LTE Principle and Optimization - Phase2 - V2

LTE Principle and Optimization - Phase2

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Contents 

LTE Air Interface Physical Layer



LTE Cell acquisition and call setup



LTE Optimization



LTE KPI



LTE Feature

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Page 2

LTE Control Plane and User Plane

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Page 3

Radio Resource Control and Physical Layer

Parameter

Value

Channel bandwidth (MHz)

1.4

3

5

10

15

20

Allocated resource blocks

6

15

25

50

75

100

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Page 4

Logical Channels

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Page 5

LTE Release 8 Transport Channels

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Page 6

Downlink Physical Channels 









PBCH (Physical Broadcast Channel) : MIB (Master Information Block): DL-Bandwidt h (6, 15, 25, 50, 75, 100), PHICH Configuration (Ng and Normal/Extended), System Fra me Number(SFN) PCFICH (Physical Control Format Indicator Channel): Indicate OFDM symbol No ca n be used for PDCCH in 1 subframe. PDCCH (Physical Downlink Control Channel): UL/DL Scheduling information, UL po wer control information. PHICH (Physical Hybrid ARQ Indicator Channel): Feedback UL HARQ （ Hybrid Aut omatic Repeat Request ） ACK/NACK PDSCH (Physical Downlink Shared Channel)

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Uplink Physical Channels 

PRACH (Physical Random Access Channel)



PUCCH (Physical Uplink Control Channel)



PUSCH (Physical Uplink Shared Channel)

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Downlink Channel/ Uplink Channel Mappin g

 Downlink Channel HUAWEI TECHNOLOGIES CO., LTD.

 Uplink Channel Page 9

Contents 

LTE Air Interface Physical Layer



LTE Cell acquisition and call setup



LTE Optimization



LTE KPI



LTE Feature

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Page 10

Cell Search Procedure  PSS • Slot synchronization decodi ng  SSS • Frame synchronization decod • Obtain PCI ing  RS meas • RSRP/RSRQ urem ent  BCCH• MIB&SIB reception decod ing

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Synchronization Signals 

UEs perform synchronization and obtain PCIs using synchronization signals. 



PCI = 3 x Physical cell group ID(1)(

) + Cell ID (

)

(2) N ID N ID Synchronization signals are classified into the primary synchronization signal (PSS) and seco

ndary synchronization signal (SSS). 

Position in the time and frequency domains: 

Time domain: The PSS and SSS have different positions in the time domain for LTE FDD and T DD .

 

Frequency domain: The PSS and SSS are located in the middle of the frequency domain.

Sequence: 

PSS: Zadoff-Chu sequence



SSS: binary M-sequence

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Functions of PSS and SSS 

PSS 

 



Provides downlink synchronization information for UEs. Each PSS uses one of t he three ZC sequence types, and different ZC sequences are used for neighbori ng cells or sectors. These three ZC sequences are mapped to three different Cell IDs. Value range: 0,1,2

SSS 



Enables the UE to perform accurate synchronization and carries the physical ce ll group ID. Value range: 0~167

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Synchronization Channel: Cell Search and Downlink Synchr onization

PSS and SSS Location for FDD

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System Information Reception Process 





Why is the system information reception procedure required ?  The UE configures each layer’s parameters based on the parameter settings in the system infor mation received on the RRC layer before requesting network camping and admission. What information does the system information contain ?  One master information block (MIB) and 13 system information blocks (SIBs), including UE para meters set by the eNodeB.

How is the system information received ? 

The figure in the right shows procedure the system information is received.

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MIB Mapping & Delivery 

MIB introduction  



Carried by BCCH->BCH->PBCH Deliver very basic system information, including system frame number, DL b andwidth and PHICH configuration Broadcast period: 40ms

MIB block

Coded block

Radio frame

4 symbols 1 2 3 4 5 6 0 1 SSS PSS

2 3 4 5 6

PBCH

40ms PBCH TTI

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Page 16

SIB Mapping & Delivery 

Type

SIBs are mapping on BC

SIB1

CH->DL-SCH-> PDSCH: 



SIB1 and SIB2 are mandat ory, and others are option al.

SIB2 SIB3 SIB4

Period of SIBs  

SIB1: 80ms From SIB2 to SIB8, SIB10 and SIB11: It is a flexible p eriod, with 80,160,320,12 80,2560 and 5120ms.

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SIB5 SI SIB6 SIB7 SIB8 SIB9 SIB10 SIB11 SIB12 SIB13

Contents Cell selection and camp related parameters ， SI period for other SIBs Common physical channel configuration, UE timer, uplink bandwidth Common parameters for cell reselection Intra-frequency neighbor list; Neighbor reselection parameters; Neighbor black list Inter-frequency list and corresponding cell reselection parameters Inter-frequency neighbor list and corresponding cell reselection parameters Inter-frequency black list UMTS frequency list GSM frequency list CDMA2000 frequency list and neighbor list Home eNodeB information ETWS primary notification ETWS secondary notification CMAS notification MBMS control information Page 17

