor1A
ü  Value range: 0~7.5; step: 0.5
ü  Content: This parameter specifies the hysteresis value of event 1A. It is related to the slow fading characteristic.
ü  The default value of this parameter is 0 (0dB)
ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .
l  1A event trigger delay time
ü  Parameter ID: TrigTime1A
ü  Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms
ü  Content: This parameter specifies the trigger delay time of event 1A. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes.
ü  The recommended value of this parameter is D320 ( 320ms )
ü  Set this parameter through SET INTRAFREQHO/ADD CELL INTRA FREQ HO/MOD CELL INTRA FREQ HO .
l  Weighted factor
ü  Parameter ID: Weight
ü  Value range: 0~20,step:0.1
ü  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 the parameter value, the higher the soft handover relative threshold. When this value is set to 0, the soft handover relative threshold is determined only by the best cell in the active set. .
ü  The Default Value of this parameter is 0
ü  Set this parameter through SET INTRAFREQHO/ADD CELL INTRA FREQ HO/MOD CELL INTRA FREQ HO .

1A Event Report Mode:

l  Event Trigger Report
l  Event to Periodical Report
l  The report mode of 1A is Event Trigger Report .
l  Generally the event 1A is reported only once. However, to avoid measurement report loss, the event 1A reporting can be turned to periodical reporting.
l  1A event to periodical rpt period
ü  Parameter ID: ReportIntervalfor1A 
ü  The default value of this parameter is D4000 (4000 ms )
l  1A event to periodical rpt number
ü  Parameter ID: PeriodMRReportNumfor1A 
ü  The default value of this parameter is D16
l  1A event to periodical rpt period
ü  Parameter ID: ReportIntervalfor1A
ü  Value range: NON_PERIODIC_REPORT, D250, D500, D1000, D2000, D4000, D8000, D16000
ü  Content: The reporting period for the event 1A. Generally the event 1A is reported only once. However, to avoid measurement report loss, the event 1A reporting can be turned to periodical reporting.
ü  The default value of this parameter is D4000 (4000 ms)
ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .
l  1A event to periodical rpt number
ü  Parameter ID: PeriodMRReportNumfor1A
ü  Value range: D1, D2, D4, D8, D16, D32, D64, infinity
ü  Content: The periodical reporting times for the event 1A. When the actual times exceed this parameter, the periodical reporting comes to an end.
ü  The recommended value of this parameter is D16
ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO

1B EVENT

1B EVENT

A: signal curve of the best cell in the active set  

B: signal curve of a cell in the monitoring set

C: Th1B curve

If the signal quality of a cell in the active set is lower than Th1B curve for a period of time specified by 1B event trigger delay time (Time to trigger in the figure), the UE reports event 1B

l  CS non VP service 1B event relative THD

ü  Parameter ID: IntraRelThdFor1BCSNVP

ü  The default value of this parameter is 12 ( 6dB )

l  VP service 1B event relative THD

ü  Parameter ID: IntraRelThdFor1BCSVP

ü  The default value of this parameter is 12 ( 6dB )

l  PS service 1B event relative threshold

ü  Parameter ID: IntraRelThdFor1BPS 

ü  The default value of this parameter is 12 ( 6dB )

l  CS non VP service 1B event relative THD

ü  Parameter ID: IntraRelThdFor1BCSNVP

ü  Value range: 0~14.5; step: 0.5

ü  Content: This parameter specifies the relative threshold of event 1B for the CS non-VP service. The smaller the parameter value is, the more easily event 1B is triggered .

ü  The default value of this parameter is 12 (6dB)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  VP service 1B event relative THD

ü  Parameter ID: IntraRelThdFor1BCSVP

ü  Value range: 0~14.5; step: 0.5

ü  Content: This parameter specifies the relative threshold of event 1A for the VP service. The smaller the parameter value is, the more easily event 1B is triggered .

ü  The default value of this parameter is 12 (6dB)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  PS service 1B event relative THD

ü  Parameter ID: IntraRelThdFor1APS

ü  Value range: 0~14.5; step: 0.5

ü  Content: This parameter specifies the PS service relative threshold of event 1B. The smaller the parameter value is, the more easily event 1B is triggered .

ü  The default value of this parameter is 12 (6dB)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  1B hysteresis

ü  Parameter ID: Hystfor1B

ü  The default value of this parameter is 0 (0dB )

l  1B event trigger delay time

ü  Parameter ID: TrigTime1B

ü  The default value of this parameter is D640 ( 640ms )

l  1B hysteresis

ü  Parameter ID: Hystfor1B

ü  Value range: 0~7.5; step: 0.5

ü  Content: This parameter specifies the hysteresis value of event 1B. It is related to the slow fading characteristic.

ü  The default value of this parameter is 0 (0dB)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  1B event trigger delay time

ü  Parameter ID: TrigTime1B

ü  Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

ü  Content: This parameter specifies the trigger delay time of event 1B. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes.

