HEARING ISA FASCINATINGSENSATION - ITU · HEARING ISA FASCINATINGSENSATION Dr.-Ing. H. W. Gierlich...
Transcript of HEARING ISA FASCINATINGSENSATION - ITU · HEARING ISA FASCINATINGSENSATION Dr.-Ing. H. W. Gierlich...
VoLTE Terminal Testing and Interworking©HEAD acoustics GmbH 1
HEARING IS A FASCINATING SENSATION
Dr.-Ing. H. W. GierlichManaging Director Telecom Division
© HEAD acoustics GmbH
Challenges in VoLTETerminal Testing and
Interworking
ITU Workshop on “Voice and Video over LTE”Geneva, Switzerland, 1 December 2015
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Outline
A variety of challenges exist in VoLTE testing andinterworking - The following selected topics are addressedin this presentation:
� LTE Setup for Voice Communication - Obstacles� Delay and Delay Testing� Network Impairments, Delay & Jitter Profile Testing� Challenges in Superwideband & Fullband� Positional Dependant Testing of Mobile Terminals� Summary
VoLTE Terminal Testing and Interworking©HEAD acoustics GmbH 2
Advanced speech quality testing © HEAD acoustics GmbHH. W. Gierlich 3
Outline
� Introduction� LTE Setup for Voice Communication - Obstacles� Delay and Delay Testing� Network Impairments, Delay & Jitter Profile Testing� Challenges in Superwideband & Fullband� Positional Dependant Testing of Mobile Terminals� Summary
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Call Handling 4G in a Test Setup
Test EquipmentWith Reference
Access
VoLTENetwork Simulator
DUT
Co-dec
IMS
Signal Generation
&Analysis
Co-dec
IMS registration
VoLTE call
IMS registration
• Both DUT and reference gateway for testing are registerd in the test IMS server
• VoLTE call takes place between DUT and reference gateway• Reference gateway takes care of encoding/decoding
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Difficulties in VoLTE Call Setup
� Network provider flash their own firmware (Branding) with their special VoLTE support => special procedures for IMS Signaling/Registration are needed.
� Network providers use different LTE Cell/Signaling settings/parameters (e.g. LTE Band, MNC/MCC, Security Settings, Shared-Key, etc…). These parameters often are confidential and unknown if not provided.
� SIM-Lock, the device under test needs a special - provider specific -UICC (SIM card) for testing.
� DUTs normally are locked to their home network. In order to connect to the radio tester the correct MNC/MCC settings must be known, otherwise the roaming procedure does not allow VoLTE connections.
� The SIP/IMS registration is very sensitive to errors or unknown SIP messages depending on the implementation of the IMS in the VoLTEnetwork simulators.
� VoLTE settings in DUTs may be fixed (e.g. P-CSCF Address set to a fixed address) -> the address used in the radio tester cannot be configured.
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Difficulties VoLTE Call Setup
� Buggy VoLTE implementation in devices under test (e. g. SIP call negotiation with octet-aligned mode but DUT is sending the speech packets in bandwidth efficient mode).
� If no IMS APN (access point name) or matching PDP (packet data protocol) contexts is available in the DUT => no IMS registration => no VoLTE call.
� IPsec parameters are needed if device under test only work with a secure connection (IMS-AKA).
� No access to VoLTE settings in DUT for changing required parameters for audio tests.
� How to handle eSIM?
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Difficulties in VoLTE Call Setup
=>Most of these issues not only lead to difficulties in testing –the differences in IMS settings prevent interworkin g between
network operators in general!
Solution for testing:Define a generic test mode and IMS setting implemen ted in all
terminals.
Potential solution for interworking:Define a minimum set of IMS settings used in interw orking.
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Outline
� Introduction� LTE Setup for Voice Communication - Obstacles� Delay and Delay Testing� Network Impairments, Delay & Jitter Profile Testing� Challenges in Superwideband & Fullband� Positional Dependant Testing of Mobile Terminals� Summary
VoLTE Terminal Testing and Interworking©HEAD acoustics GmbH 5
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3GPP & GSMA: Delay Testing
Delay measurement direction by cross correlation
Cross correlation avg. FFT Size:65536 Overlap:0,0% Envelope Normalized %
0
20
40
60
80
100
t/s0 25m 50m 75m 0.125 0.15 0.175 0.2
33 ms
Requirement 4G: Roud trip delay MTSI < 190 ms (min. Reqi rement) Performance goal < 150 ms
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Drift: 815 µs/min � 13,6 ppm
Delay in VoLTE - Not Stable, Delay Drift due to Clock Drift
t/s
0.115
0.116
0.117
0.118
0.119
0.12
0.121
0.122
0.123
0.124
0.125
t/s0 20 40 80 100 120%26 27 28 29 30 31
RCV(2)*Source
Receiving Direction
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t/s
0.115
0.116
0.117
0.118
0.119
0.12
0.121
0.122
0.123
0.124
0.125
t/s0 20 40 80 100 120%26 27 28 29 30 31
RCV(2)*Source
Delay Results VoLTE – Clock Drift Compensation
Receiving Direction
t/s
0.136
0.138
0.14