System Message Tracing Cases MIB

SIB1

SI MCC:460

MNC:01

Other SIBs excluding SIB1 and SIB2

TAC:21 Cell ID:7B8FF Cell is not barred

Intra-freq Reselection is allowed -128dBm, value range: INTEGER ( － 70 ～－ 22 ）

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Cell Selection and Camping

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Cell Selection Criteria

Criteria for cell selection: Srxlev and Squal

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Random Access Overview 

Purpose of random access  



UE randomly selects a preamble



Get uplink synchronization Acquire uplink scheduling resourc e

and sends it, conflict might occurs. (Case1, Case2 and Case5)

Scenarios:  

 





Case1: UE initial attach Case2: RRC reestablishment after RRC drops Case3: Handover to a new cell Case4: Downlink data arrival in eN odeB when UL out-of-sync occurs Case5: Uplink data detected by UE when UL out-of-sync occurs Case6: When UE trigger LCS(Locati on service)

Contention based



Before random access, eNodeB assigns a dedicated preamble to UE, so there is no conflict. (Case3, Case4 and Case6)

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Page 21

 Page21

General Procedure of Attachment  Signaling connection setup  (RRC and S1 dedicated signaling)  NAS procedure  (Authentication & NAS security)

 User plane setup  (Default EPS bearer setup)

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RRC Connection Establishment Process 

During RRC connection setup, SRB1 is set up.

 SRB 0 / CCCH / UL-SCH / PUSCH  SRB 0 / CCCH / DL-SCH / PDSCH  SRB 1 / DCCH / UL-SCH / PUSCH

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Relationship between Establishment Cause and NAS Proced ure NAS Procedure RRC Establishment Cause Attach

Attach 　

Detach

Detach

Tracking Area Update

TAU 　

Mobile Originating Signaling/Delay Tolerant Access/Emergency Mobile Originating Signaling Mobile Originating Signalling Delay Tolerant Access Emergency

User plane radio resources request

Mobile Originating Data/Delay Tolerant Access/Emergency

Service Request Uplink signaling resources request

Mobile Originating Data/Delay Tolerant Access/Emergency

Paging response for PS core network domain PDN connectivity request with cause ‘emergency’

Mobile Terminating Access

Mobile originating CS fallback

Mobile Originating Data/Delay Tolerant Access

Emergency

Mobile terminating CS fallback Mobile Terminating Access Extended Service Request Mobile originating CS fallback emergency call Emergency Packet services via S1

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Mobile Terminating Access/Delay Tolerant Access/Emergency

Page 24

RRC Connection Establishment Cases Tracing

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Initial UE Message 

After RRC connect establishment , eNodeB delivers the first NAS message , which is carried by “RRC C onnection Setup Complete” in Uu interface and “Initial UE Message” in S1 interface, to MME.



“Initial UE Message” includs the following NAS procedure:  

EMM: Attach request ESM: PDN connectivity request

 The first UL NAS message

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RRC Connection Reconfiguration Process 



Upon receiving an RRC Connection Reconfiguration message from the eNodeB over the radio i nterface, a UE configures SRB2 and the default DRB and sends an RRC Reconfiguration Compl ete message to the eNodeB.

This process is also used for radio bearer management during E-RAB setup, no specific message except for RRC Connection Reconfiguration messages is used for signaling exchange between eNodeBs and UEs.

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 Page27

RRC Reconfiguration Case– SRB2&DRB Setup 

Key IEs 





radioResourceConfiguration (for SRB2 and pos sible DRBs) （ default bearer setup ） nas-DedicatedInformation （ default bearer s etup ）

RRC Reconfiguration process can also be use d for the following configuration ： 



measurementConfiguration （ measurement control ） mobilityControlInformation （ handover com mand ）

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 Page28

RRC Reconfiguration Case– Measurement Control Mess age

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 Page29

Release Process of Signaling Connection Overview 

This process involves the following releases:  



Release of S1 connection Release of RRC connection, including all radio bearers and signaling connections between UEs and eNodeBs

The signaling connection release process starts in either of the following scenarios:  

The MME sends a UE Context Release Command message to the eNodeB. The eNodeB sends a UE Context Release Request message to the MME upon detecting the causes such as timer expi ration in the eNodeB, a handover, or other radio events. In this situation, release process of signaling connection is t riggered when the MME responds with a UE Context Release Command message.

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 Page30

Release Process of Signaling Connection 

Reasons for S1 Dedicated Signaling Release 1.eNodeB triggers ， for example, detect UE is in user inactivity for a long time 2.eNodeB O&M system triggers 3.MME O&M system triggers

UE

eNodeB

MME

S-GW

1. S1-AP: S1 UE Context Release Request 2.1 Release Access Bearers Request 2.2 Release Access Bearers Response 3. S1-AP: S1 UE Context Release Command 4. RRC connection release 5. S1-AP: S1 UE Context Release Complete

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Release of S1 Signaling Connection 

Release of S1-AP and S1-U connections 

Before the S1 connection is released

MM E

eNodeB



S-GW

P-GW

S-GW

P-GW

After the S1 connection is released MM E

eNodeB

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Release of Signaling Connection Cases 

Key IEs   

MME UE S1AP ID eNB UE S1AP ID Cause

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Contents 

LTE Air Interface Physical Layer



LTE Cell acquisition and call setup



LTE Optimization 

Basic cell parameters planning



LTE cell reselection Optimization



LTE Handover Optimization



LTE KPI



LTE Feature

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Page 34

LTE Cell ID Planning   

The WCDMA cell ID is unique on each RNC, the GSM and CDMA cell ID also is similar to the WCDMA cell ID. Different from a WCDMA cell ID, LTE cell ID consists of 20 bits eNB ID and 8 bits cell ID, which ensures that the LTE cell ID i s unique in the entire network. If the PLMN (MCC + MNC) is used, the LTE cell ID is unique worldwide. The eNB involves the local cell ID, eNodeB ID, and cell ID. It is advised to plan the three IDs starting from 0, which ensures that they are consistent.

