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Load ControlRAN13.0

Feature Parameter Description

Issue 04

Date 2012-11-30

HUAWEI TECHNOLOGIES CO., LTD.


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Copyright Huawei Technologies Co., Ltd. 2013. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior

written consent of Huawei Technologies Co., Ltd.

Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.

All other trademarks and trade names mentioned in this document are the property of their respective

holders.

Notice

The purchased products, services and features are stipulated by the contract made between Huawei and

the customer. All or part of the products, services and features described in this document may not be

within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,

information, and recommendations in this document are provided "AS IS" without warranties, guarantees orrepresentations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in the

preparation of this document to ensure accuracy of the contents, but all statements, information, and

recommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base

Bantian, Longgang

Shenzhen 518129

People's Republic of China

Website: http://www.huawei.com

Email: [email protected]
http://www.huawei.com/http://www.huawei.com/mailto:[email protected]:[email protected]:[email protected]://www.huawei.com/


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Load Control Contents

Issue 04 (2012-11-30) Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd

i

Contents

1 Introduction ................................................................................................................................ 1-1

1.1 Scope ............................................................................................................................................ 1-1

1.2 Intended Audience......................................................................................................................... 1-1

1.3 Change History .............................................................................................................................. 1-1

2 Overview of Load Control ....................................................................................................... 2-1

2.1 Load Control in Different Scenarios .............................................................................................. 2-1

2.2 Functions of Load Control ............................................................................................................. 2-1

2.3 Priorities Involved in Load Control ................................................................................................ 2-3

2.3.1 User Priority .......................................................................................................................... 2-3

2.3.2 RAB Integrated Priority ......................................................................................................... 2-4

2.3.3 User Integrated Priority......................................................................................................... 2-4

3 Load Measurement ................................................................................................................... 3-1

3.1 Load-Related Measurement Quantities ........................................................................................ 3-1

3.2 Reporting Period ........................................................................................................................... 3-2

3.3 Load Measurement Filtering ......................................................................................................... 3-2

3.3.1 Layer 3 Filtering on the NodeB Side .................................................................................... 3-2

3.3.2 Smooth Filtering on the RNC Side ....................................................................................... 3-3

3.4 Auto-Adaptive Background Noise Update Algorithm ..................................................................... 3-4

4 Potential User Control ............................................................................................................. 4-1

5 Intelligent Access Control ...................................................................................................... 5-1

5.1 Overview of Intelligent Access Control .......................................................................................... 5-1

5.2 IAC During RRC Connection Setup .............................................................................................. 5-3

5.2.1 Procedure of IAC During RRC Connection Setup ................................................................ 5-3

5.2.2 RRC Redirection based on Distance .................................................................................... 5-5

5.2.3 RRC Redirection for Service Steering .................................................................................. 5-6

5.2.4 RRC DRD ............................................................................................................................. 5-7

5.2.5 RRC Redirection After DRD Failure ..................................................................................... 5-8

5.3 Directed Retry Decision ................................................................................................................ 5-9

5.4 Rate Negotiation at Admission Control ......................................................................................... 5-9

5.4.1 PS MBR Negotiation ............................................................................................................. 5-9

5.4.2 PS GBR Negotiation ............................................................................................................. 5-9

5.4.3 Initial Rate Negotiation ....................................................................................................... 5-10

5.4.4 Target Rate Negotiation ...................................................................................................... 5-12

5.5 Admission Decision ..................................................................................................................... 5-12

5.6 Preemption .................................................................................................................................. 5-12

5.7 Queuing ....................................................................................................................................... 5-15

5.8 Low-Rate Access of the PS BE Service ...................................................................................... 5-16

5.9 IAC for Emergency Calls ............................................................................................................. 5-17


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ii

5.9.1 RRC Connection Setup Process of Emergency Calls ........................................................ 5-18

5.9.2 RAB Process of Emergency Calls ...................................................................................... 5-18

6 Intra-Frequency Load Balancing .......................................................................................... 6-1

6.1 Overview ....................................................................................................................................... 6-1

6.2 Downlink Intra-Frequency Load Balancing ................................................................................... 6-1

6.3 Uplink Intra-Frequency Load Balancing ........................................................................................ 6-2

7 Load Reshuffling ....................................................................................................................... 7-1

7.1 Basic Congestion Triggering ......................................................................................................... 7-1

7.1.1 Power Resource ................................................................................................................... 7-1

7.1.2 Code Resource ..................................................................................................................... 7-2

7.1.3 Iub Resource ........................................................................................................................ 7-3

7.1.4 NodeB Credit Resource........................................................................................................ 7-3

7.2 LDR Procedure .............................................................................................................................. 7-3

7.3 LDR Actions ................................................................................................................................... 7-7

7.3.1 Inter-Frequency Load Handover .......................................................................................... 7-7

7.3.2 BE Rate Reduction ............................................................................................................. 7-10

7.3.3 QoS Renegotiation for Uncontrollable Real-Time Services ............................................... 7-11

7.3.4 Inter-RAT Handover in the CS Domain .............................................................................. 7-11

7.3.5 Inter-RAT Handover in the PS Domain............................................................................... 7-12

7.3.6 AMR Rate Reduction .......................................................................................................... 7-12

7.3.7 Code Reshuffling ................................................................................................................ 7-13

7.3.8 MBMS Power Reduction .................................................................................................... 7-14

7.3.9 UL and DL LDR Action Combination of a UE ..................................................................... 7-14

