Admission and Congestion Control(ERAN8.1_03)

eRAN

Admission and Congestion ControlFeature Parameter Description

Issue 03Date 2015-11-03

HUAWEI TECHNOLOGIES CO., LTD.

Copyright Huawei Technologies Co., Ltd. 2015. All rights reserved.No part of this document may be reproduced or transmitted in any form or by any means without prior writtenconsent 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 respectiveholders. NoticeThe purchased products, services and features are stipulated by the contract made between Huawei and thecustomer. All or part of the products, services and features described in this document may not be within thepurchase 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 thepreparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute a warranty of any kind, express or implied. Huawei Technologies Co., Ltd.Address: Huawei Industrial Base

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Website: http://www.huawei.comEmail: [email protected]

Issue 03 (2015-11-03) Huawei Proprietary and ConfidentialCopyright Huawei Technologies Co., Ltd.

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Contents

1 About This Document.................................................................................................................. 11.1 Scope.............................................................................................................................................................................. 11.2 Intended Audience..........................................................................................................................................................11.3 Change History............................................................................................................................................................... 21.4 Differences Between eNodeB Types.............................................................................................................................. 32 Overview......................................................................................................................................... 43 Admission Control........................................................................................................................ 53.1 User Admission.............................................................................................................................................................. 63.2 Service Admission..........................................................................................................................................................93.2.1 Non-GBR Service Admission....................................................................................................................................113.2.2 GBR Service Admission............................................................................................................................................113.2.2.1 UE Capability Evaluation....................................................................................................................................... 113.2.2.2 Cell Congestion Indication..................................................................................................................................... 113.2.2.3 Admission Based on QoS Satisfaction Rates......................................................................................................... 123.3 Preemption....................................................................................................................................................................173.3.1 User Preemption........................................................................................................................................................ 173.3.2 Service Preemption....................................................................................................................................................193.4 Redirection....................................................................................................................................................................204 Congestion Control..................................................................................................................... 214.1 Load Status Evaluation.................................................................................................................................................234.2 Release of Low-Priority GBR Services........................................................................................................................235 Related Features...........................................................................................................................245.1 Features Related to LBFD-002023 Admission Control............................................................................................... 245.2 Features Related to LOFD-00102901 Radio/transport Resource Pre-emption............................................................ 245.3 Features Related to LBFD-002024 Congestion Control.............................................................................................. 256 Network Impact........................................................................................................................... 266.1 LBFD-002023 Admission Control............................................................................................................................... 266.2 LOFD-00102901 Radio/transport resource pre-emption............................................................................................. 266.3 LBFD-002024 Congestion Control.............................................................................................................................. 277 Engineering Guidelines............................................................................................................. 287.1 When to Use Admission and Congestion Control........................................................................................................28

eRANAdmission and Congestion Control Feature ParameterDescription Contents


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7.2 Required Information................................................................................................................................................... 287.3 Planning........................................................................................................................................................................ 287.3.1 RF Planning............................................................................................................................................................... 287.3.2 Network Planning...................................................................................................................................................... 287.3.3 Hardware Planning.................................................................................................................................................... 297.4 Deployment of Admission Control...............................................................................................................................297.4.1 Requirements............................................................................................................................................................. 297.4.2 Data Preparation........................................................................................................................................................ 297.4.3 Activation.................................................................................................................................................................. 367.4.4 Activation Observation..............................................................................................................................................417.4.5 Deactivation...............................................................................................................................................................447.5 Deployment of Congestion Control..............................................................................................................................467.5.1 Deployment Requirements........................................................................................................................................ 467.5.2 Data Preparation........................................................................................................................................................ 477.5.3 Activation.................................................................................................................................................................. 547.5.4 Activation Observation..............................................................................................................................................577.5.5 Deactivation...............................................................................................................................................................577.6 Performance Monitoring...............................................................................................................................................587.7 Parameter Optimization................................................................................................................................................597.8 Troubleshooting............................................................................................................................................................ 607.8.1 Admission Control.....................................................................................................................................................607.8.2 Congestion Control....................................................................................................................................................608 Parameters.....................................................................................................................................619 Counters........................................................................................................................................ 7910 Glossary.....................................................................................................................................10711 Reference Documents............................................................................................................. 108

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1 About This Document1.1 Scope

This document describes admission and congestion control, including its technical principles,related features, network impact, and engineering guidelines.This document covers the following features:l LBFD-002023 Admission Controll LOFD-001029 Enhanced Admission Controll LOFD-00102901 Radio/transport Resource Preemptionl LBFD-002024 Congestion ControlAny managed objects (MOs), parameters, alarms, or counters described herein correspond tothe software release delivered with this document. Any future updates will be described in theproduct documentation delivered with future software releases.This document applies only to LTE FDD. Any "LTE" in this document refers to LTE FDD,and "eNodeB" refers to LTE FDD eNodeB.This document applies to the following types of eNodeBs.

eNodeB Type ModelMacro 3900 series eNodeBsMicro BTS3202ELampSite DBS3900 LampSite

1.2 Intended AudienceThis document is intended for personnel who:l Need to understand the features described herein

eRANAdmission and Congestion Control Feature ParameterDescription 1 About This Document


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l Work with Huawei products

1.3 Change HistoryThis section provides information about the changes in different document versions. There aretwo types of changes:l Feature change

Changes in features and parameters of a specified version as well as the affected entitiesl Editorial change

Changes in wording or addition of information and any related parameters affected byeditorial changes. Editorial change does not specify the affected entities.

eRAN8.1 03 (2015-11-03)This issue includes the following changes.

ChangeType

Change Description Parameter Change AffectedEntity

Featurechange

None None N/A

Editorialchange

Modified monitoring methodsof admission and congestioncontrol observation. Fordetails, see the followingsections:l 7.4.4 Activation

Observationl 7.5.4 Activation

Observation

None -

eRAN8.1 02 (2015-06-30)This issue includes the following changes.

ChangeType


Featurechange

None None Macro/Micro/LampSite



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ChangeType


Editorialchange

Revised descriptions of user-number-based preemption.For details, see the followingsections:l 3.3.1 User Preemptionl 7.4.2 Data Preparationl 7.4.3 Activationl 7.4.5 Deactivation

Added theInterOpUeNumPreemptS-witch(InterOpUeNumPreemptSwitch) option of theENodeBAlgoSwitch.UeNumPreemptSwitch parameter.

Macro/Micro/LampSite

eRAN8.1 01 (2015-03-23)This issue does not include any changes.

eRAN8.1 Draft A (2015-01-15)Compared with Issue 01 (2014-04-26) of eRAN7.0, Draft A (2015-01-15) of eRAN8.1includes the following changes.

ChangeType

Change Description Parameter Change

Affected Entity

Featurechange

Added performance countersrelated to admission control andpreemption. For details, see 7.6Performance Monitoring.

None Macro/Micro/LampSite

Editorialchange

Revised the description in 2Overview.

None -

1.4 Differences Between eNodeB TypesThe features described in this document are implemented in the same way on macro, micro,and LampSite eNodeBs.



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2 OverviewIntroduction

During admission control, an eNodeB decides whether to accept a guaranteed bit rate (GBR)service request (either new service or handover) based on the physical resource block (PRB)usage and the quality of service (QoS) satisfaction rate of GBR services. During congestioncontrol, the eNodeB controls system load to ensure a high overall QoS satisfaction rate andstable system operation.

