interference cancellation(ran16.0 01)

WCDMA RAN

Interference Cancellation FeatureParameter Description

Issue 01Date 2014-04-30

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 respective holders. 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 or representationsof 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 01 (2014-04-30) 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...............................................................................................................................................................12 Overview.........................................................................................................................................32.1 Background.....................................................................................................................................................................32.2 Introduction....................................................................................................................................................................32.3 Benefits...........................................................................................................................................................................33 Technical Description...................................................................................................................43.1 Multiuser Detection........................................................................................................................................................43.2 Interference Cancellation Techniques............................................................................................................................53.2.1 Demodulation-based IC and Decoding-based IC........................................................................................................53.2.2 Parallel and Successive Interference Cancellation......................................................................................................63.3 Huawei Interference Cancellation Techniques...............................................................................................................83.3.1 Channel Types.............................................................................................................................................................83.3.2 Control Channel Interference Cancellation.................................................................................................................93.3.3 Data Channel Interference Cancellation....................................................................................................................103.3.4 Inter-Board IC and Intra-Board IC............................................................................................................................104 Parameters.....................................................................................................................................125 Counters........................................................................................................................................146 Glossary.........................................................................................................................................157 Reference Documents.................................................................................................................16

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1 About This Document1.1 Scope

This document describes the overview of interference cancellation (IC).For detailed descriptions of IC features, such as the network impact and engineering guidelines,see Control Channel Interference Cancellation Feature Parameter Description and HSUPAData Channel Interference Cancellation Feature Parameter Description.

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

RAN16.0 01 (2014-04-30)This issue does not include any changes.

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RAN16.0 Draft A (2014-01-20)Compared with Issue 02 (2013-09-30) of RAN15.0, Draft A (2014-01-20) of RAN16.0 includesthe following changes.

ChangeType

Change Description ParameterChange

Featurechange

Added brief introduction of the featuresWRFD-160201 Control Channel Parallel InterferenceCancellation (Phase 3) and WRFD-160213 Turbo ICPhase2. For details, see section 3.3 HuaweiInterference Cancellation Techniques.

Added thefollowingparameters:l CCPICPHASE

SWCTRLl TURBOICPH

ASE2Editorialchange

l Moved detailed descriptions of the followingfeatures from this document to Control ChannelInterference Cancellation Feature ParameterDescription: WRFD-010210 Control Channel Parallel

Interference Cancellation (CCPIC) WRFD-140202 Control Channel Parallel

Interference Cancellation (Phase 2)l Moved detailed descriptions of the following

features from this document to HSUPA DataChannel Interference Cancellation FeatureParameter Description: WRFD-010691 HSUPA UL Interference

Cancellation WRFD-150206 Turbo IC

None

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2 Overview2.1 Background

Wideband Code Division Multiple Access (WCDMA) is a self-interference system. The capacityand performance of this system is mainly affected by the following factors:l Multiple access interference (MAI), also known as inter-user interferencel Intersymbol interference (ISI)l Near-far interference

Near-far interference is signal interference that occurs when a desirable signal from a far-away user is interfered by the signals from another user close to the base station.

Multiuser detection (MUD), also known as joint detection, is a receiver technique to detectdesired signals from interference and noise. MUD can minimize MAI, ISI, and near-farinterference, thereby improving system capacity and performance. IC is one type of MUD.

2.2 IntroductionIC estimates the MAI by signal detection and regeneration and eliminates some or all interferencebefore the final demodulation and decoding.

2.3 BenefitsThis feature can increase the uplink system capacity.

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3 Technical Description3.1 Multiuser Detection

In single-user scenarios, interference mainly consists of N0, ISI, and external interference(including that from neighboring cells).In multi-user scenarios, interference between UEs is also considered noise. This type ofinterference is called MAI.Table 3-1 describes the noise types.

Table 3-1 Noise typesInterference Type DescriptionN0 N0 indicates background noise, which is also called noise floor. It is

caused by the thermal motion of electrons in internal componentsand its strength depends on the receiver bandwidth and ambienttemperature.

ISI Intersymbol interference (ISI) is a form of waveform distortion andmultipath spread of consecutive symbols. ISI is usually caused bymultipath propagation.

MAI MAI indicates interference between UEs, which is caused by themultiple-access technique. In a CDMA system, UEs are identifiedby their scrambling codes in the uplink. However, scrambling codesare not completely orthogonal. Therefore, MAI exists betweenuplink UEs.