20bits eNodB ID

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Page 35

8bits Cell ID

TA Planning 

TA Concept 



TAI list 





Similar to the location area and routing area in 2G/3G networks, the tracking area (TA) is used for pag ing. TA planning aims to reduce location update signaling caused by location changes in the LTE syste m. A list of TAIs that identify the tracking areas that the UE can enter without performing a tracking area updating procedure, i.e. in LTE system, if a UE changes the TAs in the TAI list, TA update won’t be trigg ered. The TAIs in a TAI list assigned by an MME to a UE belongs to the same MME area. Additionally, the TAI s in a TAI list assigned by an MME to a UE supporting CS fallback pertain to the same location area. In this case, the defining of the relationship between the tracking area(s) and the location area(s) is oper ator specific.

TA Planning content 

Include planning of TA and TAL.

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Page  Page 36 36

TAU Procedure Classification S-GW2

S-GW1

MME2

MME1

TA list 1

TA list 2

MME3

TA list 3

TA list 4

Periodic TAU Inter MME TAU with SGW change Intra MME TAU

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Inter MME TAU without SGW change

Page 37

TA Planning Principles A TA coverage should be medium. The limitations by the EPC must be considered.

TA&TAL Planning Baseline Propose scene

eNB Num. Per TA

TAL(eNB Num./TA Num.)

Urban

30~50

150 ～ 300eNBs/3 ～ 10TAs

Suburb

50~70

200~580eNBs/3~12TAs

When the suburban area and urban area are covered discontinuously, an independent TA is used for the sub urban area. A TA should be planned for a continuous geographical area to prevent segmental networking of eNBs in eac h TA. The paging area cannot be located in different MMEs. The mountain or river in the planned area can be used as the border of a TA, where fewer location updates a re performed for a small quantity of users. The LAC planning of the existing 2G/3G networks can be a reference for planning TAs. HUAWEI TECHNOLOGIES CO., LTD.

Page 38

PCI Planning In LTE system, the physical cell identifier (PCI) is used to differentiate radio signals of different cells. That is, the PCI is unique in the coverage of cells. Cell IDs are grouped in the cell search procedure. The ID of a cell group is determined through the SSCH, and then a specific cell ID is determined through the PSCH. The function of PCIs in the LTE system is similar to that of scrambling codes in the WCDMA system. PCI pla nning also aims to ensure the reuse distance. Differences between a scrambling code and a PCI: The scrambling code ranges from 0 to 511 whereas the PCI ranges from 0 to 503. In addition, the protocols do not have specific requirements for scrambling code planning. Therefore, only the reuse distance needs to be ensured in scrambling code planning. For PCI pla nning, however, 3GPP protocols require that the value of PCI/3 should be 0, 1, or 2 in each eNB. The UNET can be used for PCI planning.

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PRACH Planning - Logical Root Sequence Indexes 

What is the logical root sequence index  logical root sequence index 0~820  The random access preambles are generated from Zadoff-Chu sequences with zero correlatio n zone.  There are 64 available preamble sequences in each cell. The 64 preamble sequences are first generated from a root Zadoff-Chu sequence using cyclic shift. If less than 64 preamble seque nces are generated, the remaining are generated from the root Zadoff-Chu sequence corresp onding to the logical index.  The previously mentioned root corresponds to the logical root sequence index, which is sent to the UE through the SIB2.

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Da Nang LTE Planning GSM and UMTS DNL+Distr Local CellID CellName Site Name ict start from 1 based on code+Nod eNodeB Name eB ID(2 with extension digitals) "ABC for 1800, DEF for 2600", 1800 IBS start from "JKL", 2600 IBS use "MNO"

NodeB Name

eNodeB Name

DNHC02

DNL302

1

DNHC02 DNHC02 DNHC08 DNHC08 DNHC08

DNL302 DNL302 DNL308 DNL308 DNL308

2 3 1 2 3

Local CellID CellName DNL302A DNL302B DNL302C DNL308A DNL308B DNL308C

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CellID Huawei   start eNodeB ID from 1, from 501 depend to 550. on no of local cell.

CellID 1 2 3 1 2 3

 

Sector ID Start from 1, depend on no of sector.

eNodeBID MCC MNC SectorID 501452 501452 501452 502452 502452 502452

01 01 01 01 01 01

Huaw TAC BandWidth, 10M for   ei use plann 1800, 20M for 2600. PCI ing from based 0~24 on 0, existi other ng 3G vendo LAC r use plann PCI ing, from 1TAC 251~ mapp 490. ing to 1 3G LAC.