BenefitsLoad control maintains system stability by rejecting certain admission requests or releasingsome admitted services, while maximizing resource usage. Load control ensures the quality ofadmitted services by controlling the cell load. It also provides the required QoS for individualradio bearers and maximizes cell capacity.

eRANAdmission and Congestion Control Feature ParameterDescription 2 Overview


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3 Admission ControlThis chapter describes the basic feature LBFD-002023 Admission Control.Admission control is categorized into radio-resource-based admission control and transport-resource-based admission control. This document describes radio-resource-based admissioncontrol. For details about transport-resource-based admission control, see Transport ResourceManagement Feature Parameter Description. For details about how to configure this feature,see 7 Engineering Guidelines.Radio-resource-based admission control is categorized into user admission and serviceadmission.l When a piece of user equipment (UE) requests access to a network, that is, when a UE

requests setup of a radio resource control (RRC) connection or requests an incominghandover, the E-UTRAN NodeB (eNodeB) performs the user admission procedure.

l When a UE that has accessed a cell requests a new service, that is, when a UE requestsestablishment of an E-UTRAN radio access bearer (E-RAB) or requests an incominghandover, the eNodeB performs the service admission procedure.

eRANAdmission and Congestion Control Feature ParameterDescription 3 Admission Control


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3.1 User AdmissionWhen a UE requests to access a network, that is, when a UE requests setup of an RRCconnection or requests an incoming handover, the eNodeB performs the user admissionprocedure. Figure 3-1 shows the user admission procedure.



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Figure 3-1 User admission procedure



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The user admission procedure is as follows:1. The eNodeB checks whether the CPU resource is limited. If the CPU resource is limited,

the eNodeB rejects the access request. For details about how the eNodeB checks whetherthe CPU resource is limited, see Flow Control Feature Parameter Description.

2. The eNodeB checks whether the sounding reference signal (SRS) resource issuccessfully allocated. For details about the SRS resource allocation principle, seePhysical Channel Resource Management Feature Parameter Description. The eNodeBperforms this step differently based on whether LBBPc or BBP of another type isconfigured.

l If the LBBPc is configured, the eNodeB performs this step as follows: If the SRS resource is configured for the cell, the cell supports uplink timing

measurement using only the SRS. Therefore, if the SRS resource allocation fails,the uplink timing of the UE may not be accurate and the eNodeB rejects the accessrequest. If the SRS resource is not configured for the cell, the cell supports uplink timing

measurement using the demodulation reference signal (DMRS). Even if the SRSresource is not allocated, the eNodeB accepts the access request.

l Other types of BBPs support uplink timing measurement using the DMRS. Even if theSRS resource allocation fails, the uplink timing of the UE is accurate and the eNodeBdoes not reject the access request.

NOTE

LampSite eNodeBs do not support the LBBPc.3. The eNodeB checks whether the PUCCH resource is successfully allocated. If the

PUCCH resource allocation fails, the eNodeB rejects the access request. For detailsabout the PUCCH resource allocation principle, see Physical Channel ResourceManagement Feature Parameter Description.

4. The eNodeB checks whether the number of users is limited. If the number of admittedusers has reached the maximum or the licensed user number, the eNodeB determines thatthe number of users is limited and the admission fails.

5. For the user that is admitted by the eNodeB, if the UE requests a service (that is, toestablish an E-RAB), the eNodeB performs the service admission procedure. For details,see 3.2 Service Admission.

6. If the UE's access request is rejected by the eNodeB, the UE can initiate a userpreemption procedure. For details, see 3.3.1 User Preemption.

NOTE

The number of emergency UEs that can be admitted is restricted only by the maximum number of UEssupported by the cell rather than by the licensed number of UEs so that emergency UEs canpreferentially be admitted.In the RAN sharing scenario, the licensed user number varies depending on operators. Therefore, theeNodeB temporarily allows the access to obtain the PLMN ID to determine whether the licensed usernumber is limited. If the licensed user number is limited and the preemption based on user number fails,the eNodeB rejects the initial context setup request of the temporarily accessed user and releases theuser.

In user admission, UE numbers are reserved for privileged UEs to increase their admissionsuccess rates. Privileged UEs include emergency UEs and high-priority UEs with a"highPriorityAccess" cause value in an RRC connection establishment request. Other UEs arecommon UEs.



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Privileged UEs are defined because resource preemption is not allowed for operators in somecountries and areas by local regulations but high-priority UEs of these operators need to bepreferentially admitted. The eNodeB determines whether to admit privileged UEs based onlyon the maximum number of UEs that can be supported by the cell instead of the licensed usernumber. Therefore, user-number-reservation-based admission control can be enabled toreserve resources for privileged UEs to ensure the preferential admission of privileged UEs.The UE numbers reserved for privileged UEs are controlled by theCellRacThd.AcReservedUserNumber parameter.l If the CellRacThd.AcReservedUserNumber parameter is set to 0, user-number-

reservation-based admission control is disabled. In this case, the eNodeB rejects theaccess requests of high-priority UEs and common UEs when the number of admittedusers has reached the licensed user number. The eNodeB rejects the access requests ofboth privileged UEs and common UEs when the number of admitted users has reachedthe maximum number.

l If the CellRacThd.AcReservedUserNumber parameter is set to a non-zero value, UEnumbers are reserved for privileged UEs. In this case, the eNodeB accepts the accessrequests of high-priority UEs but rejects the access requests of common UEs when thenumber of admitted users has reached the licensed user number. The eNodeB admitsprivileged UEs and common UEs based on different UE number requirements. The number of privileged UEs that can be admitted is based on the maximum

number of UEs supported by the cell. The number of common UEs that can be admitted is the difference between the

maximum number of UEs supported by the cell and theCellRacThd.AcReservedUserNumber parameter value. TheCellRacThd.AcReservedUserNumber parameter specifies the UE numbersreserved for privileged UEs.

If the CellRacThd.AcReservedUserNumber parameter is set to a non-zero value, it isrecommended that SRS resources and PUCCH resources be set to default values. In this case,neither SRS resources nor PUCCH resources will directly cause user admission failures. It isrecommended that the ARP values of the bearers for UEs whose cause value for an RRCconnection establishment request is "highPriorityAccess" and that for emergency UEs be setto the same. This ensures the GBR services of these high-priority UEs are directly admittedsuccessfully.

3.2 Service AdmissionWhen a UE that has accessed a cell requests setup of a new service, (that is, when a UErequests to establish an E-RAB or requests a handover to the cell,) the eNodeB performs theservice admission procedure. Figure 3-2 shows the service admission procedure.



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Figure 3-2 Service admission procedure



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3.2.1 Non-GBR Service AdmissionFor a non-GBR service, the admission procedure is as follows:l If the SRS or PUCCH resource allocation fails, the eNodeB rejects the access request.l If both the SRS resource allocation and the PUCCH resource allocation are successful,

the eNodeB accepts the request. In the admission procedure, the eNodeB does not checkthe UE capabilities or whether the cell is congested, or make the admission decisionbased on the QoS satisfaction rates.

NOTE

SRS resource allocation is required only if the SRS resource is configured for the LBBPc.

3.2.2 GBR Service AdmissionFor a GBR service, its QoS has to be guaranteed. The admission procedure is as follows:l If the SRS or PUCCH resource allocation fails, the eNodeB rejects the access request.l If both the SRS resource allocation and the PUCCH resource allocation are successful,

the eNodeB makes the admission decision as follows: For an emergency call, the eNodeB accepts the request. For a non-emergency call, the eNodeB checks the UE capabilities and whether the

cell is congested, and then makes the decision based on the QoS satisfaction rates.NOTE

SRS resource allocation is required only if the SRS resource is configured for the LBBPc.

3.2.2.1 UE Capability EvaluationThe UE reports its capabilities to the evolved packet core (EPC) each time the UE attaches tothe network. When the UE needs to update its capabilities, it performs detach and then attachprocedures to report the new capabilities to the EPC. If the eNodeB does not know the UEcapabilities, it initiates a UE capability transfer procedure to request the UE to report itscapabilities to the eNodeB and the EPC. For details, see section 5.6.3 in 3GPP TS 36.331V10.6.0 (2012-06).When the UE initiates a new service request, the Mobility Management Entity (MME) sendsan INITIAL CONTEXT SETUP REQUEST message to the eNodeB over the S1 interface,indicating the UE capabilities and bearer parameters. For details about UE capabilities, seesection 4.1 in 3GPP TS 36.306 V10.6.0 (2012-06).The eNodeB stores the information and checks whether the UE supports the specified bearer.If the UE does not support the bearer parameters, the eNodeB rejects the access request. Themajor concern about the UE capabilities is whether the total rate of various services exceedsthe maximum UE capability, indicated by the maximum transport block size for the UE. Fordetails, see section 8.3.1 in 3GPP TS 36.413 V10.6.0 (2012-06).