8 Overload Control ....................................................................................................................... 8-1

8.1 Overload Triggering ....................................................................................................................... 8-1

8.2 General OLC Procedure ............................................................................................................... 8-2

8.3 OLC Actions .................................................................................................................................. 8-3

8.3.1 Performing TF Control of BE Services ................................................................................. 8-3

8.3.2 Switching BE Services to Common Channels ..................................................................... 8-5

8.3.3 Adjusting the Maximum FACH TX Power ............................................................................. 8-5

8.3.4 Releasing Some RABs ......................................................................................................... 8-5

9 Parameters.................................................................................................................................. 9-1

10 Counters.................................................................................................................................. 10-1

11 Glossary .................................................................................................................................. 11-1

12 Reference Documents ......................................................................................................... 12-1


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Load Control 1 Introduction



1-1

1 Introduction

1.1 Scope

This document describes the features related to the load control. It also describes the relatedparameters.

1.2 Intended Audience

This document is intended for:

Personnel who are familiar with WCDMA basics

Personnel who need to understand load control

Personnel who work with Huawei products

1.3 Change History

This section provides information on changes in different document versions.

There are two types of changes, which are defined as follows:

Feature change: refers to a change in the load control feature.

Editorial change: refers to a change in wording or the addition of the information that was notdescribed in the earlier version.

Document Issues

The document issues are as follows:

04 (2012-11-30)

03 (2012-05-30)

02 (2011-10-30)

01 (2011-04-30)

Draft B (2011-03-30)

Draft A (2010-12-30)

04 (2012-11-30)

This is the document for the fourth commercial release of RAN13.0.

Compared with issue 03 (2012-05-30) of RAN13.0, this issue incorporates the changes described in the

following table.

ChangeType

Change Description Parameter Change

Featurechange

Whether the feature WRFD-020137Dual-Threshold Scheduling with HSUPAInterference Cancellation is enabled affects theRTWP value used by the RNC. For details, seesection3.1 Load-Related MeasurementQuantities."

None.

Editorial

change

None. None.


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1-2

03(2012-05-30)

This is the document for the third commercial release of RAN13.0.

Compared with issue 02 (2011-10-30) of RAN13.0, this issue incorporates the changes described in thefollowing table.

ChangeType

Change Description Parameter Change

Featurechange

None None

Editorial

change

Added the description of emergency call and

wireless priority service (WPS) user preemptionpriority. For details, see section5.6"Preemption."

The following parameters have been added:

NbmWpsAlgor i thmSwitch

02 (2011-10-30)

This is the document for the second commercial release of RAN13.0.

Compared with issue 01 (2011-04-30) of RAN13.0, this issue adds load reshuffling algorithm selection ofENU. For details, see7.1.1 Power Resource.

01 (2011-04-30)This is the document for the first commercial release of RAN13.0.

Compared with issue Draft B (2011-03-30) of RAN13.0, this issue has no change.

Draft B (2011-03-30)

This is the draft of the document for RAN13.0.

Compared with Draft A (2010-12-30) of RAN13.0, this issue optimizes the description.

Draft A (2010-12-30)

This is the draft of the document for RAN13.0.Compared with issue 02 (2010-12-20) of RAN12.0, the uplink load balancing algorithm is added and thedescription is optimized.
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Load Control 2 Overview of Load Control



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2 Overview of Load Control

The WCDMA system is a self-interfering system. As the load of the system increases, the interferencerises. A relatively high interference can affect the coverage of cells and QoS of established services.

Therefore, the capacity, coverage, and QoS of the WCDMA system are mutually affected. To solve theseproblems, the load control function is introduced that controls the load in a cell.

Load control aims to maximize the system capacity while ensuring coverage and QoS by controlling thekey resources, such as power, downlink channelization codes, channel elements (CEs), Iubtransmission resources, which directly affect user experience.

Each cell has its own set of load control functions that are responsible for monitoring and controlling theresources of the cell. The load control functions monitor the load condition of the cell through loadmeasurement, make the admission decision for services through intelligent access control and calladmission control, and relieve congestion in a cell.

2.1 Load Control in Different Scenarios

Depending on the different phases of UE access, different load control functions are used, as shown inthe following figure.

Figure 2-1 Load Control functions in different UE access phases

The load control functions are applied to different UE access phases as follows:

Before UE access: Potential User Control (PUC)

During UE access: Intelligent Access Control (IAC) and Call Admission Control (CAC)

After UE access: intra-frequency Load Balancing (LDB), Load Reshuffling (LDR), and OverloadControl (OLC)

The following sections will provide detailed information about the load control functions performed in thedifferent UE access phases.

2.2 Functions of Load Control

Load control is implemented in the RNC after obtaining measurement reports from the NodeBs.


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Figure 2-2 Load control function in the WCDMA system

The load control functions are described as follows:

Potential User Control (PUC)

The function of PUC is to balance traffic load between cells on different frequencies. The RNC usesPUC to modify cell selection and reselection parameters, and broadcasts them through systeminformation. In this way, UEs are directed to the cells with light load. The UEs can be in idle mode,CELL_FACH state, CELL_PCH state, or URA_PCH state.

Intelligent Access Control (IAC)

The function of IAC is to increase the access success rate with the current QoS guaranteed throughrate negotiation, queuing, preemption, and Directed Retry Decision (DRD). For details about DRD, seetheDirected Retry Decision Feature Parameter Description.