PCI

TAC

BandWidth

2T2R Huawei use   Root Sequence Index from 0~400, other vendor use Root Sequence Index from 420~820.

ROOT ReferenceS DLEAR TxRx SEQUENCE ignalPwr(0. FCN Mode INDEX 1dBm) (PRACH)

1

0

501CELL_BW_N50(10M)

15012T2R

0

2 3 1 2 3

1 2 30 31 32

501CELL_BW_N50(10M) 501CELL_BW_N50(10M) 501CELL_BW_N50(10M) 501CELL_BW_N50(10M) 501CELL_BW_N50(10M)

15012T2R 15012T2R 15012T2R 15012T2R 15012T2R

3 6 9 12 15

Page 41

182 182 182 182 182 182

Contents 

LTE Air Interface Physical Layer



LTE Cell acquisition and call setup



LTE Optimization 

Basic cell parameters planning



LTE cell reselection Optimization



LTE Handover Optimization



LTE KPI



LTE Feature

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Page 42

Cell Reselection Principle SservingCell is worse than Thresh_serving.low &

SNonservingCell is better than Thresh_x.low Cell Reselection High Prio. eNodeB

SNonservingCell is better than Thresh_x.high

Low Prio. NodeB/BTS

LTE

SIB

(High)

UMTS

SIB

(Medium)

GSM (Low)

Cell Reselection From High -> Low

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SIB

Suggested RAT Priority:  LTE(High)  UMTS(Medium)  GSM(Low)

Cell Reselection From Low > High

Page 43

Camping - Cell Reselection between LTE and GSM/UMTS  Threshold and Measurement  Cell Reselection from LTE to GSM/UMTS network  only when UE is out of LTE coverage area

Threshold

 

Threshx,high: threshold of reselecting to High Priority Cell



  

 L T E

 GSM/UM TS

Threshx,low: threshold of reselecting to Low Priority Cell Measurement parameter SServingCell: Signal of serving cell SNonServingCell: Signal of target reselection cell

 Cell Reselection Strategy LTE->GSM/UMTS (High to Low)

  

 Cell Reselection from GSM/UMTS to LTE network when UE enters the LTE coverage area



GSM/UMTS->LTE (Low to High)  SNonServingCell > Threshx,high 

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SServingCell Threshx,low Length of camping on serving cell > 1 sec

Length of camping on serving cell > 1 sec Page 44

LTE Parameter - Idle Mode Cell Reselection (Threshold) Priority

RAT

7

Reserved

6

L2600

5

L1800

4

Reserved

3

U2100

2

Reserved

1

G900\1800

Reselection from LTE to UMTS: (Coverage based) UE will start to measure UMTS signal when: LTE signal < -110dBm UE will reselect to UMTS when: LTE signal < -114dBm & UMTS signal > -103dBm, The signal conditions need to maintenance for 1 second. Reselection from LTE to GSM: (Coverage based) UE will start to measure UMTS signal when: LTE signal < -110dBm UE will reselect to UMTS when: LTE signal < -114dBm & GSM signal > -101dBm, The signal conditions need to maintenance for 1 second. Reselection from UMTS to LTE: (Priority based) Configure UMTS network priority as 3, UE will always measure LTE signal when camping on UMTS. UE will reselect to LTE when:

U2L: LTE signal > -108dBm

Reselection from GSM to LTE: (Priority based) Configure GSM network priority as 1, UE will always measure LTE signal when camping on GSM. UE will reselect to LTE when: HUAWEI TECHNOLOGIES CO., LTD.

G2L: LTE signal > -108dBm

The signal

Page 45 conditions need to maintenance for 5 seconds, depend on GSM side parameter.

Contents 

LTE Air Interface Physical Layer



LTE Cell acquisition and call setup



LTE Optimization 

Basic cell parameters planning



LTE cell reselection Optimization



LTE Handover Optimization



LTE KPI



LTE Feature

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Page 46

Handover Outline 

Three Scenarios for Handover Within System

S1

S1 X2 Handover

Uu

Handover

Handover

Uu

Intra-eNodeB Handover

Uu

Uu

Uu

Uu

Inter-eNodeB Handover with X2 Inter-eNodeB Handover with S1

Note: If both a X2 and S1 links are available, the X2 link is preferentially used for the inter-eNodeB handover.

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Handover Procedure 

Handover consists of three stages:

HO Measurement: UE does the measurement based on the measurement configuration from eNo deB, and report to eNodeB;  HO Decision: It is eNodeB to decide if trigger handover based on the measurement result UE repo rt;  HO Execution: Based on the decision, eNodeB control UE handover to target cell; 



The whole handover procedure follows 



network control and UE assistant.

