Huawei eRAN3.0 ANR Feature Introduction

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Huawei eRAN3.0ANR Feature Introduction


Objectives

Upon completion of this course, you will be able to:

Describe the basic conceptions of ANR

Describe the principle of intra-RAT ANR

Describe the principle of inter-RAT ANR

Performance manual neighbor relation management

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Contents

1. ANR Overview

2. Intra-RAT ANR Management

3. Inter-RAT ANR Management

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Contents

1. ANR Overview



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36.300

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The Automatic Neighbour Relation (ANR)

function resides in the eNB and manages the

conceptual Neighbour Relation Table (NRT).

Located within ANR, the Neighbour Detection

Function finds new neighbours and adds them

to the NRT. ANR also contains the Neighbour

Removal Function which removes outdated

NRs.

Neighbour Detection Function

Internal Iinformation

RRC

Mrmnt reports

Mrmnt requests

Add

/Upd

ate

Nei

ghbo

r R

elat

ions

NR

rep

ort

ANR function

eNB

O&M

NRadd

NRTManagemnt

Function

NeighbourRemovalFunction

NRremove

NRupdate

Neighbor Relation Table

1

2

TCI

3

No Remove

TCI#1

TCI#1

No HO No X2

O&M controlledNeighbour Relation Attributes

Neighbour Relation

NR

TCl#1

Cell A Phy-CID=3 Global-CID =17

Cell B Phy-CID=5 Global-CID =19

1) report(Phy-CID=5, strong signal)

2) Report Global-CID Request (Target Phy-CID=5)

2b) Read BCCH()

3) Report Global-CID=19


What is ANR?

ANR ( Automatic Neighbor Relation)

ANR is a self-optimization function that belong to SON

It automatically maintains the integrity and effectiveness of

neighbor cell lists to increase handover success rates and

improve network performance

ANR automatically detects missing neighboring cells, PCI

collisions, abnormal neighboring cell coverage and analyzes

neighbor relations.

Missing Neighboring Cells

Optimized by ANR

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PCI collision

Abnormal Neighboring Cell Coverage


ANR Classification

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Based on neighbor relations, ANR is classified into intra-RAT ANR

and inter-RAT ANR.

Based on the methods of measuring neighboring cells, ANR is

classified into event-triggered ANR and fast ANR (also known as

periodic ANR).


Basic Conceptions - NCL

NCL(Neighbor Cell List) contains the information

about the external neighboring cells of a serving cell.

NCLs are classified into intra-RAT NCLs, inter-RAT

NCLs. Each eNodeB has an intra-RAT NCL and inter-

RAT NCLs.

NCL includes the E-UTRAN Cell Global Identifiers(or

CGIs for inter-RAT), PLMN,PCIs, TAC, eNodeB ID and

E-UTRA Absolute Radio Frequency Channel Numbers

(EARFCNs) of the neighboring cells.

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Basic Conceptions - NRT

NRT(Neighbor Relations Table) contains the

information about the neighbor relations between

the source cell and its neighboring cells. NRTs are

classified into intra-RAT NRTs and inter-RAT NRTs.

Each cell has an intra-RAT NRT, inter-RAT NRTs.

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SN LCI Local Cell

PLMN

Target Cell

PLMN

TCI No Remove No HO

1 LCI#1 46001 46001 TCI#1 TRUE TRUE

2 LCI#1 46001 46001 TCI#2 FALSE FALSE

3 LCI#1 46001 46001 TCI#3 TRUE TRUE


Basic Conceptions - NRT The NRT contains the following information, which can be updated

automatically or manually: SN: denotes the serial number of a neighbor relation. LCI: Local cell ID, identifies the source cell of a neighbor relation. Local Cell PLMN:The Public Land Mobile Network which Local Cell belongs to. TCI: identifies the target cell of a neighbor relation. This attribute is defined by the

ECGI of the target cell. Target Cell PLMN:The Public Land Mobile Network which Target Cell belongs to. NO Remove: indicates whether a neighbor relation can be removed from the NRT by

