zte umts overload control feature guide u9.2

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Overload ControlWCDMA RAN

Feature Guide


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Overload Control Feature Guide

ZTE Confidential Proprietary 2010 ZTE Corporation. All rights reserved. I


Version Date Author Approved By Remarks

V4.0 2010-06-18Wang

ShaojiangCui Lili / Zheng Dan Not open to the Third Party

2010 ZTE Corporation. All rights reserved.ZTE CONFIDENTIAL:This document contains proprietary information of ZTE and is not to bedisclosed or used without the prior written permission of ZTE.

Due to update and improvement of ZTE products and technologies, information in this document

is subjected to change without notice.


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ZTE Confidential Proprietary 2010 ZTE Corporation. All rights reserved. II

TABLE OF CONTENTS

1

Functions and Attributes ....................................................................................1

2

Overview .............................................................................................................1

2.1

Overview of the Functions.....................................................................................1

2.1.1 Load Control Function ..........................................................................................2

2.1.2 HSDPA Load Control ............................................................................................22.1.3 HSUPA Load Control ............................................................................................3

3 Technical Description .........................................................................................3

3.1

R99 Load Control .................................................................................................3

3.1.1

R99 Load Control Flow .........................................................................................4

3.1.2 R99 Load Control States.......................................................................................5

3.1.3 Load Decrease Methods for R99 Load Control ........ ........ ......... ....... ........ ........ .......7

3.1.4

Load Decrease Methods for R99 Common Overload ............................................103.1.5

Load Decrease Method for R99 Serious Overload ........... ........ ......... ...... ......... ..11

3.1.6

R99 Algorithm Related Measurement ..................................................................12

3.2 HSDPA Load Control..........................................................................................123.2.1 HSDPA Load Control Flow..................................................................................13

3.2.2 Decision Methods for Conversion between HSDPA Load Control States ........ ........143.2.3 Load Decrease Methods for HSDPA Load Control................................................16 3.2.4

HSDPA Load Decrease Flow ..............................................................................18

3.2.5

Dual-Cell HSDPA Overload Control ........ ........ ......... ....... ........ ........ ......... ....... .....20

3.2.6 HSDPA Algorithm Related Measurement ........ ........ ......... ....... ........ ........ ......... ....21 3.3 HSUPA Load Control..........................................................................................21

3.3.1 HSUPA Uplink Effective Load .............................................................................223.3.2 HSUPA Load Control Flow..................................................................................23

3.3.3

Decision Methods for Conversion between HSUPA Load Control States ........ ........243.3.4

Load Decrease Methods for HSUPA Load Control ........ ......... ........ ....... ........ ........25

3.3.5 Load Decrease Methods for HUSPA Common Overload.......................................273.3.6 Load Decrease Methods for HSUPA Serious Overload ........ ........ ......... ....... ........ .27

3.3.7 HSUPA Algorithm Related Measurement ........ ........ ......... ....... ........ ........ ......... ....27 3.4 MBMS Load Control ...........................................................................................283.5

GBR Resource Consumption Limiting..................................................................28

3.5.1

HSDPA GBR Resource Consumption Prevention ........ ........ ......... ....... ........ ........ .28

3.5.2 Related Measurement ........................................................................................29

4 Configuration of Parameters.............................................................................29

4.1 Common Parameters .........................................................................................294.1.1

Common Parameter List .....................................................................................29

4.1.2

Common Parameter Configuration ......................................................................30

4.2

R99 Load Control Parameters ........ ........ ......... ....... ........ ........ ......... ....... ........ .....35

4.2.1 R99 Load Control Parameter List ........................................................................35 4.2.2 Configuration of R99 Load Control Parameters ....... ........ ......... ........ ........ ......... ...36

4.3 HSDPA Load Control Parameters ......... ........ ........ ....... ......... ........ ........ ....... .......39 4.3.1 HSDPA Load Control Parameter List ...................................................................39 4.3.2

Configuration of HSDPA Load Control Parameters ......... ........ ........ ....... ......... ......39

4.4

HSUPA Load Control Parameters ......... ........ ........ ....... ......... ........ ........ ....... .......40

4.4.1 HSUPA Load Control Parameter List ...................................................................40 4.4.2 Configuration of HSUPA Load Control Parameters ......... ........ ........ ....... ......... ......41

4.5 MBMS Load Control Parameters ........ ........ ......... ....... ........ ........ ......... ....... ........ .414.6 GBR Resource Consumption Limiting Parameters................................................424.6.1

GBR Resource Consumption Limiting Paramters List ...........................................42


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ZTE Confidential Proprietary 2010 ZTE Corporation. All rights reserved. III

4.6.2 Configuration of GBR Resource Consumption Limiting Parameters ............. ........ ..42

5 Counter And Alarm ...........................................................................................445.1

Counter List .......................................................................................................44

5.2

Alarm List .... .... .... .... .... .... .... .... ... .... ... .... ... .... ... .... ... ... .... .... .... ... .... .... ... .... ... .... ...44

6 Glossary ...........................................................................................................44


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ZTE Confidential Proprietary 2010 ZTE Corporation. All rights reserved. IV

FIGURES

Figure 1

R99 load control flowchart ......................................................................................4

Figure 2 R99 load control threshold ......................................................................................5

Figure 3 Conversion between R99 load control states............................................................6

Figure 4 R99 common overload control flowchart ........... ........ ......... ....... ........ ......... ........ ....11

Figure 5

R99 serious overload control flowchart .......... ......... ........ ....... ........ ......... ........ .......11

Figure 6 Load control flowchart for the HSDPA cells ............................................................13

Figure 7 Conversion between HSDPA load control states ....................................................15

Figure 8

HSDPA overload control flowchart ........ ........ ......... ....... ........ ........ ......... ....... ........ .19

Figure 9 HSUPA load control flowchart ......... ........ ........ ....... ......... ........ ........ ....... ......... ......23

Figure 10 Classification of HSUPA load control states ...........................................................24

Figure 11

Conversion between HSUPA load control states ....................................................24


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ZTE Confidential Proprietary 2010 ZTE Corporation. All rights reserved. 1

1 Functions and Attributes

System version: [RNC V3.09, Node B V4.09, OMMR V3.09, and OMMB V4.09]

Attributes: basic functions + optional functions

NEs involved:

UE Node B RNC MSCS MGW SGSN GGSN HLR

- - - - -

Note:

*-: NEs not involved

*: NEs involved:

Dependency: [None]

Mutual exclusive functions: [None]

Remarks: [None]

2 Overview

2.1 Overview of the Functions

The load control is performed to control the load on individual cells. It takes appropriatemeasures to recover normal load as soon as possible and thus stabilizes the systemwhen overload occurs to the system. Here overload means the uplink/downlink load on a

cell exceeds the overload threshold set during network planning. In such a case, thesystem is in an unstable state, with its capacity so close to the limit. Appropriatemeasures are required to decrease the system load. Overload includes serious overload

and common overload. Serious overload means the load is so close to the limit andrequires prompt recovery.

By functional systems, the load control can be classified into the following types:

R99 load control

HSDPA load control

HSUPA load control

MBMS load control

By severity of overload, the load control can be classified into the following two types:

Common overload control

Serious overload control


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By direction of uplink/downlink, load control can be classified into the following two types:

Uplink load control

Downlink load control

2.1.1 Load Control Function

The Node B sends RTWP and TCP messages to the RNC periodically in the commonmeasurement report. The RNC compares the load threshold with RTWP and TCP. The

RNC implements load control if RTWP or TCP exceeds the threshold. Here, the uplinkload threshold is a absolute value(dBm), it is equal to the sum of backgroundnoise(dBm) and the relative value of uplink load control threshold(dB).