Six steps needed 

Issuing Measurement Control-> Measurement Result Report->Handover Decision->Resource Prepar ation->Handover Execution->Source cell Resource Release

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Measurement Control

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Measurement Report

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Handover Command

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Key Impact Factors for Handover  Coverage issue  Radio planning issues

 Parameter s& channel

•

Poor coverage in handover area • No major pilot in handover area

 Neighbor issues

•

Missing neighbor • Mistake neighbor configuration/PCI conflict • Black cell configuration

 Parameters issue •

Incorrect handover event parameters • Incorrect radius configuration

•

EPC replies handover preparation failure • EPC fault causes abnormal handover flow

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•

Admission failure CPU overload

•

 RF channel issue • UL interference •

 Transport issue

RF channel problem • •

 EPC fault  Device fault

 Capacity issue

 eNodeB fault •

Incorrect configuration Transmission fault

 UE factor

Relevant alarm exists for the modules

Page 52

•

Specific UE problem

General Process 

Determine the scale of problem 





From the performance statistic, we can determine the scale of the problem, is it global proble m, or cell level problem or just some individual UE problem. Then we can select bottom N cell as optimization target Customer complain is an effective way to locate the individual UE problem

For large scale handover failure   

Check eNodeB alarm and basic configuration Check EPC alarm and configuration Check RF channel problem 



Once RF channel is abnormal, such as high VSWR, low RSSI Too Low or RSSI is un balanced, then the access performance should be significantly affected.

After we exclude the hardware fault and transmission fault, we could analysis th e signaling to find out the root causes

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Proceed for Signaling Analysis 

Step 1: Located fault point 

From the tracing message, we can located the handover fault point, there’re 3 key fault points dur ing handover procedure





No measurement report



No handover command



No handover complete message

Step 2: Analyze the root cause 

Channel quality issue



Configuration issue



Transmission quality issue

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Generic Analysis Method 

Channel quality problem  



Configuration problem   



Observe RSRP,RSRQ, SINR IBLER, DL/UL grant from driver test tools Observer performance monitoring from M2000 including scheduling statistic, CQI report, MCS, SI NR eg. Check the neighbor/ANR configuration Check the X2 configuration Check EPC authentication & security configuration

Transmission problem  

Check relevant alarm Check the latency using some packet analysis tools

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Problem Analysis –No Measurement Control Message 

Scenario : eNodeB doesn’t send measurement control message



Solution: Check related handover switch

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Problem Analysis – Black List Configuration 

Scenario : UE receives measurement control message, but UE doesn’t send any measurement report



Possible cause: 



The neighbor cell is in black list. In the SIB message eNodeB delivers all black cell list, then U E doesn’t measure any of these cells

Solution: check if all the neighbor belongs to black list  

LST INTRAFREQBLKCELL LST INTERFREQBLKCELL

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Case 1: Inter TA Handover Due to Missing IP Path 

Description: In one project, we find a lot of handover failure. From the statistic, we observe that most of t hese failures happen between inter TA cell.



Analysis 

From the tracing message, we see that the failure cause is handover preparation failure, the failure cause is GTUP resource not available.



In the handover request message, source eNodeB deliver the target GTPU ID (SGW IP address) to let target eNodeB setup uplink S1 bearer directly. We check the IP address of SGW in the message, and find that it is not identical with target eNodeB configuration. HUAWEI TECHNOLOGIES CO., LTD.

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Solution 

Later we confirm this issue, this TA border is also the border of two regions which use diffe rent SGW. And in each region ,only one IP path is configured for current eNodeB to SGW. S o the handover will be failure when cross the different SGW.



Solution 



Configure S1 IP path from the target eNodeB to source SGW, then the problem is solved

Suggestion: This is a very typical problem, on the border cell of inter SGW, we should reme mber to configure the IP path to the SGW which belongs to the target cell as well.

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Page 59

Case 2: Handover Failure Due to No Handover Comm andDescription: UE sends measurement report to eNB several times , but no feed back fro 

m eNodeB 

Tracing message from eNodeB

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Page 60

Case 2 – Analysis 

From the previous message, we can see that before the measurement report, eNB sends one “RRC reconfiguration” message, but the UE doesn’t feedback the complete message.



Then we check trace on UE side, and find that UE doesn’t receive the RRC reconfiguration mes sage



Due to poor DL coverage, UE doesn’t receive the RRC reconfiguration message, thus no complete feedback. As the previous RRC reconfiguration procedure is not completed, eNodeB is still waiting for reconfiguration feedback and measurement report is not processed. HUAWEI TECHNOLOGIES CO., LTD.

Page 61

Contents 

LTE Air Interface Physical Layer



LTE Cell acquisition and call setup



LTE Optimization



LTE KPI



LTE Feature

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Page 62

KPI System Overview LTE KPIs

Accessability

Retainability

RRC SETUP SR

Call Drop Rate

ERAB Setup SR

Call Setup Complete Rate

Call Setup SR

Mobility

HHO SR ( Intra/Inte r Frequency )

Availability

Radio Network Unavailabi lity Rate

Utilization

UL/DL RB Utility Rate

Traffic

Cell UL/DL Traffic Volume

Integrity

Service UL/DL Throughput

Inter-RAT HHO SR CSFB SR

Radio Network KPI :

Service KPI :

Focus on the radio network performance

Focus on the user experience

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Page 63

Collection Method and Reporting Period 

Collection methods (TS 32.403)  CC (Cumulative Counter), for example, Attempted RRC connection establishments;  GAUGE (dynamic variable), used when data being measured can vary up or down during the period of measurement, for example, Maximum E-RAB Setup time;  DER (Discrete Event Registration), when data related to a particular event are captured every nth event is registered, where n can be 1 or larger, for example, Cell Unavailable Time;  SI (Status Inspection), for example, Average Number of simultaneous E-RABs;