3.2.2.2 Cell Congestion IndicationCell congestion indications are provided by congestion control to indicate that the Uuinterface resources are insufficient. There are four types of indications:l Uplink Congested and Downlink Not Congested



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l Downlink Congested and Uplink Not Congestedl Uplink and Downlink Congestedl Uplink and Downlink Congestion ClearedIf a GBR service access request arrives, the eNodeB rejects the access request (either newservices or handovers) regardless of whether congestion occurs in the downlink or uplink.

3.2.2.3 Admission Based on QoS Satisfaction RatesThe QoS satisfaction rate of GBR services in a cell reflects the QoS conditions of admittedGBR services in the cell. It is used for evaluating cell load and making admission decisions.In the downlink, radio resources such as physical resource blocks (PRBs) and power areshared by all UEs in a cell. Decreases in the downlink QoS satisfaction rates indicate limitedradio resources. The eNodeB performs downlink admission control based only on QoSsatisfaction rates.In the uplink, radio resources may not be fully used because of a limitation on uplink power.The eNodeB performs uplink admission control based on the PRB usage, wait time for uplinkscheduling of voice over IP (VoIP) services, and QoS satisfaction rates.Figure 3-3 and Figure 3-4 show the downlink and uplink admission procedures for GBRservices based on QoS satisfaction rates, respectively.

Figure 3-3 Downlink admission procedure for GBR services



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Figure 3-4 Uplink admission procedure for GBR services

PRB Usage MonitoringBy monitoring the PRB usage of services with high scheduling priorities in the uplink, theeNodeB learns about the usage of uplink time-frequency resources in the cell andpreliminarily evaluates the cell load. In the uplink, services with high scheduling priorities



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include GBR services and the signaling and services whose scheduling priorities are higherthan GBR services, such as retransmissions, signaling radio bearers (SRBs), and schedulingrequests (SRs). The Media Access Control (MAC) layer calculates the PRB usage using thefollowing formula:

After filtering, the eNodeB compares the calculated PRB usage with the uplink PRB usagethresholds CellRacThd.UlRbHighThd and CellRacThd.UlRbLowThd and then determines thePRB usage status. Using both the upper and lower thresholds prevents a possible ping-pongeffect.

Evaluation of the Wait Time for Uplink Scheduling of VoIP ServicesThe wait time starts when a VoIP service requests uplink resources and stops when the VoIPservice is allocated uplink resources. eNodeBs regard wait time longer than 100 ms to be toolong.

Evaluation of QoS Satisfaction RatesThe QoS class identifier (QCI) of a service reflects the QoS requirements of that service, andeach QCI corresponds to a unique set of QoS parameters. For details, see section 6.1.7 in3GPP TS 23.203 V10.7.0 (2012-06). This protocol describes the characteristics of differentservices and the standards for evaluating their QoS satisfaction rates in the LTE QoSmechanism.In the downlink, QoS satisfaction rates are evaluated based on the logical channelscorresponding to the QCIs. In the uplink, however, QoS satisfaction rates are evaluated basedon logical channel groups. A logical channel group is defined as a group of radio bearers withsimilar QoS requirements. For details about logical channel groups, see section 5.4.5 in 3GPPTS 36.321 V10.5.0 (2012-03). The reason for the difference between the uplink and thedownlink is that the eNodeB cannot estimate the amount of buffered data to be transmittedthrough each logical channel on the UE side. The evaluation method for the uplink helpsreduce signaling load and the number of Buffer Status Reports (BSRs).The uplink and downlink QoS satisfaction rates of GBR services are calculated per QCI, andadmission thresholds are also set per QCI to achieve admission differentiation between QCIs.

Evaluation of Downlink QoS Satisfaction RatesServices with QCI 1 are VoIP services. Their downlink QoS satisfaction rate is represented bythe average downlink satisfaction rate of VoIP services in a cell, that is, the ratio of the sum ofthe downlink satisfaction rates of all VoIP services in a cell to the total number of VoIPservices in a cell.The downlink QoS satisfaction rate of a single VoIP service is calculated by using thefollowing formula:



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A voice packet is satisfactory if it is buffered for a time less than 50 ms.Services with QCIs 2 to 4 are GBR services. The downlink QoS satisfaction rate of GBRservices with QCI 2, 3, or 4 is calculated by using the following formula:

wherei = 2, 3, or 4

NOTE

Section 6.1.7 in 3GPP TS 23.203 V11.6.0 (2012-06) provides an example mapping between QCIs andservice types but does not provide definitions of the mapping. Huawei implements the mappingaccording to the examples, where QCI 1 represents VoIP services.

Evaluation of Uplink QoS Satisfaction RatesServices with QCI 1 are VoIP services. Their uplink QoS satisfaction rate is represented bythe average uplink satisfaction rate of VoIP services in a cell, that is, the ratio of the sum ofthe uplink satisfaction rates of all VoIP services in a cell to the total number of VoIP servicesin a cell.The uplink QoS satisfaction rate of a single VoIP service is calculated by using the followingformula:

NOTE

The uplink QoS satisfaction rate of a VoIP service is calculated differently from the downlink QoSsatisfaction rate of a VoIP service. In the uplink, the eNodeB cannot obtain the time for which voicepackets are buffered on the UE. However, if an uplink voice packet is buffered on the UE for a timelonger than the length of the timer for discarding Packet Data Convergence Protocol (PDCP) PDUs, thevoice packet is discarded. Therefore, the percentage of PDCP PDUs successfully received by theeNodeB is used to determine whether there are timeout voice packets. For details, see section 5.4 "PDCPdiscard" in 3GPP 36.323 V8.6.0.

Services with QCIs 2 to 4 are GBR services. Their uplink QoS satisfaction rate is evaluatedfor each logical channel group. The QoS satisfaction rate is represented by the ratio of thetransmitted data to the total amount of data to be transmitted. A higher ratio indicates a higherQoS satisfaction rate. The uplink QoS satisfaction rate of GBR services with QCIs 2 to 4 iscalculated by using the following formula:

QCIs 1 to 4 can be mapped to logical channel groups. For details about the mapping, seeScheduling Feature Parameter Description. If QCIs 2 to 4 are mapped to logical channel



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group 2, the uplink QoS satisfaction rates for services with QCIs 2 to 4 are represented by thesatisfaction rate for logical channel group 2.

Admission Decision Based on QoS Satisfaction RatesThe admission threshold for handovers is lower than that for new services. The eNodeBdefines four handover thresholds QcixHoThd (x = 14) for the QCIs. Based on the handoverthresholds, service differentiation can be achieved by setting admission offsets for new gold-,silver-, and bronze-level services, based on the mapping between ARP values and servicepriorities. The admission offsets are CellRacThd.NewGoldServiceOffset,CellRacThd.NewSilverServiceOffset, and CellRacThd.NewCopperServiceOffset. Theseoffset values apply to both the uplink and downlink.The eNodeB categorizes services based on their ARP values. The ARP values are mapped tothree service priorities: gold, silver, and bronze. The mapping can be adjusted by settingCellRacThd.GoldServiceArpThd (the ARP threshold for gold-level services) orCellRacThd.SilverServiceArpThd (the ARP threshold for silver-level services). The ARPvalues beyond the ranges defined by these two parameters correspond to bronze-levelservices. A small ARP value indicates a high priority level. Table 3-1 shows a typicalmapping between the ARP values and the service priorities.

