1 lte eran6.0 idle mode issue1.00

8/12/2019 1 Lte Eran6.0 Idle Mode Issue1.00

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Copyright 2013 Huawei Technologies Co., Ltd. All rights reserved.

LTE eRAN6.0 Idle Mode


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Contents

1. UE Idle Mode Overview

2. PLMN Selection Procedure

3. Cell Search & Selection Procedure

4. Cell Reselection Procedure

5. Cell Barring and Reservation

6. Paging Procedure

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General UE Initial Procedure

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BCH decoding (MIB/SIBs)

PSS/SSS decoding

UE eNodeB MME

PLMN register

1.UE selfPLMN

selection

2.Frequencyselection

WhenPower on

UE

3. Cell search (ObtainPCI and get DL sync

If no valid SS, go to step 2

4. Obtain the systemmessage

5. Cell selection

RS measurement

If fails, go to step 26. Initial

Attachment(PLMNregistion)

If fails, go to step 1RRC connected mode

Initial attachement procedure

UE inactive timerexpires

RRC idle modeStart cell reselection

procedure


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UE Idle Mode Behaviors

A UE that is powered on but does not have an RRC connection tothe radio network is considered to be in idle mode

Idle mode management can increase the access success rate,improve the quality of service, and ensure that UEs camp on cells

with good RX signal levels and qualitiesIn the idle mode, UE can perform:

PLMN selection

Cell search & selection

Cell reselection

TA update

Periodic paging monitoring

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RRC Status Transition

LTE is capable with always online functions, after UE initialattach, the default RRC status is active.

There is a timer(UE inactive timer) in eNodeB to control

active to idle transition, when a UE has neither received norsent data for a duration exceeding this period of time, the

eNodeB releases the radio resources for the UE.

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Contents





5. Cell Barring & Reservation

6. Paging Procedure

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PLMN Classification

Home PLMN: the PLMN which the user is subscribed, thereis only one PLMN

The Equivalent Home PLMN (EHPLMN): It is a list of

PLMNs that can provide the same service as home PLMN.This PLMN is recoded in USIM

Visited PLMN: The Visited PLMN (VPLMN) is the PLMN

where the UE is located.

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PLMN Selection Introduction

PLMN selection includes two stages

UE self-PLMN selection

Automatic selection mode: UE will automatic select one suitable

PLMN based on the priority

Manual selection mode: UE search all the valid PLMN in the

network, and the user could select one of them

PLMN register: After UE select one PLMN, it will register it to

EPC during attachment flow, if this procedure is failure, UEgoes back to self PLMN selection procedure. If all PLMN

registration fails, UE enters the limited service state

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PLMN Selection Procedure

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Priority of Automatic PLMN Selection

Scenario 1: Initial PLMN selection, with no RPLMN information

UE AS initiate cell search, read all the PLMN from SIB1, and

report it to UE NAS

UE NAS will select one of them based on the predefined priority

Scenario 2: If last VPLMN exists in USIM, UE will select this

PLMN and start cell search with last frequency, if no valid cell was

found all PLMN registration fails, then UE goes back to initial

PLMN selection

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Contents





5. Cell Barring & Reservation Operation

6. Paging Procedure

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Cell Search Procedure

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Slot synchronization

Frame synchronization andPCI identification

System message receptionand RS measurement


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SS Search

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Subframe

Correlation

PSS 0

PSS1

PSS 2

Device can identify Cell ID andframe timing


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System Message Reception

After SS decoding, UE turns to BCCH logic channelacquires all the necessary information for the further

network access and operation.

Classification of system messageMIB(Master Info Block): There is only one MIB, is carried by

PBCH

SIB: Up to 13 SIBs can be delivered by PDSCH, SIB1 and

SIB2 are mandatory

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MIB Introduction

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MIB (Master Information Block)DL-Bandwidth (6, 15, 25, 50, 75, 100)PHICH Configuration (Ng and Normal/Extended)System Frame Number One frame (10 ms)

: BCH

: PrimarySynchronizationSignal

: SecondarySynchronizationSignal

1st slot 2 nd slot


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SIB Information

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Type Contents

SIB1 Cell selection and camp related parameters SI period for otherSIBs.