Reporting period  The measurement results are collected in a pre-defined reporting period, and this reporting period, in general, is configurable at EMS, for example, 15mins, 60mins…

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Page 64

Danang LTE Trial KPI Category

KPI Items

17-Jul-16

18-Jul-16

19-Jul-16

20-Jul-16

21-Jul-16

RRC Connection Establishment SR(%)

99.7365

99.842

99.8351

99.8442

99.8848

Initial E-RAB Establishment SR(%)

99.9551

99.9489

99.9578

99.9389

99.9567

Addition E-RAB Establishment SR(%)

99.4118

99.3827

100

99.5614

99.6403

E-RAB Retainability for UE level(%)

0.3

0.2906

0.2498

0.2861

0.2554

Inter eNB HO SR via X2(%)

99.3676

99.4014

99.5381

99.5501

99.6134

Inter eNB HO SR via S1(%)

100

99.7567

99.6805

99.6795

99.6324

Intra Frequency HO SR(%)

99.5056

99.5253

99.6358

99.6402

99.687

Inter Frequency HO SR(%)

99.6885

100

99.3186

99.6753

99.842

Inter-RAT HO Out SR (LTE to UMTS)(%)

95.6042

94.4228

92.3779

93.9486

95.1845

E-UTRAN IP Throughput DL(Kbps)

16328

13866.29

15223.5408

14770.3511

15250.2427

E-UTRAN IP Throughput UL(Kbps)

1785.255

1501.656

1813.6444

1362.1843

1644.9753

Traffic

Data Traffic(GBits)

317.6122

302.4348

319.6397

295.3225

323.1579

CSFB

CSFB Preparation Success rate (%)

99.9188

99.9366

99.9671

99.9838

99.9534

Available

Available(%)

98.4375

98.3832

98.4313

98.4375

98.4322

Accessability KPIs

Retainability KPI

Mobility KPIs

Integrity KPIs

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RRC Connection Establishment Success Rate KPI Name KPI Index Managed Object Formula

Related PM Mapping counter Unit

Description

RRC Connection Establishment Success Rate (service)   Cell RRCS_SRservice = (RRCConnectionSuccessservice/RRCConnectionAttemptservice) * 100% RRC Setup Success Rate (Service) =((L.RRC.ConnReq.Succ.Emc + L.RRC.ConnReq.Succ.HighPri + L.RRC.ConnReq.Succ.Mt + L.RRC.ConnReq.Succ.MoData + L.RRC.ConnReq.Succ.DelayTol)/ (L.RRC.ConnReq.Att.Emc + L.RRC.ConnReq.Att.HighPri + L.RRC.ConnReq.Att.Mt + L.RRC.ConnReq.Att.MoData + L.RRC.ConnReq.Att.DelayTol)) *100%  (1526728222+ 1526728223+ 1526728224+ 1526728226+ 1526728358)/( 1526728217+ 1526728218+ 1526728219+ 1526728221+ 1526728357 )*100%

% According to 3GPP TS 36.331, the RRC connection setup procedure is triggered by different causes, which are identified in the "establishmentCause" field in an RRC Connection Request message as emergency, highPriorityAccess, mt-Access, moSignaling, mo-Data, or delayTolerantAccess-v1020. The UE sets the establishmentCause in accordance with the information it receives from upper layers. The mo-signaling cause is a signaling-related cause. All other causes are service-related causes. The accessibility KPI evaluates the RRC setup success rate using service-related causes in a cell or radio network.

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E-RAB Setup Success Rate KPI Name KPI Index Managed Object Formula Related PM Mapping counter Unit

Description

E-RAB Setup Success Rate (All) E-RAB Setup Success Rate (All) Cell (ERABSetupSuccess/ERABSetupAttempt) *100%   (L.E-RAB.SuccEst/L.E-RAB.AttEst) * 100% (1526727544/1526727545) * 100% %   The E-RAB Setup Success Rate (All) KPI indicates the E-RAB setup success rate for all services, including the VoIP service in a cell or radio network

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Page 67

Call Drop Rate KPI Name

Service Drop Rate (All)

KPI Index

Service Drop Rate (All)  

Managed Object

Cell

Formula

(ERABAbnormalRelease/ERABRelease) * 100%

Related PM Mapping counter Unit Description

(L.E-RAB.AbnormRel/(L.E-RAB.AbnormRel + L.E-RAB.NormRel)) * 100% (1526727546/ (1526727546+1526727547))*100% % The Service Drop Rate (All) KPI indicates the call drop rate of all the services in a cell or radio network, including the VoIP service.