Table 3-1 Typical mapping between the ARP values and the service prioritiesARP Value Service Priority15 Gold610 Silver1115 Bronze

For details about ARPs, see section 4.7.3 in 3GPP TS 23.401 V10.8.0 (2012-06).For GBR services whose QCIs range from 1 to 4, the admission thresholds for handovers andnew services corresponding to a QCI are as follows:l The admission threshold for handovers is QcixHoThd.l The admission threshold for new gold-level services is QcixHoThd plus

CellRacThd.NewGoldServiceOffset.l The admission threshold for new silver-level services is QcixHoThd plus

CellRacThd.NewSilverServiceOffset.l The admission threshold for new bronze-level services is QcixHoThd plus

CellRacThd.NewCopperServiceOffset.The relationship between these thresholds is as follows:QcixHoThd QcixHoThd + CellRacThd.NewGoldServiceOffset QcixHoThd +CellRacThd.NewSilverServiceOffset QcixHoThd +CellRacThd.NewCopperServiceOffset 100%Assume that SQCI = x (x = 14) represents the QoS satisfaction rate for QCI x. The followingrules apply to downlink admission evaluation:



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l For SQCI = x QcixHoThd + CellRacThd.NewCopperServiceOffsetIf the QoS satisfaction rates of all QCIs except QCI x are higher than the correspondinghandover admission thresholds, then the eNodeB accepts requests for new gold-, silver-,and bronze-level services and handovers with QCI x.If the QoS satisfaction rate of any QCI is lower than the corresponding handoveradmission threshold, then the eNodeB rejects requests for new gold-, silver-, and bronze-level services with QCI x but accepts requests for incoming handovers with QCI x.

l For QcixHoThd + CellRacThd.NewCopperServiceOffset > SQCI = x QcixHoThd +CellRacThd.NewSilverServiceOffsetIf the QoS satisfaction rates of all QCIs except QCI x are higher than the correspondinghandover admission thresholds, then the eNodeB accepts requests for new gold- andsilver-level services and handovers with QCI x but rejects requests for new bronze-levelservices with QCI x.If the QoS satisfaction rate of any QCI is lower than the corresponding handoveradmission threshold, then the eNodeB rejects requests for new gold-, silver-, and bronze-level services with QCI x but accepts requests for incoming handovers with QCI x.

l For QcixHoThd + CellRacThd.NewSilverServiceOffset > SQCI = x QcixHoThd +CellRacThd.NewGoldServiceOffsetIf the QoS satisfaction rates of all QCIs except QCI x are higher than the correspondinghandover admission thresholds, then the eNodeB accepts requests for new gold-levelservices and handovers with QCI x but rejects requests for new silver- and bronze-levelservices with QCI x.If the QoS satisfaction rate of any QCI is lower than the corresponding handoveradmission threshold, then the eNodeB rejects requests for new gold-, silver-, and bronze-level services with QCI x but accepts requests for incoming handovers with QCI x.

l For QcixHoThd + CellRacThd.NewGoldServiceOffset > SQCI = x QcixHoThdThe eNodeB rejects requests for new gold-, silver-, bronze-level services with QCI x butaccepts requests for handovers with QCI x.

l For QcixHoThd > SQCI = xThe eNodeB rejects requests for new services and handovers with QCI x.

The rules for uplink admission evaluation are similar to the rules for downlink admissionevaluation. The difference is that the eNodeB evaluates the QoS satisfaction rates of logicalchannel groups when admitting GBR services in the uplink. For details, see Evaluation ofUplink QoS Satisfaction Rates.

3.3 PreemptionThis section describes radio resource preemption in the optional feature LOFD-00102901Radio/transport Resource Pre-emption.For details about transport resource preemption, see Transport Resource Management FeatureParameter Description.

3.3.1 User PreemptionWhen an emergency UE accesses the network and fails to be allocated SRS or PUCCHresources, the UE preempts the resources of the common UE in the synchronization state and



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with the lowest ARP in the same cell. If the common UE has multiple services with differentARPs, the highest ARP is considered as the ARP of the UE.When a UE with a high ARP or an emergency UE attempts to access to the network and theeNodeB rejects the access attempt due to the limited number of UEs:l If the IntraOpUeNumPreemptSwitch(IntraOpUeNumPreemptSwitch) option of the

ENodeBAlgoSwitch.UeNumPreemptSwitch parameter is selected, this UE preempts theresources of common UEs with low ARPs served by the same operator. The preemptionis not allowed if this option is deselected.

l If the InterOpUeNumPreemptSwitch(InterOpUeNumPreemptSwitch) option of theENodeBAlgoSwitch.UeNumPreemptSwitch parameter is selected, this UE preempts theresources of common UEs with low ARPs served by different operators. The preemptionis not allowed if this option is deselected.

NOTE

In the user-number-based preemption, the eNodeB establishes a temporary RRC connection for any UErequesting access to the eNodeB in order to obtain the UE's ARP attributes.

In the user-number-based preemption, the resources for the following types of low-ARP UEsare preempted in descending order of priority:l Low-ARP UEs in the out-of-synchronization state performing non-GBR servicesl Low-ARP UEs in the out-of-synchronization state performing GBR servicesl Low-ARP UEs in the synchronized state performing non-GBR servicesl Low-ARP UEs in the synchronized state performing GBR servicesIf the preemption succeeds and redirection is enabled, the eNodeB performs a redirection forthe UE whose resource is preempted. If the preemption request is rejected and redirection isenabled, the eNodeB performs a redirection for the UE that requests preemption. For detailsabout redirection procedure, see 3.4 Redirection.The ARP value of a bearer of a UE is generally allocated by the EPC. The EPC allocates alow ARP value for the bearer of a CSFB UE. When the licensed number of UEs is limited,such a UE fails to preempt resources and then experiences an admission failure.CSFB UEs can be classified as emergency CSFB UEs and common CSFB UEs. If the valueof the IE CS Fallback Indicator in the INITIAL CONTEXT SETUP REQUEST message sentfrom the EPC to the eNodeB is CS Fallback High Priority, the UE is an emergency CSFBUE; otherwise, the UE is a common CSFB UE.You can set the CsFallbackPolicyCfg.CsfbUserArpCfgSwitch parameter to increase the ARPvalues of bearers for CSFB UEs. The IEs contained in the ARP values of default bearers forCSFB UEs are configured as follows:l Pre-emption Capability

The value of this IE for CSFB UEs is may trigger pre-emption, indicating that theUEs can preempt resources of other low-priority UEs.

l Pre-emption Vulnerability The value of this IE for CSFB UEs is not pre-emptable, indicating that resources

of the UEs cannot be preempted by other UEs.l Priority Level

The value of this IE for emergency CSFB UEs is 1.



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The ARP IE priority level for common CSFB UEs can be specified by theCsFallbackPolicyCfg.NormalCsfbUserArp parameter.

To ensure that common CSFB UEs are capable of preempting users when the number of UEsallowed to be admitted is limited, it is recommended that the bearers of common CSFB UEsbe configured with high ARP priorities.

3.3.2 Service PreemptionWhen a new emergency service requests preemption and fails to be allocated SRS or PUCCHresources, the service preempts the resources of the common UE in the synchronization stateand with the lowest ARP in the same cell. If the common UE has multiple services withdifferent ARPs, the highest ARP is considered as the ARP of the UE.When a GBR service with a high ARP requests service preemption, it preempts GBR serviceswith low ARPs if the request is rejected because the cell is congested or the admission basedon the QoS satisfaction rates fails. Service preemption is triggered if one of the conditionsshown in Figure 3-3 or Figure 3-4 is met.Service preemption is enabled by selecting the PreemptionSwitch(PreemptionSwitch)option of the CellAlgoSwitch.RacAlgoSwitch parameter. Note that SRBs, IP multimediasubsystem (IMS) signaling, and emergency calls cannot be preempted.A service can preempt other services only if its ARP information element (IE) "pre-emptioncapability" is "may trigger pre-emption". If a service is not capable of preemption, it cannotbe admitted. If service A is capable of preemption, it can preempt a service B that meets all ofthe following conditions:l Only non-emergency GBR services can be preempted.l The value of the ARP IE "pre-emption vulnerability" of service B is "pre-emptable".l The value of the ARP IE "priority level" of service B is greater than that of service A.l If service B is a GBR service, the resources allocated to it are greater than or equal to the

resources required by GBR service A.Preemption fails if any one of the preceding conditions is not met. If none of the GBRservices of a UE is admitted or preemption for all GBR services of a UE fails, the UE isredirected if redirection is enabled. For details about operations related to redirection, see 3.4Redirection.