0.142
0.144
t/s0 20 40 80 100 120%29 30 31 32 34 35 36 37 38
RCV(2)*Source
� Clock Drift- Not compensated:
815 µs/min48000 Hz
- Compensated:0 µs/min48000,67 Hz
� Synchronized testing possible
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Call by call delay variation and theoretical background:• Clock syncronization absolutely required to avoid delay drift during
testing• Clock sychronization does NOT allow packet stream synchronization
VoLTE Terminal Delay: Call by Call Variation
Phase shiftbetween packet
streams from callto call
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Call by call delay variation: measurement examples in sending• Delay variation measured over 30 calls• Delay variation within the expected range of 20 ms (packet size)
Delay Testing: Results in Sending
=> In 3GPP:5 Tests, take maximum to
address call to callvariation
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Jitter & Packet Loss – Simulation in Testing
USB
AES/EBUAcoustic
Analog
RF(LTE / 4G)
DUT
HMS II.3HHP III.1
Ethernet
USB
= Speech= Control
EthernetJitter & Packet
Loss byTCN - Profiles
USB
Delay & lossprofiles from
TS 26.131, Rel. 12,synchronized to
audio data
VoLTE NetworkSimulator
Network ImpairmentSimulator (MFE IX)
IP Reference Gateway (MFE VIII.1)
Analog/Digital Interfavce (MFE VI)
Testsystem
VoLTE Terminal Testing and Interworking©HEAD acoustics GmbH 8
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Simulated Jitter & Packet Loss: Typical Test Results
0 20 40 60 80 100 120 140 1600
20
40
60
80
Time [s]
Del
ay [m
s]
delay_profile_20msDRX_10pctBLER_e2e
DelayDrops
0 20 40 60 80 100 120 140 160
0.05
0.1
0.15
0.2
Time [s]
De
lay
[s]
DUT #3 - Delay vs. Time (delay_profile_20msDRX_10pctBLER_e2e)
Delay vs. Time: Profile 1Delay vs. Time: Clean Channel
0 20 40 60 80 100 120 140 1601
2
3
4
5DUT #3 - POLQA vs. Time (delay_profile_20msDRX_10pctBLER_e2e)
Time [s]
PO
LQA
[MO
S]
Profile 1Clean Channel
Increased meandelay due to jitterbuffer increase
POLQA scoresalmost
unchanged
Example for one terminal: 20 ms DRX cycle, 10% BLER
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Outline
� Introduction� LTE Setup for Voice Communication - Obstacles� Delay and Delay Testing� Network Impairments, Delay & Jitter Profile Testing� Challenges in Superwideband & Fullband� Positional Dependant Testing of Mobile Terminals� Summary
VoLTE Terminal Testing and Interworking©HEAD acoustics GmbH 9
Advanced speech quality testing © HEAD acoustics GmbHH. W. Gierlich 18
How does it sound?Frequency response tolerance schemes under discussion;
Superwideband & Fullband with EVS
EVS FB @ 16,4 kbit/s
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How does it sound?….when combining 2 terminals performing within the limits
Interoperability - Superwideband & Fullband with EVS
Fullband:OptimumWorst highpassWorst lowpass
For comparison narrowband:OptimumWorst highpassWorst lowpass
VoLTE Terminal Testing and Interworking©HEAD acoustics GmbH 10
Advanced speech quality testing © HEAD acoustics GmbHH. W. Gierlich 20
Outline
� Introduction� LTE Setup for Voice Communication - Obstacles� Delay and Delay Testing� Network Impairments, Delay & Jitter Profile Testing� Challenges in Superwideband & Fullband� Positional Dependant Testing of Mobile Terminals� Summary
Advanced speech quality testing © HEAD acoustics GmbHH. W. Gierlich 21
Artificial Head & Artificial Ear
• HATS acc. to ITU-T P.58
• Artificial ear acc. to ITU-T P.57
• Positioning acc. to ITU-T P.64
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HHP IV Video
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Positional Robustness 1 / 2 Without Background Noise
3rd octave FFT Size:4096 Overlap:0,0% Hanning Ch.1 - Ch.2 L/dB
-35
-30
-25
-20
-15
-10
-5
0
5
10
f/Hz100 200 500 2000 5000
normal Positiondow nw ards
3rd octave FFT Size:4096 Overlap:0,0% Hanning Ch.1 - Ch.2 L/dB
-35
-30
-25
-20
-15
-10
-5
0
5
10
f/Hz100 200 500 2000 5000
normal Positiondow nw ards
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Positional Robustness 2 / 2 With Background Noise
3rd octave FFT Size:4096 Overlap:0,0% Hanning Ch.1 - Ch.2 L/dB
-35
-30
-25
-20
-15
-10
-5
0
5
10
f/Hz100 200 500 2000 5000
normal Positiondow nw ards
3rd octave FFT Size:4096 Overlap:0,0% Hanning Ch.1 - Ch.2 L/dB
-35
-30
-25
-20
-15
-10
-5
0
5
10
f/Hz100 200 500 2000 5000
normal Positiondow nw ards
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Summary
� Advanced mobile terminals require more advanced and morerealistic testing procedures
� Still many unresolved issues in VoLTE call setup and IMS-b asedinterworking
� VoLTE introduces more variability in communicational qua lity –e.g. for delay and delay variation
� Terminal interworking concerning sound quality in super -wideband and fullband from mouth to ear is critical and still an unresolved topic
� Testing taking into account time variant user behavior an d signalprocessing gets more important – e.g. positional robustne sstesting
VoLTE Terminal Testing and Interworking©HEAD acoustics GmbH 13
Dr.-Ing. H. W. GierlichHead of Telecom Division
© Copyright HEAD acoustics GmbH