SI

SIB2 Basic radio parametersSIB3 Common parameters for cell reselection

SIB4Intra-frequency neighbor list; Neighbor reselection parameters;Neighbor black list

SIB5

Inter-frequency list and corresponding cell reselection

parametersInter-frequency neighbor list and corresponding cell reselectionparametersInter-frequency black list

SIB6 UMTS frequency list and neighbor list

SIB7 GSM frequency list and neighbor list

SIB8 CDMA2000 frequency list and neighbor list

SIB9 Home eNodeB informationSIB10 ETWS primary notificationSIB11 ETWS secondary notification SIB12 CMAS primary notification SIB13 CMAS secondary notification


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SIB Mapping & Delivery

SIBs are mapping on PDSCH: SIB1 and SIB2 aremandatory, and others are optional.

Period of SIBs

SIB1: 80ms

From SIB2 to SIB8, SIB10 and SIB11: It is a flexible period,

with 80,160,320,1280,2560 and 5120ms .

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SI Mapping Configuration

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Initial System Message ReceptionScenario

A UE reads the first SI messages in the following scenarios:

After cell search

After UE reselect a new cell

After handover in a new cell

UE returns to coverage area from non-coverage area

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System Message Update Scenario

After obtaining the SI message properly, the UE does notread the message repeatedly. It rereads and updates the SI

message only in the following scenarios:

The UE receives the SI message change notification in thepaging message

The UE receives the SI message 3 hours after receiving an SI

message

The UE receives the ETWS message broadcast notification in

the paging message transmitted from the eNodeB.

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System Information Update Procedure

eNodeB pages the UE firstly , then transmits the updated systeminformation in next modification period

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RS Measurement

After receiving all necessary system messages, UE start tomeasure RS for cell selection and reselection

The following quantity should be evaluated for UE idle

status measurementRSRP: RS receiving power

RSRQ: RS receiving quality

RSRQ= N *RSRP/RSSI (N indicates the number of RS RE inone sysmble)

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Cell Selection Criteria

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Criteria for cell selectionSrxlev > 0 and Squal > 0

Srxlev = Qrxlevmeas - (Qrxlevmin + Qrxlevminoffset) PcompensationSqual = Qqualmeas (Qqualmin + Qqualminoffset)


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Cell Selection Configuration

MOD CELLSEL

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Cell Selection Configuration ( Cont .)

MOD CELLRESEL

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Contents






6. Paging Procedure

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Cell Reselection Introduction

The signal strength of both serving cell and neighboringcells varies with the movement of a UE and so the UE

needs to select the most suitable cell to camp on. This

process is called cell reselection which is considered as UE

mobility management in idle mode

Cell reselection process:

Measurement start criteria

Cell reselection criteria

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Frequency Priority Handling forMeasurement

For intra-frequency neighbor measurement: The priority isthe same between source cell and neighbor cell, so UE will

ignore it.

For inter-frequency and inter-RAT neighbor measurement:UE will take the priority between source cell and neighbor

cell for the measurement

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Priority Setting

The priorities of inter frequency and inter-RAT areclassified into two types:

Absolute priority

Static configuration

Dedicated priority

Temporarily configured by RRC for some the

dedicated UE.

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Absolute Priority Configuration Serving Cell

MOD CELLRESEL

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Absolute Priority Configuration EUTRAN Target Cell

MOD EUTRANINTERNFREQ

Note: if priority indicator is set Not CFG , then UE doesnt

implement cell reselection to the target frequency

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Absolute Priority Configuration UTRAN/GERAN Target Cell

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GSM

UMTS


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Dedicated Priority For Flexible UserSteering

If flexible user steering feature is activated, we can set thededicated priority based on subscriber profile ID, and valid

duration is 180 min.

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Dedicated Priority For RAN Sharing

You can configure dedicated priority for RAN sharing witheither of following solution

Solution 1: Set dedicated priority for UE select different PLMN

operators. This priority will be shared by all operators in the

serving cell.

Solution 2: Set dedicated priority for all operators in the

serving cell with a specific frequency. This priority is individual

for each operators in serving cell

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Solution 1 Introduction

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Operator 1

Operator 2

Operator 3

Source cellTarget cell


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Relevant Configuration

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Solution 2 Introduction

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Operator 1

Operator 2

Operator 3

Source cellSpecific

Target cell


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Relevant Configuration

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Intra-Frequency Measurement Criteria

If the intra frequency measurement triggering threshold isnot configured, the UE always performs intra frequency

measurements.