The conventional detection technique uses a matched filter to despread received signals andmakes a decision on the filter output. The receiver does not consider MAI or use transmissioninformation of other UEs for a joint detection.The MUD technique enables the receiver to detect signals from a UE by considering the MAIfrom all other UEs. This increases the system's anti-interference capability, effectively utilizes

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uplink spectrum resources, and greatly increases system capacity. IC is a first-choice MUDtechnique for the third-generation mobile communications system. It can improve receiverperformance and leave room for further expansion.

3.2 Interference Cancellation TechniquesIC estimates the MAI by signal detection and regeneration and eliminates some or all interferencebefore the final demodulation and decoding.IC can be categorized in the following ways:l IC is categorized into demodulation-based IC and decoding-based IC based on whether

regeneration and cancellation are performed after demodulation or decoding.l IC is categorized into parallel interference cancellation (PIC) and successive interference

cancellation (SIC) based on whether IC is performed in parallel or in succession.

3.2.1 Demodulation-based IC and Decoding-based ICDemodulation-based IC

Demodulation-based IC implements regeneration and cancellation on demodulated signals fora UE before decoding. This minimizes interference to other UEs and improves demodulationperformance. Figure 3-1 illustrates demodulation-based IC.

Figure 3-1 Demodulation-based IC

As shown in Figure 3-1, demodulation-based IC involves the following operations:l Demodulation: Upon receiving signals from UEs, the NodeB demodulation module

demodulates signals of different UEs or signals on different channels based on informationsuch as finger delays and the channel estimation result.

l Decoding: Upon receiving the demodulated signals of a UE, the NodeB decoding moduleretrieves the primitive information of the UE.



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l Regeneration: The NodeB regeneration module estimates and regenerates the primitivesignals of the UE or on the channel based on information such as the demodulation/decodingresult, channel estimation result, and multipath conditions.

l Cancellation: The NodeB cancellation module removes the regenerated signals of the UEfrom the received signals to cancel any interference to other UEs or channels.

Decoding-based ICDecoding-based IC implements regeneration and cancellation on decoded signals for a UE. Thisminimizes interference to other UEs and improves demodulation performance. Figure 3-2illustrates decoding-based IC.

Figure 3-2 Decoding-based IC

3.2.2 Parallel and Successive Interference CancellationParallel Interference Cancellation

With PIC, the NodeB performs detection, regeneration, and cancellation of signals of multipleUEs in parallel. PIC can be implemented in multiple stages to further improve performance.Figure 3-3 illustrates two-stage PIC.



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Figure 3-3 Two-stage PIC

As illustrated in Figure 3-3, PIC in each stage involves three operations: detection, regeneration,and cancellation. Upon receiving signals, the NodeB detection module detects signals fordifferent UEs by demodulation or by demodulation and decoding. After implementing first-stageand second-stage PIC, the NodeB demodulates and decodes the signals where PIC is performedto obtain the decoded signals of UEs.

Successive Interference CancellationWith SIC, the NodeB performs detection and regeneration on signals of only one UE at a time.The NodeB removes the regenerated signals of a UE before detecting the next UE to reduce theMAI from this UE on subsequent UEs. SIC can be implemented in multiple stages to furtherimprove performance. Figure 3-4 illustrates two-stage SIC.

Figure 3-4 Two-stage SIC



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3.3 Huawei Interference Cancellation Techniques3.3.1 Channel Types

In WCDMA, the physical channels DPCCH and DPDCH are introduced to the uplink to supportbasic R99 circuit switched (CS) and packet switched (PS) services. The E-DPCCH and E-DPDCH are added as uplink physical channels to support HSUPA, which is introduced in 3GPPRelease 6 to meet requirements for uplink data transmission. Figure 3-5 shows channels usedwhen an R99 UE and an HSUPA-capable UE are processing an R99 and HSUPA service,respectively.

Figure 3-5 Channels for R99 and HSUPA services

DPDCH: dedicated physical data channelDPCCH: dedicated physical control channelHSDPCCH: dedicated physical control channel (uplink) for HS-DSCHE-HICH: E-DCH HARQ acknowledgement indicator channelE-RGCH: E-DCH relative grant channelE-AGCH: E-DCH absolute grant channelE-DPCCH: E-DCH dedicated physical control channelE-DPDCH: E-DCH dedicated physical data channelHuawei introduces various techniques to implement interference cancellation on uplinkchannels. Figure 3-6 shows the mapping between channels and Huawei interference cancellationtechniques.