Call Admission Control (CAC)

The function of CAC is to decide whether to accept resource requests from UEs, such as access,reconfiguration, and handover requests, depending on the resource status of the cell.

For details about CAC, see theCall Admission Control Feature Parameter Description.

Intra-frequency Load Balancing (LDB)

The function of intra-frequency LDB is to balance the cell load between intra-frequency neighboringcells to provide better resource usage. When the load of a cell increases, the cell reduces its coverageto lighten its load. When the load of a cell decreases, the cell extends its coverage so that some trafficis sent from its neighboring cells to it.

Load Reshuffling (LDR)

The function of LDR is to reduce the cell load when the cell enters the basic congestion state. Thepurpose of LDR is to increase the access success rate by taking the following actions:

Inter-frequency load handover

Code reshuffling

BE service rate reduction

AMR voice service rate reduction

QoS renegotiation for uncontrollable real-time services

CS inter-RAT load handover

PS inter-RAT load handover

MBMS power reduction

Overload Control (OLC)

The function of OLC is to reduce the cell load rapidly when the cell is overloaded. The purpose of OLCis to ensure the system stability and the QoS of most UEs in the following ways:
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2-3

Restricting the Transport Format (TF) of the BE service

Switching BE services to common channels

Adjusting the maximum transmit power of FACHs

Releasing some RABs

Table 2-1 lists the resources that are considered by different load control functions.

Table 2-1 Resources considered by different load control functions

Load Control Function Resources

Power Code NodeB Credits Iub Bandwidth

CAC

IAC

PUC - - -

LDB - - -

LDR

OLC - -

NOTE

- : not considered

: considered

2.3 Priorities Involved in Load ControlDifferent types of priorities are used in load control to preferentially ensure the QoS of the services orusers with high priorities.

The priorities involved in load control are user priority, Radio Access Bearer (RAB) integrated priority,and user integrated priority.

2.3.1 User Priority

User priorities are adopted to provide differentiated services for users. For ease of application, the RNCmaps the 15 levels of Allocation/Retention Priority (ARP) that is carried in the RAB ASSIGNMENTREQUEST message from the core network (CN) onto three user priorities, that is, gold (high priority),

silver (medium priority), and copper (low priority). The relation between user priority and ARP can be setby running SET UUSERPRIORITYcommand; the typical relation is shown inTable 2-2.

Table 2-2 Typical relation between user priority and ARP

ARP 1 2 3 4 5 6 7 8

User Priority Gold Gold Gold Gold Gold Silver Silver Silver

ARP 9 10 11 12 13 14 15

User Priority Silver Silver Copper Copper Copper Copper Copper


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2-4

If ARP is not received in messages from the Iu interface, the user priority is regarded as copper.

2.3.2 RAB Integrated Priority

The priority of an RAB is determined by its traffic class, ARP, and carrier type. Such a priority is calledRAB integrated priority. When resources are insufficient, services with the highest integrated priority arepreferentially processed.

The values of RAB integrated priority are set according to the integrated priority configuration referenceparameter (PriorityReference):

IfPriorityReferenceis set to Traffic Class, the integrated priority abides by the following rules:

Traffic classes: conversational > streaming > interactive > background

Services of the same traffic class: priority based on ARP, that is, ARP1 > ARP2 > ARP3 > ... >ARP14 > ARP15

Service of the same traffic class and ARP (only for interactive services): priority based on TrafficHandling Priority (THP) that is carried in the RAB ASSIGNMENT REQUEST message, that is,THP1 > THP2 > THP3 > ... > THP14 > THP15

Services of the same traffic class, ARP and THP (only for interactive services): High Speed PacketAccess (HSPA) or Dedicated Channel (DCH) service preferred depending onCarrierTypePriorInd.

IfPriorityReferenceis set to ARP, the integrated priority abides by the following rules:

ARP: ARP1 > ARP2 > ARP3 > ... > ARP14 >ARP15

Services of the same ARP: priority based on traffic classes, that is, conversational > streaming >interactive > background

Only for the interactive service of the same ARP value: priority based on Traffic Handling Priority(THP), that is, THP1 > THP2 > THP3 > ... > THP14 > THP15

Services of the same ARP, traffic class and THP (only for interactive services): HSPA or DCH servicepreferred depending onCarrierTypePriorInd.

2.3.3 User Integrated Priority

A user may have multiple RABs, and the RABs may have different priorities. In this case, the highestpriority is considered as the priority of this user. Such a priority is called user integrated priority. Userintegrated priority is used in user-specific load control. For example, the selection of R99 users duringpreemption, the selection of users during inter-frequency load handover for LDR, and the selection ofusers during switching of BE services to common channels are performed according to the userintegrated priority.
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Load Control 3 Load Measurement



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3 Load Measurement

This chapter describes the WRFD-020102 Load Measurement Feature.

The load control functions, such as OLC and CAC, use load measurement values in the uplink and thedownlink. A common Load Measurement (LDM) function is used to control load measurement in theuplink and the downlink separately.

Load measurement is implemented by the NodeB. The filtering of measurement quantities isimplemented by the NodeB and the RNC.