If the intra frequency measurement triggering threshold isconfigured:

Srxlev > SIntraSearch and Squal > SIntraSearchQ the UE

dose not perform intra frequency measurement

Srxlev SintraSearch or Squal SIntraSearchQ , the UE

perform intra frequency measurement

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Inter Frequency/RAT MeasurementCriteria

For the neighbors with higher priorityThe UE always perform inter frequency /RAT measurement

For the neighbor with lower or equal priority

If the threshold is not configured, the UE always perform interfrequency/RAT measurement

If the threshold is configured :

When Srxlev > SNonIntraSearch and Squal > SNonIntraSearchQ,

UE does not perform inter frequency/RAT measurement

When Srxlev SnonIntraSearch or Squal SNonIntraSearchQ UE

perform inter frequency /RAT measurement

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Threshold Configuration Rx Level

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Threshold Configuration Rx Quality

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Black List

During cell reselection, UEs are not allowed to measure orreselect the blacklisted cells of the serving cell.

Intra-frequency blacklist : Broadcast in SIB4

Inter-frequency blacklist: Broadcast in SIB5

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Intra-Frequency Cell ReselectionConfiguration -Hysteresis

MOD CELLRESEL

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Intra-Frequency Cell ReselectionConfiguration - Cell Offset

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High Priority Cell Reselection Criteria

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Neighbor cell

Criteria for Rx quality based (only for LTE&UMTS) :Srxlev = Qqualmeas Qqualmin> ThreshXHighQ

No need consider

serving cell

Criteria for Rx level based (For all system) :Squal = Qqua lmeas (Qqualmin + Pcompensation) > ThreshXHigh


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Low Priority Cell Reselection Criteria

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Serving cell Neighbor cell

Criteria ba sed on Rx quality ( only for LTE & UMTS)Squal_S < ThrshServLo w Q andSqual_N > ThreshXLow

Both serving cell andneighbor cell should beconsidered

Criteria bas ed on Rx level (fo r all system)Squal_S < ThrshServLo w Q andSqual_N > ThreshXLow
http://d/LTE/eRAN3.0/lte/para/CellResel-ThrshServLowQ.htmlhttp://d/LTE/eRAN3.0/lte/para/EutranInterNFreq-ThreshXlow.htmlhttp://d/LTE/eRAN3.0/lte/para/CellResel-ThrshServLowQ.htmlhttp://d/LTE/eRAN3.0/lte/para/EutranInterNFreq-ThreshXlow.htmlhttp://d/LTE/eRAN3.0/lte/para/EutranInterNFreq-ThreshXlow.htmlhttp://d/LTE/eRAN3.0/lte/para/CellResel-ThrshServLowQ.htmlhttp://d/LTE/eRAN3.0/lte/para/EutranInterNFreq-ThreshXlow.htmlhttp://d/LTE/eRAN3.0/lte/para/CellResel-ThrshServLowQ.html


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Contents






6. Paging Procedure

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Cell Barring & Reservation

Cell barring and reservation control are two mechanisms foroperators to control their networks.

It is only used to control the cell selection and reselection for

idle UE

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Relevant UE Behavior

If a cell is neither barred nor reserved for operator use, UEscan consider this cell as a candidate during cell selection

and reselection procedures.

If a cell is not barred but is reserved for operator use, UEstreat this cell during cell selection and reselection

procedures as follows:

If UEs of access class 11 or 15 camp on their HPLMN or an

EHPLMN, the UEs can treat this cell as a candidate.

Otherwise, UEs treat this cell as a barred cell

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Relevant UE Behavior ( Cont .)

If a cell is barred, UEs behave as follows during cellselection and reselection procedures:

The UEs cannot select or reselect this cell

When intraFreqReselection in the SIB1 indicates that intra-frequency reselection is allowed, the UEs may select another

cell on the same frequency if reselection criteria are fulfilled.

Otherwise, UE cant reselect the other cell.

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6. Paging Procedure

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Trigger of Paging

Triggered by MMEMME initiates a paging message according to the TAL

information in the message, the eNodeB transmits the paging

message over the PCCH to the UE in all the cells belonging to

the TAs in the TAL

Triggered by eNodeB

When the SI message changes, the eNodeB transmits a

paging message to notify all the UEs in the EMM-

REGISTERED state in the cell and transmits the updated SI

message in the next SI message modification period

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Paging Mechanism

PF: Paging frame, in one paging cycle , there could be many

paging frames, depends on NB configuration

PO: Paging occasion, is the paging subframe for each UE, the PFand PO is assigned by eNodeB using hash algorithm based on

IMSI

The PO number = NB x TPage57


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Paging Channel Configuration

MOD PCCHCFG

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Summary

What is UE behaviors in idle mode?What is priority for PLMN selection?

How to perform cell search?

What is criteria for cell selection?

And how about cell selection?

How to configure paging channel capacity?

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1 lte eran6.0 idle mode issue1.00

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