quality of service for…. mobile, fixed, roaming,...

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Quality of Service for….

mobile, fixed, roaming, billing

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Speech evaluation :

- where did we start from

- the product / applications today

- the speech quality evaluation method

- ITU - T activities

- calibrations

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In 1993, Ascom delivered the …..

first system in the world to use real speech for

speech quality evaluation

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AvgQualIF

Motivation : RxQual = speech qualitysp

eech

qua

lity

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MobilkomMax.mobil

Mobistar

Radiomobil

Tele Danmark MobileSonofonMobilix

France Telecom MobileNortel Matra Cellular

T-MobilLucentMannesmann

Hutchison

Westel

P.T. SatelindoTelkomsel

Esat Digifone

Omnitel

ONPT Marocco

Netcom

Isla Communic.

era GSM

TMNTelecelMain Road

MTSKB Impuls

Telefonica MovilesAirtel

Telia

MOPT Lucent

Swisscom

Etisalat

Cellnet

Airtouch Intl.

Nokia

Pannafon

Chungwa

Ascom speech evaluation round the world

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End to end measurements :End to end measurements :

Speech quality (excellent, good, medium, poor, bad )

Ping Pong Robotic voice

EchoEcho

Signal level

Silence

Speech samples in use : English, French, German, Mandarin,Cantonese

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Products on the market :

mobile network measurements --- QVoice

fixed network measurements ------ QNet

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Q V M I n d o o rQ V M O u t d o o r

Q V P

Q V o i c e

1 . . . 4

G P S A n t e n n a

Q V S

Q V o i c e

M e a s u r e m e n tD a t a

Q V S

Q V MC e l l u l a rN e t w o r k 1 . . . 4

I S D N / P S T N

C a l l s , S p e e c h S a m p l e s

QVoice Principles of operation

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Purposely designed QVoice hardware for :

Indoor measurements Drive tests

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QVoice Results analysis :

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QNetend-to-end network

performance measurementfor PSTN/ISDN/GSM

switching quality

transmission quality

charging quality

from a customer’s point ofview

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QNet: different applications simultaneously

Q-Statistics Q-Monitoring

Q-Analysis

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LAN

QNet PUQNet PU

S0

QNet CUQNet PU

S0, a/bClient 1

Client n

ISDN / PSTN

Server

TSU

S0, a/b S0, a/bRS232 RS232

RS232

QNet system architecture

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QNet supports complex test scenarois

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Parameter ISDN PSTNteleservice, bearer capability Y Y

time, date Y Y

duration Y Y

call progress indicator Y

signaling tone measurement Y

d-channel protocol analysis Y

cause/location value Y

unsuccessfull call attempt Y Y

connection setup delay Y Y

connection release delay Y

unsuccessfull release attempt Y Y

premature release Y Y

Switching parameter

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Parameter ISDN PSTNloop transfer delay Y

BERT (G.821: ES, SES, DM) Y

unweighted noise (O.41) Y Y

weighted noise (O.41) Y Y

impulsive noise (O.71) Y Y

notch noise Y Y

envelope delay distortion Y Y

interruptions (O.61, O.62) Y Y

echo: level/delay (G.122, sine-burst) Y Y

attenuation (on 4 frequencies) Y Y

speech quality measurement (Ascom PACE) Y Y

Transmission parameter

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Parameter ISDN PSTNcharging out of rating Y Y

initial charge out of rating Y Y

no charging Y Y

CDR verification Y Y

Charging parameter

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PACE :

a robust objective speech quality assessment

testing wireless & wired networks in service

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3 types of objective methods :

Comparison of transmitted signal and a reference

Absolute Estimation without known reference e.g. INMD

Transmission Rating from knowledge of network e.g. E model

PACE is a comparison method

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Spe

ech

Coder

Source

Signal

Coded

Signal

Transm

ission

Channel

Decoder

Source Coding

Sound PressureProduced by Talker

Room Noise

Loss BetweenMicrophone and Earphone

Loss BetweenEarphone and Microphone

Transmission Path BetweenEarphone and Eardrum

Attenuation

Delay / Echo

Distortions

Time-Variation

Noise

Room Noise

Tra

nsm

ission Param

eters

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PACE Principle

Time align.Level equal.

SourceSignal

SpeechQuality

AssessmentPost-

processing

CodedSignal

Pre-processing

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PACE Preprocessing

HammingWindow DFT

TimeSpreading

Critical BandFiltering

| |

FrequencySpreading

CodedSignal

SourceSignal

ToAssessmentToAssessmentToAssessment

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Similaritycalculation

forfourth

energylevel


forthird

energylevel


forsecondenergylevel


forfirst

energylevel

SimilarityWeightingdependent

onenergylevel

FromPreprocessingFromPreprocessingFromPreprocessing

////

To PostprocessingTo PostprocessingTo Postprocessing

PACE Assessment

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dcxbxaxMOS +++= 23

xxx MOSpMOSpMOSp

Maping Auditory distance to the MOS

X

MO

S

PACE Postprocessing

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Codecs and Systems used to calibrate PACE

G.711 64 kbit/s PCM

G.726 32 kbit/s ADPCM

IS-54 8 kbit/s American Cellular

GSM-FR GSM Full Rate

G.729 8 kbit/s CS-ACELP

G.728 16 kbit/s Low-Delay Code Excited Linear Prediction

JDC 3.45 kbit/s Japanese Digital Cellular (Half Rate)

DCME Digital Circuit Multiplication Equipment: Quad-Coder, DTX-240 (24 kbit/s variable)

IS-9x CDMA 8 kbit/s Code Division Multiple Access

Multiple Transcodings, Random -Burst frame erasure, Random bit errors

Circuit noise, Comfort noise, etc.

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Calibration results presented to ….

ITU-T SG 12 Q 13

Speech Quality Expert Group (SQEG)

2nd international workshop on

Advances in Objective Speech Quality Assesment

September 98 , UK

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Results of ITU-T Supplem. 23 test data, Exp.1

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PACE

MO

S

ρ ρ = 0.955

Experiment 1: Interworking with fixed and mobile codecs (G.726, G.728 …).Multiple encodings by tandeming with other coding standards.

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Correlations between different Algorithms and MOS

Experime Languag eCand. 1 Cand. 2 Cand. 3 Cand. 4 Cand. 5 PACEExp1 French 0.94 0.92 0.82 0.93 0.96 0.94Exp1 Japanese 0.94 0.86 0.87 0.94 0.93 0.94Exp1 English 0.96 0.83 0.89 0.92 0.94 0.97Exp2 French 0.95 0.37 0.94 0.97Exp2 Japanese 0.93 0.96 0.41 0.91 0.95Exp2 English 0.94 0.96 0.47 0.9 0.97Exp3 French 0.74 0.74 0.74 0.75 0.94Exp3 Italian 0.95 0.71 0.86 0.46 0.94Exp3 Japanese 0.91 0.85 0.88 0.55 0.92Exp3 English 0.82 0.85 0.82 0.65 0.93

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QVoice (mobile) QNet (fixed)

PACE speech evaluation

testing of Interconnected networks

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BRA

LAN

BRA, PRA, a /b

Client 1 Client nClient 2 Applicat ions

QNet

Server

QNet

GSMMSC BSC BTS

BRA, a /b

PSTN / ISDN

PU

QVoice

Customer

QVoice

GSM

PU

BRA, a /b

PSTN / ISDN

PU

GSM

QoS in an Interconnected Environment

quality of service for…. mobile, fixed, roaming,...

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