There are two types of overload: serious overload and common overload. According to

the overload type, the RNC system should take actions accordingly. Serious overloadmeans that the payload approaches the limit of system capacity. At the moment, the

RNC system must adjust its payload to a normal level. Therefore, the system canforcedly drop calls to reduce payload of a cell until the payload deceases to a valuebelow the threshold of common overload. In the case of common overload, the system

can take the following measures to reduce the system payload to a normal level:

Decreasing the service rate of R99 subscribers;

Forcedly deleting the UE soft handover radio link of the overloaded cell (the link is

for downlink connection and is not for the best cell)

Forcedly handing over subscribers to an inter-frequency cell or an inter-RAT cell(the target cell has the same coverage as the overloaded cell or contains the

overloaded cell)

Forcedly transferring the interactive subscribers or background subscribers to the

CELL_FACH status

Decreasing GBR of C/S traffic through the GBR renegotiation

Forcedly dropping calls

When overloading occurs, the system selects services or UEs through the overloadcontrol priority and then takes above actions for these services. In this way, the systemcan maintain the stability for services of high-priority subscribers. .

2.1.2 HSDPA Load Control

The load control of the HSDPA is based on the transmit power of a cell. The load controlfunction is triggered when the downlink power reaches a certain value (which isconfigurable through the OMCR).During the implementation of load control, the HSDPA

reduces the payload of a cell according to the difference of subscribers. The HSDPAtakes the following measures:


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Decreasing the service rate of R99 subscribers

Forcedly deleting the UE soft handover radio link from the overloaded cell (including

DCH subscribers and HS-DSCH subscribers)

Forcedly handing over DCH and HSDPA subscribers to an inter -frequency cell or an

inter-RAT cell (the target cell has the same coverage as the overloaded cell or

contains the overloaded cell)

Forcedly transferring the interactive subscribers or background subscribers to the

CELL_FACH status

Decreasing GBR of C/S traffic through the GBR renegotiation.

Forcedly dropping calls of low-priority services (DCH and HSDPA).

2.1.3 HSUPA Load Control

When overloading occurs in the E-DCH cell, the system can take the following load

control measures:

Decreasing the service rate of R99 subscribers

Forcedly handing over DCH and HSUPA subscribers to an inter -frequency cell or an

inter-RAT cell (the target cell has the same coverage as the overloaded cell or

contains the overloaded cell)

Decreasing GBR of C/S traffic through the GBR renegotiation.

Forcedly dropping low-priority services (DCH and HSDPA)

3 Technical Description

3.1 R99 Load Control

For R99 cells, the Node B periodically sends common measurement reports to the RNC,

and updates their uplink load RTWP and downlink load TCP. RNC compares the RTWPand TCP with the load control threshold. If the RTWP or TCP exceeds the threshold, itmeans occurrence of overload and the load control process is carried out. Overload

includes serious overload and common overload.

Serious overload means the load is close to the limit and requires prompt recovery. Insuch a case, the following load reduction measures should be taken to decrease the

system load to a normal level as soon as possible.

Forcing call drop until the load is recovered below the common overload threshold.


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For common overload, the following load reduction measures are available to decreasethe system load to a normal level as soon as possible:

Decreasing the service rate of R99 subscribers;

Forcedly handing over to inter-frequency or inter-RAT neighboring cell;

Deleting the radio link of any soft handover UE from the overloaded cell;

Transferring services of I/B subscribers to the RACH/FACH channels;

Decreasing GBR (GBR renegotiation)

Forcedly releasing the service.

3.1.1 R99 Load Control Flow

The figure below shows the overall R99 load control flowchart. The load control isclassified into serious overload control and common overload control depending ondifferent overload states. The load control is triggered by common measurement reports

from the Node B.

Upon the receipt of a common measurement report from the Node B, the systemdecides the state of load control with the methods described in section 3.1.2, and

performs an appropriate process depending on the decision result. In the state ofcommon overload, the common overload control is carried out; in the sate of seriousoverload, the serious overload control is carried out.

The overload control in all states is performed in the direction of uplink and downlink

respectively.

Figure 1 R99 load control flowchart


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Common Measurement

Report

To make a

decision

for status

The status of

serious overload

The status of

normal load

The status of common

overload

To perform serious

overload controlReturn

To perform common

overload control

3.1.2 R99 Load Control States

3.1.2.1 Classification of R99 Load Control States

Load control has three thresholds, which are serious overload threshold, commonoverload threshold, and overload recovery threshold. Relations among the threethresholds are: serious overload threshold (uplink: UlSeriousOverLd, downlink:

DlSeriousOverLd) > common overload threshold (uplink: UlOverLd, downlink:DlOverLd) > overload recovery threshold (uplink: UlAlrmLd, downlink: DlAlrmLd). SeeFigure 2. The overload thresholds are set in the direction of uplink and downlink

respectively.

Figure 2 R99 load control threshold

The Threshold of Serious Overload

(uplink: UlSeriousOverLd,

downlink:DlSeriousOverLd)

The Threshold of Overload Recovery

(uplink: UlAlrmLd,downlink: DlAlrmLd)

The Threshold of Common Overload

(uplink: UlOverLd,downlink:DlOverLd)

The Load of Cell


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Depending on the load on a cell, load control is performed in three states: normal state,common overload state, and serious overload state.

3.1.2.2 Conversion between R99 Load Control States

With the change of load on a cell, the three states of load control are inter-convertible in

a relationship as shown inFigure 3.

Figure 3 Conversion between R99 load control states

normal

load

common

overload

serious

overload

4. Load below the threshold of load recovery


3. Load over the threshold of serious overload

(uplink: UlSeriousOverLd, downlink:DlSeriousOverLd)

6. Load below the threshold of serious overload


But over threshold of common overload


5. Load over the threshold of serious overload


1. Load over the threshold of common overload


2. Load below the threshold of load recovery


Note: When a cell is set up, the cell load is in the normal state.

1 In the normal state, when the load is found over the common overload threshold butbelow the serious overload threshold, the cell enters the common overload state.

2 In the common overload state, when load control helps decrease the load below theoverload recovery threshold, the cell returns to the normal state.

3 In the normal state, when the load is found over the serious overload threshold, the

cell enters the serious overload state.

4 In the serious overload state, when load control helps decrease the load below theoverload recovery threshold, the cell returns to the normal state.

5 In the common overload state, when the load is found over the serious overloadthreshold, the cell enters the serious overload state.

6 In the serious overload state, when load control helps decrease the load below the

serious overload threshold but above the common overload threshold, the cellenters the common overload state.


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7 These mutual conversions between load control states are implemented in thedirection of uplink and downlink respectively.

3.1.3 Load Decrease Methods for R99 Load Control

The load decrease measures available with load control include decrease of service rate,forced handover to an inter-frequency cell or a 2G cell under the same coverage, forceddeletion of the radio link of the UE in the macro diversity state from the overloaded cell

(the forced deletion of a macro diversity link is also referred to as a mode of forcedhandover), transfer of interactive and background services to the RACH/FACH channel,decreasing GBR (GBR renegotiation) and forced drop of service. The following outlines

these load decrease methods:

Downgrade

Forced handover

Forced transfer of DCH to FACH


Call drop (service disconnection)

The priorities of the methods in descending order: Downgrade -> forced handover ->forced transfer to RACH/FACH -> decreasing GBR (GBR renegotiation) ->call drop

These load control methods are performed in the direction of uplink and downlink

respectively. Whether a load control method is used can be configured in thebackground.

3.1.3.1 Downgrade

Downgrade includes AMR service downgrade and PS service downgrade. The AMRdowngrade must fall within the dynamic AMR rate range supported by the RNC and UE.

For information on AMR speed grading, refer to the ZTE UMTS AMR Feature Guide. Fora subscriber with concurrent DCH service in addition to AMR service, downgrade isapplicable only to the PS service rather than the AMR service except for concurrence of

additional HS services. The stream services of the PS domain can be decreased to theMax(the lowest level of DRBC, Guarantee Bit Rate); the I/B service has no Guarantee

Bit Rate (GBR), with its rate can be decreased to the lowest level of DRBC. For detailson specifying the lowest level of DRBC, refer to the ZTE UMTS DRBC Algorithm FeatureGuide.

The rate of a service can be decreased by many levels at a time. The rate can be

divided into many levels according to the rate levels of DRBC. The maximum rate levels(UlDnMaxStgin the uplink and DlDnMaxStg in the downlink)that can be decreased at atime is configurable at the daemon.

When decreasing service rate, the system selects the subscribers for which the servicerate should be decreased: First, sort all the services according to the load controlpriorities in descending order, decrease speed for the subscriber with the lowest priority.

