Relative Priority Scheduling.pdf

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Relative Priority Scheduling

USER DESCRIPTION

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Copyright

Ericsson AB 2012. 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.

Trademark List

All trademarks mentioned herein are the property of their respective owners.These are shown in the document Trademark Information.

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Contents

Contents

1 Introduction 1

1.1 Basic Characteristics 1

1.2 Benefits 1

2 Feature Operation 3

2.1 Network Requirements 3

2.2 Feature Interworking 3

2.3 Uplink Relative Priority Scheduling Groups 4

2.4 Limitations 4

3 Parameters 7

3.1 Introduced Parameters 7

3.2 Affected Parameters 7

4 Network Impact 9

5 Associated Features and Affected Functions 11

5.1 Prerequisite Features 11

5.2 Affected Features 11

5.3 Related Features 11

5.4 Affected System Functions 11

6 Performance 13

6.1 KPIs 13

6.2 Counters 13

6.3 Events 14

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Introduction

1 Introduction

This document describes the Relative Priority Scheduling feature, its benefits,and how it impacts the LTE RAN.

1.1 Basic Characteristics

This section describes the basic characteristics of the feature.

Feature identity:FAJ 221 2037, Relative Priority Scheduling

Replaces: N/A

Dependencies

This feature requires the following RAN features to be active:

QoS-Aware Scheduler

Minimum Rate Proportional Fair Scheduler

This feature affects the following RAN features:

This feature affects no other features.

1.2 Benefits

This section describes the benefits of this feature.

RPS allows the operator to control the bit rate proportions that a servicesusing a specific QCI would get with respect to services using other QCIs.RPS modifies the PFS bit rate component. Since PFS also has channel radiocondition component, RPS provides the specified bit rate ratios only wheneither the radio conditions are ignored (PFS equal rate) or when all UEs havesimilar radio conditions. Otherwise the resulting bit rate proportions are onlypartially influenced by RPS based on the channel quality fraction (CQF) used.Specific CQF values are associated with different PFS flavors.

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Feature Operation

2 Feature Operation

This section describes the Relative Priority Scheduling feature in more detail,including network configuration requirements and operation flows.

2.1 Network Requirements

The following must be fulfilled at feature activation:

Minimum Rate Proportional Fair Scheduler feature license must be active.

QoS-Aware Scheduler feature license must be active.

Relative Priority Scheduling feature license must be active.

2.2 Feature Interworking

Relative Priority Scheduling interacts with the Minimum Rate Proportional FairScheduler feature.

2.2.1 Proportional Fair Scheduler Interworking

The following points highlight the Relative Priority Scheduling and ProportionalFair Scheduler interworking:

RPS refines the rate component of a specific PFS flavor.

RPS is used to differentiate services within a PFS flavor.

RPS distributes the bit rate of a group as per the proportions configuredper QCI.

The PFS allows us to balance fairness and cell throughput. PFS consists of twocomponents: the rate component and the channel component. The channelcomponent provides higher cell throughput by scheduling the UEs with betterRF. The rate component provides fairness by providing weights that reflect theaverage bit rates of services. When the scheduling decision uses only thiscomponent, all services get similar bit rates independent of channel conditions.

PFS supports five different flavors:

Equal Rate: 100% rate component.

Proportional Fair High: 60% rate component.

Proportional Fair Medium: 40% rate component.

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Proportional Fair Low: 20% rate component.

Max C/I: 100% channel component.

RPS can be combined with Equal Rate, Proportional Fair High, ProportionalFair Medium, and Proportional Fair Low. Since Max C/I does not have a ratecomponent, RPS does not impact it.

2.2.2 Minimum Rate Interworking

The minimum rate for uplink and downlink may be configured in a QCI thathas RPS enabled. In this case, the minimum rate is used in combination withthe RPS scheduling weights when a service bit rate is below its minimumrate configured.

In the case when two or more services are under their minimum rate, theservice with the higher combined relative priority and priority receives a higherscheduling weight.

2.3 Uplink Relative Priority Scheduling Groups

In the uplink direction, the QCI entries are grouped into logical channel groups(LCG). There are groups 1, 2, and 3 supported.

All the QCI entries in one LCG are condensed into a single RPS entry. Differentfields are combined to create the RPS entry. The RPS feature uses the LCG,the priority, and the minimum rate as follows:

The resulting minimum rate is the sum of all the uplink minimum rates ofall QCI entries in the LCG.

