Minimization of Drive Test (MDT) - itu.int · correlate this information with other events (RSCP, Ec/N0, etc.) LTE • Immediate MDT: LTE1308 (LTE16) enables GPS periodic position

Minimization of Drive Test (MDT)

An Innovative Methodology for Measuring

Customer Performance on Mobile Network“The GeoSynthesis Project”

Andrea Scaloni

ITU Workshop on "Benchmarking of emerging technologies and applications. Internet related performance measurements"

Geneva, Switzerland, March 11th 2019

Confidential © Nokia 2016

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What is MDT and how does it work?

Agenda

Key Performances Indicators available

Potentiality of MDT for Operators, TLC, Vendors

Agenda


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Agenda



Agenda


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Main strengths:• Accuracy: plain GPS data with high precision (< 10 m

in outdoor environment)

• Simplicity: no terminal agent to be installed on

friendly users’ terminals, nor probes tapping data from

the network, no high-resolution maps

• Convenience: effective methodology for drive test

minimization

• Short lead time: data can be collected by centralized

systems (Data Collector) and processed to be

available a short time after collection

• Statistical relevance of georeferenced data

• Flexibility: off-the-shelf modules & bespoke reports

thanks to low-level data made available to network

optimization engineers for customized aggregation

and correlation.

• No Impact on User Plan data throughput or extra

billing for final user

MDT is built on three main pillars:

1. Periodic reporting of GPS location of the

UE, if the GPS receiver is enabled and the

UE supports GPS reporting over Layer 3

(RRC Measurement Report)

2. Periodic reporting of legacy/ordinary L3

and L2 measurements at UE and NB/eNB,

already used for signaling and radio

resource management

3. MDT Data collector and Big Data platform

for processing and analysis

The Minimization of Drive Tests (MDT) concept

A NEW methodology was NECESSARY to

manage and process a big amount of data.

A SMART and EFFICIENT process with

different METHODOLOGIES to share data to

different stakeholders


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UMTS• The feature RAN2496 (RU50) enables sending

periodic GPS measurements locations of UE,

supporting UE-Based reporting during CS/PS

connection. Only UEs in Cell_DCH state

(Immediate MDT) will report measurements

• Periodicity from 2 to 32 s

• Measurements are contained in measurements

report between UE and RNC and it possible to

correlate this information with other events

(RSCP, Ec/N0, etc.)

LTE• Immediate MDT: LTE1308 (LTE16) enables

GPS periodic position identification of UEs via

Cell trace interface eNB in connected mode.

• The information can be correlated to other

network events or UE using call trace

• Reporting interval from 120 ms to 60 min

• Logged MDT: LTE 1049 (LTE15A) enables GPS

periodic position identification with radio

information of UEs in idle Mode.

• Logging interval from 1.280 to 61.440 s

• Logginq duration from 10 to 120 min

UMTS : UE in Connected

Mode and GPS enabled

Positioning information source (3GPP TS 37.320)

RNC

UMTS

NodeB

LTE

NodeB

L3 Data Collector

LTE: UE in Connected and

Idle Mode and GPS

enabled

L3 Data Collector

GPS reporting capability of UE from real

networks:

UMTS: 20 ÷ 25%

LTE: 3 ÷ 5%

Confidential

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The GeoSynthesis Project

Network Capacity and Performance optimization is best supported by

georeferenced information providing a clear view about network quality,

radio signal coverage and traffic localization.

Specific events or complete call traces can be located on map for

hundreds of thousands of users.

This is a brand new process and, in order to take the maximum value from

this comprehensive source of information, the GeoSynthesis Project was

built around this concept.

MDT opens an innovative approach

to Network Capacity and

Performance Optimization with GPS

georeferenced data correlated to

radio events reported in the UMTS

and LTE signaling messages.