NOTE

A service whose ARP value is 15 can neither preempt other services nor be preempted by other services.For details, see section 9.2.1.60 in 3GPP TS 36.413 V10.6.0 (2012-06).

During the preemption procedure, the eNodeB first groups GBR services with low prioritiesand then selects services that can be preempted from this group. The procedure is as follows:1. The eNodeB groups the GBR services with low priorities.

The eNodeB first selects releasable GBR services and then groups the services with thelowest priorities among them. A releasable GBR service must meet the followingconditions: The value of the ARP IE "pre-emption vulnerability" of the service is "pre-

emptable". The service is not an emergency call.

The service rate is not 0.



19

The eNodeB sorts these GBR services based on the following rule: The service withthe largest value of the ARP IE "priority level" has the lowest priority and ranksfirst. If two services have the same "priority level" value, the service that occupiesmore PRBs ranks ahead of the other.

2. The eNodeB selects services to be preempted.The eNodeB estimates the number of PRBs required by a preempting service based onthe average spectral efficiency of the cell. The eNodeB calculates the number of PRBsreleased from the group of GBR services with low priorities. The calculation stops afterthe number of released PRBs meets the requirements of the preempting service. Thepreemption fails if no service can be preempted or the number of PRBs released from tenpreempted services does not meet the requirements of the preempting service.If the GBR service to be preempted is the only GBR service on a UE, the UE can beredirected when redirection is enabled. For details about redirection, see 3.4Redirection.

3.4 RedirectionDuring a redirection, the eNodeB sends the UE an RRCConnectionRelease message thatincludes the target frequency information for the redirection. Redirection is enabled ifLoadBasedSwitch under the ENodeBAlgoSwitch.RedirectSwitch parameter is on.The eNodeB selects the target frequency as follows:l If a subscriber profile ID (SPID) has been specified for the UE, the eNodeB determines

the UE-supported RATs and frequency bands and checks for the mapping betweenfrequencies and priorities in the associated SPID configuration. The eNodeB then selectsthe highest-priority frequency except the serving frequency as the target frequency. Fordetails about SPIDs, see Flexible User Steering Feature Parameter Description.

l If an SPID is not specified for the UE or frequency priorities are not set in the SPIDconfiguration for the UE, the eNodeB considers the operator-specific dedicated cell-reselection priorities for frequencies. Among the UE-supported frequency bands, theeNodeB selects the highest-priority frequency except the serving frequency as the targetfrequency. The priorities are specified in the EutranNFreqRanShare, UtranRanShare,and GeranRanShare MOs or in the EutranNFreqSCellOp, UtranNFreqSCellOp,GeranNFGroupSCellOp, and Cdma2000BcSCellOp MOs.

l If an SPID is not specified for the UE or frequency priorities are not set in the SPIDconfiguration for the UE, and if operator-specific dedicated cell-reselection priorities arenot specified, the eNodeB considers common cell-reselection priorities. Among the UE-supported frequency bands, the eNodeB selects the highest-priority frequency except theserving frequency as the target frequency. The priorities are specified in theEutranInterNFreq, UtranNFreq, and GeranNfreqGroup MOs.

NOTE

If the admission fails for a UE requesting a handover, the UE cannot be redirected to another cell.



20

4 Congestion ControlThis chapter describes the basic feature LBFD-002024 Congestion Control.Congestion control reduces congestion caused by an insufficiency of radio resources ortransport resources. This document describes only the former. For details about the latter, seeTransport Resource Management Feature Parameter Description.Congestion can be prevented in most cases if admission control is performed. However,congestion may occur in the following cases:l The services are diverse and the data rates of certain services vary significantly.

Variations in the data volume inevitably affect the cell load.l The radio conditions vary because of user mobility. The same service at the same data

rate may require different radio resources on different occasions.In these two cases, the cell load varies and the quality of admitted services gets affected, evenif the number of users in the cell does not change. The congestion control algorithm isrequired to handle possible congestion.Figure 4-1 shows the congestion control process. Congestion control is enabled if theDlLdcSwitch(dlLdcSwitch) or UlLdcSwitch(ulLdcSwitch) check box under theCellAlgoSwitch.RacAlgoSwitch parameter is selected.

eRANAdmission and Congestion Control Feature ParameterDescription 4 Congestion Control


21

Figure 4-1 Congestion control process

When the cell is congested, congestion control releases the GBR services with low prioritiesfirst to make some resources available. The release reduces system load and helps ensure thequality of other admitted services.To ensure continuity and stability of emergency calls, the eNodeB does not release emergencycalls.For details about how to configure this feature, see 7 Engineering Guidelines.



22

4.1 Load Status EvaluationThe eNodeB checks the load status by monitoring the PRB usage and QoS satisfaction rate.The cell status can be either of the following:l Congested state

A cell is regarded as congested in the downlink if the downlink QoS satisfaction rate ofone or more QCIs is lower than the relevant congestion threshold.A cell is regarded as congested in the uplink if the uplink QoS satisfaction rate of one ormore QCIs is lower than the relevant congestion threshold and the uplink PRB usage ishigh, or if the uplink QoS satisfaction rate of one or more QCIs is lower than the relevantcongestion threshold and the wait time for uplink scheduling of VoIP services is toolong.When the cell is congested, the congestion control algorithm instructs the admissioncontrol algorithm to reject all access requests and, in addition, takes actions to reducecell load. When the QoS satisfaction rates of QCIs 1, 2, 3, and 4 all become higher thanthe sum of the related congestion threshold and CellRacThd.CongRelOffset, the cellreturns to the normal state. The congestion thresholds are specified by QcixCongThd (x= 14), that is, by the CellRacThd.Qci1CongThd, CellRacThd.Qci2CongThd,CellRacThd.Qci3CongThd, and CellRacThd.Qci4CongThd parameters.For each QCI, the sum of QcixCongThd (x = 14) and CellRacThd.CongRelOffsetmust be lower than the corresponding QcixHoThd (x = 14).

l Normal stateThe cell is regarded as normal if the QoS satisfaction rates of QCIs 1, 2, 3, and 4 are allhigher than the corresponding QcixCongThd (x = 14).

4.2 Release of Low-Priority GBR Servicesf a cell is congested, congestion control selects a service that ranks the first in the group ofadmitted low-priority GBR services and releases the selected service.If the only GBR service on the selected UE is released and redirection is enabled, the eNodeBredirects the UE to another frequency or RAT, increasing the access success rate of the UE.For details about redirection, see 3.4 Redirection.After the GBR service is released, the eNodeB checks whether the QoS satisfaction rates ofGBR services are restored. If the QoS satisfaction rates of GBR services are not restored, theeNodeB performs the GBR service release procedure again until the congestion is relieved.



23

5 Related Features5.1 Features Related to LBFD-002023 Admission ControlPrerequisite Features

None

Mutually Exclusive FeaturesNone

Impacted FeaturesNone

5.2 Features Related to LOFD-00102901 Radio/transportResource Pre-emptionPrerequisite Features

LOFD-00102901 Radio/transport Resource Pre-emption is dependent on LBFD-002023Admission Control. Preemption can be triggered only if admission fails.


Impacted FeaturesLBFD-002028 Emergency Call has an impact on LOFD-00102901 Radio/transport ResourcePre-emption. Emergency calls are assigned the highest priority. If the admission of anemergency call fails, preemption is performed for the emergency call.

eRANAdmission and Congestion Control Feature ParameterDescription 5 Related Features


24

5.3 Features Related to LBFD-002024 Congestion ControlPrerequisite Features

None


Impacted FeaturesNone

eRANAdmission and Congestion Control Feature ParameterDescription 5 Related Features


25

6 Network Impact6.1 LBFD-002023 Admission ControlSystem Capacity

The admission control algorithm maximizes system capacity while satisfying the QoSrequirements of admitted services. For example, if the QoS satisfaction rate of GBR servicesis low, new services cannot be admitted and preemption will be triggered. System capacitycan be maximized on condition that the QoS requirements are satisfied.

