pucch overdimensioning.pdf

PUCCH Overdimensioning

USER DESCRIPTION

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Copyright

Ericsson AB 2011. All rights reserved. No part of this document may bereproduced in any form without the written permission of the copyright owner.

Disclaimer

The contents of this document are subject to revision without notice due tocontinued progress in methodology, design and manufacturing. Ericsson shallhave no liability for any error or damage of any kind resulting from the useof this document.

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Contents

Contents

1 Introduction 1

1.1 Basic Characteristics 1

1.2 Dependencies and Associated Features 1

2 Feature Overview 3

2.1 Benefits 3

2.2 Impacts 3

2.3 Further Information 3

3 Feature Operation Details 5

3.1 PUCCH Frequency Region 5

3.2 Interaction with A-MPR 6

3.3 Network Configuration Requirements 6

3.4 High Level Flow 7

3.5 Process Steps 7

4 Parameters 9

4.1 Introduced Parameters 9

4.2 Affected Parameters 9

5 Network Impact 11

5.1 Throughput 11

5.2 Coverage 11

6 Associated Features 13

6.1 Prerequisite Features 13

6.2 Affected Features 13

6.3 Affected System Functions 13

6.4 Related Features 13

7 Performance 15

7.1 KPIs 15

7.2 Counters and Events 15

8 O&M Information 17

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Introduction

1 Introduction

This document describes the PUCCH Overdimensioning feature.

The information in this document reflects the feature at the time of its release.

The main characteristics of the feature are presented below.

1.1 Basic Characteristics

Feature identity:FAJ 221 0990, PUCCH Overdimensioning

This feature has replaced:N/A

Connected to: N/A

1.2 Dependencies and Associated Features

This section lists related features. For more detailed information, see Section 6on page 13.

This feature requires the following RAN features to be active:

No prerequisite features are required.

This feature may affect the following RAN features:

Scheduler, part of LTE Basic

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Feature Overview

2 Feature Overview

This section describes the benefits and impacts of the PUCCHOverdimensioning feature in the LTE RAN.

PUCCH Overdimensioning is a feature that is used to change the frequencyposition of the Physical Uplink Control Channel (PUCCH).

2.1 Benefits

In specific deployment scenarios where Additional Maximum Power Reduction(A-MPR) restrictions apply, the User Equipment (UE) is allowed to reduce theoutput power at the band edges to reduce interference in neighboring frequencybands. Since the PUCCH is located at the band edges, its performance will bedegraded. The PUCCH Overdimensioning feature allows the PUCCH region tobe moved to another part of the Uplink (UL) system bandwidth where A-MPRrestrictions are less severe. In this way, PUCCH performance can be secured.

In the reverse scenario, where the transmission in neighboring frequencybands degrades LTE system performance at the band edges, the PUCCHOverdimensioning feature can be used to move the PUCCH region to frequencyregions with less interference from the neighboring bands.

It is only recommended to use the PUCCH Overdimensioning feature in specificdeployment scenarios as described above. Under normal conditions, no gainis expected from the feature.

2.2 Impacts

The feature affects system throughput in specific deployment scenarios withinterference from adjacent frequency bands or in deployment scenarios withadditional requirements on spectral emission.

2.3 Further Information

Further information about this feature and related topics can be found in thefollowing documentation:

Scheduler

Power Control

System and Node Description

(More information can be found in the section regarding A-MPR.)

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3GPP TS36.101, 3GPP TS 36.211, 3GPP TS 36.213, 3GPP TS 36.331

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Feature Operation Details

3 Feature Operation Details

This section describes the PUCCH Overdimensioning feature in more detail,including network configuration requirements and operation flows.

3.1 PUCCH Frequency Region

The PUCCHs are by default located at the lower and upper band edges of theUL system bandwidth as shown in Figure 1.

L0000420A

UL system bandwidth

UL system bandavailable for PUSCH

ActivePUCCH

ActivePUCCH

Figure 1 UL Band Configuration without PUCCH Overdimensioning

The PUCCH Overdimensioning feature increases the number of resourceblocks configured for periodic Channel Quality Indicators (CQI) on PUCCH, butthis is done without assigning any CQI in this region. In this way, no PUCCHtransmissions will be allocated in the overdimensioned PUCCH region closestto the band edges. In this context, this region is referred to as the InactivePUCCH region, while the region closer to the band center that actually carriesPUCCH signaling, that is, CQI, Scheduling Request (SR), and HARQ-ACK, isreferred to as the Active PUCCH region as shown in Figure 2.

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L0000421A

UL system bandwidth

UL system bandsavailable for PUSCH

InactivePUCCH

InactivePUCCH

ActivePUCCH

pucchOverdimensioning

ActivePUCCH

Figure 2 UL Band Configuration with PUCCH Overdimensioning

Since no PUCCH transmissions are performed in the Inactive PUCCH region,this feature can be used to secure PUCCH performance in deploymentscenarios where the UE is allowed to reduce output power at the band edges.

The Inactive PUCCH region is available for scheduling of Physical UplinkShared Channel (PUSCH).

3.2 Interaction with A-MPR

The A-MPR function enables the operator to control the UE out-of-bandinterference in some specific frequency bands by broadcasting NetworkSignalling (NS) values in the cell in accordance with 3GPP TS 36.101. TheA-MPR command then allows the UE to reduce the output power to fulfill theadditional spectrum emission requirements in these bands.

The networkSignallingValue parameter defines how much powerreduction the UE is allowed to use. By default, no power reduction is allowed.