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RNC

UMTS

NodeB

LTE

NodeB

UE Signalling

Statistical Anonymous Data

ProcessingL3 Data Collector

UMTS

L3 Data Collector

LTE

Analysis and correlation of

Radio Measurements

End-User Analysis

• Radio Levels

• Radio Quality

• Radio Path Loss

• Radio

Propagation

• Distance UE-NB

• UE Profiling

• Traffic Analysis

• Mobility Analysis

Traffic maps

Interference maps

Coverage maps

MDT data processing : Nokia GeoSynthesis Ecosystem

Event maps

UE Signalling

Average figures

Mid-sized city (100 nodes), per dayUMTS LTE

Distinct users ~ 2×104 ~ 5×104

Connections ~ 2×105 ~ 8×105

GPS & measurement reports ~ 5×106 ~ 2×106


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Agenda


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MDT measurements in detail (UMTS)

Connected Mode

• GPS location shape: latitude, longitude, altitude, uncertainty

semi-axes

• RSCP and Ec/N0 of up to 3 Active Set cells

• RSCP and Ec/N0 of up to 2 best monitored cells

• Ue Tx Power

• UeRxTxTimeDifference Type 1 for each of the Active Set cellsLayer 3

Layer 2

• Round Trip Time for each radio link in Active Set

• Transport Channel DL BLER for each radio link in Active Set

• SIR and SIR Error

Unlike LTE, UMTS has quite a few Layer 2 periodic reports: payload

and TTI assignment are not available. Payload can be retrieved with

other non-periodical internal RNC reports and pivoted on each GPS

coordinate. TTI assignment cannot be retrieved, thus preventing a

reliable throughput estimation.

Idle Mode

Estimated distance over the radio path


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MDT measurements in detail (LTE)

Idle ModeConnected Mode

• GPS location shape: latitude, longitude, altitude, uncertainty semi-

axes

• RSRP and RSRQ of serving cell (primary cell in case of CA)

• RSRP and RSRQ of 1st to 8th monitored LTE intra-frequency

neighbour cells, identified with PCI

Layer 3

Layer 2

• PUCCH and PUSCH SINR

• Power Headroom

• Timing Advance (instantaneous or continual)

• Rank Indicator

• Single/Dual code word Tx

• Single/Dual code word Tx failures

• Downlink/uplink delays

• Downlink/uplink PDCP data volumes

• Number if TTIs with buffered data

• Wideband CQI

• Uplink Modulation and Coding Scheme

• PDSCH and PUSCH Physical Resource Blocks allocation

• GPS location shape: latitude, longitude, altitude, uncertainty semi-

axes

• Acquisition timestamp

• RSRP and RSRQ of serving cell

• RSRP and RSRQ of 1st to 8th monitored LTE intra-frequency

neighbour cells, identified with eutraCelId

• RSRP and RSRQ of 1st to 8th monitored LTE inter-frequency

neighbour cells, identified with eutraCelId (**)

• RSCP and Ec/N0 of 1st to 8th monitored UMTS neighbour cells,

identified with PSC

• RxLev of 1st to 8th monitored GSM inter-RAT neighbour cells,

identified with BSIC

(**) Inter-frequency layering policies overridden: lower-priority

layers are measured by Idle UE even when the higher-priority

layer is beyond threshSrvLow

MIMO

VoLTE MOS (*)

L2 Throughput

(*) Modified Wideband E-Model (ITU-T G.107.1)

No MDT data


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Agenda


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• Replacement of drive tests for site

certification and quality assessment

• Coverage analysis

• End-user experience

• Hot spot detection and network capacity

upgrades

• Detection of system/coverage anomalies:

sector inversion/rotation

• Tracking of single users/connections

• Radio channel characterization

MDT potential for Operators, TLC, Vendors


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• Real network performance straight from the user in real traffic conditions

• Area of analysis wider and far more significant than in a classical drive test, which is limited only to few roads in a

short time frame

• 1 MDT campaign: >20000 Km2/day (1 Italian region)