Network PerformanceIf network congestion results in limited system capacity, the implementation of admissioncontrol algorithm decreases the access success rate and handover success rate.For admission control based on QoS satisfaction rates, if the admission threshold is set to asmaller value, GBR services are easier to be admitted and the admission success rate of GBRservices increases. However, the service quality of admitted GBR services becomes poorer.

6.2 LOFD-00102901 Radio/transport resource pre-emptionSystem Capacity

No impact.

Network PerformancePreemption increases the access success rate for users with high ARPs. However, users withlow ARPs are forcibly released and their service drop rate increases.The way the eNodeB performs user-number-based preemption will increase the amount ofradio signaling because of the following three actions:l The eNodeB establishes a temporary RRC connection for any UE requesting access to

the eNodeB in order to obtain its ARP attributes.

eRANAdmission and Congestion Control Feature ParameterDescription 6 Network Impact


26

l The eNodeB releases temporary RRC connections for those UEs that eventuallyencounter preemption failures.

l The eNodeB releases RRC connections for preempted UEs.

6.3 LBFD-002024 Congestion ControlSystem Capacity

The congestion control algorithm maximizes system capacity while preferentially satisfyingthe QoS requirements of users with high ARPs. When congestion occurs, the congestioncontrol algorithm informs the admission control algorithm. Then, the admission controlalgorithm starts to reject access requests.

Network PerformanceThe congestion control algorithm increases the service drop rate because the congestion-control-triggered releases of users are regarded as service drops. Counters are provided toindicate congestion-triggered service drops. For details about the counters, see 9 Counters.

eRANAdmission and Congestion Control Feature ParameterDescription 6 Network Impact


27

7 Engineering Guidelines7.1 When to Use Admission and Congestion Control

When a network becomes congested with an increasing number of users and higher QoSrequirements, eNodeBs need to perform radio resource management so that QoS requirementsof ongoing services can be fulfilled and differentiated services can be provided.When radio resource congestion occurs (for example, QoS requirements cannot be fulfilled orradio bearers cannot be set up), activate admission control to relieve congestion and provideservice-priority-based access services.When congestion increases so that QoS requirements still cannot be fulfilled, activatecongestion control to enable low-priority service release.

7.2 Required InformationFor both admission control and congestion control, collect the QoS satisfaction rates anduplink PRB usage of cells.

7.3 Planning

7.3.1 RF PlanningN/A

7.3.2 Network PlanningNetwork planning is required for redirection. Redirection can transfer loads to inter-frequencyor inter-RAT cells if admission fails or a low-priority service needs to be released.During network planning, operators can coordinate resources of the GERAN, UTRAN, and E-UTRAN in a hierarchical structure to increase return on investment, better utilize existingresources, and achieve service steering.

eRANAdmission and Congestion Control Feature ParameterDescription 7 Engineering Guidelines


28

7.3.3 Hardware PlanningN/A

7.4 Deployment of Admission Control7.4.1 RequirementsFeature

For details, see 5.1 Features Related to LBFD-002023 Admission Control in the section"Impacted Features".

HardwareNone

LicenseThe required licenses for the Enhanced Admission Control feature must be activated beforeservice preemption is enabled.The operator must purchase and activate the licenses of the features listed in the followingtable.

Feature ID FeatureName

Model LicenseControl Item

NE Sales Unit

LOFD-001029

EnhancedAdmissionControl

LT1S000EAC00

EnhancedAdmissionControl (FDD)

MacroeNodeB/LampSiteeNodeB/BTS3202E

per RRCConnectedUser

Other RequirementsAs required by congestion control, the preemption capability and vulnerability must bespecified in the EPC for services with different priorities.

7.4.2 Data PreparationThis section describes the data that you need to collect for setting parameters. Required data isdata that you must collect for all scenarios. Collect scenario-specific data when necessary fora specific feature deployment scenario.There are three types of data sources:l Network plan (negotiation required): parameter values planned by the operator and

negotiated with the EPC or peer transmission equipment



29

l Network plan (negotiation not required): parameter values planned and set by theoperator

l User-defined: parameter values set by users

Required DataN/A

Scenario-specific DataScenario 1: Admission Based on QoS Satisfaction RatesThe following table describes the parameters that must be set in the CellAlgoSwitch MO toenable admission based on QoS satisfaction rates.

ParameterName

Parameter ID

DataSource

Setting Notes

Local cellID

CellAlgoSwitch.LocalCellId

Networkplan(negotiationnotrequired)

This parameter specifies the local ID of a cell. Ituniquely identifies a cell within an eNodeB. Setthis parameter based on the network plan.

RACalgorithmswitch

CellAlgoSwitch.RacAlgoSwitch


l To enable downlink admission based on QoSsatisfaction rates, select theDlSwitch(dlCacSwitch) option.

l To disable downlink admission based on QoSsatisfaction rates, deselect theDlSwitch(dlCacSwitch) option.


l To enable uplink admission based on QoSsatisfaction rates, select theUlSwitch(ulCacSwitch) option.

l To disable uplink admission based on QoSsatisfaction rates, deselect theUlSwitch(ulCacSwitch) option.

The following table describes the parameters that must be set in the CellRacThd MO toconfigure admission based on QoS satisfaction rates.

ParameterName

Parameter ID

DataSource

Setting Notes

Local cellID

CellRacThd.LocalCellId





30

ParameterName

Parameter ID

DataSource

Setting Notes

Goldservice arpthreshold

CellRacThd.GoldServiceArpThd


This parameter specifies the ARP threshold forgold-level services. A service is defined as agold-level service if its ARP value is less than orequal to this parameter value.A smaller ARP value indicates a higher priority.The value 5 is recommended.

Silverservice arpthreshold

CellRacThd.SilverServiceArpThd


This parameter specifies the ARP threshold forsilver-level services. A service is defined as asilver-level service if its ARP value is less than orequal to this parameter value and greater than thevalue of CellRacThd.GoldServiceArpThd.A service is defined as a bronze-level service ifits ARP value is greater than the value ofCellRacThd.SilverServiceArpThd. A smallerARP value indicates a higher priority.The value 10 is recommended.

QCI1handoveradmissionthreshold

CellRacThd.Qci1HoThd


This parameter specifies the handover admissionthreshold for QCI 1. The parameter applies toboth uplink and downlink.l If the QoS satisfaction rate of services with a

QCI of 1 in the cell is higher than or equal tothis threshold, handover services with a QCIof 1 are admitted.

l If the QoS satisfaction rate of these services islower than this threshold, handover serviceswith a QCI of 1 are not admitted.

The value 90 is recommended.QCI2handoveradmissionthreshold






The value 90 is recommended.



31

ParameterName

Parameter ID

DataSource

Setting Notes

QCI3handoveradmissionthreshold






The value 90 is recommended.QCI4handoveradmissionthreshold






The value 90 is recommended.Gold newserviceadmissionthresholdoffset

CellRacThd.NewGoldServiceOffset


This parameter specifies admission offset for newgold-level services. The parameter applies toboth uplink and downlink.l New gold-level services and handover

services with a specific QCI are admitted ifthe following conditions are both met: TheQoS satisfaction rate of services with this QCIis higher than or equal to the sum of thisoffset and the admission threshold forhandover services with this QCI. The QoSsatisfaction rates of all other QCIs are higherthan the corresponding handover admissionthresholds.

l New services are not admitted if the QoSsatisfaction rate of any QCI is lower than thecorresponding handover admission threshold.

The value 5 is recommended.



32

ParameterName

Parameter ID

DataSource

Setting Notes

Silver newserviceadmissionthresholdoffset

CellRacThd.NewSilverServiceOffset


This parameter specifies admission offset for newsilver-level services. The parameter applies toboth uplink and downlink.l New silver-level services and handover


l New services with a specific QCI are notadmitted if the QoS satisfaction rate of anyQCI is lower than the corresponding handoveradmission threshold.

The value 5 is recommended.Bronze newserviceadmissionthresholdoffset

CellRacThd.NewCopperServiceOffset


This parameter specifies admission offset for newbronze-level services. The parameter applies toboth uplink and downlink.l New bronze-level services and handover


l New services with a specific QCI are notadmitted if the QoS satisfaction rate of anyQCI is lower than the corresponding handoveradmission threshold.