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Figure 3-6 Mapping between channels and Huawei interference cancellation techniques

When the WRFD-151205 Uplink CoMP (Joint Reception) or WRFD-151206 HetNet UplinkCoMP(Joint Reception) feature is activated, IC also takes effect on DPCCHs and E-DPDCHscarrying coordinated links. The implementation and gains of IC on these DPCCHs and E-DPDCHs are the same as those on ordinary DPCCHs and E-DPDCHs.With IC available to these particular DPCCHs and E-DPDCHs, the uplink interference of UEsusing coordinated links to other UEs in the same cell is reduced and uplink cell capacity isexpanded.For details about the WRFD-151205 Uplink CoMP (Joint Reception) and WRFD-151206HetNet Uplink CoMP(Joint Reception) features, see Uplink CoMP Feature ParameterDescription.

3.3.2 Control Channel Interference CancellationEach UE is allocated a standalone DPCCH. Uplink interference from this channel reduces theuplink system capacity.CCPIC eliminates interference from the DPCCH, thereby reducing the interference from thisDPCCH on other channels and increasing the uplink system capacity. The gains are obviouswhen the uplink DPCCH uses a large proportion of the RTWP in the cell. For example, the gainsare obvious when a large number of UEs camp on the cell and the uplink throughput is low.Each HSUPA UE has an independent E-DPCCH, and each HSDPA UE has an independent HS-DPCCH. If there are a large number of HSUPA UEs and HSDPA UEs, system capacity isaffected by uplink interference caused by the E-DPCCH and HS-DPCCH. The Control ChannelParallel Interference Cancellation (Phase 3) feature is developed from the CCPIC (Phase 2)feature. In addition to cancellation of the interference caused by the DPCCH, this featureintroduces regeneration and cancellation of interference caused by the HS-DPCCH and E-DPCCH, significantly improving uplink system capacity.Interference cancellation of control channels is implemented by the following features:l WRFD-010210 Control Channel Parallel Interference Cancellation (CCPIC)l WRFD-140202 Control Channel Parallel Interference Cancellation (Phase 2)l WRFD-160201 Control Channel Parallel Interference Cancellation (Phase 3)For details about these features, see Control Channel Interference Cancellation FeatureParameter Description.



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3.3.3 Data Channel Interference CancellationWith the continuous increase of the HSUPA rate, uplink interference increases, thereby imposinga great impact on the uplink system capacity. E-DPDCH IC increases the uplink system capacityby canceling interference from the E-DPDCH.Interference cancellation of data channels is implemented by the following features:l WRFD-010691 HSUPA UL Interference Cancellationl WRFD-150206 Turbo ICl WRFD-160213 Turbo IC Phase2For details about these features, see HSUPA Data Channel Interference Cancellation FeatureParameter Description.

3.3.4 Inter-Board IC and Intra-Board ICWhen there are multiple boards in an uplink resource group, a UE can be served by any boardin the uplink resource group. UEs served by IC-capable boards can participate in IC. Signals ofthese UE undergo detection, regeneration, and cancellation to reduce interference to other UEs.l Inter-board IC indicates that IC benefits can be shared by all the boards in an uplink resource

group. With inter-board IC, the MAI caused by a UE to other UEs served by the same boardas well as to the UEs served by other boards is reduced.

l Intra-board IC indicates that IC benefits are only shared within an IC-capable board. Intra-board IC reduces only the MAI caused by a UE to other UEs served by the same board.

Inter-Board ICInter-board IC enables the IC benefits to be shared among the boards in an uplink resource groupof a NodeB.l By default, IC-capable boards support inter-board IC. If there are multiple IC-capable

boards in an uplink resource group, IC benefits can be shared by the IC-capable boards.l IC-incapable boards can share IC benefits only when certain conditions are met and

INTERBOARDICSW is set to ON.If INTERBOARDICSW is set to ON for a NodeB, UEs served by IC-incapable boards must setup control channels on IC-capable boards. The new channels consume extra resources, andconsequently the total number of users supported by IC-capable boards is reduced.Inter-board IC also enables interference from other UEs to be canceled from the signals of UEsthat are carried on IC-incapable boards before signals are demodulated. This also improves thedemodulation performance of the UEs carried on IC-incapable boards.Figure 3-7 illustrates how inter-board IC functions.As illustrated in Figure 3-7, inter-board IC functions as follows:1. IC-capable boards consisting of non-centralized IC boards and a centralized IC board

perform detection and regeneration on signals of UEs carried on them and send theregenerated signals to the centralized IC module on the centralized IC board.

