Mobitel’sInitiatives for Evaluating

Customer QoE and Ensuring Network QoS

- Ishantha Pandigamage - Ruwan Liyanage

Our Telecommunication Industry• Sri Lanka – Small Island in South East Asia• Four Mobile Operators & Two Fixed Operators• Competitive Market for Mobile Industry• Quality of Experience and Quality of Service

decides the retention of a customer• Sri Lanka has among the lowest prices in the

world, ITUo Lowest entry level charges for fixed

broadbando Ranked at no.21 for mobile broadband out of

181 • Removal of floor based price rate in 2018 • Reduction of Telecommunications Levy• Mobile Broadband : Price vs. Affordability • Compare to early years a significant improvement

in Mobile data speed • Fixed FTTH & Mobile 4.5G deployment• First 5G device Pre-Release testing , Ookla

• Customer base of over 10 million• Engineering Excellence Award - Stage VII Expansion project• Awarded prestigious ISO 27001:2005 certification for the company’s solid and reliable Information Security Management

System

Journey of Mobitel

CEO

CUSTOMER CARE

MARKETING

SALES

ENGINEERING

Service Quality Functions at Mobitel

SQ

IA

RA

Enterprise Risk & Information Security

REGULATOR’S QoS & QoE FUNCTION WITHIN THE ORGANISATION

KEY AREAS OF SQ

• Network Performance Monitoring & Troubleshooting

• Network Service Quality Auditing

• Network Data Analytics

• Benchmarking & Drive Testing

NETWORK PERFORMANCE MONITORING&

TROUBLESHOOTING

Internet Data Speed Clipping• Reduction of monthly data traffic• Compared to competitor less number of

samples > 10Mbps in 3G throughput DT

• RSCP/RSRP vs. Application Throughput

• 34Mbps data clipping on application throughput while in LTE

• Further testing was carried stationary

o FTP/HTTP Download – Finland o FTP/HTTP Download – Netherland o FTP/HTTP Download – Singaporeo FTP/HTTP Download – USAo Local FTP/HTTP Download – Mobitel SL

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Monthly Data UsageDec-18 Jan-19

• The maximum data speed for Netherland recorded as 34.95 Mbps

• Finland was 31.74 Mbps• All Europe links had data clipping• No data limitation on US, Singapore & Local

links

Cause:• ISP traffic routing issue• Routing most Europe traffic via Singapore

ISP link

Impact:• Data revenue loss • Affected the customer experience of high

speed data downloading

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HTTP Application DL - Finland

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HTTP Application DL - Singapore

Internet Data Speed Clipping…

• Sudden RTWP increase• Omni directional and very high RTWP (> -80

dBm)

Impact:• Poor user experience in data speed

Cause:• Faulty 3G Repeater

High RTWP - External Interference

NETWORK SERVICE QUALITY AUDITING

Internal Network Interference• Identification of internal interference sources• Pollution was analyzed for pilot count of

greater than 3 with a pilot level difference of -6 to -12dB of EcNo below and -95dBm of RSCP above the threshold

• Scrambling code analysis• Cross feeder analysis

UARFCN 10587 is heavily affected with cells >5

PSC 438 of COL424O is overshooting to Colombo 11

COL027K and COL267K are configured in same

scrambling code and clashing each other

IP BSC Conversion• A-interface over IP• Conversion of AoTDM to AoIP• Voice Codec selection • QoS Control• Tested Scenarios:

o M2M (2G-2G, 2G-3G) o M2F (2G-PSTN)

Findings:2G – 2G Voice MOS improvement Nearly 70% of voice samples were

experiencing excellent voice quality with MOS > 4.0

Average MOS for NB 5.9 codec improved significantly

2G – 3G Voice MOS degradation

• Issue: No excellent values of MOS > 4

• Initial Codec Negotiationo Previously all the initial voice samples

started with NB 5.9 o After the conversion majority of samples

started from NB 4.75 codec.

• Solution : The rate-0 is not carried in the Assignment

request Adding of AMR Codec in all RNC

2G – PSTN acceptable Voice MOS maintained

IP BSC Conversion…

• Filtering neighbor relation cells > 20 km • longest neighbor distance - 207 Km• 1214 long distance neighbors removed from each

NE

Cause: • Due to Cell ID duplication• Not using the CGI in creating the Handover Table

Impact:• Customer impact minimum but nearest neighbors

were missed

Long Distance Neighbor Cell Audit

NETWORK DATA ANALYTICS

Network Data Analytic ToolsMTD – Mobitel Traffic Distribution viewer• Distribution of Voice & Data traffic into

1Km2 BINs• Correlation with population density• Identification of best/worst performing

GNDs• Bin-wise serving technology and cell

details

MTG – Mobitel Traffic Growth viewer• Distribution of Voice & Data traffic

growth into BINs• Analysis of traffic growth with reference

to a selected week• Serving cell patterns and cell wise traffic

growth

Data Traffic Growth in 3D• Network data traffic extracted from

Mobitel Traffic Distribution(MTD) viewer • Real time 3D map with high traffic growth

regions• Drilled down to ZIP levels and District

Secretariat Division (DSD) levels• Colombo District : The highest data growth• Kaduwela DSD : The highest growth among

all island DSD’s• Sales and marketing insights• Improve customer data penetration • Engineering assist in capacity and coverage

planning

• Dark red BIN : Negative Traffic growth

• Addition of 21GB daily from a 2.4km LTE cell

• IBS configured only with 3G and No LTE.

• 3G IBS traffic reduction with increased LTE traffic

• Low data speed experiencing inside IBS

Data Reduction in Customer In-Building

• Completion of Island wide LTE Expansion project

• Comparison of Data Traffic growth for two years

• Analysis for Districts and DSDs

• Identification of strong and weak areas

• Insights for Sales & Marketing promotions

• Capacity and bandwidth increment

• LTE device penetration

Data Traffic Growth Analysis

Data Traffic Demand Pattern

• Incremental growth

• Data traffic usage on Full moon days

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Daily Total Data Traffic

• Aftermath of Easter attack (21/04/2019)

• Social media ban lift – highest data download per day

Lowest

Highest

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Data Traffic (TB)

DL UL

BENCHMARKING & DRIVE TESTING

• Web browsing : Plays important QoE in MBB• Benchmark of Webpage Loading Time • Testing of popular websites• Dynamic content changes• Accuracy of test results

Suggestion:

A Sample Webpage for Objective testinghosted in different geographical locations,to be introduced

Parameters:

Web Page loading time Downlink/uplink bandwidth RTT Device dependency A Web Page MOS

Web Page Loading

• Receiving or making a CS call with background data

• Data disconnection• Reduction of data speed

Cause• Multi RAB scenario• CSFB to direct 2G • 3G to 2G handover• Data disconnection in 2G

Rectification I-RAT handover audit Activation of Voice Service Optimization

for Multi RAB Feature

Data Experience with Continuing Voice

Android application developed to collect service quality related voice and broadband issues as well as no coverage

issues using end users’ location data

Main Menu

SQ Zoom Mobile App

GUI to monitor and rectify collected end user issues Issue Rectification process

SQ Zoom Mobile App

Ishantha Pandigamage ishanthap@mobitel.lk

Ruwan Liyanageruwanl@mobitel.lk