The value 5 is recommended.Uplink RBused ratiohighthreshold

CellRacThd.UlRbHighThd


This parameter specifies the threshold fordeciding whether the uplink RB usage is high.This threshold is used in uplink admissiondecisions. If the MAC layer reports that theuplink RB usage is greater than this parametervalue, the uplink RB usage is regarded to behigh.The value 95 is recommended.



33

ParameterName

Parameter ID

DataSource

Setting Notes

Uplink RBused ratiolowthreshold

CellRacThd.UlRbLowThd


This parameter specifies the threshold fordeciding whether the uplink RB usage is low.This threshold is used in uplink admissiondecisions. If the MAC layer reports that theuplink RB usage is less than this parameter value,the uplink RB usage is regarded to be low.The value 90 is recommended.

Scenario 2: Service PreemptionThis section describes data preparation for radio resource preemption. For details about datapreparation for transport resource preemption, see Transport Resource Management FeatureParameter Description.Before collecting the parameters for enabling and configuring service preemption, collect theparameters in the CellAlgoSwitch MO for enabling admission based on QoS satisfactionrates. For the parameters for enabling admission based on QoS satisfaction rates, see scenario1.The following table describes the parameters that must be set in the CellAlgoSwitch MO toenable service preemption.

ParameterName

Parameter ID

DataSource

Setting Notes

Local cell ID CellAlgoSwitch.LocalCellId



RACalgorithmswitch

CellAlgoSwitch.RacAlgoSwitch


PreemptionSwitch(PreemptionSwitch) of thisparameter specifies whether to enable servicepreemption.l If the

PreemptionSwitch(PreemptionSwitch)option is selected, new higher-priorityservices that have failed to be admitted canpreempt the admitted lower-priority servicesin the cell.

l If thePreemptionSwitch(PreemptionSwitch)option is deselected, only emergency callscan be admitted to the cell.

Scenario 3: User-Number-based Preemption



34

The following table describes the parameter that must be set in the EnodeBAlgoSwitch MOto enable user-number-based preemption.

ParameterName

Parameter ID

DataSource

Setting Notes

UE numberpreemptionswitch

EnodeBAlgoSwitch.UeNumPreemptSwitch

Networkplan(negotiation notrequired)

This parameter specifies whether to enable user-number-based preemption.l IntraOpUeNumPreemptSwitch: This option

specifies whether to enable intra-operator user-number-based preemption. If theIntraOpUeNumPreemptSwitch option isselected, when a user cannot access thenetwork because of the user numberrestriction, the user can preempt resources ofother lower-priority users served by the sameoperator. If this option is deselected,preemption is not allowed.

l InterOpUeNumPreemptSwitch: This optionspecifies whether to enable inter-operator user-number-based preemption. If theInterOpUeNumPreemptSwitch option isselected, when a user cannot access thenetwork because of the user numberrestriction, the user can preempt resources ofother lower-priority users served by differentoperators. If this option is deselected,preemption is not allowed.

Scenario 4: User-Number-Reservation-based Admission Control of Privileged UEsThe following table describes the parameter that must be set in the CellRacThd MO to enableuser-number-reservation-based admission control of privileged UEs.

ParameterName

Parameter ID

DataSource

Setting Notes

AdmissionControlReservedUserNumber

CellRacThd.AcReservedUserNumber

Networkplan(negotiation notrequired)

This parameter specifies the UE numbers reservedfor privileged UEs. If this parameter is set to 0, noUE numbers are reserved for privileged UEs. Anon-zero value of this parameter indicates themaximum UE numbers reserved for privilegedUEs. A larger value of this parameter indicates alarger UE number reserved for privileged UEs anda smaller UE number available for common UEs.The value 0 is recommended.

Scenario 5: ARP Configuration for Common UEs Initiating CSFB Procedures



35

The following table describes the parameters that must be set in the CSFallBackPolicyCfgMO to configure ARPs for common UEs initiating CSFB procedures.

ParameterName

Parameter ID Data Source Setting Notes

Csfb UserArpConfiguration Switch

CSFallBackPolicyCfg.CsfbUserArpCfgSwitch

Network plan(negotiation notrequired)

This parameter specifies whetherthe ARPs for common UEsinitiating CSFB procedures can beconfigured.The value OFF(Off) isrecommended.

NormalCsfb UserArp

CSFallBackPolicyCfg.NormalCsfbUserArp

Network plan(negotiation notrequired)

This parameter specifies the ARPfor common UEs initiating CSFBprocedures. If this parameter is setto 1, the ARP for these UEs is thesame as that for emergency UEsinitiating CSFB procedures.The value 2 is recommended.

7.4.3 ActivationUsing the CME to Perform Batch Configuration for Newly Deployed eNodeBs

Enter the values of the parameters listed in Table 7-1, Table 7-2, Table 7-3, Table 7-4, orTable 7-5 in a summary data file, which also contains other data for the new eNodeBs to bedeployed. Then, import the summary data file into the Configuration Management Express(CME) for batch configuration. For detailed instructions, see "Creating eNodeBs in Batches"in the initial configuration guide for the eNodeB, which is available in the eNodeB productdocumentation.The summary data file may be a scenario-specific file provided by the CME or a customizedfile, depending on the following conditions:l The managed objects (MOs) in Table 7-1, Table 7-2, Table 7-3, Table 7-4, or Table 7-5

are contained in a scenario-specific summary data file. In this situation, set theparameters in the MOs, and then verify the parameter settings and save the file.

l Some MOs in Table 7-1, Table 7-2, Table 7-3, Table 7-4, or Table 7-5 are not containedin a scenario-specific summary data file. In this situation, customize a summary data fileto include the MOs before setting the parameters.

Table 7-1 Parameters for admission based on QoS satisfaction ratesMO Sheet in the

Summary DataFile

Parameter Group Remarks

CellAlgoSwitch

CellAlgoSwitch Local cell ID, RAC algorithmswitch

User-definedtemplate



36

MO Sheet in theSummary DataFile


CellRacThd

CellRacThd Local cell ID, Gold service arpthreshold, Silver service arpthreshold, QCI1 handoveradmission threshold (%), QCI2handover admission threshold (%),QCI3 handover admissionthreshold (%), QCI4 handoveradmission threshold (%), Gold newservice admission threshold offset(%), Silver new service admissionthreshold offset (%), Copper newservice admission threshold offset(%), Uplink RB used ratio highthreshold(%), Uplink RB used ratiolow threshold (%)


Table 7-2 Parameters for service preemptionMO Sheet in the

Summary DataFile


CellAlgoSwitch CellAlgoSwitch Local cell ID, RACalgorithm switch




37



CellRacThd CellRacThd Local cell ID, Goldservice arp threshold,Silver service arpthreshold, QCI1handover admissionthreshold (%), QCI2handover admissionthreshold (%), QCI3handover admissionthreshold(%), QCI4handover admissionthreshold(%), Goldnew service admissionthreshold offset(%),Silver new serviceadmission thresholdoffset(%), Copper newservice admissionthreshold offset(%),Uplink RB used ratiohigh threshold(%),Uplink RB used ratiolow threshold(%)


Table 7-3 Parameters for UE-number-based preemptionMO Sheet in the

Summary DataFile


EnodeBAlgoSwitch

ENodeBAlgoSwitch UE number preemptionswitch


Table 7-4 Parameters for admission control of privileged UEs based on reserved resourcesMO Sheet in the

Summary DataFile


CellRacThd CellRacThd Admission ControlReserved UserNumbers




38

Table 7-5 Parameters for ARP configuration for common UEs initiating CSFB procedureswhen the number of UEs to be admitted is limited



CsFallbackPolicyCfg

CsFallbackPolicyCfg

Csfb User ArpConfigure Switch,Normal Csfb User Arp


Using the CME to Perform Batch Configuration for Existing eNodeBsBatch reconfiguration using the CME is the recommended method to activate a feature onexisting eNodeBs. This method reconfigures all data, except neighbor relationships, formultiple eNodeBs in a single procedure. The procedure is as follows:

Step 1 Customize a summary data file with the MOs and parameters listed in section "Using theCME to Perform Batch Configuration for Newly Deployed eNodeBs". For online help, pressF1 when a CME window is active, and choose Managing the CME > CME Guidelines >LTE Application Management > eNodeB Related Operations > Customizing a SummaryData File for Batch eNodeB Configuration.