3.1 Load-Related Measurement Quantities

The major load-related measurement quantities are as follows:

Uplink Received Total Wideband Power (RTWP)

When the feature WRFD-020137 Dual-Threshold Scheduling with HSUPA Interference Cancellation

is not enabled, the RNC uses the measured RTWP value.When the feature WRFD-020137 Dual-Threshold Scheduling with HSUPA Interference Cancellationis enabled, the RNC uses the RTWP value after interference cancellation

For details about the feaure WRFD-020137 Dual-Threshold Scheduling with HSUPA InterferenceCancellation, see theHSUPA Feature Parameter Description.

OLC always uses the measured RTWP value no matter whether the RNC uses the measured RTWP value. For detailsabout OLC, see chapter8 Overload Control".

Downlink Transmitted Carrier Power (TCP)

Non-HSPA power: TCP excluding the power used for transmission on HSPA channels. For the detailedinformation about HSPA channels, see theHSDPA Feature Parameter Description and theHSUPA

Feature Parameter Description Provided Bit Rate (PBR) on HS-DSCH. For details about PBR, see the 3GPP 25.321.

Power Requirement for GBR (GBP) on HS-DSCH: minimum power required to ensure the GBR onHS-DSCH

PBR on E-DCH

Received Scheduled E-DCH Power Share (RSEPS): power of the E-DCH scheduling service in theserving cell

The NodeB measures the major quantities related to load control. After layer 1 and layer 3 filtering, themeasurement values are reported to the RNC through the COMMON MEASUREMENT REPORTmessage.

The RNC performs smooth filtering of the measurement values reported from the NodeB and thenobtains the measurement values, which further serve as data input for the load control algorithms.

The measurement procedure is shown inFigure 3-1.
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Figure 3-1 LDM procedure

3.2 Reporting Period

The NodeB periodically reports each measurement quantity to the RNC. The following table lists thereporting period parameters for setting different measurement quantities.

Measurement Quantity Reporting Period Parameter

RTWP ChoiceRprtUnitForUlBasicMeas

TenMsecForUlBasicMeas

MinForUlBasicMeas

ChoiceRprtUnitForDlBasicMeas

TenMsecForDlBasicMeas

MinForDlBasicMeas

RSEPS

TCP

Non-HSDPA power

GBP ChoiceRprtUnitForHsdpaPwrMeas

TenMsecForHsdpaPwrMeas

MinForHsdpaPwrMeas

HS-DSCH PBR ChoiceRprtUnitForHsdpaRateMeas

TenMsecForHsdpaPrvidRateMeas

MinForHsdpaPrvidRateMeas

E-DCH PBR ChoiceRprtUnitForHsupaRateMeasTenMsecForHsupaPrvidRateMeas

MinForHsupaPrvidRateMeas

3.3 Load Measurement Filtering

3.3.1 Layer 3 Filtering on the NodeB Side

The following figure shows the measurement model at the physical layer that is compliant with 3GPP25.302.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsdparatemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsdparatemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsdpaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsdpaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsdpaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsdpaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsuparatemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsuparatemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsupaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsupaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsupaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsupaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsupaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsupaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsuparatemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsdpaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsdpaprvidratemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsdparatemeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforhsdpapwrmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitfordlbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_minforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_tenmsecforulbasicmeas.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_choicerprtunitforulbasicmeas.html


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3-3

Figure 3-2 Measurement model at the physical layer

InFigure 3-2:

A is the sampling value of the measurement.

B is the measurement value after layer 1 filtering.

C is the measurement value after layer 3 filtering.

C' is another measurement value (if any) for measurement evaluation.

D is the reported measurement value.

Layer 1 filtering is not standardized by protocols and it depends on vendor equipment. Layer 3 filtering isstandardized. The filtering effect is controlled by a higher layer. The alpha filtering that applies to layer 3filtering is calculated according to the following formula:

Here:

Fnis the new post-filtering measurement value. Fn-1is the last post-filtering measurement value.

Mnis the new measurement value from the physical layer.

= (1/2)k/2

, k is the measure filter coefficient which is specified by the following parameters.

For load control algorithms (excluding OLC), k is specified by theUlBasicCommMeasFi l terCoefforDlBasicCommMeasFi l terCoeffparameter.

For OLC algorithm, k is specified by theUlOlcMeasFilterCoefforDlOlcMeasFilterCoeffparameter.

3.3.2 Smooth Filtering on the RNC Side

After the RNC receives the measurement report, it filters the measurement value using the smooth

window method.

Assuming that the reported measurement value is Qnand that the length of the smooth window is N, thefiltered measurement value is

LDM must apply different smooth window length and measurement periods to PUC, CAC, LDR, andOLC to obtain appropriate filtered values.

The following table lists the smooth window length parameters for setting different functions.
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3-4

Function Smooth Window Length Parameter

PUC PucAvgFi l terLen

CAC UlCacAvgFi l terLen

DlCacAvgFi l terLen

LDB LdbAvgFi l terLen

LDR UlLdrAvgFi l terLen

DlLdrAvgFi l terLen

OLC UlOlcAvgFi l terLen

DlOlcAvgFi l terLen

GBP measurements have the same smooth window length in all related functions. The filter length for GBP measurementis specified by theHsdpaNeedPwrFilterLenparameter.

The length of the PBR smooth filter window is specified by theHsdpaPrvidBitRateFilterLen/HsupaPrvidBitRateFilterLenparameter.

3.4 Auto-Adaptive Background Noise Update Algorithm

Uplink (UL) background noises are sensitive to environmental conditions, and the fluctuation of thebackground noises has a negative impact on the RTWP measurement value. Therefore, the LDMfunction includes an auto-adaptive update algorithm to restrict the background noise within a specifiedrange, as described here:

If the temperature in the equipment room is constant, the background noise changes slightly. In thiscase, the background noise requires no adjustment after initial correction.