ANR. By default, the NO Remove attribute of a neighbor relation is set to FALSE. If the NO Remove attribute of a neighbor relation is TRUE, this neighbor relation

cannot be removed from the NRT. If the NO Remove attribute of a neighbor relation is FALSE, this neighbor relation

can be removed from the NRT. NO HO: indicates whether this neighbor relation can be used for a handover. By

default, the NO HO attribute of a neighbor relation is set to FALSE. If the NO HO attribute of a neighbor relation is TRUE, this neighbor relation

cannot be used for a handover. If the NO HO attribute of a neighbor relation is FALSE, this neighbor relation can

be used for a handover.Page10


HO Black List and HO White List

HO Black list

No remove = TrueNo HO= True

HO White list

No remove = TrueNo HO= False

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No remove: cannot be removed automatically from the

NRT by ANR


Abnormal Neighbor Cell

The coverage of neighboring cells may be abnormal in any

of the following scenarios:

The antenna tilt or orientation changes because of improper

installation or a natural phenomenon such as strong wind

In mountains, the signals of the umbrella cell cover lower cells

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Expected coverageActual coverage

Deteced by ANR

Cell1 Cell2


Contents

1. ANR Overview



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Contents


2.1 Event- Triggered ANR

2.2 Fast ANR

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Event-Triggered ANR Overview

Main function of event-triggered ANR

Missing neighbor detection

Neighbor relations maintenance

Abnormal neighbor coverage detection

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Detecting

missing neighbor

Result output

NRT Neighbor relations

maintenance

Detecting Abnormal NeighborCoverage


MML to Switch on the Intra-RAT ANR

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Intra-RAT event-triggered ANR is controlled by the IntraRatEventAnrSwitch check box under the AnrSwitch parameter. The intra-RAT event-triggered ANR function is activated when the IntraRatEventAnrSwitch check box is selected.


Missing Neighbor Detection – By UE Measurement

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Cell PCI ECGI

Cell A 3 17

Cell B 5 19


Missing Neighbor Detection – By UE Measurement The procedure is described as follows:

1. The source eNodeB delivers the inter-frequency measurement configuration to

the UE and requests the UE to measure inter-frequency neighboring cells that

meet the measurement configuration.

Note: The UE performs intra-frequency neighbor cell measurements by

default. And inter-frequency neighbor cell measurement is triggered by A2

event.

2. The UE detects that the PCI of cell B that meets the measurement

configuration and reports it to the source eNodeB. Then, the source eNodeB

checks whether the intra-RAT NCL of cell A includes the EARFCN-PCI

combination of cell B. If yes, the procedure ends. If no, the following steps

continue.

3. The source eNodeB instructs the UE, using the newly discovered PCI as a

parameter, to read the ECGI, Tracking Area Code (TAC), and Public Land Mobile

Network (PLMN) ID list of cell B.

4. The source eNodeB schedules appropriate idle periods to allow the UE to read

the ECGI, TAC, and PLMN ID list of cell B over the broadcast channel (BCH).

5. The UE reports the detected ECGI, TAC, and PLMN ID list of cell B to the source

eNodeB. Page18


Missing Neighbor Detection – By UE History Information

In this case, Cell B exist in the NCL/NRT of Cell A, but there is no Cell A info in NCL/NRT of Cell B

Source Cell (Cell A)

Target Cell (Cell B)

M2000

2.Handover response

1.Handover request

3.Report cell A ECGI

Information query

4.Send info to cell B

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Missing Neighbor Detection – By UE History Information UE history information is containing the previous cell information. This

information is contained in handover request message. Following is the

contents of information ECGI of last visit cell Type of last visit cell Duration of UE for camping on the cell

The above flow shows how to detect missing neighbor cell by using UE

history information1. The source eNodeB sends a Handover Request message to the target eNodeB

including UE history information

2. The target eNodeB obtains the UE history information from the message. If the

target eNodeB detects that the ECGI of the last visited cell (that is, cell A, the

source cell) does not exist in the NCL of the target cell (cell B), cell A is

considered as a new neighboring cell of cell B.