ü  The recommended value of this parameter is D640 ( 640ms )

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

1C EVENT 

1C EVENT

A: signal curve of the best cell in the active set  

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: Th1C curve

If the signal quality of a cell not in the active set is higher than Th_1C for a period of time specified by 1C event trigger delay time (Time to trigger in the figure), the UE reports event 1C

l  1C hysteresis

ü  Parameter ID: Hystfor1C

ü  The default value of this parameter is 8 (4dB )

l  1C event trigger delay time

ü  Parameter ID: TrigTime1C

ü  The default value of this parameter is D640 ( 640ms )

l  1C hysteresis

ü  Parameter ID: Hystfor1C

ü  Value range: 0~7.5; step: 0.5

ü  Content: This parameter specifies the hysteresis value of event 1C. It is related to the slow fading characteristic.

ü  The default value of this parameter is 8 (4dB)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  1C event trigger delay time

ü  Parameter ID: TrigTime1C

ü  Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

ü  Content: This parameter specifies the trigger delay time of event 1C. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes.

ü  The recommended value of this parameter is D640 ( 640ms )

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

1C Event Report Mode:

1. Event Trigger Report

2. Event to Periodical Report

The report mode of 1C is Event Trigger Report .

Generally the event 1C is reported only once. However, to avoid measurement report loss, the event 1C reporting can be turned to periodical reporting.

l  1C event to periodical rpt period

ü  Parameter ID: ReportIntervalfor1C 

ü  The default value of this parameter is D4000 (4000 ms )

l  1C event to periodical rpt number

ü  Parameter ID: PeriodMRReportNumfor1C 

ü  The default value of this parameter is D16

l  1C event to periodical rpt period

ü  Parameter ID: ReportIntervalfor1C

ü  Value range: NON_PERIODIC_REPORT, D250, D500, D1000, D2000, D4000, D8000, D16000

ü  Content: The reporting period for the event 1C. Generally the event 1C is reported only once. However, to avoid measurement report loss, the event 1C reporting can be turned to periodical reporting.

ü  The default value of this parameter is D4000 (4000 ms)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  1C event to periodical rpt number

ü  Parameter ID: PeriodMRReportNumfor1C

ü  Value range: D1, D2, D4, D8, D16, D32, D64, infinity

ü  Content: The periodical reporting times for the event 1C. When the actual times exceed this parameter, the periodical reporting comes to an end.

ü  The recommended value of this parameter is D16

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO

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1D EVENT 

1D EVENT

A: signal curve of the best cell in the active set  

B: signal curve of a cell in the active set or monitoring set

C: Th1D curve

If the signal quality of a cell not in the active set is higher than Th1D for a period of time specified by 1D event trigger delay time (Time to trigger in the figure), the UE reports event 1D

l  1D hysteresis

ü  Parameter ID: Hystfor1D

ü  The default value of this parameter is 8 (4dB )

l  1D event trigger delay time

ü  Parameter ID: TrigTime1D

ü  The default value of this parameter is D640 ( 640ms )

l  1D hysteresis

ü  Parameter ID: Hystfor1D

ü  Value range: 0~7.5; step: 0.5

ü  Content: This parameter specifies the hysteresis value of event 1D. It is related to the slow fading characteristic.

ü  The default value of this parameter is 8 (4dB)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  1D event trigger delay time

ü  Parameter ID: TrigTime1D

ü  Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

ü  Content: This parameter specifies the trigger delay time of event 1D. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes.

ü  The recommended value of this parameter is D640 ( 640ms )

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO 

1J EVENT

1J EVENT

A: signal quality curve of a cell in the E-DCH active set

B: signal quality curve of the worst cell in the E-DCH active set

C: signal quality curve of a cell not in the E-DCH active set but included in DCH active set

D: signal quality curve of a cell not in the E-DCH active set but included in DCH active set

In the figure, the hysteresis and the cell individual offsets for all cells equal 0

l  1J Event function

ü  3GPP define the maximum DCH active set size is 6 and the maximum E-DCH active set size is4    

ü  The DCH active set covers the E-DCH active set or they are the same

ü  The best cell in E-DCH active set should be the same as that in DCH active set

ü  Uplink channel type of UE is decided by the best cell in DCH active set

--Uplink channel is E-DCH if the best cell in DCH active set supports HSUPA

--Uplink channel is DCH if the best cell in DCH active set can NOT support HSUPA

l  Processing procedure for 1J Event

ü  The UE reports 1J Event if it find a non-active E-DCH but active DCH cell PCICH becomes better than an active E-DCH PCIPCH

--RNC will add the target cell into E-DCH active set if the E-DCH active set is NOT full

--RNC will perform replace procedure if the E-DCH active set is full

l  1J hysteresis

ü  Parameter ID: Hystfor1J

ü  The default value of this parameter is 8 (4dB )

l  1J event trigger delay time

ü  Parameter ID: TrigTime1J

ü  The default value of this parameter is D640 ( 640ms )

l  Max number of cell in edch active cell

ü  Parameter ID: MAXEDCHCELLINACTIVESET

ü  The default value of this parameter is 3

l  1J hysteresis

ü  Parameter ID: Hystfor1J

ü  Value range: 0~7.5; step: 0.5

ü  Content: This parameter specifies the hysteresis value of event 1J. It is related to the slow fading characteristic.