If the temperature in the equipment room varies with the ambient temperature, the background noisechanges greatly. In this case, the background noise requires auto-adaptive upgrade.

The following figure shows the flow chart of auto-adaptive background noise update, which is enabled bytheBGNSwitchparameter.

BGNSwitchis set to ONby default.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_pucavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_pucavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulcacavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulcacavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlcacavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ldbavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ldbavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulldravgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulldravgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlldravgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlldravgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulolcavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulolcavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlolcavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlolcavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaneedpwrfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaneedpwrfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaneedpwrfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaprvidbitratefilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaprvidbitratefilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaprvidbitratefilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsupaprvidbitratefilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsupaprvidbitratefilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsupaprvidbitratefilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaprvidbitratefilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_hsdpaneedpwrfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlolcavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulolcavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlldravgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulldravgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ldbavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_dlcacavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_ulcacavgfilterlen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uldm_pucavgfilterlen.html


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3-5

Figure 3-3 Flow chart of auto-adaptive background noise update


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3-6

The Alpha filter formula is: Fn = (1 - ) x Fn-1+ x Mn (n1). For details about this formula, see section3.3.1 "Layer 3Filtering on the NodeB Side."

Counting threshold = (Duration of background noise)/(RTWP reporting period). The duration of background noise isused in auto-adaptive upgrade decision and is set by theBGNAdjustTimeLenparameter. For the setting of RTWP

reporting period, see section3.2 "Reporting Period."

The procedure of auto-adaptive background noise update is as follows:

1. The RNC initializes the counter and filter that are used for auto-adaptive upgrade and sets the initialvalue (F0) of the filter toBackgroundNoise.

2. The RNC receives the latest RTWP measurement value (Mn)from the physical layer.

3. The RNC checks whether the current time is within the effective period of the algorithm, that is,whether the current time is later thanBgnStartTimeand earlier thanBgnEndTime.If the currenttime is within the effective period, the RNC performs the next step. Otherwise, the RNC waits for thenext RTWP measurement value.

4. The RNC determines whether the current Equivalent Number of Users (ENU) in the cell is greater

than the value ofBGNEqUserNumThd:If the current ENU is greater than this threshold value, the RNC infers that Mnincludes other noises inaddition to the background noise, and therefore it does not feed Mnto the filter. In addition, the RNCsets the counter to zero, retains the current background noise, sets the initial value of the filter to thecurrent background noise, and waits for the next RTWP measurement value.

If the current ENU in the cell is smaller than or equal to the threshold value, the RNC feeds Mnto thefilter and performs the next step.

5. The RNC checks whether |Mn - Fn-1| is smaller than the value ofBgnAbnormalThd.If it is smallerthan this threshold value, the RNC increments the counter by one, calculates F naccording to theAlpha filter formula, and performs the next step. Otherwise, the RNC waits for the next RTWPmeasurement value.

6. The RNC checks whether the counter reaches the counting threshold. If it reaches the countingthreshold, the RNC performs the next step. Otherwise, the RNC waits for the next RTWPmeasurement value.

7. The RNC checks whether |Fn -BackgroundNoise|is smaller than the value ofBgnAbnormalThd.The purpose is to prevent burst interference and RTWP spike. If it is smaller than the value ofBgnAbnormalThd,the RNC performs the next step. Otherwise, the RNC sets the counter to zeroand waits for the next RTWP measurement value.

8. The RNC checks whether |Fn - current background noise| is greater than the value ofBgnUpdateThd.The purpose is to prevent frequent background noise upgrades on the Iub interface.If it is greater than the value ofBgnUpdateThd,the RNC sets the current background noise to Fn,sets the counter to zero, and waits for the next RTWP measurement value. Otherwise, the RNC setsthe counter to zero and waits for the next RTWP measurement value.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnadjusttimelen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnadjusttimelen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnadjusttimelen.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnstarttime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnstarttime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnstarttime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnendtime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnendtime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnendtime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnequsernumthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnequsernumthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnequsernumthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnupdatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnupdatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnupdatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnupdatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnupdatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnupdatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnupdatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnabnormalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnequsernumthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnendtime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnstarttime.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_backgroundnoise.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_bgnadjusttimelen.html


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Load Control 4 Potential User Control



4-1

4 Potential User Control

This chapter describes the WRFD-020105 Potential User Control feature.

The Potential User Control (PUC) function controls the cell selection and cell reselection of a UE that isin idle mode, in the CELL_FACH state, CELL_PCH state, or URA_PCH state and prevents the UE fromcamping on a heavily loaded cell.

The PUC is valid only for inter-frequency cells, and it takes effect only in the downlink.

Figure 4-1 shows the PUC procedure.

Figure 4-1 PUC procedure

The PUC function is enabled only when the PUCsubparameter of theNBMLdcAlgoSwi tchparameteris set to 1.

For a cell not supporting DC-HSDPA, the RNC periodically monitors the downlink load of the cell.

If the cell load is higher than the upper threshold (SpucHeavy)plus the load level division hysteresis(SpucHyst), the cell load is considered heavy.

If the cell load is lower than the lower threshold (SpucLight)minusSpucHyst,the cell load isconsidered light.

For a cell supporting DC-HSDPA, the RNC concurrently monitors the load state of each single cell andload state of the cell group.