3. The target eNodeB reports the ECGI of cell A to the M2000.

4. The M2000 queries the PCI, TAC, and PLMN ID list of cell A based on the

reported ECGI and sends the parameters to the target eNodeB.

The target eNodeB adds cell A to the intra-RAT NCL of cell B and adds the

neighbor relation to the intra-RAT NRT.Page20


Neighbor Relations Maintenance—NRT Maintenance

Remaining in NRT

Period calculation

Adjust the list of NRT

Result analysis Is removed from NRT

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Neighbor Relations Maintenance—NCL Maintenance

Period calculation

Adjust the list of NCL

Result analysis Is removed from the NCL

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Is kept in NCL


Contents


2.1 Event- Triggered ANR

2.2 Fast ANR

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Fast ANR

In order to reduces the impact of event-triggered UE

measurements on handover performance, system

supports period measurement.

Period measurement report

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Fast ANR Restriction

Periodic UE measurements have a negative impact

on the uplink throughput of the network. Therefore,

intra-RAT fast ANR restricts the number of concurrent

UEs involved in periodic measurements by several

mechanisms.

When current UE number involved in fast ANR achieve the threshold, eNodeB stop selecting new UE for fast ANRWhen the specific UE measurements achieve the threshold, the UE stop fast ANR report

When the total Ue number involved in fast ANR achieve the threshold in the certain period, the eNodeB will get into the state of monitoring or start a new FastAnr Period .


Related Parameters

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Contents

1. ANR Overview



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Event-Triggered ANR

Inter-RAT event-triggered ANR support GERAN and

UTRAN system, controlled by the

GeranEventAnrSwitch and

UtranEventAnrSwitch check boxes under the

AnrSwitch parameter

CDMA doesn’t support event-triggered ANR

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Flow of Event-Triggered ANR

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Flow of Event-Triggered ANR The procedure is described as follows:

The source eNodeB delivers the inter-RAT measurement configuration

(including target RATs and Frequencys) to the UE, activates the measurement

gap mode, and instructs the UE to measure the neighboring cells that meet

the measurement configuration. It is triggered by A2 event.

The UE detects that the PCI of cell B meets the measurement configuration

and reports it to cell A. If the source eNodeB detects that its NCL does not

include the Frequency-PCI combination of cell B, it proceeds to the following

step.

The source eNodeB instructs the UE, using the newly discovered PSC(For

UTRAN) as a parameter, to read other parameters of cell B.

The source eNodeB schedules appropriate measurement gaps to allow the UE

to read the CGI and other parameters of cell B over the BCH.

The UE reports the source eNodeB the CGI and other parameters of cell B. The

source eNodeB adds the newly detected neighboring cell to its inter-RAT NCL

and adds the neighbor relation to the inter-RAT NRT.Page30


Fast ANR

Inter-RAT fast ANR has similar processing as intra-

RAT fast ANR.

It is controlled by the GeranFastAnrSwitch,

UtranFastAnrSwitch, and CdmaFastAnrSwitch

check boxes under the AnrSwitch parameter.

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Related Parameters

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Summary

ANR is a self-optimization function that belong to SON.

Based on neighbor relations, ANR is classified into intra-

RAT ANR and inter-RAT ANR. Based on the methods of

measuring neighboring cells, ANR is classified into event-

triggered ANR and fast ANR (also known as periodic ANR).

ANR function includes automatic missing neighboring

cells detection, PCI conflict detection, abnormal

neighboring cell coverage query and analyzes neighbor

relations. With these functions, ANR automatically

maintains the integrity and effectiveness of neighbor cell

lists to increase handover success rates and improve

network performance.Page33

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Huawei eRAN3.0 ANR Feature Introduction

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