ü  The default value of this parameter is 8 (4dB)

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

l  1J event trigger delay time

ü  Parameter ID: TrigTime1J

ü  Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

ü  Content: This parameter specifies the trigger delay time of event 1D. It is related to the slow fading characteristic.

ü  The recommended value of this parameter is D640 ( 640ms )

ü  Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

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l  Max number of cell in edch active cell

ü  Parameter ID: MAXEDCHCELLINACTIVESET

ü  Value range: 1 to 4

ü  Content: This parameter specifies the maximum number of cells in the E-DCH active set. 

ü  The recommended value of this parameter is 3

ü  Set this parameter through SET HOCOMM .

l  1J Event Report Mode:

ü  Event Trigger Report

ü  Event to Periodical Report

l  Parameters

ü  1J event to periodical rpt period

l  Parameter ID: ReportIntervalfor1J 

l  The default value of this parameter is D1000 (1000 ms )

ü  1J event to periodical rpt number

l  Parameter ID: PeriodMRReportNumfor1J 

l  The default value of this parameter is D64

The report mode of 1J is Event Trigger Report .

Generally the event 1J is reported only once. However, to avoid measurement report loss, the event 1J reporting can be turned to periodical reporting.

l  1J event to periodical rpt period

ii.  Intra-Frequency Handover Decision and Execution:-

RNC will make decision and execute handover depends on the Events the RNC receives.

ü  1A Event

ü  1B Event

ü  1C Event

ü  1D Event

ü  1J Event

l  Max number of cell in active set

ü  Parameter ID: MaxCellInActiveSet

ü  The default value of this parameter is 3

l  Minimum Quality Threshold for SHO

ü  Parameter ID: SHOQualmin 

ü  The default value of this parameter is -24 ( -24dB)

Rate Reduction After an SHO Failure

For R99 NRT services to increase the probability of a successful soft handover, the rate reduction is triggered after a admission failure

Rate Reduction After an SHO Failure

If the RNC receives a 1A, 1C, or 1D measurement report, the corresponding cell tries to admit the UE. If the cell fails to admit the UE, the RNC performs the estimation procedure for rate reduction.

l  procedure for rate reduction

p Estimation

p Execution

Estimation Procedure for Rate Reduction

Estimation Procedure for Rate Reduction

iii.  Neighboring Cell Combination Algorithm:-

l  When the UE is in soft handover state

p Intra-frequency neighboring cells

p Inter-frequency neighboring cells

p Inter-RAT neighboring cells

l  The combined neighboring cell list is affect by :

p Repeat times

p Serving cell signal quality (Ec/No) order

p Neighboring cell priority

Neighboring Cell Combination Algorithm

l  After obtaining the intra-frequency neighboring cells of each cell in the active set, the RNC calculates the union neighboring cell set of the intra-frequency cells, which is also referred as Sall, by using the following method. This method can also be used to generate the Sall of inter-frequency or Inter-RAT cells.

1,The intra-frequency, inter-frequency and Inter-RAT neighboring cells of each cell in the current active set are obtained.

2,The RNC sequences the cells in the active set in descending order of CPICH Ec/No according to the latest measurement report (event 1A, 1B, 1C, or 1D) from the UE. The best cell is based on event 1D, whereas other cells are based on the latest measurement report.

3,The cells in the active set are added to Sall.

4,The neighboring cells of the best cell in the active set are added to Sall. The priority of neighbor cell, which are set for each neighboring cell, are used to change the order of adding the neighboring cells to Sall.

5,The neighboring cells of other cells in the active set are added to Sall in descending order by CPICH Ec/No values of these cells in the active set. The neighboring cells of the same cell in the active set are added according to The priority of neighbor cell and repeated number of repeated neighboring cell is recorded.

6,If there are more than 32 neighboring cells in Sall, delete the neighboring cells whose repeat number in Sall is less. The top 32 neighboring cells are grouped into the final Sall.

p If The flag of the priority is switched to FALSE, The priority of neighbor cell is cleared.

p If The flag of the priority is switched to TRUE, The priority of neighbor cell is set simultaneously.

C.    Signaling Procedures for Intra-Frequency Handover

There are five types of signaling procedures for intra-frequency handover:

•        Intra-NodeB Intra-Frequency Soft Handover

•        Intra-RNC Inter-NodeB Intra-Frequency Soft Handover

•        Inter-RNC Intra-Frequency Soft Handover

•        Intra-RNC Inter-NodeB Intra-Frequency Hard Handover

Intra-NodeB Intra-Frequency Soft Handover:-

Intra-NodeB Intra-Frequency Soft Handover

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Intra-RNC Inter-NodeB Intra-Frequency Soft Handover:-

Intra-RNC Inter-NodeB Intra-Frequency Soft Handover

Inter-RNC Intra-Frequency Soft Handover:-

Inter-RNC Intra-Frequency Soft Handover

Intra-RNC Inter-NodeB Intra-Frequency Hard Handover:-

Intra-RNC Inter-NodeB Intra-Frequency Hard Handover