The checking of load state of a single cell is the same as that of a cell not supporting DC-HSDPA.

The checking of load state of the cell group is as follows:

If the load of the two cells is higher than their upper thresholds (SpucHeavy)plus their load leveldivision hysteresis (SpucHyst), the load of the cell group is considered heavy.

If the load of the two cells is lower than their lower thresholds (SpucLight)minus their load leveldivision hysteresis (SpucHyst), the load of the cell group is considered light.

The load state of a cell supporting DC-HSDPA is determined based on the following table.
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Load of Single Cell Load of Cell Group Load of Cell Supporting DC-HSDPA

Heavy Heavy, normal, or light Heavy

Heavy, normal, or light Heavy Heavy

Normal Normal, or light Normal

Normal, or light Normal Normal

Light Light Light

The states of a cell load are heavy, normal, and light, as shown inFigure 4-2.

Figure 4-2 Cell load states

Based on the cell load, the PUC works as follows:

If the cell load becomes heavy, the PUC modifies cell selection and reselection parameters andbroadcasts them through system information. In this way, the PUC leads UEs to the neighboring cellswith light load.

If the cell load becomes normal, the PUC uses the cell selection and reselection parametersconfigured on the RNC LMT.

If the cell load becomes light, the PUC modifies cell selection and reselection parameters andbroadcasts them through system information. In this way, the PUC leads UEs to this cell.

The variables related to cell selection and reselection are Qoffset1(s,n)(load level offset), Qoffset2(s,n)(load level offset), and Sintersearch(start threshold for inter-frequency cell reselection). The followingtable describes PUC-related variables and their impacts on UEs.


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Table 4-1 PUC-related variables and their impacts on UEs

Item Description

Implementation The NodeB periodically reports the transmit power of the cell, and the PUC

periodically triggers the following activities:Assessing the cell load level based on the non-HSPA power and HS-DSCH GBP

Setting Sintersearch, Qoffset1(s,n), and Qoffset2(s,n)based on the cell load level

Updating the parameters in system information SIB3 and SIB11

Adjustment Based on the characteristics of inter-frequency cell selection and reselection, the UEmakes the corresponding adjustments:

Sintersearch

- When this value is increased by the serving cell, the UE starts inter-frequencycell reselection ahead of schedule.

- When this value is decreased by the serving cell, the UE delays inter-frequency

cell reselection. Qoffset1(s,n): applies to R (reselection) rule with CPICH RSCP

- When this value is increased by the serving cell, the UE has a lower probabilityof selecting a neighboring cell.

- When this value is decreased by the serving cell, the UE has a higher probabilityof selecting a neighboring cell.

Qoffset2(s,n): applies to R (reselection) rule with CPICH Ec/I0

- When this value is increased by the serving cell, the UE has a lower probabilityof selecting a neighboring cell.

- When this value is decreased by the serving cell, the UE has a higher probability

of selecting a neighboring cell.

Depending on the load status of the serving cell, the cell reselection variable Sintersearch is adjusted upor down or kept unchanged. Changes to the variable Sintersearch are made as shown inTable 4-2.

Table 4-2 Changes made to Sintersearchaccording to the load state

Load State of theServing Cell

S'intersearch Change to Sintersearch

Light S'intersearch = Sintersearch +OffSinterLight

Normal S'intersearch = Sintersearch

Heavy S'intersearch = Sintersearch +OffSinterHeavy

: indicates that the parameter value decreases.

: indicates that the parameter value remains unchanged.

: indicates that the parameter value increases.

The configurations of Qoffset1and Qoffset2are related to the load of the serving cell and the load of theneighboring cells. Changes to Qoffset1and Qoffset2are made as shown inTable 4-3.
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Table 4-3 Changes made to Qoffset1and Qoffset2according to the load state

Load State oftheNeighboring

Cells

Load Stateof theServing

Cell

Q'offset1 ChangetoQoffset1

Q'offset2 ChangetoQoffset2

Light Light Q'offset1 = Qoffset1 Q'offset2 = Qoffset2

Light Normal Q'offset1 = Qoffset1 Q'offset2 = Qoffset2

Light Heavy Q'offset1 = Qoffset1+OffQoffset1Light

Q'offset2 = Qoffset2+OffQoffset2Light

Normal Light Q'offset1 = Qoffset1 Q'offset2 = Qoffset2

Normal Normal Q'offset1 = Qoffset1 Q'offset2 = Qoffset2

Normal Heavy Q'offset1 = Qoffset1

+OffQoffset1Light

Q'offset2 = Qoffset2

+OffQoffset2Light

Heavy Light Q'offset1 = Qoffset1+OffQoffset1Heavy

Q'offset2 = Qoffset2+OffQoffset2Heavy

Heavy Normal Q'offset1 = Qoffset1+OffQoffset1Heavy

Q'offset2 = Qoffset2+OffQoffset2Heavy

Heavy Heavy Q'offset1 = Qoffset1 Q'offset2 = Qoffset2

The prerequisite for changing the preceding parameters is that these parameters should be in their default values.
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5-1

5 Intelligent Access Control

5.1 Overview of Intelligent Access Control

IAC is used to increase the access success rate, that is, RRC connection success rate and RAB setupsuccess rate.

There are two types of IAC, namely, IAC for RRC connection processing and IAC for RAB connectionprocessing.