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Page 68

Intra Frequency Handover Success Rate KPI Name KPI Index Managed Object Formula

Intra Frequency Handover Success Rate IntraFreqHOOut_SR Cell (IntraFreqHOOutSuccess/IntraFreqHOOutAttempt) * 100% Intra-Frequency Handover Out Success Rate = [(L.HHO.IntraeNB.IntraFreq.ExecSuccOut + Related PM L.HHO.IntereNB.IntraFreq.ExecSuccOut)/(L.HHO.IntraeNB.IntraFreq.ExecAttOut + L.HHO.IntereNB.IntraFreq.ExecAttOut)] * 100% Mapping counter (1526726997 + 1526727003 )/( 1526726996 + 1526727002)*100 Unit % The Intra-Frequency Handover Out Success Rate KPI indicates the success rate of intra-frequency Description handovers (HOs) from the local cell to neighboring E-UTRAN cells. The intra-frequency HOs are classified into intra- and inter-eNodeB HOs.

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Page 69

Inter-RAT Handover Out Success Rate (LTE to UMTS) KPI Name KPI Index Managed Object

Inter-RAT Handover Out Success Rate (LTE to UMTS) IRATHO_L2W_SR Cell

Formula

(IRATHO_L2W_Success/IRATHO_L2W_Attempt ) * 100%

Related PM

(L.IRATHO.E2W.ExecSuccOut/L.IRATHO.E2W.ExecAtt Out) * 100%

Mapping counter Unit Descriptio n

(1526726991 / 1526726990 ) * 100% % The Inter-RAT Handover Out Success Rate (LTE to WCDMA) KPI indicates the success rate of handovers from an LTE cell or radio network to WCDMA networks

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Page 70

CSFB Preparation Success Rate KPI Name

CSFB Preparation Success Rate

KPI Index

CSFB_Preparation_SR

Managed Object

Cell

Formula

CSFB_Preparation_SR = (CSFB_Preparation_Success/CSFB_Prepar ation_Attempt) * 100%

Related PM

(L.CSFB.PrepSucc/L.CSFB.PrepAtt) * 100%

Mapping counter

(1526728322/1526728321)*100%

Unit

%

Descriptio n

This KPI shows CSFB Preparation Success Rate

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Page 71

Cell Downlink Average Throughput KPI Name KPI Index Managed Object Formula

Cell Downlink Average Throughput CellDLAveThp Cell CellDLAveThp = CellDLTrafficVolume/CellDLTransferTime

Related KPI Cell Downlink Average Throughput = L.Thrp.bits.DL/L.Thrp.Time.Cell.DL.HighPrecision Mapping counter Unit Description

(1526728261/1526728997) Kbps The Cell Downlink Average Throughput KPI indicates a cell's average downlink throughput when data is transferring at the downlink. The Cell Downlink Average Throughput KPI reflects the cell's capacity.

 L.Thrp.bits.DL : The traffic volume of transmitted PDCP SDUs of services with a specific QCI ranging from 1 to 9 is accumulated as the value of the corresponding counter.  L.Thrp.Time.Cell.DL.HighPrecision: The duration of uplink or downlink data transmission in a cell is sampled per millisecond. If there is uplink or downlink data transmission within a sampling period, the sampling result is 1 ms. At the end of a measurement period, the sum of these sampling results is used as the value of the L.Thrp.Time.Cell.DL.HighPrecision counter.

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Cell Uplink Average Throughput KPI Name KPI Index Managed Object Formula Related KPI Mapping counter Unit Description

Cell Uplink Average Throughput CellULAveThp Cell CellULAveThp = CellULTrafficVolume/CellULTransferTime L.Thrp.bits.UL/L.Thrp.Time.Cell.UL.HighPrecision     The Cell Uplink Average Throughput KPI indicates the average cell uplink throughput when data is transferring at the uplink. The Cell Uplink Average Throughput KPI reflects the cell's capacity

 L.Thrp.bits.UL : The traffic volume of transmitted PDCP SDUs of services with a specific QCI ranging from 1 to 9 is accumulated as the value of the corresponding counter.  L.Thrp.Time.Cell.UL.HighPrecision: The duration of uplink or downlink data transmission in a cell is sampled per millisecond. If there is uplink or downlink data transmission within a sampling period, the sampling result is 1 ms. At the end of a measurement period, the sum of these sampling results is used as the value of the L.Thrp.Time.Cell.UL.HighPrecision counter.

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Page 73

Contents 

LTE Air Interface Physical Layer



LTE Cell acquisition and call setup



LTE Optimization



LTE KPI



LTE Feature

HUAWEI TECHNOLOGIES CO., LTD.

Page 74

Background 

The Automatic Neighbor Relation (ANR) feature manages neighbor cell lists (NCLs) on the eNodeB side. ANR au tomatically detects and adds new neighboring cells to neighbor relation tables (NRTs). In addition, ANR autom atically identifies and removes redundant neighboring cells and neighbor relationships.



The ANR feature automatically maintains the neighbor relationship, reducing manual intervention in the maint enance of neighboring cells.