• 1 Drive Test campaign: <100 Km2/day/person

• Time & cost saving: No Drive Test tools (Nemo/TEMS), no car to be used, no people to be sent on field

• Saving of more than 60%

• Faster process (data collection, elaboration and report generation); more areas can be simultaneously analyzed without

lack of resources like in classical drive tests

• Wider statistical basis than in classical drive tests, and wider list of KPI for analysis

Replacement of drive tests for site certification and quality

assessment


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Coverage analysis

RSRP coverage map

Best Server map

E-RAB drop events

Localization of main radio events with GPS precision (OSS KPIs offer cell-level

detail at most)

Network

Optimization

& Targeted

Capacity UpgradeOPEX Reduction

&

Efficiency

Increase

Best server maps from real measurements and

not simulated by planning tools

Localization of LOW coverage/HIGH

interference areas


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End-user experienceL2 downlink data volumes

L2 downlink throughput

Wideband CQI MIMO usage


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Hot spot detection and network capacity upgrades

identification• Detection of local peaks of traffic (density of

MDT measurement reports) in space and

time over a given search area

• Differentiation of traffic type (indoor, outdoor,

mobility)

• Analysis of network performances during

peak hours: serving cells, KPIs within the

hotspot

Accurate small cells deployment plan

(best candidates’ list to ensure high

ROI)

Identification of high traffic areas that

requires capacity upgrade

Local peak of

traffic

Localization of

traffic peak

Drill-down of

traffic amount on

pixel basis

(10x10 m)


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Detection of system/coverage anomalies: sector

inversion/rotation

WR13L2

WR13L1

• Sector inversion/rotation is evaluated by comparing the barycentre of the space distribution of measurement samples with the nominal azimuth of the sector related to those samples

• If the barycentre of two distributions reciprocally fit (within a margin of 45°) different azimuths, then a sector inversion is detected

• If the barycentre of one distribution doesn’t fit its nominal azimuth but there is no other reciprocal fitting with any other azimuth, then a sector rotationis detected


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Radio channel characterization

• Innovative approach to cellular

radio propagation analysis, by

exploiting MDT features. UEs are

allowed to report their radio

measurements (e.g. RSRP,

RSRQ) and GPS coordinates

when available. The observation

of local variations of RSRP and

TA, together with GPS position,

opens to new fields of

investigation in the mobile radio

channel, unreachable with drive

tests, e.g.:

• Multi-path fading and level

notches

• Coherence bandwidth

• Doppler shift

• Paper published on IEEE Access

(Jan. 2019)

https://ieeexplore.ieee.org/d

ocument/8620498/

https://ieeexplore.ieee.org/document/8620498/


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Tracking of single users/connections

Report iniziale

• The geo-location of every measurement report within a single call allows a complete knowledge of the

connection history in time and space

• It is possible to know the experienced radio conditions before any event traced from L3 signaling

Connection starts

Connection drops

Connection drops

Connection starts

Mobility connection Outdoor/indoor connection


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Venice February 26 2017 – Trial Trace with GeoSynthesis during Venice Carnival

User density distribution during a single day from 00:00 to 23:59 with a sampling period of 5 minutes in area of 10x10 m

A City Day Life during Carnival

Detection of Mobility Flow form Smart City Concept


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What could be next?

• GPS reporting penetration (currently: 3÷5% in LTE) can be increased: some

UE manufacturers do not implement all MDT features for commercial reasons

• End-user measurements can be improved: throughput estimation, layer-2

resource (TTI) scheduling

• Reporting with MDT of additional measuraments already available from UE

internal sensors for innovative uses cases like :

• temperature

• humidity

• barometric pressure

• magnetic field

• thermal noise

• MDT extension to 5G

Documents

Minimization of Drive Test (MDT) - itu.int · correlate this information with other events (RSCP, Ec/N0, etc.) LTE • Immediate MDT: LTE1308 (LTE16) enables GPS periodic position