IAC for RRC connection processing is used to select a suitable cell for a UE to access throughredirection and RRC DRD. It also implements load balancing and service steering.

IAC for RAB connection processing is used to select a suitable cell for a UE to access through DRDand CAC. It also implements load balancing and service steering. Features such as preemption,queuing, and low-rate access are used to further improve the RAB setup success rate.

In addition, IAC provides differentiated services for users with different priorities. For example, when the

system resources are insufficient, procedures such as direct admission, preemption, and redirection canbe performed to ensure the successful access of emergency calls to the network.

Figure 5-1 shows a typical procedure of service access control.

Figure 5-1 Service access control procedure


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As shown inFigure 5-1,the procedure of service access includes the procedures for RRC connectionsetup and RAB setup. The successful setup of the RRC connection is one of the prerequisites for theRAB setup.

During the RRC connection processing, the RNC performs the following steps.

1. RRC redirection based on distance (only for UE-originating AMR services). For details, see section5.2.2 "RRC Redirection based on Distance". If the RNC decides to obtain UE access from anothercell, it sends an RRC connection reject message to the UE; otherwise, the RNC performs the nextstep.

2. RRC redirection for service steering. For details, see section 5.2.3 "RRC Redirection for ServiceSteering."

If the RNC decides to obtain UE access from the current cell, it then makes a resource-basedadmission decision. If the resource-based admission fails, the RNC performs directed retry decision(DRD) and redirection.

If the RNC decides to obtain UE access from another cell, it then sends an RRC connection rejectmessage to the UE. The message carries the information about the cell and instructs the UE to set up

an RRC connection to the cell.For details, see section5.2 "IAC During RRC Connection Setup."

During the RAB connection processing, the RNC performs the following steps:

1. Performs inter-frequency DRD to select a suitable cell for service steering or load balancing. Fordetails about DRD, see theDirected Retry Decision Feature Parameter Description

2. Performs rate negotiation according to the service requested by the UE. For details, see section5.4"Rate Negotiation at Admission Control."

3. Makes cell resource-based admission decision. If the admission is successful, UE access is granted.Otherwise, the RNC performs the next step. For details about admission decision, see the CallAdmission Control Feature Parameter Description.

4. Selects a suitable cell, according to the inter-frequency DRD, from the cells where no admissionattempt has been made, and then performs step5.If all the attempts fail, the RNC performs the nextstep.

5. Selects a suitable cell according to the inter-RAT DRD. If the inter-RAT admission is successful, UEaccess is granted in the inter-RAT cell. If the inter-RAT DRD fails or is not supported, the RNCperforms the next step.

6. Makes a preemption attempt. For details about preemption, see section 5.6 "Preemption." If thepreemption is successful, UE access is granted. If the preemption fails or is not supported, the RNCperforms the next step.

7. Makes a queuing attempt. For details about queuing, see section5.7 "Queuing." If the queuing issuccessful, UE access is granted. If the queuing fails or is not supported, the RNC performs the nextstep.

8. Performs low-rate access. For details about low-rate access, see section5.8 "Low-Rate Access ofthe PS BE Service." If the low-rate access is admitted, UE access is granted. If the low-rate access isunsuccessful, the RNC performs the next step.

9. Rejects UE access.

After the admission attempts of an HSPA service request fail in all candidate cells, the service falls back to the DCH. Then,the service reattempts to access the network.
http://localhost/var/www/apps/conversion/tmp/scratch_7/Directed%20Retry%20Decision.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Directed%20Retry%20Decision.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Call%20Admission%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Call%20Admission%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Call%20Admission%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Call%20Admission%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Call%20Admission%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Directed%20Retry%20Decision.htm


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Table 5-1 IAC procedure supported by services

ServiceType

Low-RateAccess

Rate Negotiation Preemption Queuing DRD

MBR

Negotiation

GBR

Negotiation

InitialRat

e

Negotiation

TargetRa

te

Negotiation

Inter-

Frequenc

y

Inter-RAT

DCH

HSUPA - -

HSDPA - - - -

5.2 IAC During RRC Connection Setup5.2.1 Procedure of IAC During RRC Connection Setup

Before a new service is admitted to the network, an RRC connection must be set up.

As shown inFigure 5-2,when the switchDrSwitch:DR_RRC_DRD_SWITCH is set to ON, the RRCconnection setup procedure is performed as follows.
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Figure 5-2 RRC connection setup procedure

.

After receiving an RRC CONNECTION REQUEST message from the UE, the RNC performs the RRCredirection based on distance (only for UE-originating AMR services). For details, see section5.2.2"RRC Redirection based on Distance". If the RNC decides to obtain UE access from another cell, itsends an RRC connection reject message to the UE; otherwise, the RNC performs the next step.

Then, the RNC uses the RRC redirection algorithm for service steering to decide whether the UE canaccess the network from the current cell:


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If the UE can access the network from the current cell according to the decision result, the RNC usesthe CAC algorithm to decide whether an RRC connection can be set up between the UE and thecurrent cell.

If the RRC connection can be set up between the UE and the current cell, the RNC sends an RRC

CONNECTION SETUP message to the UE.If the RRC connection cannot be set up between the UE and the current cell, the RNC attempts toselect a cell for RRC connection setup through RRC DRD. If the RRC DRD fails, RRC redirection willbe performed.

If the UE needs to access the network from another cell according to the decision result, the RNCsends an RRC CONNECTION REJECT message to the UE. The message carries the informationabout this cell.