How to detect and query unknown neighbor cell info: a) Measurement Report (Phy-CID=5) Cell A Phy-CID=3 Global-CID=17

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

c) Read BCCH

a) UE is source Cell A, and detect unknown

Cell B b) Cell A inform UE to read CGI info of Cell B c) UE read CGI of Cell B from BCCH d) UE report CGI of Cell B, and report to Cell A

d) Report Global-CID=19 b) CGI request (Target Phy-CID=5)

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75

Basic Concepts (1) NCL SN

Target Cell PLMN

eNodeB ID

Cell ID

DlEarfcn

PhyCellId

TAC

1

46001

eNodeB ID#1

Cell ID#1

F1

PhyCellId#1

TAC#1

46001

eNodeB ID#2

Cell ID#2

F2

PhyCellId#2

TAC#2

2



3 

The NCLs of an eNodeB contain information about the external cells of the eNodeB, which belong t 46001 base stations. eNodeB ID#3 Cell as ID#3 PhyCellId#3 TAC#3 has one intr o other NCLs are categorized intra-F1and inter-RAT NCLs. Each eNodeB a-RAT NCL and multiple inter-RAT NCLs, such as the GERAN NCL and the UTRAN NCL. An NCL records the information about an external cell, such as the E-UTRAN cell global identifier (E CGI) or the UTRAN/GERAN CGI, public land mobile network (PLMN), physical cell identifier (PCI), tra cking area code (TAC), eNodeB ID, and E-UTRA absolute radio frequency channel number (EARFCN).

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Huawei Confidential

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76

Basic Concepts (2) NRT SN





LCI

Target Cell

eNodeB ID

Cell ID

No Remove

No HO

1

LCI#1

PLMN 46001

eNodeB ID#1

Cell ID#1

FORBID_RMV

FORBID_HO

2

LCI#1

46001

eNodeB ID#2

Cell ID#2

PERMIT_RMV

PERMIT_HO

3

LCI#1

46001

eNodeB ID#3

Cell ID#3

FORBID_RMV

FORBID_HO

The NRTs of a cell contain information about the neighbor relationships of the cell with its neighboring cells. Each cell has one intra-RAT intra-frequency NRT, one intra-RAT inter-frequency NRT, and multiple interRAT NRTs.

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77

ANR adding Ncells introduction CGI: Global cell ID PCI: Physical Cell ID NRT of Cell1 Cell2: PCI=2 CGI=17 …… Cell3: PCI=5 CGI=25 NRT of Cell2 Cell1: PCI=3 CGI=27 ……

3 Add Cell2 in NCL of eNodeB1 and NRT of Cell1 by Event ANR (UE measurement) 6

Add Cell1 in NCL of eNodeB2 and NRT of Cell2 by Event ANR (UE history info.)

3 Add Cell3 in NCL of eNodeB1 and NRT of Cell1 by Fast ANR

Event Triggered ANR Fast ANR

U2000

eNodeB1 Cell1 Source Cell PCI=3 CGI= 27

5 Cell2 obtains CGI of Cell1 by UE history info, and queries PCI info from U2000.

eNodeB2 Cell2 N-Cell PCI=4 CGI=17

2 Report CGI and PCI of Cell2

2 Report CGI and PCI 4 HO from Cell1 to Cell2 of Cell3 1Detect new Cell2 PCI and CGI by Event ANR 1 Detect new Cell3 PCI and CGI by Fast ANR eNodeB3 Cell3 N-Cell PCI=5 CGI=25

Description:  UE can detect new neighboring cells and report CGI measurement result by Event ANR.  During handover procedure, target cell adds source cell as NR by UE history information. (only for intra-RAT)  Source cell selects some UE do periodic measurement, and new neighboring cells can be added by Fast ANR.

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ANR deleting Ncells introduction NRT/NCL Deletion Policies Wrongly configured Ncells deletion

Auto deletion when NRT is maxed out.

Redundant Ncells deletion

Y ANR.StatisticNumForNRTDel > 0

If the Ncell has never been If handover success rate handover to for a period of time, of Ncell is below threshold, the NRT will be deleted. the NCL/NRT will be deleted. Period: ANR.StatisticPeriod HO success rate threshold: ANR. DelCellThd (Default value 0%)

Period: 4*ANR.StatisticPeriodForNRTDel

If the NCL has no NRT and X2 in period, NCL will be deleted.

N

Ncells which have never been measured by UE will be deleted. Period: ANR.StatisticPeriodForNRTDel

Description Description The Thefollowing followingthree threecriterions criterionscan canbe beapplied appliedininIntra-LTE Intra-LTEANR ANRauto autodeletion deletion Wrongly Wronglyconfigured configuredneighboring neighboringcells cellsdeletion: deletion:Periodic Periodictrigger trigger(The (Thesame sameas as eRAN7.0) eRAN7.0) Redundant Redundantneighboring neighboringcells cellsdeletion deletion: :Periodic Periodictrigger trigger(Newly (Newlyadded addedinineRAN7.0) eRAN7.0) Auto Autodeletion deletionwhen whenNRT NRThas hasreached reachedthe themaximum maximum: :Event Eventtrigger trigger(Enhanced (Enhancedinin eRAN7.0) eRAN7.0) The Thethree threecriterions criterionscan cantake takeeffect effectindependently. independently.

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Ncells which has not been measured for a period of time will be deleted. Period: ANR.StatisticPeriodForNRTDel If no Ncells meet the condition Ncells to which HO hasn’t happened for a period of time will be deleted. Period: ANR.StatisticPeriodForNRTDel If no Ncells meet the condition Ncells to which the handover times are below threshold and ranked with descent of HO times in the last position will be deleted. Handover threshold is configurable. ANR.NcellHoForNRTDelThd

79

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