The system does not select a service that is already at the lowest rate. The load control


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priority adopts the settings of application priority and is based on basic priority, bearertype, and real-time rate of a service. Since the load control priority is associated with thecurrent service rate, it is necessary to remap the load control priority against the new

rate after the service rate is decreased. The Traffic Rate in the table indicates the

current allocated rate for the DCH. It is the GBR for the S traffic of HSPA, and the NBRfor the I/B traffic of HSPA. NBR (Nominal Bit Rate) refers to ZTE UMTS QoS Feature

Guide.

For details on the rules of mapping between the load control priority and basic priority,bearer type, and service real-time rate, refer to ZTE UMTS QoS Feature Guide.

The parameter MaxNumUeOfDecRat controls the number of subscribers whose linerates can be decreased in the uplink and downlink at a time.

The load control can trigger the downgrade rather than the rate increase. The cell load

state serves as a constraint on the service rate increase. That is, if the current cell loadis abnormal, the rate increase is forbidden.

3.1.3.2 Forced Handover

Forced handover is to hand over the subscribers of a cell to an inter-frequency cell or a

2G cell (the target cell has the same coverage as the overloaded cell or contains theoverloaded cell), or forcedly delete macro diversity links.

If it is required to hand over a call to an inter-frequency cell or 2G cell, the overloaded

cell must be configured with an adjacent cell of different frequency with the samecoverage or a 2G cell with the same coverage, and the capability of the UE and serviceattributes satisfy the requirements for inter-frequency handover or inter-RAT handover.

For details, refer to the ZTE UMTS Handover Control Feature Guide. Measurement isnot applied to the forced handover of load control, which is known as a kind of blindhandover.

Forced deletion of macro diversity link is to delete a radio link of the UE working inmacro diversity status in the overloaded cell. If the UE is in the best cell, the UE cannotbe deleted. If the deleted link is not in the best cell, the link deletion does not seriouslyaffect the service quality of the subscribers. The link deletion is applied only to downlink

overload, because the uplink interference is common to all cells. If the channel qualityturns poorer due to link deletion, greater interference may occur.

To perform forced handover, the system sorts all the subscribers by load control priority,

and then processes the subscriber with the lowest priority as needed. The load control

priority of a subscriber is determined by the service with the highest load control priorityamong all his services.

For details on the rules of mapping between the load control priority and basic priority,bearer type, and service real-time rate, refer to ZTE UMTS QoS Feature Guide.

The maximum number of subscribers allowed in a forced uplink handover is controlled

by the parameter UlMaxForHoNum; the maximum number of subscribers allowed in aforced downlink handover and the maximum number of downlink radio links that can bedeleted each time are controlled by the parameter DlMaxForHoNum.


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3.1.3.3 Forced Transfer to FACH

Forced transfer to FACH means to decrease the system load by migrating interactiveand background subscribers to RACH/FACH channels in the case of overload. (Do not

perform this operation unless all services of the subscriber are of the I/B category.)

To perform forced transfer to FACH, the system should first sort all interactive andbackground subscribers by load control priority, and then start with the subscriber withthe lowest priority as needed. Because the operation of forced transfer to FACH is for a

subscriber, when the subscriber has multiple RABs, and the RABs have different loadcontrol priorities, RNC should select the highest load control priority among all theservices of the subscriber.

For details on the rules of mapping between the load control priority and basic priority,bearer type, and service real-time rate, refer to ZTE UMTS QoS Feature Guide.Themaximum number of subscribers allowed in a transfer is controlled by the parameter

NFach.

3.1.3.4 GBR Decrease

When the cell is in the overload state, the switch for QoSnegotiation/renegotiation(QosNegRenegSwi) is QoS renegotiation openand the switchfor shielding GBR reduction(DecGbrSw) is open, configured at the daemon, GBRdecrease targets at services with current GBR higher than their lowest level ofnegotiation GBR and then decrease GBR to their lowest level negotiation GBR at a time.

When performing GBR decrease, the system sorts all the services according to the load

control priorities in descending order, decrease GBR of the subscriber with the lowestpriority. It is necessary to remap the load control priority use new GBR after the HSPA SGBR is decreased. The maximum number of services that can be performed GBR

decrease at a time (MaxDecGbrNum) is configured at the daemon.

Note:

1 The GBR exists in the C/S services only.

2 The load control priority is mapped from the BP, rate, and bearer type, where therate is MBR for HSPA C traffic, GBR for HSPA S traffic, and the current allocatedrate for the R99 traffic. It is necessary to remap the load control priority for the

HSPA S traffic use the new GBR after the GBR is decreased, but no need for theR99 traffic

3 For details of the GBR negotiation and the parameters QosNegRenegSwi,

DecGbrSw, and MaxDecGbrNum involved, refer to ZTE UMTS Services and RadioAccess Bearers Feature Guide.

3.1.3.5 Call Drop

Forced service drop is a measure taken to release the RAB with low load control priority

when the above-mentioned methods fail to produce any effect or expected effect.

Call drop triggered by load control mechanism is based on RABs. When there aremultiple RABs in a subscriber, it is unnecessary to process the priorities.


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To perform call drop, the system should first sort all the subscribers by load controlpriority, and then start with the subscriber with the lowest priority as needed.

For details on the rules of mapping between the load control priority and basic priority,

bearer type, and service real-time rate, refer to ZTE UMTS QoS Feature Guide.

The maximum number of subscribers allowed in a forced uplink call drop is controlled bythe parameter UlMaxDrpUrNum ; the maximum number of subscribers allowed in a

forced downlink call drop is controlled by the parameter DlMaxDrpUrNum.

3.1.4 Load Decrease Methods for R99 Common Overload

When the system load rises over the common overload threshold, the system enters the

common overload state. It is necessary to take appropriate load decrease measures.The load decrease action continues until the system load drops below the overloadrecovery threshold.

The load decrease for the common overload goes through the following steps:

1 If the downgrade switch is on (the uplink downgrade switch is UlDecRateSw; thedownlink downgrade switch is DlDecRateSw) and the cell contains services with

high rates, sort the service according to the priorities of these services in ascendingorder and then decrease the rates of the services. For details on downgrade, referto " 3.1.3.1 Downgrade".

2 If the forced handover switch is on (the uplink handover switch isUlForceHandoffSw; the downlink handover switch is DlForceHandoffSw) and thecell contains subscribers supporting forced handover, sort the subscribers

according to the priorities in ascending order and then perform the forced handoverfor these subscribers. For details on forced handover, refer to "3.1.3.2 ForcedHandover".

3 If the switch of forced transfer from DCH to FACH (SwitchToFach)is on and the cellcontained DCH subscribers supporting transfer to the FACH, sort the subscribersaccording to the priorities in ascending order and then transfer these subscribers to

the FACH channel. For details on CELL_FACH method, refer to "3.1.3.3 ForcedTransfer to FACH".

4 If the switch for QoS negotiation/renegotiation(QosNegRenegSwi) is QoSrenegotiation open , the switch for shielding GBR reduction(DecGbrSw)is openand services with GBR higher than the minimum negotiation GBR exists, the

system sorts all the services according to the load control priorities in descendingorder, decrease GBR of the subscriber with the lowest priority. For details on GBRdecrease method, refer to "3.1.3.4 GBR Decrease". Parameter DecGbrSw refers toZTE UMTS Services and Radio Access Bearers Feature Guide.

5 If the forced call drop switch (UlDropSwfor the uplink or DlDropSwfor the downlink)is open, and the cell contains some subscribers suitable for forced call drop, thesystem selects certain number of subscribers for call drop by priority in an

ascending sequence. For more details, refer to "3.1.3.5 Call Drop".

The figure below shows the common overload control flowchart.


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Figure 4 R99 common overload control flowchart

Findthemethodsofloaddecreasingissupportedby

eachUEinthecell

Downgra

de

Forced

Handove

r

Transfer

DCHtoFACHof

I/Btraffic

Forced

Call

Drop

SwitchforDowngradeis

open(UlDecRateSw=1foruplink;

DlDecRateSw=1fordownlink)?

End

SwitchforForcedHandoverisopen

(UlForceHandoffSw=1foruplink;

DlForceHandoffSw=1fordownlink)?

SwitchforTransferDCHtoFACHofI/Btrafficisopen(SwitchToFach=1)?

SwitchforForcedCallDropis

open(UlDropSw=1foruplink;DlDropSw=1

fordownlink)?

No

Yes

No

No

Yes

Yes

Yes

No

SwitchforshieldingGBRreductionis

open(DecGbrSw=1)?

Decreasin

gGBRof

C/Straffic

Yes

No

3.1.5 Load Decrease Method for R99 Serious Overload

When the system load rises over the serious overload threshold, the system enters theserious overload state. For quick decrease of cell load, the system should force service

drop to release the calls of some subscribers in the cell. That is to perform the forcedservice drop in the common overload control process which is described in section3.1.3.4 Call Drop. When the system load recovers below the common overload

threshold, the system enters the common overload state, and performs the downgradeand forced handover for the common overload.

The figure below shows the serious overload control flowchart:

Figure 5 R99 serious overload control flowchart


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End

Start

Forced Call Drop

Load is below the threshold of the serious

overload(uplink: UlSeriousOverLd,

downlink:DlSeriousOverLd) ?No

Yes

Load is below the threshold of load

recovery(uplink: UlAlrmLd,downlink:DlAlrmLd)?

YesNo

Dereasing load with the method

of common overload

3.1.6 R99 Algorithm Related Measurement

3.1.6.1 Node B Common Measurement

The Node B common measurement information required for R99 load control includes:

Received Total Wide Band Power (RTWP)

Transmitted Carried Power (TCP)

Node B needs to report the measurement results to the RNC periodically. The Node Breports RTWP and TCP at the interval of 2s. Load control judges whether the load

control trigger condition is satisfied. If yes, the load control process is started.

3.2 HSDPA Load ControlAs the load control is performed in the uplink and downlink separately, and HSDPA

involves downlink alone, this section describes only the policies for downlink load controlin the cells supporting the HSDPA.

In a cell supporting HSDPA, the load control policies are performed in two conditions:

1 NoHsPower>= R99 common overload threshold (DlOverLd), or NoHsPower>= R99serious overload threshold (DlSeriousOverLd), where NoHsPower is theTransmitted Carrier Power Of All Codes Not Used For HSTransmission in the

common measurement report:


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In the case of NoHsPower>= R99 common overload threshold (DlOverLd), enable HSload decrease or R99 load decrease according to the setting of parameter AglLdDec. Ifthe algorithm of load decreasing (AglLdDec) is set to R99 load decrease algorithm, start

the R99 load decrease for the DCH services (the downgrade action targets at the

services carried over the DPCH channel; forced handover targets at subscribers of theDPCH physical channel; call drop targets at services over the DCH channel). The load

decrease policy is s imilar to "3.1.3Load Decrease Methods for R99 Load Control". If thealgorithm of load decreasing (AglLdDec) is set to HS load decrease algorithm, the loaddecrease action targets at DCH and HS-DSCH subscribers. The load decrease actions

and priorities based subscribers selection policies are the same as those described in"3.2.3 Load Decrease Methods for HSDPA Load Control".

In the case of NoHsPower>= R99 serious overload threshold (DlSeriousOverLd), the

call drop action targets at the DCH service at first. And than If there is no DCHsubscriber, the call drop action targets at the HS service. The methods to decease theload are the same as those adopted for R99 serious overload.

2 When there are HS subscribers and NoHsPower +spi

rquiredPoweHsRe >= HS

overload threshold, where HsRequiredPower is the HS-DSCH Required Power inthe common measurement report, the system starts the load decrease policies

described in3.2.3.

If the conditions specified in (1) and (2) are satisfied simultaneously, the systemimplements the load decrease policies of (1).

3.2.1 HSDPA Load Control Flow

Figure 6 shows the load control flowchart of the HSDPA cell. The load control statusesinclude R99 common overload control, R99 serious overload control, and HS overload

control. The load control is triggered by common measurement reports from the Node B.In the case of R99 common overload control, the AglLdDec switch may trigger differentload decrease actions. The load decrease actions also target at different object set.

For a cell supporting the HSDPA, this section describes only the downlink load control.The uplink load control is the same as that for the R99 cells. Hence, the uplink loadcontrol is omitted here.

Figure 6 Load control flowchart for the HSDPA cells


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Common

measurement

report of node B

AglLdDec indicate

R99 reducing

load?

Load status

judgment

Normal

load

R99 common

overload

R99 serious

overload

HS

overload

Back

Reduce load of

R99 serious

overload

Reduce load of

HS overload

Reduce Load of

R99 overload

No

Yes

3.2.2 Decision Methods for Conversion between HSDPA Load ControlStates

3.2.2.1 Classification of HSDPA Load Control States

For a cell supporting the HSDPA, two thresholds are set for the HS load control (the R99

thresholds are omitted here):

HS-DSCH common overload threshold (HsdsOverLdThr)

HS-DSCH overload recovery threshold (HsdsRecoverThr)

A comparison between t he current load and each threshold can determine four states:normal state, R99 common overload state, R99 serious overload state, and HS overloadstate.

3.2.2.2 Conversion between HSDPA Load Control States

With the change of load on a cell, the four states of overload described in figure 6 areinter-convertible in a relationship as shown below, where R99 overload states containsR99 common overload state and R99 serious overload state:


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Figure 7 Conversion between HSDPA load control states

Normal loadHs overload

NoHsPower+HsRequiredPower over the threshold of

hs overload(HsdsOverLdThr) and NoHsPower below

the threshold of R99 common overload(DlOverLd)

NoHsPower+HsRequiredPower below the threshold of hs overload recovery(HsdsRecoverThr)

and NoHsPower below the threshold of R99 overload recovery(DlAlrmLd)

R99 overload

NoHsPower over the threshold of

R99 common Overload(DlOverLd) or

serious overload(DlSeriousOverLd)

NoHsPower+HsRequiredPower below the threshold of

hs overload recovery(HsdsRecoverThr) and NoHsPower

below the threshold of R99 overload recovery(DlAlrmLd)

NoHsPower+HsRequiredPower over the threshold

of hs overload(HsdsOverLdThr) and NoHsPower over

the threshold of R99 overload recovery(DlAlrmLd)

NoHsPower over the threshold of R99

common overload(DlOverLd)

or serious overload(DlSeriousOverLd)

Process description: When a cell is set up, the cell load is in the normal state.

1 In the normal state, when NoHsPower is found below the R99 common overloadthreshold and NoHsPower+

spi

rquiredPoweHsRe exceeds the HS overload

threshold, the cell enters the HS overload state.

2 In the HS overload state, when NoHsPower is found below the R99 overload

recovery threshold and NoHsPower+ spi

rquiredPoweHsRe decreases below

the HS overload recovery threshold, the cell returns to the normal state.

3 In the normal state, when NoHsPower is found over the R99 common overload

threshold but below the R99 serious overload threshold, the cell enters the R99

common overload state.

4 In the normal state, when NoHsPower is found over the R99 serious overload

threshold, the cell enters the R99 serious overload state.

5 In the R99 common overload state, when NoHsPower is found over the R99 seriousoverload threshold, the cell enters the R99 serious overload state.

6 In the R99 serious overload state, when No HsPower is found down below the R99common overload threshold but above the R99 overload recovery threshold, the cellenters the R99 common overload state.


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7 In the R99 common or serious overload state, when NoHsPower is found downbelow the R99 overload recovery threshold and

NoHsPower+ spi

rquiredPoweHsRe is below the HS overload recovery threshold,

the cell returns to the normal state.

8 In the R99 common or serious overload state, when NoHspower is found over the

threshold of R99 overload recovery, and NoHsPower+ spi

rquiredPoweHsRe

over the HS overload threshold, the cell enters the HS overload state.

3.2.3 Load Decrease Methods for HSDPA Load Control

R99 overload and HS overload occur in cells supporting HSDPA. In the case of R99

common overload, there are two load decrease methods correspond to the R99 load

decrease method and HSDPA load decrease method. The R99 load decrease method isdescribed in section 3.1.4, so it is not need to describe again.