DrSwitch:DR_RRC_DRD_SWITCHis the general switch of the following four algorithms:

RRC Redirection based on Distance

RRC Redirection for Service Steering

RRC DRD RRC Redirection After DRD Failure

Before enabling the four algorithms, turn on theDrSwitch:DR_RRC_DRD_SWITCH.

5.2.2 RRC Redirection based on Distance

This section describes the WRFD-020401 Inter-RAT Redirection Based on Distance feature.

In actual situations, a UE may receive signals from a distant cell and subsequently access the cell.However, the cells that are adjacent to this cell are not configured as its neighboring cells. If the UEmoves out of this cell, call drops may occur. To solve this problem, RRC redirection based on distance isintroduced.

The RRC redirection based on distance technique estimates the distance between the UE and the cellcenter by considering the propagation delay. Based on the estimation result, the RNC checks whether toperform RRC redirection. The propagation delayis the one-way propagation delay of the radio signalfrom the UE to the NodeB. The NodeB measures the propagation delay and then reports it to the RNC.The propagation delay is directly proportional to the distance between the UE and the NodeB.

The switch of RRC redirection based on distance can be set through theRedirSwitchparameter. RRCredirection based on distance is applicable only to the UE-originating AMR services.

The procedure of RRC redirection based on distance is as follows:

1. Upon receiving an RRC CONNECTION REQUEST message from the UE, the RNC checks whetherthe requested service is the UE-originating AMR service. If yes, the RNC performs the next step. If no,the RNC does not perform RRC redirection based on distance, and handles the RRC connectionsetup request of the UE in the current cell.

2. The RNC obtains the propagation delay from the NodeB and compares it withDelayThs.

If the propagation delay is greater thanDelayThs,the RNC performs the next step.

If the propagation delay is equal to or less thanDelayThs,the RNC does not perform RRCredirection based on distance, and handles the RRC connection setup request of the UE in thecurrent cell.

3. The RNC checks the load status of the current cell and checks whether to perform RRC redirectionbased on distance by considering the load status.

If the cell is in the normal state, the RNC generates a random value ranging from 0 to 1 and

compares the value with theRedirFactorOfNormparameter. If the random value is equal to or
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smaller than the parameter, the RNC performs the next step. Otherwise, the RNC does not performRRC redirection based on distance, and handles the RRC connection setup request of the UE in thecurrent cell.

If the cell is in the basic congestion state or is overloaded, the RNC generates a random value

ranging from 0 to 1 and compares the value with theRedirFactorOfLDRparameter. If the randomvalue is equal to or smaller than the parameter, the RNC performs the next step. Otherwise, the RNCdoes not perform RRC redirection based on distance, and handles the RRC connection setuprequest of the UE in the current cell.

4. The RNC sends the UE an RRC CONNECTION REJECT message containing information on theneighboring GSM cells of the current cell.

If the current cell does not have any neighboring GSM cell, the UE spontaneously selects a proper cell to access.

5.2.3 RRC Redirection for Service Steering

Overview

This section describes the WRFD-020120 Service Steering and Load Sharing in RRC Connection Setupfeature.

The RRC redirection for service steering is used to enable the successful RRC connection setup byselecting an appropriate cell for the UE based on the requested service. This algorithm is not applicableto combined services.

During the RRC connection setup, the RNC implements service steering between inter-frequency orinter-RAT cells according to the service type requested by the UE. In addition, the RNC considers theload of the cell for access and the redirection factors to control the degree of load sharing. Therefore,this function is also called service steering and load sharing in RRC connection setup.

Procedure of RRC Redirection for Service SteeringThe procedure of RRC redirection for service steering is as follows:

1. The RNC obtains the information about the service requested by the UE and the capability of the UE.

If the DR_RRC_DRD_SWITCHof the parameterDrSwitchis set to 1, the RNC determines theservice type requested by the UE. If the RNC succeeds in determining the service type requested bythe UE and the switch of RRC direction for service steering (RedirSwitch)is set toONLY_TO_INTER_FREQUENCYor ONLY_TO_INTER_RAT, the RNC performs the next step.Otherwise, the RNC handles the RRC connection setup request of the UE in the current cell.

If the DR_ RRC_DRD_SWITCH of the parameterDrSwitchis set to 0, the RNC handles the RRCconnection setup request of the UE in the current cell.

2. Based on the cell load and the redirection factors, the RNC decides whether to perform RRCredirection for service steering.

If the cell is in the normal state, the RNC generates a random number between 0 and 1 andcompares it with the corresponding unconditional redirection factor (RedirFactorOfNorm). If therandom number is smaller than this factor, the RNC performs the next step. Otherwise, the RNChandles the RRC connection setup request of the UE in the current cell.

If the cell is in the basic congestion or overload state, the RNC generates a random number between0 and 1 and compares it with the value ofRedirFactorOfLDR.If the random number is smaller thanthis factor, the RNC performs the next step. Otherwise, the RNC handles the RRC connection setuprequest of the UE in the current cell.

3. Based on the setting ofRedirSwitch,the RNC takes the corresponding actions:
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldistanceredirection_redirfactorofldr.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldistanceredirection_redirfactorofldr.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldistanceredirection_redirfactorofldr.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofnorm.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofnorm.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofnorm.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofldr.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofldr.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofldr.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofldr.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirfactorofnorm.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellredirection_redirswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitc