Sharing Drive Test Analysis training 21 feb.pdf

LTE Drive Test Analysis Using Actix

By : Abdul Ghony Fattah Ifur

TOPIC 1

• LTE Drive Test KPI

2

• Optimization Principle

3

• Drive Test Analysis Using Actix

4

• Bad Spot Analysis and Reporting

LTE Drive Test and KPI


1. DRIVE TEST INTRODUCTION

DRIVE TEST CONCEPTUAL : • •

Drive test is conducted for checking coverage criteria of a cell with RF The data collected by drive test tool as log files is analyzed to evaluated various RF parameters of the network

What we have to do before DT ? Site Parameter Consistency Check Network performance and system status KPIs health check DT Road

DT Scenario and Supporting tools like scrip

2. Drive Test KPI Drive Test Tools

Accessibility

• RRC connection request Success Rate

Retain ability

• E-RAB Abnormal Release Rate • Drops call rate • Round trip time

Integrity

• DL User Throughput • UL User Throughput

Mobility

• HO Success Rate

2.1 Accessibility (1) LTE STATE

RRC Connection Request Success Rate= # RRC CONNECTION RECONFIGURATION COMPLETE / # RRC CONNECTION REQUEST * 100%

Drive test methodology 1.UE connect to server 2.Perform FTB download for 30 second 3.Call end 4.Idle 15 second 5.Repeat

2.1 Accessibility (2) CALL SETUP OVERVIEW

2.2 Retain Ability LTE RADIO LINK FAILURE DIAGRAM

ERAB Drop Rate= # Call dropped / # success calls * 100%

DATA RADIO BEARER

Drive test methodology 1.UE connect to server 2.Perform FTB download for 5 minutes 3.Call end 4.Idle 15 second 5.Repeat

2.3 Integrity (1) DL User Throughput, shall be calculated for each sample in the call and aggregated over bins of between 10x10m resolutions (morphology dependent) and presented in PDF and CDF format with the 5th, average and 95th percentiles, DL Max Throughput, at least one data sample shall be found that exceeds the maximum throughput specification

Drive test methodology 1.UE connect to server 2.Multi stream FTB download for 5 Minute 3.Call end 4.Idle 30 second 5.Repeat

2.3 Integrity (2)

2.3 Integrity (3) DL THP COMPARE TO SINR

UL THP COMPARE TO RSRP

2.4 Mobility HO PROCEDURE : 1. Measurement 2. Filtering of Measurement 3. Reporting of Measurement result 4. Hard HO algorithm 5. Execution of HO

HO SUCCES RATE = (HO SUCCESS / HO ATTEMP)* 100%

LTE Optimization Principle


Optimization Index Detecting interference using field measurement

Detecting interference and bad coverage using counter

Detecting overshooting site

PCI optimization

Impact of interference on LTE network performance- importance of physical RF Optimization

Detecting Interference - Indicator SINR • • •

SINR measurement can indicate interference area, but it’s doesn’t necessary see all interference source : Impacted by traffic load Depend on PCI Planning

RSRQ • •

RSRQ depend on network load RSRQ similar with Ec/No in 3G

RSRP • • •

RSRP measurement with scanner is the most reliable way to detect area with possible interference problems and bad dominance. Not impacted by network load The number of PCI with same mod 3 in e.g 5 dB Power window is a useful indicator

Detecting Interference – SINR (SINR VS RSRP)

Detecting Interference - RSRQ

Detecting Interference - RSRP




PCI optimization


GOOD DL VS BAD DL

GOOD UL VS BAD UL

PUSCH SINR, PUSCH RSSI Measurement




PCI optimization


OVERSHOOTING SITE

How to detect overshooting site ? Overshooting Site 1. Cell with to large or largely distributed dominance area 2. Will cause increase interference to other cells 3. Can collect excessive amount of traffic.

1. Drive Test : Analyzing HO performance and neighbor cell measurement from DT Log 2. Counter : Cell pair HO analysis with inter site distance information. Indicating Hos to cell with long inter site distance 3. Timing Advance Trace : Cell TA Trace analyze to finding long distance user




PCI optimization


PCI Conflict PCI Collision

PCI Confusion

•

A PCI collision occurs between two or more intra-frequency cells that use an identical PCI but are insufficiently isolated.

•

In this case, UEs in the overlapping area of the two cells cannot implement signal synchronization or decoding.

A PCI confusion occurs between a detected cell and a neighboring cell if the two cells have the same frequency and PCI and if the reference signal received power (RSRP) of the two cells reaches the handover threshold. The PCI confusion may lead to UE handover failures or service drops. Case : eNodeB mistakenly considers that the detected cell is cell C and then initiates a handover to cell C. If the spot that the UE is on is not covered by cell C but cell B, a handover failure may occur. If two or more neighboring cells of a cell have the same frequency and PCI, there is a PCI conflict between these neighboring cells

Impact of PCImod3 collision on Tput




PCI optimization


RF OPTIMIZATION Basic Optimization principle : •

Clear cell dominance areas, minimize cell overlapping

•

Avoid sit overshooting overlarge area with other cell

•

Can’t fix bad RF by tuning parameter

•

Antenna tilting and antenna replacement has big impact on other cell interference

Impact of DL Load , 0% VS 70%

Antenna tilt tuning example (SINR before and after)

Antenna tilt tuning example (CQI before and after)

Antenna tilt tuning example (HO before and after)

LTE Drive Test Analys Using Actix


1. Open Actix Application Click this

1

2

3

2. Import Log File

1

2

3

3. Create super stream

4. Import CellRef

6. Setup Map

7. Setup Workspace Analysis 1/2

7. Setup Workspace Analysis 2/2

8. DL Analysis

9. UL Analysis

10. Statistic analysis

11. Save Workspace

LTE Bad Spot Analysis and Reporting


Confidential

1. Cross Feeder Analysis

2. PCI Confusion Analysis

3. Poor RSRP Analysis RECOMMENDATION : 1. 2.

Add new site near by poor RSRP Area Healthy Check Site with Red Sign and give antenna down tilt or up tilt

4. Poor SINR Analysis RECOMMENDATION : 1. 2.

Give down tilt overshooting site Healthy Check, site audit Site with Red Sign and give antenna down tilt or up tilt

5. Low DL THP Analysis RECOMMENDATION : 1. 2.

3. 4.

Low DL THP because poor SINR and Value RI 1 Value RI = 1 it’s mean MIMO in mode transmit diversity, it because poor SINR. Poor SINR is caused by there are no site dominance Improve SINR, we need to give down tilt overshooting site, and give up tilt/down tilt site near by poor SINR coverage area.

6. Low UL THP Analysis RECOMMENDATION : 1. 2. 3.

Low UL THP due to low MCS usage and Low RB usage RSRP indicate good Probably, in this spot UE just start UL

7. HO Failure Analysis RECOMMENDATION : 1. 2.

HO Failure due to poor coverage Area Need to add new site.

Sharing Drive Test Analysis training 21 feb.pdf

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