This chapter focuses on HS overload status and load decrease actions. The HS loaddecrease can be performed with the following methods:

Downgrade

Forced handover

Forced transfer to FACH


Call drop

The priorities of the above five load decrease methods can be sorted as downgrade ->forced handover-> forced transfer to FACH -> Decreasing GBR (GBR renegotiation) ->

call drop

You can configure switches to control the use of the above load control methods. Fordetails on the switch parameters, refer to 3.2.4. The following describes the differences

between above methods and the methods applied in R99 cells.

3.2.3.1 Downgrade

Since the RNC cannot control the rate of HSDPA services, the downgrade for the HSload decrease actually means to decrease the rate of DCH services as well, and thedowngrade method is the same as that for the R99 cells.


Forced handover is to hand over the subscribers a cell to an inter -frequency cell or a 2Gcell (the target cell has the same coverage as the overloaded cell or contains theoverloaded cell), or forcedly delete macro diversity links.


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Forced handover to an inter-frequency cell or a 2G cell under the same coverage isapplied only to the subscribers with DCH services and the subscribers with streamingclass services on the HS-DSCH in the cell. The deletion of macro diversity link is based

on a DPCH channel. If the cell is the serving cell of the UE HS-DSCH or the best cell of

DCH channel, the link cannot be deleted even though the DPCH channel is in the macrodiversity status. If the cell is not a serving cell of UE HS-DSCH, the associated DPCH

channel can be deleted.

When forcedly handing over services to an inter-frequency cell with the same coverage,the system first sorts the DCH subscribers or the subscribers of the stream services

carried over the HS-DSCH channel according to load control priorities, and thenperforms the forced switchover for the subscriber with the lowest priority. When there aremultiple concurrent services, the system selects the service with the highest load control

priority among all the services of the subscriber.

The method for selecting the UE on the HS for link deletion: first make sure the UE is inthe macro diversity state and the cell is not its HS-DSCH serving cell, and then make

selection by the application priority of the load control on the DCH in an ascendingsequence (note: i f there is only signaling on the DCH, the rate used by the subscriber todetermine its application priority should be set to the signaling rate, and other

parameters should follow the RAB parameters on the HS-DSCH. If there are multipleRABs, the one with the highest load control should be followed). If there are concurrentservices on the DCH, the load control priority should be determined by the service with

the highest priority.

The load control priority is obtained by mapping the basic priority (BP), bearer type, andsubscribers real-time rate. For stream services carried over the HS -DSCH channel, thereal-time rate of the stream service is the assured rate; for I/B service, the real-time rateis NBR for the I/B traffic of HSPA. NBR (Nominal Bit Rate) refers to ZTE UMTS QoSFeature Guide.

DlMaxForHoNum(the maximum number of subscribers involved in a forced handover orthe maximum number of links deleted at a time) is the same as the parameter adoptedby R99 downlink load control and can be configured at the OMC.

3.2.3.3 Forced Transfer to FACH

Forced transfer to FACH means transfer of interactive and background RABs to the

FACH channel. This action is applied to all the services in the cell. As the associatedchannel of the HS-DSCH subscribers also occupies certain power, if this action is notperformed on the HS-DSCH service, the last resort for the subscriber will be service

drop when the cell has only HS-DSCH service and is overloaded.

To perform forced transfer to FACH, the system should first sort all interactive andbackground subscribers by load control priority, and then start with the subscriber with

the lowest priority as needed. The load control priority of a subscriber is determined bythe service with the highest load control priority among all his services.

For details on the factors related to load control priorities and mapping methods, refer to

ZTE UMTS QoS Feature Guide. For I/B traffic, the real-time rate is NBR for I/B traffic ofHSPA. NBR (Nominal Bit Rate) refers to ZTE UMTS QoS Feature Guide.

The maximum number of subscribers in a forced transfer ( NFach) is the same as the

parameter used in R99 load control, and can be configured through the daemon.


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3 If the switch of forced transfer from DCH to FACH (SwitchToFach) is opened andthe cell contained DCH subscribers supporting transfer to the FACH, sort thesubscribers according to the priorities in ascending order and then transfer these

subscribers to the FACH channel. For details on transfer to CELL_FACH method,

refer to "3.2.3.3Forced Transfer to FACH".

4 If the switch for QoS negotiation/renegotiation(QosNegRenegSwi) is QoSrenegotiation open , the switch for shielding GBR reduction(DecGbrSw)is openand services with GBR higher than the minimum negotiation GBR exists, thesystem sorts all the services according to the load control priorities in descending

order, decrease GBR of the subscriber with the lowest priority. For details on GBRdecrease method, refer to "3.2.3.4 GBR Decrease". Parameter DecGbrSw refers toZTE UMTS Services and Radio Access Bearers Feature Guide.

5 If the forced call drop switch (DlDropSw) is opened and the cell containssubscribers supporting forced handover, sort the subscribers according to thepriorities in ascending order and then perform the forced handover for these

subscribers. For details on call drop, refer to "3.2.3.5 Call Drop".

The figure below shows the HS overload control flowchart:

Figure 8 HSDPA overload control flowchart


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Strat

End

SwitchforDowngrade

isopen

(DlDecRateSw=1)?Existtraffic

canbe

downgrade?

Downgrade

SwitchforForced

HandoverorDeletingRL

ofMacroDiversityis

open

(DlForceHandoffSw=1)? ThecellisthebestcellofDCHchannelorthe

servingcellofHS-DSCH

channeloftheUE?

therewereinter-

frequencycellsor2G

cellshavethesame

coverageorcontains

theoverloadedcell?

SwitchforTransferDCH

toFACHofI/Btrafficis

open(SwitchToFach=1)?Canbe

convertedto

FACH?

SwitchforCall

Dropisopen

(DlDropSw=1)?

DeletingRLof

MacroDiversity

(UEinmacro-

diversity)

ForcedHandover

(UEhassingle

RLormacro-

diversityRLs)

TransferDCHto

FACHofI/B

traffic

CallDrop

Yes

No

Yes

No

Yes

NO

NoNo

Yes

Yes

No

Yes

Yes

No

No

Yes

No

SwitchforshieldingGBR

reductionis

open(DecGbrSw=1)? QoSrenegotiationswitchisopen?AndexistC/Sservices

canberenegotiationedto

lowerGBRlevel?

Yes

YesDecreasingGBR

ofC/Straffic

No

3.2.5 Dual-Cell HSDPA Overload Control

For Dual-Cell HSDPA overload control, the algorithm of downgrade, forced transfer toCELL_FACH and GBR decrease are consistent with which for single frequency HSDPA

cell.


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For Dual-Cell HSDPA, the method to select the user to be forced handover is also sameas that for single frequency HSDPA cell. But if the overload cell is the secondaryfrequency cell of the UE selected to handover, it only needs to remove the secondary

frequency of this UE.

For Dual-Cell HSDPA, the method to select the user to be forced call drop is also thesame as that for single frequency HSDPA cell. But the selection range contains all the

single frequency UEs and the Dual-Cell HSDPA UEs whose HS-DSCH Required Poweris not zero.

3.2.6 HSDPA Algorithm Related Measurement

3.2.6.1 Node B Common Measurement

The Node B common measurement information required for HSDPA load controlincludes:

HS-DSCH Required Power(HsRequiredPower)

Transmitted carrier power of all codes not used for HS-PDSCH or HS-SCCH

transmission(NoHsPower)

Node B reports the measurement results to the RNC at the interval of 2s. Load control

judges whether the load control trigger condition is satisfied. If yes, the load controlprocess is started.

3.3 HSUPA Load Control

In the cell supporting E-DCH, the Node B can effectively control the fluctuation of theuplink RTWP. Therefore, the overload threshold of the E-DCH cell is higher than theuplink overload threshold configured for a common R99 cell. The database does not add

new thresholds and still uses the original common overload threshold and seriousoverload threshold of the DCH.

In addition to the normal load control mechanism of the RNC, Node B also controls the

load of the UE in the non-service link of the E-DCH through the scheduling mechanismof the HSUPA. The RNC can also set up a physically-shared channel to the Node B andconfigure the parameter NServToTotalPwr, which is the percentage of the E-DCH

receive power of the non-service link over the total E-DCH receive power. Thepercentage of the receive power over the total receive power of the E-DCH isNServToTotalPwr. Node B keeps NServToTotalPwr to control the scheduling of the E-

DCH so that the percentage of the power of the E-DCH subscriber in the non-servicelink of the cell over the the power of all E-DCH subscribers does not exceedNServToTotalPwr. To achieve this purpose, Node B sends DOWN message (power

decrease authorization) to the UE in the non-service link.

As the measurement information of the RSEPS was introduced, the uplink load state ofHSUPA cell is judged based on the uplink effective load.


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3.3.1 HSUPA Uplink Effective Load

In order to forecast the uplink interference and judge the uplink load state, we mustknow the uplink effective load, which is the part load that Node B can not control. The

uplink effective load can be expressed in the formula as following:

Uplink effective load = the load produced by uplink DCH + the load produced by non-scheduling E-DCH services + the load produced bynon-serving E-DCH services +the loadproduced by neighboring cell interference + the load produced by the GBR throughput of

scheduling E-DCH GBR services.

Order:

a=10^((RSEPS)/10);

Itotal=10^((RTWP*)/10)[mW];

Then,

Uplink effective load = Itotal(1-a) + the load produced by the GBR throughput of scheduling E-

DCH GBR services.

Where,

i. Itotal(1-a) = background noise + the load produced byuplink DCH + the load produced by

non-serving E-DCH services + the load produced by neighboring cell interference(contains the load produced bynon-scheduling E-DCH services). It can be get from theRTWP and RSEPS common measurement report.

ii. The load produced by the GBR throughput of scheduling E-DCH GBR services can beget from the uplink interference forecast formula as following:

I( ) I1

Ltotal

CdBm

Where,

Itotal is get from common measurement report (RTWP*);

= 1 - N0/ Itotal

N0 is uplink background and receiver noise. If the background noise adjustment

switch (BckNoiseAdjSwh) is closed, N0 can be get from the parameterOriBckNoise. And if the background noise adjustment switch

(BckNoiseAdjSwh) is opened, N0 can be get from the uplink background noise

automatic measurement result, refer to the section 3.1.1.3 Automatic

Measurement of Uplink Background Noise of ZTE UMTS Admission Control

Feature Guide.

Load forecast factor

W

RiCL

)1( , W=3.84e6[bit/s];

is the uplink activation gain of the services, determined by the parameter Alfa;


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3.3.3 Decision Methods for Conversion between HSUPA Load ControlStates

3.3.3.1 Classification of HSUPA Load Control States

The HSUPA load control has three thresholds, which are serious overload

threshold(UlSeriousOverLd*), common overload threshold(UlOverLd*), and overloadrecovery threshold(UlAlrmLd*). The relationship between these three thresholds and themaximum target RTWP(MaxRTWP*) is: UlSeriousOverLd* > UlOverLd* > MaxRTWP* >

UlAlrmLd*, as shown in the following diagram, where the relationship is specific to theuplink direction. Where, UlSeriousOverLd*(dBm)=cell background noise(dBm)+UlSeriousOverLd(dB); UlOverLd*(dBm)= cell background noise(dBm)+ UlOverLd(dB);

UlAlrmLd*(dBm) = cell background noise(dBm)+ UlAlrmLd(dB); MaxRTWP*(dBm)= cellbackground noise(dBm)+ MaxRTWP(dB). How to get cell background noise refer to ZTEUMTS Admission Control Feature Guide.

The E-DCH cells adopt the common overload threshold and serious overload thresholdconfigured for the original DCH. The serious overload threshold is configured the sameas that for the DCH, while the common overload threshold in the E-DCH cells is

configured higher than that in the DCH cells.

Figure 10 Classification of HSUPA load control states

The Threshold of Serious

Overload(UlSeriousOverLd*)

The Threshold of Overload

Recovery(UlAlrmLd*)

The Threshold of Common

Overload(UlOverLd*)

The Uplink Load

Maximum Target RTWP(MaxRTWP*)

Forbid to use in the period of load recovering

Depending on the load on a cell, load control is performed in three states: normal state,common overload state, and serious overload state.

3.3.3.2 Conversion between HSUPA Load Control States

With the change of load on a cell, the three states of load control are inter-convertible ina relationship as shown below:

Figure 11 Conversion between HSUPA load control states


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normal

load

common

overload

serious

overload

4. Load below the threshold of

overload recovery(UlAlrmLd*)

3. Load over the threshold of

serious overload(UlSeriousOverLd*)

6. Load below the threshold of serious

Overload(UlSeriousOverLd*)But over the threshold of

common overload(UlOverLd*)


serious overload(UlSeriousOverLd*)


common overload(UlOverLd*)

2. Load below the threshold of

overload recovery(UlAlrmLd*)

Note: When a cell is set up, the cell load is in the normal state.

1 In the normal state, when the load is found over the common overload threshold butbelow the serious overload threshold, the cell enters the common overload state.

2 In the common overload state, when load control helps decrease the load below the

overload recovery threshold, the cell returns to the normal state.

3 In the normal state, when the load is found over the serious overload threshold, thecell enters the serious overload state.

4 In the serious overload state, when load control helps decrease the load below theoverload recovery threshold, the cell returns to the normal state.

5 In the common overload state, when the load is found over the serious overload

threshold, the cell enters the serious overload state.

6 In the serious overload state, when load control helps decrease the load below theserious overload threshold but above the common overload threshold, the cell

enters the common overload state.

7 These mutual conversions between load control states are implemented in thedirection of uplink.

3.3.4 Load Decrease Methods for HSUPA Load Control

In the overload state, the Node B has decreased, through scheduling, the rate of non-GBR services on the E-DCH extremely low nearly to zero and the rate of GBR services

on the E-DCH down to the guaranteed bit rate (GBR). That is, it is impossible now forthe Node B to decrease the uplink load further through scheduling, and the load can bedecreased only by the RNC through load control.


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The RNC can take the load control measures as follows:

Downgrade

Forced handover


Call drop

The priorities of the above three downgrade methods can be sorted as downgrade ->

forced handover-> decreasing GBR (GBR renegotiation) ->forced call drop

3.3.4.1 Downgrade

Downgrade is applied only to the DCH services, including PS service and CS service, inthe same way as for the R99 cells.


Forced handover is to forcedly hand over DCH subscribers to an inter-frequency

adjacent cell or a 2G cell (the target cell has the same coverage as the overloaded cellor contains the overloaded cell). Forced handover targets at all subscribers of thespecified cell, including DCH and E-DCH subscribers. Performing forced handover

selects target subscriber according to load control priority, which is mapped from the BP,real-time rate, and bearer type. The real-time rate is GBR for HSUPA S traffic, and the

current allocated rate for the DCH traffic. The mapping rules between load controlpriority and BP, Bearer type and real-time rate and NBR (Nominal Bit Rate) refer to ZTEUMTS QoS Feature Guide.

If the subscriber selected for handover is an E-DCH subscriber, the system selects an E-

DCH cell with the same coverage; if the handover fails or the mentioned cell does notexist, the handover process accompanies the transfer from the E-DCH to the DCH.

3.3.4.3 GBR Decrease

The method of GBR decrease in HSPA is same as that in R99, referring to 3.1.3.4. Notethat it is necessary to remap the load control priority use new GBR after the HSPA S

GBR is decreased.

3.3.4.4 Call Drop

Forced call drop is applied to all the subscribers selected according to load controlpriority (3.3.4.2) in the overloaded cell, who might be either DCH subscriber or E -DCH

subscriber. The specific steps are the same as those for the R99 cells.


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This common measurement information contains the RSEPS and RTWP*, in thisinformation we can get the RTWP of current cell and RTWP produced by scheduling E -DCH services.

Node B reports the measurement results to the RNC at the interval of 2s. Load controljudges whether the load control trigger condition is satisfied. If yes, the load controlprocess is started.

3.4 MBMS Load Control

For details on the technical description on MBMS load control, refer to MBMS Technical

Attribute Description.

3.5 GBR Resource Consumption Limiting

Because GBR services need to guarantee the GBR, so when the radio condition is bad,

it will consume too much resource of the cell. In order to resolve this problem, ZTE RNCcan limit the GBR resource consumption.

For R99 and HSUPA services, configure maximum power of DCH and E-DCH channelto limit the DCH and E-DCH transmit power, in t his way, the GBR resource consumptioncan be limited.