Step 2 Choose CME > LTE Application > Export Data > Export Base Station BulkConfiguration Data (U2000 client mode), or choose LTE Application > Export Data >Export Base Station Bulk Configuration Data (CME client mode), to export eNodeB datastored on the CME into a customized summary data file.

Step 3 In the summary data file, set the parameters in the MOs according to the setting notesprovided in section "Data Preparation" and close the file.

Step 4 Choose CME > LTE Application > Import Data > Import Base Station BulkConfiguration Data (U2000 client mode), or choose LTE Application > Import Data >Import Base Station Bulk Configuration Data (CME client mode), to import the summarydata file into the CME, and then start the data verification.

Step 5 Choose CME > Planned Area > Export Incremental Scripts (U2000 client mode), orchoose Area Management > Planned Area > Export Incremental Scripts (CME clientmode), to export and activate the incremental scripts. For detailed operations, see Managingthe CME > CME Guidelines > Script File Management > Exporting Incremental Scriptsfrom a Planned Data Area in the CME online help.----End

Using the CME to Perform Single ConfigurationOn the CME, set the parameters listed in the "Data Preparation" section for a single eNodeB.The procedure is as follows:

Step 1 In the planned data area, click Base Station in the upper left corner of the configurationwindow.

Step 2 In area 1 shown in Figure 7-1, select the eNodeB to which the MOs belong.



39

Figure 7-1 MO search and configuration window

Step 3 On the Search tab page in area 2, enter an MO name, for example, CELL.Step 4 In area 3, double-click the MO in the Object Name column. All parameters in this MO are

displayed in area 4.Step 5 Set the parameters in area 4 or 5.Step 6 In the planned data area, choose CME > Planned Area > Export Incremental Scripts

(U2000 client mode), or Area Management > Planned Area > Export Incremental Scripts(CME client mode), to export and activate the incremental scripts.----End

Using MML CommandsScenario 1: Admission Based on QoS Satisfaction Rates

Step 1 Run the MOD CELLALGOSWITCH command to enable uplink and downlink admissioncontrol based on QoS satisfaction rates.

Step 2 Run the MOD CELLRACTHD command to configure admission control.----EndScenario 2: Service Preemption

Step 1 Run the MOD CELLALGOSWITCH command to enable uplink and downlink admissioncontrol based on QoS satisfaction rates, and then to enable service preemption.

Step 2 Run the MOD CELLRACTHD command to configure admission control.----EndScenario 3: User-Number-based Preemption



40

Run the MOD ENODEBALGOSWITCH command to enable user-number-basedpreemption.Scenario 4: Admission Control of Privileged UEs Based on Reserved ResourcesRun the MOD CELLRACTHD command to set the number of UEs reserved for admissioncontrol.Scenario 5: ARP Configuration for Common UEs Initiating CSFB Procedures When theNumber of UEs to Be Admitted Is LimitedRun the MOD CSFALLBACKPOLICYCFG command to turn on the switch forconfiguring ARP for common UEs initiating CSFB procedures and to configure the ARPs forcommon UEs initiating CSFB procedures.

MML Command Examplesl Enabling Admission Control Based on QoS Satisfaction Rates

MOD CELLALGOSWITCH: LocalCellId=0, RacAlgoSwitch=DlSwitch-1&UlSwitch-1;

l Enabling Service PreemptionMOD CELLALGOSWITCH: LocalCellId=0, RacAlgoSwitch=PreemptionSwitch-1;

l Configuring Admission ControlMOD CELLRACTHD: LocalCellId=0, GoldServiceArpThd=5, SilverServiceArpThd=10, Qci1HoThd=80, Qci2HoThd=80, Qci3HoThd=80, Qci4HoThd=80, NewGoldServiceOffset=5, NewSilverServiceOffset=5, NewCopperServiceOffset=5, UlRbHighThd=90, UlRbLowThd=80;

l Enabling User-Number-based PreemptionMOD ENODEBALGOSWITCH:UeNumPreemptSwitch=IntraOpUeNumPreemptSwitch-1&InterOpUeNumPreemptSwitch-1;

l Enabling Admission Control of Privileged UEs Based on Reserved ResourcesMOD CELLRACTHD:LocalCellId=0,AcReservedUserNumber=15;

l Enabling ARP Configuration for Common UEs Initiating CSFB Procedures Whenthe Number of UEs to Be Admitted Is LimitedMOD CSFALLBACKPOLICYCFG:CSFBUSERARPCFGSWITCH=ON,NORMALCSFBUSERARP=2;

7.4.4 Activation ObservationScenario 1: Admission Based on QoS Satisfaction Rates

Step 1 On the U2000 client, start S1 interface tracing and start monitoring on the following items:QoS satisfaction rate, RB usage, and the number of services.1. Choose Monitor > Signaling Trace > Signaling Trace Management.2. In the navigation tree on the left of the Signaling Trace Management window:

Choose LTE > Application Layer > S1 Interface Trace to create an S1 interfacetracing task. Choose LTE > Cell Performance Monitoring > Satisfaction of Service

Monitoring to create a task for monitoring QoS satisfaction rates.Step 2 Use UEs to access a cell, and perform GBR services with a QCI in the range of 2 to 4 on the

UEs. Move some UEs towards the cell center and increase the traffic volume of GBR serviceson these UEs. Move some UEs towards the cell edge until the cell is congested, which can bemonitored based on Congestion State in the monitoring results.



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Step 3 Initiate new GBR services with a QCI in the range of 2 to 4. These new GBR service requestsare rejected in admission based on QoS satisfaction rates.

Step 4 Check the S1AP_ERAB_SETUP_REQ and S1AP_ERAB_SETUP_RSP messages in the S1interface tracing result. If the cause value for E-RAB setup failures is "radioNetwork: radio-resources-not-available" in the S1AP_ERAB_SETUP_RSP messages, as shown in Figure7-2, or if the number of services does not increase with the S1AP_ERAB_SETUP_REQmessages, the new GBR service requests have been rejected.

Figure 7-2 S1AP_ERAB_SETUP_RSP message that indicates failed admission based onsatisfaction rates

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Scenario 2: Service PreemptionIn this scenario, two GBR services (A and B) are involved. GBR service A has a QCI of 3 andan ARP value of 7, and GBR service B has a QCI of 4 and an ARP value greater than 7. TheGBR service with a larger ARP value has a lower priority. Both GBR services can preemptother services and can be preempted.To check whether a service can preempt other services or can be preempted, observe theS1AP_ERAB_SETUP_REQ message in the S1 interface tracing result. In this message forGBR service A, as shown in Figure 7-3, the value 1 (may-trigger-pre-emption) of the IEpre-emptionCapability indicates that the service can preempt other services and the value 1(pre-emptable) of the IE pre-emptionVulnerability indicates that the service can bepreempted. The value 0 indicates the opposite.

Figure 7-3 S1AP_ERAB_SETUP_REQ message that includes the ARP value and thepreemption attributes

Step 1 On the U2000 client, start S1 interface tracing and start monitoring on the following items:QoS satisfaction rate, RB usage, and the number of services.1. Choose Monitor > Signaling Trace > Signaling Trace Management.2. In the navigation tree on the left of the Signaling Trace Management window:



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Choose LTE > Application Layer > S1 Interface Trace to create an S1 interfacetracing task. Choose LTE > Cell Performance Monitoring > Satisfaction of Service

Monitoring to create a task for monitoring QoS satisfaction rates.Step 2 Use UEs to access a cell, and perform GBR service B (with a QCI of 4) on some UEs.

Admission and Congestion Control(ERAN8.1_03)

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