IRAT HO Parameters in mvhHuawei System

IRAT HO Parameters in Huawei system

Function:

Use "SET UINTERRATHOCOV" command to set the parameters in the RNC-oriented

coverage-based inter-RAT handover measurement algorithm.

Coverage-based handovers are triggered by the 2D or 2F event. For coverage-based inter-

RAT handovers, inter-RAT measurement is required.

The reporting modes of coverage-based inter-RAT handovers consist of event-triggered

reporting mode and periodical reporting mode.

Note:

1. The value of Time to Trigger Handover to Non-Verified GSM Cell is greater than or

equal to that ofInter-RAT Period Reporting Interval.

2. The value of Time to Trigger for Verified GSM Cell should be smaller than or equal to

that of Time to Trigger Handover to Non-Verified GSM Cell.

3. The value of Time to Trigger Handover to Non-Verified GSM Cell or Time to

Trigger for Verified GSM Cell should be an integer multiple of the value of Inter-RAT

Period Reporting Interval.

4. Inter-RAT PS or CS Used Frequency Trigger THD is subject to 3A Measure

Quantity when the value of Inter-RAT Report Mode is EVENT_TRIGGER. It is invalid

when the value of Inter-RAT Report Mode isPERIODICAL_REPORTING.

Parameter ID Parameter

Name

Parameter Description

InterRatReportMode Inter-RAT Meaning: Inter-RAT measurement reporting


Name


Report

Mode

mode.

When PERIODICAL_REPORTING is selected, the

periodical reporting is used for inter-RAT

measurement. When EVENT_TRIGGER is

selected, the event-triggered reporting is used

for inter-RAT measurement.

The RNC provides two inter-RAT measurement

reporting modes, event-triggered reporting and

periodical reporting.

Event-triggered reporting

To avoid the ping-pong effect before and after

the inter-RAT handover, use event 3A (quality of

the currently used frequency is lower than the

absolute threshold and the signal level of the

GSM cell is higher than another absolute

threshold) as the triggering event that

determines the inter-RAT handover. To improve

the handover success rate, the BSIC of the GSM

cell whose event 3A needs to be triggered must

be decoded correctly by the UE. The reporting

mode of event 3A is not changed from event-

triggered reporting to periodical reporting.

Therefore, no handover re-attempt is made

when the handover fails unless event 3A is

triggered in this cell again.

The advantage of event-triggered reporting is

that the signaling transmission and processing

load are saved. Comparing the signal quality

between intra-frequency and inter-frequency

handovers, the ping-pong effect in handover is

prevented to some extent. The drawback of

event-triggered reporting is that the event is

reported only once and cannot be changed to

periodical reporting. For the cell-oriented

algorithm parameters, each time when the best


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cell is updated, the inter-frequency

measurement parameters should be updated

accordingly.

Periodical reporting

When the quality of the GSM cell reported by the

UE meets the criteria for inter-RAT handover,

the delay trigger timer is started. If the quality of

the GSM cell always meets the criteria for inter-

RAT handover before timeout, the inter-RAT

handover is triggered after the delay trigger

timer expires.

For the GSM cell whose BSIC can be decoded

correctly, a shorter delay trigger time should be

set to indicate the high priority attribute of the

GSM cell. For the GSM cell whose BSIC is not

verified, a longer delay trigger time should be

set to indicate the low priority attribute of the

GSM cell. In this manner, the BSIC can be

decoded faster.

If the handover fails, the handover re-attempt is

made again according to the periodical inter-

RAT measurement report.

The advantage of periodical reporting is that it

can be used for repeated handover re-attempts

on the same cell when the handover fails, and

that subsequent algorithms can be flexibly

developed. In addition, for the cell-oriented

algorithm parameters, the RNC updates the

parameters when making internal handover

decision and the system needs not to inform the

UEs of the parameter change through signaling

messages after the handovers. The drawback of

periodical reporting is that it requires large

amount of signaling and increases the load on

the air interface and for signaling processing.


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The two reporting modes have both advantage

and drawback. Currently, the traditional

periodical reporting mode is preferred.

GUI Value Range:

PERIODICAL_REPORTING(Periodical reporting),

EVENT_TRIGGER(Event trigger)

Actual Value Range: PERIODICAL_REPORTING,

EVENT_TRIGGER

Unit: None

Default Value: None

Recommended Value: PERIODICAL_REPORTING

Parameter Relationship: None

Service Interrupted After Modification : No (No

impact on the UE in idle mode)

Impact on Network Performance: The advantage

of the periodical reporting mode is that it can be

used for repeated handover re-attempts on the

same cell when the handover fails, and that the

subsequent algorithms can be flexibly

developed. In addition, the UE needs not to be

informed when the parameters are changed.

The drawback of periodical reporting is that it

requires large amount of signaling and increases

the load on the air interface and for signaling

processing. The advantage of event-triggered

reporting is that the signaling transmission and

processing load are saved. Comparing the signal

quality between intra-frequency and inter-

frequency handovers, the ping-pong effect in

handover is prevented to some extent. The

drawback of event-triggered reporting is that

the event is reported only once and cannot be

changed to periodical reporting.

FilterCoefOf2D2F 2D/2F Filter Meaning: L3 filtering coefficient for event 2D or


Name


Coefficient event 2F measurement

If this parameter is set to a greater value, the

effect of smoothing signals and the ability of

anti-fast-fading improve. However, the ability of

tracing the signal change becomes low and call

drops are likely to occur because handover is

not performed in time. If this parameter is set to

a smaller value, the number of unnecessary

handovers increases.

The parameter has the same physical meaning

and measurement model as the inter-frequency

L3 filter coefficient. The reporting period is 480

ms. For specific analysis, see the intra-frequency

L3 filter coefficient and inter-frequency L3 filter

coefficient.

Parameter adjustment suggestions:

In cells where the average moving speed of UEs

is low, there is a comparatively big shadow

fading square error. Therefore, the

recommended value is 4. The value can be

increased in a certain degree.


is medium, there is a comparatively smaller

shadow fading square error. Therefore, the

recommended value is 3.


is high, there is a comparatively small shadow



GUI Value Range: D0, D1, D2, D3, D4, D5, D6,

D7, D8, D9, D11, D13, D15, D17, D19

Actual Value Range: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,

11, 13, 15, 17, 19

Unit: None


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Default Value: None

Recommended Value: D3




Impact on Network Performance: If this

parameter is set to a larger value, call drops are

likely to occur because handover is not

performed in time. If this parameter is set to a

smaller value, unnecessary inter-RAT handovers

may increase.

MeasQuantityOf3A 3A Measure

Quantity

Meaning: Measurement quantity used in

coverage-based inter-RAT measurement in

event 3A-triggered reporting mode.

When CPICH_Ec/No is selected, it indicates that

the Ec/No measurement quantity is used for

event 3A measurement. The physical unit is dB.

When CPICH_RSCP is selected, it indicates that

the RSCP measurement quantity is used for

event 3A measurement. The physical unit is

dBm.

When AUTO is selected, it indicates that the

Ec/No measurement quantity is used for event

3A measurement if the RNC receives Ec/No 2D

firstly. If the RNC receives the RSCP 2D firstly,

the RSCP measurement quantity is used for

event 3A measurement.

GUI Value Range: CPICH_EC/NO~0

CPICH_RSCP~1 AUTO

Actual Value Range: CPICH_EC/NO, CPICH_RSCP,

AUTO

Unit: None

Default Value: None


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Recommended Value: AUTO

Parameter Relationship: This parameter is valid

whenInterRatReportMode is set to

EVENT_TRIGGER.



Impact on Network Performance: If the

parameter value does not match the network

environment (for example, the Ec/No

measurement quantity is used for event 3A

measurement in areas with low RSCP), inter-RAT

handover may fail.

InterRATFilterCoef Inter-RAT

Filter

Coefficient

Meaning: This parameter specifies the Layer 3

filter coefficient for the inter-RAT measurement.


effect of smoothing signals and the ability of

anti-fast-fading improve. However, the ability of

tracing the signal change becomes low and call

drops are likely to occur because handover is

not performed in time. If this parameter is set to

a smaller value, the number of unnecessary

handovers increases.

The parameter has the same physical meaning

and measurement model as the inter-frequency

L3 filter coefficient. The reporting period is 480

ms. For specific analysis, see the intra-frequency

L3 filter coefficient and inter-frequency L3 filter

coefficient.

Parameter adjustment suggestions:


is low, there is a comparatively big shadow


recommended value is 4. The value can be

increased in a certain degree.


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is medium, there is a comparatively smaller

shadow fading square error. Therefore, the



is high, there is a comparatively small shadow



GUI Value Range: D0, D1, D2, D3, D4, D5, D6,

D7, D8, D9, D11, D13, D15, D17, D19

Actual Value Range: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,

11, 13, 15, 17, 19

Unit: None

Default Value: None






parameter is set to a greater value, the effect of

smoothing signals and the ability of anti-fast-

fading improve. However, the ability of tracing

the signal change becomes low, and call drops

are likely to occur because handover is not

performed in time. If this parameter is set to a

smaller value, the number of unnecessary Inter-

RAT handovers increases.

WeightForUsedFreq Weight for

Used

Frequency

Meaning: The parameter WeightForUsedFreq is

the frequency weighting factor used to calculate

the quality of the current frequency.

This parameter is used for event 3A evaluation.

For detailed information of this parameter, refer

to 3GPP TS 25.133.


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To set this parameter, see the method for

setting the intra-frequency handover weighting

factor Weight.

GUI Value Range: 0~20

Actual Value Range: 0~2, step:0.1

Unit: None

Default Value: None

Recommended Value: 0





parameter is set to a greater value, the

estimated general quality of the current

frequency in the same condition is higher. In this

case, inter-RAT handover is unlikely to be

triggered. If this parameter is set to a smaller

value, the estimated general quality of the

current frequency in the same condition is

lower. In this case, inter-frequency handover is

likely to be triggered. When the parameter value

is set to 0, the quality of the best cell in an

active set is regarded as the general quality of

an active set.

InterRATPeriodReportInterval Inter-RAT

Period

Reporting

Interval

Meaning: Interval that the UE reports inter-RAT

measurement results to the RNC.

This parameter specifies the interval that the UE

sends inter-RAT measurement results to the

RNC in periodical reporting mode. It is not

recommended that this parameter is set to

NON_PERIODIC_REPORT since the UE behavior

may be unknown.

The GSM RSSI measurement period is 480 ms.


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Therefore, the inter-RAT periodical reporting

interval should be longer than 480 ms. If the

periodical reporting interval is excessively high,

the handover decision time will be long, and

handovers will be slow.

The adjustment should be made according to

the configured GSM RSSI measurement

compressed mode sequence. According to the

current configured GSM RSSI measurement

compressed mode sequence, the RSSI

measurement of eight GSM cells can be finished

in 480 ms. Therefore, the RSSI measurement of

16 GSM cells can be finished in 1000 ms.

According to 3GPP specifications, the number of

inter-RAT neighboring cells should not exceed

32. Therefore, the parameter value can be set to

2000 ms if the number of neighboring GSM cells

exceeds 16.

The setting of this parameter has impact on the

Uu signaling traffic. If the period is too short and

the reporting frequency is too high, the RNC

may have high load in processing signaling. If

the period is too long, the network cannot detect

the signal changes in time, which may delay the

inter-RAT handover and thus cause call drops.

GUI Value Range: NON_PERIODIC_REPORT(Non

periodical reporting), D250~1 D500~2 D1000~3

D2000~4 D3000~5 D4000~6 D6000~7

D8000~8 D12000~9 D16000~10 D20000~11

D24000~12 D28000~13 D32000~14 D64000

Actual Value Range: NON_PERIODIC_REPORT,

250, 500, 1000, 2000, 3000, 4000, 6000, 8000,

12000, 16000, 20000, 24000, 28000, 32000,

64000

Unit: ms


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Default Value: None




PERIODICAL_REPORTING.



Impact on Network Performance: The setting of

this parameter has impact on the Uu signaling

traffic. If the period is too short and the

reporting frequency is too high, the RNC may

have high load in processing signaling. If the

period is too long, the network cannot detect the

signal changes in time, which may delay the

inter-RAT handover and thus cause call drops.

Hystfor2D 2D

Hysteresis

Meaning: Hysteresis for event 2D.

This parameter is used to avoid the ping-pong

reporting of event 2D (the estimated quality of

the currently used frequency is below a certain

threshold). The value of this parameter is

associated with slow fading. If this parameter is

set to a greater value, the probability of ping-

pong reporting or wrong decision is lower, but

the event may not be triggered in time. If this

parameter is set to a smaller value, ping-pong

reporting of event 2D is likely to occur.

The setting of this parameter should consider

the radio conditions (slow fading), actual

handover distance, and moving speed of the UE.

The value of this parameter ranges from 2 dB to

5 dB. In addition, filter coefficient and triggering

delay must be considered in setting this

parameter.



Name


Actual Value Range: 0~14.5, step:0.5

Unit: dB/ dBm

Default Value: None






this parameter should consider the radio

conditions (slow fading), actual handover

distance, and moving speed of the UE. If this


probability of ping-pong reporting or wrong

decision is lower, but the event may not be

triggered in time.

Hystfor2F 2F

Hysteresis

Meaning: Hysteresis for event 2F.

The value of this parameter is associated with

slow fading. If this parameter is set to a greater

value, the probability of ping-pong reporting or

wrong decision is lower, but the event may not

be triggered in time.

The inter-RAT measurement hysteresis in

periodical reporting mode is used to prevent the

ping-pong reporting of event 2D (the estimated

quality of the currently used frequency is below

a certain threshold) and event 2F (the estimated

quality of the currently used frequency is above

a certain threshold). Event 2D is used to enable

the compressed mode and event 2F is used to

disable the compressed mode. Hystfor2D can

be increased slightly based on the

recommended value, considering inter-

frequency handover statistics. Hystfor2D can

also be increased slightly to prevent the


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compressed mode from being frequently

enabled and disabled and to avoid unnecessary

active set updates.

The setting of this parameter should consider

the radio conditions (slow fading), actual

handover distance, and moving speed of the UE.

The value of this parameter ranges from 2 dB to

5 dB. In addition, filter coefficient and triggering

delay must be considered in setting this

parameter.



Unit: dB/ dBm

Default Value: None






this parameter should consider the radio

conditions (slow fading), actual handover

distance, and moving speed of the UE. If this


probability of ping-pong reporting or wrong

decision is lower, but the event may not be

triggered in time.

Hystfor3A 3A

Hysteresis

Meaning: Hysteresis for event 3A.



value, the ability of resisting signal fluctuation

improves and the number of ping-pong

handovers decreases; however, the handover

algorithm becomes slow in responding to the


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signal change. If this parameter is set to a larger

value, the cell of another RAT where the UE

needs to be handed over to must be of good

quality. Therefore, the criteria for triggering the

inter-RAT handover decision is hard to be

fulfilled, and the call drop rate will increase.

The emulation result shows that in a cell where

the average moving speed of UEs is high (for

example, a cell that covers highways), this

parameter can be set to a smaller value 1.5 dB,

because in the cell the terrain is flat, barriers are

fewer, and thus the shadow fading variation is

small. In a cell where the average moving speed

of UEs is low, this parameter can be set to a

larger value 3.0 dB, because there are usually

many tall buildings and thus the shadow fading

variation is comparatively high.



Unit: dB

Default Value: None




EVENT_TRIGGER.



Impact on Network Performance: The value of

this parameter is associated with slow fading. If

this parameter is set to a larger value, the cell of

another RAT where the UE needs to be handed

over to must be of good quality. Therefore, the

criteria for triggering the inter-RAT handover

decision is hard to be fulfilled, and the call drop


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rate will increase. If this parameter is set to a

smaller value, ping-pong handover is likely to

occur.

HystforInterRAT Inter-RAT

Hysteresis

Meaning: Hysteresis for inter-RAT periodical

reporting.

This parameter is used to avoid incorrect

decisions caused by unexpected jitters of signals

during inter-RAT handover decisions.

HystforInterRAT and the inter-RAT handover

decision threshold determine whether to trigger

inter-RAT handovers.


ability of resisting signal fluctuation improves

and the number of ping-pong handovers

decreases; however, the handover algorithm

becomes slow in responding to the signal

change. If this parameter is set to a larger value,

the cell of another RAT where the UE needs to

be handed over to must be of good quality.

Therefore, the criteria for triggering the inter-

RAT handover decision is hard to be fulfilled, and

the call drop rate will increase.

The emulation result shows that in a cell where

the average moving speed of UEs is high (for

example, a cell that covers highways), this

parameter can be set to a smaller value 1.5 dB,

because in the cell the terrain is flat, barriers are

fewer, and thus the shadow fading variation is

small. In a cell where the average moving speed

of UEs is low, this parameter can be set to a

larger value 3.0 dB, because there are usually

many tall buildings and thus the shadow fading

variation is comparatively high.



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Unit: dB

Default Value: None









this parameter is set to a larger value, the cell of

another RAT where the UE needs to be handed

over to must be of good quality. Therefore, the

criteria for triggering the inter-RAT handover

decision is hard to be fulfilled, and the call drop

rate will increase. If this parameter is set to a

smaller value, ping-pong handover is likely to

occur.

TrigTime2D 2D Event

Trigger

Delay Time

Meaning: Interval time between detection of

event 2D and sending of the measurement

report.



value, the probability of incorrect decision

becomes low; however, the handover algorithm

becomes slow in responding to signal change.

The emulation result shows that the hysteresis

setting can effectively reduce the average

number of handovers and the number of

incorrect handovers, thus preventing

unnecessary handovers. The emulation result

also shows that the UE at different data rates

may react differently to the delay for triggering


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the event. For the fast-moving UE, the call drop

rate is more sensitive to the delay, whereas, for

the slow-moving UE, the call drop rate is less

sensitive to the delay. This can also reduce ping-

pong handovers and incorrect handovers.

Therefore, for the cell where most UEs are in

fast movement, this parameter can be set to a

smaller value, whereas for the cell where most

UEs are in slow movement, this parameter can

be set to a greater value. The value of this

parameter can be adjusted according to the

actual network statistics.

GUI Value Range: D0, D10, D20, D40, D60, D80,

D100, D120, D160, D200, D240, D320, D640,

D1280, D2560, D5000

Actual Value Range: 0, 10, 20, 40, 60, 80, 100,

120, 160, 200, 240, 320, 640, 1280, 2560, 5000

Unit: ms

Default Value: None







this parameter is set to a greater value, the

probability of incorrect decision becomes low;

however, the handover algorithm becomes slow

in responding to signal change.

TrigTime2F 2F Event

Trigger

Delay Time


event 2F and sending of the measurement

report.



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value, the probability of incorrect decision























D100, D120, D160, D200, D240, D320, D640,

D1280, D2560, D5000


120, 160, 200, 240, 320, 640, 1280, 2560, 5000

Unit: ms

Default Value: None






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this parameter is set to a greater value, the

probability of incorrect handover decision



This leads to the decrease in the number of

handovers.

TrigTime3A 3A Event

Trigger

Delay Time


event 3A and sending of the measurement

report.


the slow fading. If this parameter is set to a

greater value, the probability of incorrect

handover decision becomes low; however, the

handover algorithm becomes slow in responding

to signal change. If this parameter is set to a

smaller value, the handover algorithm becomes

fast in responding to signal change; however,

the probability of incorrect decision becomes

high.















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The inter-frequency measurement reporting

period is 480 ms. Therefore, the trigger delay

time shorter than 480 ms is invalid.

If the parameter is set to a larger value,

handover is unlikely to be triggered. However,

call drops may increase as the parameter value

increases.


D100, D120, D160, D200, D240, D320, D640,

D1280, D2560, D5000


120, 160, 200, 240, 320, 640, 1280, 2560, 5000

Unit: ms

Default Value: None




EVENT_TRIGGER.




parameter is set to a larger value, handover is

unlikely to be triggered. However, call drops

may increase as the parameter value increases.

TimeToTrigForNonVerify Time to

Trigger

Handover

Meaning: Time delay for triggering handovers to

GSM cells with non-verified BSIC.

During the period of time specified by this


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to Non-

Verified

GSM Cell

parameter, if the signal quality in a neighboring

GSM cell fulfills inter-RAT handover criteria and

the neighboring GSM cell is not verified, an inter-

RAT handover is triggered. When this parameter

value is 65535, the RNC does not perform inter-

RAT handovers to non-verified GSM cells. If this

parameter is set to a larger value, the average

number of handovers decreases, but call drops

may occur.

GUI Value Range: 0~64000, 65535

Actual Value Range: 0~64000, 65535

Unit: ms

Default Value: None











TimeToTrigForVerify Time to

Trigger

Handover

to Verified

GSM Cell

Meaning: Time delay for triggering handovers to

GSM cells with verified BSIC.

During the period of time specified by this

parameter, if the signal quality in a neighboring

GSM cell fulfills inter-RAT handover criteria and

the neighboring GSM cell is verified, an inter-

RAT handover is triggered.

The criterion for triggering inter-RAT handover is

as follows:

Mother_RAT + CIO >= Tother_RAT + H/2


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If the quality of the neighboring GSM cell meets

the preceding criterion, the RAN starts the

trigger timer. After the timer expires, the RAN

makes inter-RAT handover decision. The length

of the trigger timer is called the time to trigger

verified GSM cell.

This parameter and the hysteresis are used

together to prevent incorrect decisions caused

by signal jitters during inter-RAT handover

decisions.

Considering that the UE is on the edge of the

system, this parameter should be set to a

comparatively low value. In situations where a

GSM cell is verified, the performance of the GSM

cell is generally regarded as good. In this case,

the parameter can be set to 0, which indicates

that the handover is performed immediately.

If this parameter is set to a larger value, the

average number of handovers decreases, but

call drops may occur.


Actual Value Range: 0~64000

Unit: ms

Default Value: None












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BSICVerify BSIC Verify

Switch

Meaning: Switch for verifying the Base Station

Identity Code (BSIC).

This parameter is used to control cells where

inter-RAT measurement reports are triggered.

When the parameter is set to "REQUIRED", the

measurement reporting is triggered after the

BSIC of the measured cell is decoded correctly.

When the parameter is set to "NOT_REQUIRE",

the measurement reporting is triggered

regardless of whether the BSIC of the measured

cell is decoded correctly. This parameter is valid

for both periodical reporting mode and event-

triggered reporting mode. However, to ensure

handover reliability, it is recommended that the

system reports only the cells whose BSIC is

decoded correctly, that is, the recommended

value of the parameter is "REQUIRED". If the

parameter is set to "NOT_REQUIRED", handovers

are likely to be triggered, but the handover

reliability is lower than that in the situation the

parameter is set to "REQUIRED".

GUI Value Range: REQUIRED(Verify mode),

NOT_REQUIRE(Non-verify mode)

Actual Value Range: REQUIRED, NOT_REQUIRE

Unit: None

Default Value: None

Recommended Value: REQUIRED





parameter is set to "NOT_REQUIRED", handovers

are likely to be triggered, but the handover

reliability is lower than the situation the


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parameter is set to "REQUIRED".

InterRATCSThd2DEcN0 Inter-RAT

CS Measure

Start Ec/No

THD

Meaning: Threshold of triggering inter-RAT

measurement for CS services when

measurement quantity is Ec/No.

The threshold of triggering the inter-RAT

measurement (the threshold of enabling the

compressed mode) is a key parameter in the

inter-RAT handover policy. The setting of this

parameter affects the proportion of the UEs in

compressed mode in a cell and the success rate

of the hard handover. The setting of this

parameter should consider two factors, moving

speed of the UE and cell radius.

When Ec/No is used as the measurement

quantity for CS services, the UE reports event

2D when the measured Ec/No value is lower

than this threshold. Then, the RNC sends the

signaling to enable the compressed mode and

start inter-RAT measurement.

For the UE moving at a speed of 5 km/h, the

recommended threshold is -17 dB; for the UE

moving at a speed of 50 km/h, the



recommended threshold is -12 dB. In actual

networks, set this parameter to -14 dB because

the UEs in a cell usually move at different

speeds. The emulation result shows that the call

drop rate remains low for the UEs moving at a

speed of 120 km/h when this parameter is set to

-14 dB.

If the cell is a macro cell, it indicates that micro

cells exist in this cell. To enable the micro cells

to handle more traffic, the compressed mode


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start and stop thresholds should be set higher,

that is, the thresholds for events 2D and 2F

using CPICH RSCP are set higher.

If the cell is a micro cell, the default value

should be modified according to the link

budgeting result.

Event 2D and event 2F are used to enable and

disable the compressed mode respectively.

When the cell is located in the center of the

frequency coverage or the inter-frequency

measurement quantity uses both Ec/No and

RSCP, then the Ec/No value is used as the

criterion for events 2D and 2F. To enable the

compressed mode earlier, increase the

threshold of triggering event 2D; otherwise,

decrease the threshold of triggering event 2D.

To prevent the frequent enabling and disabling

of the compressed mode, increase the

difference between the thresholds of triggering

event 2D and event 2F.


disable the compressed mode respectively in

inter-RAT measurement. The requirements on

the signal quality and inter-RAT handover

policies vary with the service type. Therefore,

the thresholds of enabling and disabling inter-

RAT measurement are distinguished by CS, PS,

and signaling.

To enable the compressed mode earlier,

increase the threshold of triggering event 2D;

otherwise, decrease the threshold of triggering

event 2D. To prevent the frequent enabling and

disabling of the compressed mode, increase the




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GUI Value Range: -24~0

Actual Value Range: -24~0

Unit: dB

Default Value: None

Recommended Value: -14

Parameter Relationship: The value of this

parameter must be smaller

than InterRatCsThd2FEcN0.




this parameter affects the proportion of the UEs

in compressed mode in a cell and the success

rate of the hard handover. If this parameter is

set to a greater value, hard handover is likely to

be triggered, but ping-pong handover may

occur. If this parameter is set to a smaller value,

hard handover is unlikely to be triggered, but


InterRATCSThd2FEcN0 Inter-RAT

CS Measure

Stop Ec/No

THD

Meaning: Threshold of stopping inter-RAT



The threshold of stopping the inter-RAT

measurement (the threshold of disabling the









quantity for CS services, the UE reports event 2F


Name


when the measured Ec/No value is higher than

the value of this parameter. Then, the RNC

sends the signaling to disable the compressed

mode and stop the inter-frequency

measurement.









budgeting result.

















Unit: dB

Default Value: None




Name


parameter must be larger

than InterRatCsThd2DEcN0.






rate of the hard handover. If the threshold for

event 2F is set to a larger value, more UEs will

enter compressed mode, thus affecting user

experience. If the threshold for event 2F is set to

a smaller value, it becomes difficult for UEs to

trigger inter-RAT measurement, thus decreasing

handovers.

InterRATR99PsThd2DEcN0 Inter-RAT

R99 PS

Measure

Start Ec/No

THD


measurement for PS domain non-HSPA services

when the measurement quantity is Ec/No.











quantity for PS domain non-HSPA services, the

UE reports event 2D when the measured Ec/No

value is lower than this threshold. Then, the RNC

sends the signaling to enable the compressed

mode and start inter-RAT measurement.




Name





recommended threshold is -12 dB.

In actual networks, set this parameter to -14 dB

because the UEs in a cell usually move at

different speeds. The emulation result shows

that the call drop rate remains low for the UEs

moving at a speed of 120 km/h when this

parameter is set to -14 dB.









budgeting result.


















Name







and signaling.










Unit: dB

Default Value: None




than InterRatR99PsThd2FEcN0.












InterRATHThd2DEcN0 Inter-RAT Meaning: Threshold of triggering inter-RAT


Name


HSPA

Measure

Start Ec/No

THD

measurement for HSPA services when












quantity for HSPA services, the UE reports event

2D when the measured Ec/No value is lower

than this threshold. Then, the RNC sends the


start inter-RAT measurement.






recommended threshold is -12 dB.

In actual networks, set this parameter to -14 dB

because the UEs in a cell usually move at

different speeds. The emulation result shows

that the call drop rate remains low for the UEs

moving at a speed of 120 km/h when this

parameter is set to -14 dB.








Name




budgeting result.






















and signaling.











Name


Unit: dB

Default Value: None




than InterRatHThd2FEcN0.












InterRATR99PsThd2FEcN0 Inter-RAT

R99 PS

Measure

Stop Ec/No

THD



when the measurement quantity is Ec/No.











quantity for PS domain HSPA services, the UE

reports event 2F when the measured Ec/No

value is higher than this threshold. Then, the

RNC sends the signaling to disable the


Name


compressed mode and stop the inter-frequency

measurement.









budgeting result.

















Unit: dB

Default Value: None




than InterRatR99PsThd2DEcN0.



Name












handovers.

InterRATHThd2FEcN0 Inter-RAT

HSPA

Measure

Stop Ec/No

THD















2F when the measured Ec/No value is higher

than the value of this parameter. Then, the RNC

sends the signaling to disable the compression

mode and stop the inter-frequency

measurement.






Name






budgeting result.

















Unit: dB

Default Value: None




than InterRatHThd2DEcN0.









Name






handovers.

InterRATCSThd2DRSCP Inter-RAT

CS Measure

Start RSCP

THD



measurement quantity is RSCP.

When RSCP is used as the measurement

quantity for CS services, the UE reports event

2D when the measured RSCP value is lower than

this threshold. Then, the RNC sends the


start the inter-RAT measurement.








In most cases, users want to be maintained

within a 3G network. Therefore, the start

threshold of the inter-RAT measurement is set

smaller than that of the inter-frequency

measurement in order to trigger inter-frequency

easily. In scenarios where inter-frequency

neighboring cells are unavailable or where inter-

frequency coverage is insufficient, the inter-RAT

measurement start threshold should be set

relatively larger in order to trigger inter-RAT

measurement easily, thus reducing call drops.

GUI Value Range: -115~-25

Actual Value Range: -115~-25


Name


Unit: dBm

Default Value: None




than InterRatCsThd2FRscp.












InterRATCSThd2FRSCP Inter-RAT

CS Measure

Stop RSCP

THD





quantity for CS services, the UE reports event 2F

when the measured RSCP value is larger than


signaling to disable the compressed mode and

stop the inter-RAT measurement.



Unit: dBm

Default Value: None





Name


than InterRatCsThd2DRscp.



Impact on Network Performance: If the threshold

for event 2F is set to a larger value, more UEs

will enter compressed mode, thus affecting user




handovers.

InterRATR99PsThd2DRSCP Inter-RAT

R99 PS

Measure

Start RSCP

THD



when the measurement quantity is RSCP.



UE reports event 2D when the measured RSCP

value is lower than this threshold. Then, the RNC

sends the signaling to enable the compressed

mode and start the inter-RAT measurement.

















Name







Unit: dBm

Default Value: None




than InterRatR99PsThd2FRscp.












InterRATHThd2DRSCP Inter-RAT

HSPA

Measure

Start RSCP

THD






2D when the measured RSCP value is lower than



start the inter-RAT measurement.




Name




















Unit: dBm

Default Value: None




than InterRatHThd2FRscp.












Name



InterRATR99PsThd2FRSCP Inter-RAT

R99 PS

Measure

Stop RSCP

THD



when the measurement quantity is RSCP.



UE reports event 2F when the measured RSCP

value is larger than this threshold. Then, the

RNC sends the signaling to disable the

compressed mode and stop the inter-RAT

measurement.



Unit: dBm

Default Value: None




than InterRatR99PsThd2DRscp.









handovers.

InterRATHThd2FRSCP Inter-RAT

HSPA

Measure

Stop RSCP

THD







Name


2F when the measured RSCP value is larger than


signaling to disable the compressed mode and

stop the inter-RAT measurement.



Unit: dBm

Default Value: None




than InterRatHThd2DRscp.









handovers.

TargetRatCsThd Inter-RAT

CS

Handover

Decision

THD

Meaning: Quality requirement for the cell of

another RAT during inter-RAT handover for CS

domain services.

For CS services, if the value of "Inter-RAT

Reporting Mode" is set to "EVENT_TRIGGER",

this parameter is used to set the criterion for

triggering event 3A. That is, event 3A is

triggered only when the quality of the target

frequency is higher than this threshold and the

measurement quality of the current CS services

is lower than the quality of the currently used

frequency. If the value of "Inter-RAT Reporting


Name


Mode" is set to "PERIODICAL_REPORTING", this

parameter is used to evaluate inter-RAT

coverage handovers at the RNC. Note that 0

means a value smaller than -110 dBm.

If the value of "Inter-RAT Reporting Mode" is set

to "PERIODICAL_REPORTING", this parameter is

used for the assessment of inter-RAT coverage

handover. That is, Tother_RAT in the following

formulas. This parameter is the absolute

threshold of the cell of another RAT (Received

Signal Strength Indicator: RSSI) for the inter-RAT

handover decision.

If the quality of the cell of another RAT in the

inter-RAT measurement report fulfils the

following criterion:


Then, the system starts the trigger timer, and

makes the handover decision after the timer

expires. If the quality of the cell of another RAT

fulfills the following criterion before timeout:

Mother_RAT + CIO < Tother_RAT - H/2

The RNC stops the timer and waits for another

inter-RAT measurement report.

Here,

Mother_RAT is the measurement result of the

GSM RSSI.

Tother_RAT is the inter-RAT handover decision

threshold.

Cell Individual Offset (CIO) is the offset for the

cell of another inter-RAT.

H represents the hysteresis, the setting of which

can reduce wrong decisions caused by signal

jitters.

The sensitivity of a GSM mobile phone is -102


Name


dBm. Considering a margin of 3 dB for

compensation of fast fading, 5 dB for

compensation of slow fading, 2 dB for

compensation of interference noise, and 2 dB for

compensation of ambient noise, the outdoor

reception level should not be lower than -90

dBm.

The parameter value can vary with the handover

policy. To have UEs handed over only to GSM

cells of high quality, the inter-RAT handover

decision threshold can be set to a comparatively

large value, for example -85 dBm.


Actual Value Range: lower than -110, -110~-

48(Actual value meets the condition: Actual

Value = GUI Value - 111)

Unit: dBm

Default Value: None






this parameter affects number of hard

handovers. If this parameter is set to a greater

value, hard handover is likely to be triggered,

but ping-pong handover may occur. If this

parameter is set to a smaller value, hard

handover is unlikely to be triggered, but call

drops may occur.

TargetRatR99PsThd Inter-RAT

R99 PS

Handover


another RAT during inter-RAT handover for PS

domain non-HSPA services.


Name


Decision

THD

For PS domain non-HSPA services, if the value of

"Inter-RAT Reporting Mode" is set to

"EVENT_TRIGGER", this parameter is used to set

the criterion for triggering event 3A. That is,

event 3A is triggered only when the quality of

the target frequency is higher than this

threshold and the measurement quality of the

current PS services is lower than the quality of

the currently used frequency. If the value of

"Inter-RAT Reporting Mode" is set to

"PERIODICAL_REPORTING", this parameter is

used to evaluate inter-RAT coverage handovers

at the RNC. Note that 0 means a value smaller

than -110 dBm.








handover decision.












Here,


Name



GSM RSSI.


threshold.





jitters.








dBm.










Unit: dBm

Default Value: None







Name








drops may occur.

TargetRatHThd Inter-RAT

HSPA

Handover

Decision

THD


another RAT during inter-RAT handover for HSPA

services.

For PS services, if the value of "Inter-RAT


this parameter is used to set the criterion for

triggering event 3A. That is, event 3A is

triggered only when the quality of the target

frequency is higher than this threshold and the

measurement quality of the current PS services

is lower than the quality of the currently used

frequency. If the value of "Inter-RAT Reporting

Mode" is set to "PERIODICAL_REPORTING", this

parameter is used to evaluate inter-RAT

coverage handovers at the RNC. Note that 0

means a value smaller than -110 dBm.








handover decision.





Name










Here,


GSM RSSI.


threshold.





jitters.








dBm.










Name



Unit: dBm

Default Value: None












drops may occur.

UsedFreqCsThdEcN0 Inter-RAT

CS Used

Frequency

Trigger

Ec/No THD

Meaning: Ec/No quality threshold for used

frequency of CS services.

For CS services, if Ec/No is used as the

measurement quantity for inter-RAT

measurement and the value of "Inter-RAT


this parameter is used to set the measurement

control of event 3A. That is, event 3A is

triggered only when the quality of the currently

used frequency is lower than this threshold and

the TargetRatCsThd criterion is fulfilled.

The following factors should be considered

during setting:

When the value of "Inter-RAT Reporting Mode" is

set to "EVENT_TRIGGER", the quality of the

currently used frequency fulfills the criterion

QUsed <= TUsed - H3a/2, and the quality of the

target frequency fulfills the criterion Mother_RAT


Name


+ CIO >= Tother_RAT + H/2, the RNC starts the

trigger timer and reports event 3A when the

timer expires.

Here,

QUsed is the estimated quality of the currently

used frequency of UTRAN.

Tused is the quality threshold for the currently

used frequency of GSM.


GSM RSSI.


threshold.





jitters.

When the signal quality of the currently used

frequency is poor, that is, below the specified

value of this parameter, you can infer that the

frequency cannot meet the coverage

requirements of the current services. Event 2F

indicates that the quality of the currently used

frequency is restored. Therefore, this parameter

is usually set lower than the triggering threshold

of event 2F, or is set equally to the triggering

threshold of event 2D.

For combined services, the parameter

configuration for CS services should be adopted

as long as CS services are involved.

Impact on network performance:

If this parameter is set to a larger value, event

3A is likely to be triggered. However, handover

is likely to be triggered when the frequency


Name


quality in the current system is acceptable for

the UE if the value of this parameter is set too

large.



Unit: dB

Default Value: None






parameter is set to a larger value, event 3A is

likely to be triggered. However, handover is

likely to be triggered when the frequency quality

in the current system is acceptable for the UE if

the value of this parameter is set too large.

UsedFreqR99PsThdEcN0 Inter-RAT

R99 PS

Used

Frequency

Trigger

Ec/No THD


frequency of PS domain non-HSPA services.

For PS domain non-HSPA services, if Ec/No is

used as the measurement quantity for inter-RAT







the TargetRatR99PsThd criterion is fulfilled.


during setting:





Name






timer expires.

Here,






GSM RSSI.


threshold.





jitters.

















Name






large.



Unit: dB

Default Value: None











UsedFreqHThdEcN0 Inter-RAT

HSPA Used

Frequency

Trigger

Ec/No THD


frequency of HSPA services.

For HSPA services, if Ec/No is used as the










during setting:



Name








timer expires.

Here,






GSM RSSI.


threshold.





jitters.















Name








large.



Unit: dB

Default Value: None











UsedFreqCsThdRscp Inter-RAT

CS Used

Frequency

Trigger

RSCP THD

Meaning: RSCP quality threshold for used

frequency of CS domain services.

For CS services, if RSCP is used as the








the TargetRatCsThd criterion is fulfilled.



Name


during setting:








timer expires.

Here,






GSM RSSI.


threshold.





jitters.













Name










large.



Unit: dBm

Default Value: None











UsedFreqR99PsThdRscp Inter-RAT

R99 PS

Used

Frequency

Trigger

RSCP THD


frequency of PS domain non-HSPA services.

For PS domain non-HSPA services, if RSCP is

used as the measurement quantity for inter-RAT








Name




during setting:








timer expires.