And for HSDPA services, the method to limit the GBR resource consumption is based

on HS-DSCH Required Power Per UE Weight (Expressed in percentage of the valueprovided in the HS-DSCH Required Power Value IE)in the common measurementreport.

3.5.1 HSDPA GBR Resource Consumption Prevention

When the switch for limiting HSDPA GBR resource consumption (HsGBRLimitSwi) isopened, the following method can be used to limit the HSDPA GBR resourceconsumption.

When the required power of HSDPA GBR service is bigger then a threshold

(RequiredPower>RequiredPowerlimit), if the GBR of this service can be decreased bythe method of GBR renegotiation, the GBR of this service would be decreased, and if

the GBR of this service can not be decreased, the service would be forced drop. Thedescription of the GBR decrease please refer to the section 3.1.3.4 of this paper, and

also refer to ZTE UMTS Services and Radio Access Bearers Feature Guide.

Where,

1 The required power of HSDPA GBR service is get form HS-DSCH Required PowerPer UE Weight(Expressed in percentage of the value provided in the HS-DSCH

Required Power Value IE)in common measurement report, and it need to beconverted to an absolute value (unit: dBm).

2 RequiredPowerlimit(dBm) is the upper limit for HS-DSCH required power. Firstly,

get the required power offset(dB) relative to P-CPICH power from the arrayUEHsReqPwrUplim[MAX_NUM_HS_GBR] according to the GBR grade of theservice, and then add the P-CPICH power(dBm), the result is

RequiredPowerlimit(dBm). Here, UEHsReqPwrUplim[MAX_NUM_HS_GBR] is UE


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HS-DSCH required power upper limit for limiting HSDPA GBR resourceconsumption according to each GBR grades. its elements and the GBR levels ofHSDPA services (HsGBRLev[MAX_NUM_HS_GBR]) have a one to one

relationship. The number of HSDPA GBR levels is HsGBRLevNum.We can get a

index by reading the cell limiting HSDPA GBR resource consumptionindex(CHsGBRResLmtIdx) in the cell, and then get the corresponding

index(HsGBRResLimitId) in the GBR resource consumption limiting parameterstable, in this way, we get the value of theUEHsReqPwrUplim[MAX_NUM_HS_GBR], HsGBRLev[MAX_NUM_HS_GBR] and

HsGBRLevNum.

Note:

1 If the UE has multi-services, and the services have same SPI, we get the sum of the

GBRs of each HSDPA GBR service with same SPI in one UE, and then get therequired power threshold according to this GBR sum result.

2 If the UE has multi-services, but the service have different SPI, we get the requiredpower thresholds and compare with required power of the services respectively.

(HS-DSCH Required Power in the common measurement report is the totalrequired power for all services with same SPI in the cell, while the HS-DSCHRequired Power Per UE Weight is the required power for services with sameSPI in the same UE ) .

3 The HS-DSCH required power limiting can make GBR decreased, and the event 4A

can make GBR increased, in order to avoiding the ping-pong between GBRincrease and decrease, after the GBR be decreased by HS-DSCH required powerlimiting, if the serving RL of the service is not change, the GBR of this service can

not be increased. The description of the GBR increased please refer to ZTE UMTSServices and Radio Access Bearers Feature Guide.

3.5.2 Related Measurement

HS-DSCH Required Power Per UE Weight(Expressed in percentage of the value

provided in the HS-DSCH Required Power Value IE)

4 Configuration of Parameters

4.1 Common Parameters

4.1.1 Common Parameter List

Abbreviated name Parameter name

MaxNumUeOfDecRatMaximum Number of UE Decreasing Rate When

Congestion

AglLdDec Algorithm of Load Decreasing

UlDecRateSw Uplink Switch for Shielding Rate Reduction

UlForceHandoffSw Uplink Switch for Shielding Forced Handover


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UlDropSw Uplink Switch for Shielding Forced Drop

UlDnMaxStgMaximum Number of Degraded Uplink Load Steps

Every Time

UlMaxForHoNum Maximum Number of Uplink Forced Handover UsersEvery Time

UlMaxDrpUrNumMaximum Number of Uplink Forced Drop Users Every

Time

DlDecRateSw Downlink Switch for Shielding Rate Reduction

DlForceHandoffSw Downlink Switch for Shielding Forced Handover

DlDropSw Downlink Switch for Shielding Forced Drop

DlDnMaxStgMaximum Number of Degraded Downlink Load Steps

Every Time

DlMaxForHoNumMaximum Number of Downlink Forced Handover or

Deleted Radio Links Users Every Time

DlMaxDrpUrNumMaximum Number of Downlink Forced Drop Users

Every Time

4.1.2 Common Parameter Configuration

4.1.2.1 Maximum Number of UE Decreasing Rate When Congestion

OMC Path

Path: View->Configuration Management->RNC NE->RNC Radio ResourceManagement->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load Control

Relationship ->Maximum Number of UE Decreasing Rate When Congestion

Parameter configuration

The parameter is used when load decrease is triggered due to congestion. The systemdecides the number of uplink/downlink DCH subscribers according to the current

congestion level.

If the system increases the value of the parameter for load decrease, the number ofDCH subscribers ready for downgrade also increases accordingly, and released

resources also increase; if the system reduces the value of the parameter, the numberof DCH subscribers ready for downgrade also decreases accordingly, and releasedresources decreases.

4.1.2.2 Algorithm of Load Decreasing

OMC Path


Relationship ->Algorithm of load Decreasing


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This parameter describes a general method for reducing load for an overload cell. WhenR99 common overload takes place in a cell supporting HS, the system selects an HS

load decrease action or an R99 load decrease action.

To take R99 load decrease action and adopt the R99 common load control method,refer to 3.1.4;to configure HS load decrease action for all subscribers of a cell (including

R99 and HS subscribers), refer to 3.2.4.By default, the system adopts R99 loaddecrease action.

4.1.2.3 Uplink Switch for Shielding Rate Reduction

OMC Path

Path: View->Configuration Management->RNC NE->RNC Radio ResourceManagement->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship ->Uplink Switch for Shielding Rate Reduction


This parameter indicates whether the uplink downgrade switch is on or off. Thisparameter is used only when load decrease takes place in the uplink.

If the setting of the parameter is disabled, the system does not reduce rate in the uplink

when the uplink load reaches the overload threshold; if the setting of the parameter isenabled, the system reduces rate in the uplink when the uplink load reaches theoverload threshold. By default, the settings are enabled.

4.1.2.4 Uplink Switch for Shielding Forced Handover

OMC Path


Relationship -> Uplink Switch for Shielding Forced Handover


This parameter indicates whether the forced handover attribute of the uplink load controlfunction is on or off. This parameter is valid only when the uplink is overloaded and it isnecessary to decrease the load.

If the setting of the parameter is disabled, the system does not perform forced handover

when the uplink load reaches the overload threshold; if the setting of the parameter isenabled, the system performs forced handover for load decrease when the uplink loadreaches the overload threshold. By default, the settings are disabled.

4.1.2.5 Uplink Switch for Shielding Forced Drop

OMC Path


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Path: View->Configuration Management->RNC NE->RNC Radio ResourceManagement->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship -> Uplink Switch for Shielding Forced Drop


This parameter indicates whether the forced call drop attribute of the uplink load controlfunction is on or off. This parameter is valid only when the uplink is overload.

If the setting of the parameter is disabled, the system does not perform forced call dropwhen the uplink load reaches the overload threshold; if the setting of the parameter isenabled, the system performs forced call drop for load decrease when the uplink load

reaches the overload threshold. By default, the settings are enabled.

4.1.2.6 Maximum Number of Degraded Uplink Load Steps Every Time

OMC Path


Relationship ->Maximum Number of Degraded Uplink Load Steps Every Time


This parameter specifies the maximum number of DRBC rate steps that can be

decreased at a time during the implementation of the load decrease measures in theuplink. You can configure the parameter in reference to the configuration of DRBCuplink rate steps.