The network signaling value for Band 13 must be used together with thePUCCH Overdimensioning feature. The A-MPR specification for Band 13allows the UE to reduce power for PUCCH transmissions at the band edgesup to 12 dB. Without the use of PUCCH Overdimensioning, this would havesignificant impact on PUCCH performance and UL throughput and coverage.

3.3 Network Configuration Requirements

PUCCH Overdimensioning is a licensed feature in the LTE system. A license isrequired to activate it.

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Feature Operation Details

3.4 High Level Flow

The PUCCH Overdimensioning feature is a stage in the UL L1/L2 controlchannel configuration. More information can be found in 3GPP TS 36.331,3GPP TS 36.211 and 3GPP TS 36.213.

3.5 Process Steps

This section describes the main process steps for the feature flow.

3.5.1 Configuration of PUCCH Overdimensioning

The operator sets the required number of resource blocks that must be used forthe PUCCH Overdimensioning feature at each edge of the system bandwidth.This is done using the pucchOverdimensioning parameter. By default,this parameter is set to zero.

If required by the deployment scenario, related parameters, such as thefrequency band dependent A-MPR parameter networkSignallingValue,must be set by the operator.

When the A-MPR setting for Band 13 is used, by setting the networkSignallingValue parameter to NS_07, the pucchOverdimensioning parametervalue must be set to 13.

3.5.2 Configuration of UL Control Channels

The PUCCH Overdimensioning feature value, pucchOverdimensioning,together with the number of CQI resources configured on PUCCH,noOfPucchCqiUsers, is used by the RBS to determine the numberof resource blocks available for CQI. This number is broadcast to allusers in the cell. No CQI resources are, however, assigned in thepucchOverdimensioning resource blocks closest to each band edgemaking them available for scheduling of PUSCH.

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Parameters

4 Parameters

This section describes the parameters introduced by the PUCCHOverdimensioning feature and parameters affected by activating the feature.

4.1 Introduced Parameters

Table 1 describes the parameters introduced by the feature.

Table 1 Introduced Parameters

Parameter Description

pucchOverdimensioning Specifies the number of resource blocks at each band edgeoutside of the active PUCCH region that are available forscheduling of PUSCH

4.2 Affected Parameters

No parameters are affected by the implementation of this feature.

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Network Impact

5 Network Impact

This section describes how the PUCCH Overdimensioning feature impactsthe network functions and capabilities.

5.1 Throughput

In specific deployment scenarios, for example for Band 13 where tougher UEspectral emission requirements apply, the PUCCH Overdimensioning featurewill improve both the peak and the cell throughput, compared to a systemwithout the PUCCH Overdimensioning feature. This is due to the improvedperformance of the CQI and SR signaling on PUCCH.

In systems where no additional adjacent band spectral requirements orinterferences requirements are present, the peak throughput is expected todecrease due to the UL band fragmentation.

5.2 Coverage

In specific deployment scenarios, for example for Band 13 where tougherUE spectral emission requirements apply, the PUCCH Overdimensioningfeature will increase the coverage, compared to a system without the PUCCHOverdimensioning feature. This is due to the improved performance of the CQIand SR signaling on PUCCH.

In systems where no additional adjacent band spectral requirements orinterferences requirements are present, no coverage improvements can beexpected.

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Associated Features

6 Associated Features

This section describes how the PUCCH Overdimensioning feature affects otherfeatures and functions.

6.1 Prerequisite Features

There are no prerequisite features for this feature.

6.2 Affected Features

The following features are affected by PUCCH Overdimensioning feature:

FAJ 121 0484, Scheduler part of LTE BasicWhen the PUCCH Overdimensioning feature is used,UL system bandwidth becomes fragmented since thePUCCH region is not placed at the band edges. Thiswill impact scheduling efficiency.

6.3 Affected System Functions

The following functions are affected by the PUCCH Overdimensioning feature:

A-MPR The A-MPR configurations that allow for a frequencydependent UE power back-off will exhibit improvedperformance when the PUCCH Overdimensioningfeature is matched to the frequency characteristics ofthe A-MPR configuration.

6.4 Related Features

There are no other features related to his feature.

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Performance

7 Performance

This section describes performance indicators, counters, and events associatedwith the PUCCH Overdimensioning feature.

7.1 KPIs

The following are the main Key Performance Indicators (KPIs) associated withthis feature:

DL Throughput Data volume per time unit in the Downlink (DL)

UL Throughput Data volume per time unit in the UL

7.2 Counters and Events

The important counters and events associated with the PUCCHOverdimensioning feature are listed in Table 2.

Table 2 Counters and Events

Counter Description

pmRadioThpVolDl Total successfully transferred data volume on MAC levelin the DL

pmRadioThpVolUl Total successfully transferred data volume on MAC levelin the UL

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O&M Information

8 O&M Information

This section provides Operation and Maintenance (O&M) information for thePUCCH Overdimensioning feature.

Activating the PUCCH Overdimensioning feature requires that thecorresponding license is installed. See the document License Management formore information on handling licenses.

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toc1 Introduction1.1 Basic Characteristics1.2 Dependencies and Associated Features2 Feature Overview2.1 Benefits2.2 Impacts2.3 Further Information3 Feature Operation Details3.1 PUCCH Frequency Region3.2 Interaction with A-MPR3.3 Network Configuration Requirements3.4 High Level Flow3.5 Process Steps3.5.1 Configuration of PUCCH Overdimensioning3.5.2 Configuration of UL Control Channels4 Parameters4.1 Introduced Parameters4.2 Affected Parameters5 Network Impact5.1 Throughput5.2 Coverage6 Associated Features6.1 Prerequisite Features6.2 Affected Features6.3 Affected System Functions6.4 Related Features7 Performance7.1 KPIs7.2 Counters and Events8 O&M Information

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