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Voice over Wi-Fi Test Methodology

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Voice over Wi-Fi Test Methodology Powered By Docstoc
					Toyo and Azimuth

Voice over Wi-Fi
Test Methodology

Fanny Mlinarsky
Founder and CTO, Azimuth
May 2005
Outline

• VoWiFi - history and current status
• IEEE 802.11 overview and update
• Wi-Fi Alliance overview and update
• Azimuth VoWiFi test solution
• Azimuth demonstration                     VoIP




                                 Cellular          Wi-Fi



                                                      Slide 2
VoIP-Data Convergence




  Traditional Enterprise     Converged Telephony
      Connectivity            and Data Networks
                           First VoIP products emerged in 1996


                                                     Slide 3
VoWiFi - Legacy PBX Systems
• VoWiFi manufacturers
   –   Cisco, Symbol, Spectralink
   –   Spectralink WiFi phones
       available since 1999
   –   802.11b only for now
• Most IP PBXs use
  proprietary protocols
   –   Cisco SCCP
       (skinny call control protocol)
   –   Alcatel UA
   –   NEC Protims
   –   Avaya CCMS
   –   Nortel UniStim
   –   Siemens CorNet IP
   –   Mitel MiNet
   –   Spectralink SVP
• Standard IP telephony protocols
   –   Session Initiation Protocol (SIP)
   –   H.323
   –   Media Gateway Control Protocol (MGCP)



                                               Slide 4
Cell-WiFi Convergence


                                       Private Network
                                                           Base
Dual-Mode                                                 Station
  UMA                           Cellular Radio Access    Controller     Core
                                    Network (RAN)
 Handset                                                  (BSC)        Mobile
                                                                      Network


                                          IP Access
                                           Network
                                                            UMA
                                                          Network
                              Unlicensed Mobile Access   Controller
                                   Network (UMAN)          (UNC)



• Significant Cell-WiFi Convergence efforts throughout the
  telecom industry
   – 3GPP GAN (generic access network), a.k.a. UMA (unlicensed mobile access)
   – 3GPP WLAN Interworking (IMS)
   – SCCAN (seamless converged communication across networks)


                                                                            Slide 5
Cell-WiFi Convergence Standards
• 3GPP GAN (generic access network),
  a.k.a. UMA (unlicensed mobile access)
   –   An extension of GSM/GPRS
       3GPP* to Wi-Fi
   –   Alcatel, AT&T Wireless,
       British Telecom, Cingular,
       Ericsson, Kineto Wireless,
       Motorola, Nokia, Nortel Networks,
       O2, Rogers Wireless, Siemens,
       Sony Ericsson, T-Mobile US
• 3GPP WLAN Interworking
  IMS (internet multimedia subsystem)
   –   VoIP, SIP-based
   –   SBC, Bellsouth, Cingular, Rogers (Canada), Telefonica (Mexico), Mobilkom (Austria),
       GoMobile (Malta), Azaire Systems
• FOMA (freedom of mobile multimedia access)
   –   NTT DoCoMo N900iL dual-network 3G FOMA / WiFi handset
   –   SIP-based
• SCCAN (seamless converged communication across networks)
   –   First converged system, SIP-Based
   –   Proxim, Motorola, Avaya


                                                          *3rd Generation Partnership Project
                                                                                         Slide 6
Voice Quality

• ITU-T Voice Quality Standards
  – MOS (mean opinion score)
    uses a wide range of human
    subjects to provide a subjective
    quality score (ITU-T P.800)

  – PESQ (perceptual speech quality measure)
    sends a voice pattern across a network and
    then compares received pattern to the original
    pattern and computes the quality rating (ITU-T P.862)

  – E-Model
    computes Rating Factor or R-Factor as a function
    of delay and packet loss;
    R-Factor directly translates into MOS (ITU-T G.107)


                                                            Slide 7
ITU-T PESQ Model




                   Slide 8
ITU-T E-Model (G.107)