2. The centralized IC module centrally cancels interference. It adds up the regenerated signalsof all UEs carried on the IC-capable boards, removes the sum from the received signals,



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and sends the remaining signals to all the boards, including IC-incapable boards, in thesame uplink resource group.

3. All boards perform demodulation and decoding using the remaining signals.

Figure 3-7 Working principles of inter-board IC

Intra-Board ICIntra-board IC is a type of interference cancellation whose benefits are shared only within anIC-capable board. Intra-board IC cannot benefit UEs carried on other boards, regardless ofwhether they are IC-capable. Assume that IC-capable boards 1 and 2 and IC-incapable board 3form an uplink resource group and intra-board IC is applied. IC gains from board 1 benefit onlyUEs carried on board 1. Similarly, IC gains from board 2 benefit only UEs carried on board 2.Interference between UEs carried on IC-incapable board 3 cannot be canceled.



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4 ParametersTable 4-1 Parameters

Parameter ID

NE MMLCommand

FeatureID

FeatureName

Description

CCPICPHASESWCTRL

BTS3900,BTS3900WCDMA

SETNODEBALGPARALSTNODEBALGPARA

WRFD-160201

ControlChannelParallelInterferenceCancellation(Phase3)

Meaning: Indicates the switch for selecting the CCPICphase. The value DEFAULT indicates that CCPICPhase 3 is disabled.GUI Value Range: DEFAULT(CCPIC Phase 3 OFF),CCPICPHASE3(CCPIC Phase 3 ON)Unit: NoneActual Value Range: DEFAULT, CCPICPHASE3Default Value: DEFAULT(CCPIC Phase 3 OFF)

TURBOICPHASE2


ADDULOCELLMODULOCELLLSTULOCELL

WRFD-160213

TurboICPhase2

Meaning: Indicates whether the cell supports Turbo ICPhase2.GUI Value Range: FALSE(FALSE), TRUE(TRUE)Unit: NoneActual Value Range: FALSE, TRUEDefault Value: FALSE(FALSE)

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Parameter ID

NE MMLCommand

FeatureID

FeatureName

Description

INTERBOARDICSW


SETNODEBICMODELSTNODEBICMODE

WRFD-010691WRFD-150206WRFD-140202WRFD-160201

HSUPAULInterferenceCancellationTurboICControlChannelParallelInterferenceCancellation(Phase2)ControlChannelParallelInterferenceCancellation(Phase3)

Meaning: Indicates the inter-board cancellation gainswitch between the WBBPa/WBBPb board and a boardsupporting IC. This parameter is valid when featuresrelated to inter-board cancellation take effect. Thefeatures related to inter-board cancellation includeHSUPA IC, Turbo IC, CCPIC Phase2 and CCPICPhase3.GUI Value Range: FULL_IC(All board can share ICgain), PART_IC(Old board can not share IC gain)Unit: NoneActual Value Range: FULL_IC, PART_ICDefault Value: PART_IC(Old board can not share ICgain)

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5 CountersThere are no specific counters associated with this feature.

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6 GlossaryFor the acronyms, abbreviations, terms, and definitions, see Glossary.

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7 Reference Documents1. Control Channel Interference Cancellation Feature Parameter Description2. HSUPA Data Channel Interference Cancellation Feature Parameter Description3. Uplink CoMP Feature Parameter Description

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Contents1 About This Document1.1 Scope1.2 Intended Audience1.3 Change History

2 Overview2.1 Background2.2 Introduction2.3 Benefits

3 Technical Description3.1 Multiuser Detection3.2 Interference Cancellation Techniques3.2.1 Demodulation-based IC and Decoding-based IC3.2.2 Parallel and Successive Interference Cancellation

3.3 Huawei Interference Cancellation Techniques3.3.1 Channel Types3.3.2 Control Channel Interference Cancellation3.3.3 Data Channel Interference Cancellation3.3.4 Inter-Board IC and Intra-Board IC

4 Parameters5 Counters6 Glossary7 Reference Documents