The resulting priority is the highest priority in the LCG.

The resulting algorithm strategy is that of the QCI with the highest priority.

The resulting relative priority is the highest relative priority of all the QCIentries in the LCG.

2.4 Limitations

The Relative Priority Scheduling feature has the following limitations:

Absolute priority override (APO) must be enabled for all or none of the QCIentries that belong to the same RPS group.

When enabling APO, all entries in an RPS group should use exactly thesame priority.

The relative priority is meaningful only within an RPS group.

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Feature Operation

The resulting bit rate for an RPS enabled service varies based on thefollowing factors:

The overall priority of the group.

The number of services in the RPS group.

The relative priority of the service.

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Parameters

3 Parameters

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

3.1 Introduced Parameters

Table 1 and Table 2 describe the parameters introduced by the feature.

Table 1 Introduced Parameters to QciProfileOperatorDefined MO by RelativePriority Scheduling

Parameter Description

relativePriority Defines the bit rate proportion of the QCI in relation to other QCIs.

This parameter can be configured with a valid range of 1..65535.

Default value is 1.

Note that this parameter is ignored if the feature is not enabled.

Table 2 Introduced Parameters to QciProfilePredefined MO by RelativePriority Scheduling

Parameter Description

relativePriority Defines the bit rate proportion of the QCI in relation to other QCIs.

This parameter can be configured with a valid range of 1..65535.

Default value is 1.

Note that this parameter is ignored if the feature is not enabled.

3.2 Affected Parameters

The implementation of this feature affects no parameters.

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Network Impact

4 Network Impact

The implementation of this feature has no impact on the network.

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Associated Features and Affected Functions

5 Associated Features and AffectedFunctions

This section describes how the Relative Priority Scheduling feature affectsother features and functions.

5.1 Prerequisite Features

This feature has no prerequisite features.

5.2 Affected Features

This feature affects no other feature.

5.3 Related Features

This feature is not related to any other feature.

5.4 Affected System Functions

This feature affects no system functions.

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Performance

6 Performance

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

6.1 KPIs

This feature has no associated Key Performance Indicators (KPIs).

6.2 Counters

Table 3 and Table 4 list the counters associated with the Relative PriorityScheduling feature.

Table 3 Counters, QciProfileOperatorDefined MO

Counter Description

pmActiveDrbDlSumQci The sum of number of DL active DRBs per QCI. A DL DRB isactive if there are buffered DL data for the DRB.

Associated events:

LOCAL_PER_BB_QCI_EVENT

pmPdcpVolDlDrbQci The total volume (PDCP SDU) that has been transferred(acknowledged by the UE) on Data Radio Bearers in the downlinkdirection per QCI.

Associated events:

LOCAL_PER_BB_RB_EVENT

LOCAL_PER_BB_RB_ON_CELL_QCI_LEVEL_EVENT

Table 4 Counters, QciProfileOperatorDefined MO

Counter Description

pmActiveDrbDlSumQci The sum of number of DL active DRBs per QCI. A DL DRB isactive if there are buffered DL data for the DRB.

Associated events:

LOCAL_PER_BB_QCI_EVENT

pmPdcpVolDlDrbQci The total volume (PDCP SDU) that has been transferred(acknowledged by the UE) on Data Radio Bearers in the downlinkdirection per QCI.

Associated events:

LOCAL_PER_BB_RB_EVENT

LOCAL_PER_BB_RB_ON_CELL_QCI_LEVEL_EVENT

More information about counters can be found in Managed Object Model RBS.

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6.3 Events

This events associated with this feature are listed in Section 6.2 on page 13.

More information about events can be found in PM Event List.

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toc1 Introduction1.1 Basic CharacteristicsDependencies1.2 Benefits2 Feature Operation2.1 Network Requirements2.2 Feature Interworking2.2.1 Proportional Fair Scheduler Interworking2.2.2 Minimum Rate Interworking2.3 Uplink Relative Priority Scheduling Groups2.4 Limitations3 Parameters3.1 Introduced Parameters3.2 Affected Parameters4 Network Impact5 Associated Features and Affected Functions5.1 Prerequisite Features5.2 Affected Features5.3 Related Features5.4 Affected System Functions6 Performance 6.1 KPIs6.2 Counters6.3 Events

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Relative Priority Scheduling.pdf