Provided that the number of uplink DRBC rate grades is set to 2 grades [64 384], thecurrent bit rate is 384kbit/s and the parameter is set to 1. If the uplink rate is decreasedby 1 step, the rate is decreased to 64kbit/s. Provided that the number of uplink DRBC

rate grades is set to 3 grades [64 128 384], the current bit rate is 384kbit/s, and theparameter is set to 1. If the uplink rate is decreased by 1 step, the rate is decreased to128kbit/s. if the parameter is set to 2, the rate is decreased by 2 steps to 64kbit/s. By

default, the settings is 1 step

4.1.2.7 Maximum Number of Uplink Forced Handover Users Every Time

OMC Path

Path: View->Configuration Management->RNC NE->RNC Radio Resource

Management->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship -> Maximum Number of Uplink Forced Handover Users Every Time


This parameter specifies the maximum number of subscribers that can be switched ineach forced handover operation when the uplink is overloaded.


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To switch more subscribers in the uplink forced handover operation, increase the settingof the parameter; to switch fewer subscribers in the uplink forced handover operation,decrease the setting of the parameter. By default, the setting of the parameter is 5.

4.1.2.8 Maximum Number of Uplink Forced Drop Users Every Time

OMC Path

Path: View->Configuration Management->RNC NE->RNC Radio ResourceManagement->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship -> Maximum Number of Uplink Forced Drop Users Every Time


This parameter specifies the maximums number of subscribers supported in each forced

call drop operation when the uplink is overload.

To drop calls of more subscribers in the implementation of uplink forced call dropsolution, increase the setting of the parameter; to drop calls of fewer subscribers in theimplementation of uplink forced call drop solution, decrease the setting of the parameter.

By default, the setting is 5.

4.1.2.9 Downlink Switch for Shielding Rate Reduction

OMC Path


Management->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship ->Downlink Switch for Shielding Rate Reduction


This parameter indicates whether the downlink downgrade switch is on or off. Thisparameter is used only when downgrade takes place in the downlink.

If the setting of the parameter is disabled, the system does not reduce the rate in the

downlink when the downlink rate reaches the overload threshold; if the setting of theparameter is enabled, the system reduces the rate in the downlink when the downlinkload reaches the overload threshold. By default, the settings are enabled.

4.1.2.10 Downlink Switch for Shielding Forced Handover

OMC Path

Path: View->Configuration Management->RNC NE->RNC Radio ResourceManagement->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship -> Downlink Switch for Shielding Forced Handover



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This parameter indicates whether the forced handover attribute of the downlink loadcontrol function is on or off. This parameter is valid only when the downlink isoverloaded and it is necessary to decrease the load.

If the setting of the parameter is disabled, the system does not perform forced handoverwhen the downlink load reaches the overload threshold; if the setting of the parameter isenabled, the system performs forced handover for load decrease when the downlink

load reaches the overload threshold. By default, the settings are disabled.

4.1.2.11 Downlink Switch for Shielding Forced Drop

OMC Path


Relationship -> Downlink Switch for Shielding Forced Drop


This parameter indicates whether the forced call drop attribute of the downlink load

control function is on or off. This parameter is valid only when the downlink isoverloaded and it is necessary to decrease the load.

If the setting of the parameter is disabled, the system does not perform forced call drop

when the downlink load reaches the overload threshold; if the setting of the parameter isenabled, the system performs forced call drop for load decrease when the downlink loadreaches the overload threshold. By default, the settings are enabled.

4.1.2.12 Maximum Number of Degraded Downlink Load Steps Every Time

OMC Path


Relationship -> Maximum Number of Degraded Downlink Load Steps Every Time


This parameter specifies the maximum number of degraded downlink load steps at a

time during the implementation of the load decrease measures in the downlink. You canconfigure the parameter in reference to the configuration of DRBC downlink rate grades.

Provided that the number of downlink DRBC rate grades is set to 4 [8 64 128 384], and

the current bit rate is 384kbit/s. If the parameter is set to 1 step, the downlink rate isdecreased by 1 grade to 128kbit/s. If the parameter is set to 2 steps, the rate isdecreased by 2 steps to 64kbit/s. If the parameter is set to 3 steps, the rate is decreased

by 3 steps to 8kbit/s. By default, the setting is 1 step.

4.1.2.13 Maximum Number of Downlink Forced Handover Users Every Time

OMC Path


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4.2.2 Configuration of R99 Load Control Parameters

4.2.2.1 Uplink Serious Overload Upper Limit(dB)

OMC Path


Management->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship ->Uplink Serious Overload Upper Limit(dB)


If the value of the uplink RTWP of the current cell exceeds this parameter, it means thatthe system is in serious overload status and must take measures to decrease the load.

If the value of the parameter increases, it is relatively difficult to trigger uplink seriousoverload; if the value of the parameter decreases, it is relatively easy to trigger uplinkserious overload. By default, the setting is 62dB.

4.2.2.2 Uplink Overload Upper Limit(dB)

OMC Path


Management->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship ->Uplink Overload Upper Limit(dB)


The value of the uplink RTWP of the current cell exceeds this parameter, it means thatthe system is in common overload status and must take common overload decreasemeasures to decrease the load.

If the value of the parameter increases, it is relatively difficult to trigger uplink commonoverload; if the value of the parameter decreases, it is relatively easy to trigger uplinkcommon overload. By default, the setting is 61dB.

4.2.2.3 Uplink Overload Recovering Lower Limit(dB)

OMC Path

Path: View->Configuration Management->RNC NE->RNC Radio ResourceManagement->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship -> Uplink Overload Recovering lower Limit (dB)


This parameter indicates the lower limit of the uplink overload recovery.


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If the value of the uplink RTWP of the current cell is lower than this parameter, it meansthat the system is not in overload status and the load decrease measures can bestopped. If the value of the parameter increases, it is relatively easy to reach uplink

overload recovery; if the value of the parameter decreases, it is relatively hard to reach

uplink overload recovery status. By default, the setting is 57dB.

4.2.2.4 Downlink Serious Overload Upper Limit(%)

OMC Path


Management->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship -> Downlink Serious overload Upper Limit(%)


This parameter indicates the downlink overload upper threshold.

The value of the downlink TCP of the current cell exceeds this parameter, it means thatthe system is in serious overload status and must take measures to decrease the load. If

the value of the parameter decreases, it is relatively easy to trigger downlink seriousoverload. If the value of the parameter increases, it is relatively hard to trigger downlinkserious overload. By default, the setting is 100%.

4.2.2.5 Downlink Overload Upper Limit(%)

OMC Path


Relationship ->Downlink Overload Upper Limit(%)


This parameter indicates the upper limit of the downlink overload.

If the value of the downlink TCP of the current cell exceeds this parameter, it means thatthe system is in common overload status and must take common measures to decreasethe downlink load immediately. If the value of the parameter increases, it is relatively

difficult to trigger downlink common overload; if the value of the parameter decreases, itis relatively easy to trigger downlink common overload. By default, the setting is 90%.

4.2.2.6 Downlink Overload Recovering Lower Limit(%)

OMC Path


Management->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship ->Downlink Overload Recovering Lower Limit(%)



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This parameter indicates the lower threshold of downlink overload recovery.

If the value of the downlink TCP of the current cell is lower than this parameter, it meansthat the system is not in overload status and the load decrease measures can be

stopped. If the value of the parameter increases, it is relatively easy to reach downlinkoverload recovery status; if the value of the parameter decreases, it is relatively hard toreach downlink overload recovery status. By default, the setting is 60%.

4.2.2.7 Switch of Interactive Class/Background Class RAB->FACH for Overload

OMC Path

Path: View->Configuration Management->RNC NE->RNC Radio ResourceManagement->Utran Cell->Utran Cell XXX->Modify Advanced Parameter->Load ControlRelationship ->Switch of Interactive Class / Background Class RAB->FACH for Overload


This parameter is the switch of migrating interactive/background RABs to the FACHwhen the cell is in the overload state.

If the setting of the parameter is off, the system does not transfer theinteractive/background DCH/HSDPA subscribers to the FACH forcedly when overload; ifthe setting of the parameter is on, the system transfers the interactive/background

DCH/HSDPA subscribers to the FACH forcedly when overload. By default, the setting isoff.

4.2.2.8 Maximum Users of Interactive Class/Background Class RAB->FACH for

zte umts overload control feature guide u9.2

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