Here,






GSM RSSI.


threshold.





jitters.











Name












large.



Unit: dBm

Default Value: None











UsedFreqHThdRscp Inter-RAT

HSPA Used

Frequency

Trigger

RSCP THD


frequency of HSPA services.

For HSPA services, if RSCP is used as the







Name






during setting:








timer expires.

Here,






GSM RSSI.


threshold.





jitters.









Name














large.



Unit: dBm

Default Value: None











InterRATMeasTime Inter-RAT

Measure

Timer

Length

Meaning: Length of the timer for inter-RAT

measurement.

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 (if activated)


Name


should be deactivated. The value 0 indicates

that the inter-RAT measurement timer is not

started.


during setting:

This parameter is designed to prevent that the

UE being in compressed mode for a long time

when the handover criteria are not fulfilled,

because the UE does not move or is moving in a

low speed. If the compressed mode is

maintained for a long time, the service quality is

adversely affected and the total available

capacity of the system decreases.

Most inter-RAT handovers can be finished within

60s.


If the parameter is set to a smaller value, the UE

cannot finish inter-RAT handover. If the

parameter is set to a larger value, the

compressed mode will not be disabled, thus

affecting UE measurement. In actual networks,

statistics can be made to obtain the delay for a

successful inter-RAT handover, thus to get a

proper value of InterRATMeasTime that

satisfies most UEs.



Unit: s

Default Value: None






Name



parameter is set to a smaller value, the UE

cannot finish inter-RAT handover. If the

parameter is set to a larger value, the user

experience is affected.

InterRATPingPongTimer Inter-RAT

Ping-Pong

Timer

Meaning: Length of the timer to avoid ping-pong

handovers between 2G and 3G networks.

When a UE in the CS domain is handed over

from a 2G network to a 3G network, the system

increases the hysteresis used for event 3A to

prevent the ping-pong handover between the 2G

network and the 3G network in the period

specified by this parameter. During the penalty

time, the previous periodical report will be

changed to the event 3A report. The value 0

indicates that the system does not take

measures to avoid ping-pong handover between

2G and 3G networks.



Unit: s

Default Value: None






parameter is set to a larger value, the UEs

handed out from the 2G network are unlikely to

be handed back to the 2G network. If this

parameter is set to a smaller value, the effect of

penalty is unobvious, causing ping-pong

handover between 2G and 3G networks.


Name


InterRATPingPongHyst Inter-RAT

Ping-Pong

Hysteresis

Meaning: Hysteresis to avoid ping-pong

handover between 2G and 3G networks.

When a UE in the CS domain is handed over

from a 2G network to a 3G network, the system

increases the hysteresis used for event 3A to

prevent the ping-pong handover between the 2G

network and the 3G network in the handover

penalty period specified

by InterRATPingPongTimer. During the

penalty time, event-triggered reporting is used

for inter-RAT measurement. The value 0

indicates that the system does not take

measures to avoid ping-pong handover between

2G and 3G networks.



Unit: dBm

Default Value: None






parameter is set to a larger value, the UEs

handed over from the 2G network are unlikely to

be handed over back to the 2G network. If this

parameter is set to a smaller value, the risk for

ping-pong handovers increases.

PeriodFor3A 3A Event

Retry

Period

Meaning: Interval between handover attempts

for event 3A.

This parameter specifies the interval between

handover attempts for event 3A. If this

parameter is set to a smaller value, handover


Name


attempts increase when the inter-RAT handover

fails. In this case, the UE can be quickly handed

over to the target cell whose load is reduced,

thus lowering the probability of call drops. More

handover re-attempts, however, cause the

increase in the RNC load.


Actual Value Range: 500~32000, step:500

Unit: ms

Default Value: None




EVENT_TRIGGER.




parameter is set to a smaller value, handover







AmntOfRpt3A 3A Event

Maximum

Retry Times

Meaning: Maximum number of handover

attempts after inter-RAT handover triggered by

event 3A fails.

This parameter specifies the maximum number

of handover re-attempts for event 3A when the

measurement control is valid. If this parameter

is set to a greater value, the number of inter-

RAT handover re-attempts increases and the

possibility of successfully handing over the UE to


Name


the target cell whose load becomes normal

increases. After reaching the value specified by

this parameter, the RNC makes no further

handover attempt to the target cell. If the

compressed mode is disabled, the handover re-

attempt will be aborted.


Actual Value Range: 0~62, 63: Infinity

Unit: None

Default Value: None




EVENT_TRIGGER.




parameter is set to a larger value, handover







InterRatPhyChFailNum Inter-RAT

HO Physical

Channel

Failure THD

Meaning: Maximum number of inter-RAT

handover failures allowed due to physical

channel failure. When the number of inter-RAT

handover failures due to physical channel failure

exceeds the threshold, a penalty is given to the

UE. During the time specified by

[PARA]PenaltyTimeForInterRatPhyChFail[/para],

the UE is not allowed to make inter-RAT

handover attempts.


Name


For details about the physical channel failure,

see 3GPP TS 25.331.



Unit: None

Default Value: None






parameter is set to a smaller value, many users

will not be handed over to the 2G network in

time. If this parameter is set to a larger value,

the penalty effect is unobvious.

PenaltyTimeForPhyChFail Inter-RAT

HO Physical

Channel

Failure

Penalty

Timer

Meaning: Duration of the penalty for inter-RAT

handover failure due to physical channel failure.

The UE is not allowed to make inter-RAT

handover attempts within the penalty time.

For details about the physical channel failure,

see 3GPP TS 25.331.



Unit: s

Default Value: None






parameter is set to a larger value, many users

will not be handed over to the 2G network in


Name


time. If this parameter is set to a smaller value,

the penalty effect is unobvious.

Documents

IRAT HO Parameters in mvhHuawei System