                        Slide 9
E-Model Parameters
Parameter                                 Abbr.   Unit    Default Value   Permitted Range
Send Loudness Rating                       SLR     dB          +8              0 … +18
Receive Loudness Rating                    RLR     dB          +2             -5 … +14
Sidetone Masking Rating                   STMR     dB          15              10 … 20
Listener Sidetone Rating                  LSTR     dB          18              13 … 23
D-Value of Telephone, Send Side            Ds       -           3              -3 … +3
D-Value of Telephone Receive Side          Dr       -           3              -3 … +3
Talker Echo Loudness Rating               TELR     dB          65              5 …65
Weighted Echo Path Loss                   WEPL     dB          110             5 ... 110
Mean one-way Delay of the Echo Path         T      ms           0              0 … 500
Round-Trip Delay in a 4-wire Loop           Tr     ms           0             0 … 1000
Absolute Delay in echo-free Connections    Ta      ms           0              0 … 500
Number of Quantization Distortion Units    qdu      -           1              1 … 14
Equipment Impairment Factor                 Ie      -           0              0 … 40
Packet-loss Robustness Factor              Bpl      -           1              1 … 40
Random Packet-loss Probability             Ppl      %           0              0 … 20
Circuit Noise referred to 0 dBr-point      Nc     dBmOp        -70            -80 … -40
Noise Floor at the Receive Side            Nfor   dBmp         -64                 -
Room Noise at the Send Side                Ps     dB(A)        35              35 … 85
Room Noise at the Receive Side             Pr     dB(A)        35              35 … 85
Advantage Factor                            A       -           0              0 … 20

          G.107 – Default values and permitted ranges for the parameters
                                                                                            Slide 10
R-Factor to MOS Conversion




                             Slide 11
Voice over Wi-Fi Use Cases
• SOHO
  –   WiFi or WiFi-Cell handset, soft phone
  –   Service providers: Vonage, ATT CallVantage, Net2Phone
  –   No handoff, low capacity, basic security
  –   Range
• Enterprise
  –   WiFi or WiFi-Cell handset, soft phone
  –   Range
  –   Handoff speed
  –   Call capacity
  –   Security
• Public Access (Wi-Fi Hotspots)
  –   WiFi-Cell handset, soft phone
  –   Range
  –   Call Capacity
  –   Roaming issues



                                                              Slide 12
Voice Network Requirements

• Client
  – Range
  – Power-save
  – Fast roaming


• Infrastructure
  – Call capacity
  – Delay, jitter,
    packet loss
  – Power-save
  – Fast roaming




                             Slide 13
IEEE 802.11 Standards for VoWiFi

• Minimize bursty packet loss by controlling roaming time
           802.11r Fast Roaming
           802.11k Radio Resource Measurement (RRM)
           802.11i Pre-authentication
• Manage power consumption
           802.11e Power-save
• Maintain isochronous nature of voice packet
  streams by controlling delay, jitter and packet loss
           802.11e Quality of Service (QoS) prioritization




                                                             Slide 14
  IEEE 802.11 Standards

                                       802.11s      802.11p
                                        Mesh         WAVE

                                       802.11r     802.11u
                                      Fast Roam    WIEN SG
                       802.11h
                      DFS & TPC        802.11e      802.11v
                                        QoS          WNM
      802.11 (’99)      802.11i
        MAC +           Security                                          ADS SG
                                       802.11k
      2Mbps PHY
                                        RRM         802.11n
                         802.11f
                                                     High                 APF SG
MAC                     Inter AP
                                                  Throughput    802.11T
                                      802.11m
                                                  (>100 Mbps)    Test
                                       Maint
PHY                   802.11a (’99)                             Methods
                        54 Mbps
                       5GHz PHY                                           Study
      802.11b (’99)     802.11g                                           Groups
        11 Mbps         54 Mbps                   Current
      2.4GHz PHY      2.4GHz PHY
                                                   Work

             Published
                                                                          Slide 15
QoS Protocols
• WMM (Wireless MultiMedia)
   –   Subset of 802.11e
   –   Specifies 4 priorities: voice (highest), video, background, best effort (lowest)
   –   Wi-Fi certification has started in September 04
• AC (Admission Control)
   –   Subset of 802.11e
   –   Enables APs to reject calls when call capacity is reached
• WMM SA (WMM Scheduled Access)
   –   Subset of 802.11e
   –   Specifies polling mechanism to optimize bandwidth utilization
   –   Wi-Fi certification expected in July 05
• APSD (Automatic Power Save Delivery)
   –   Subset of 802.11e
   –   Unscheduled APSD works with WMM
   –   Scheduled APSD works with WMM-SA
• SVP (Spectralink Voice Priority)
   –   Proprietary prioritization scheme that combines priority mechanism with tight synchronization
       to optimize bandwidth utilization



                                                                                          Slide 16
Security Protocols

• WPA
 –   Subset of 802.11i
 –   TKIP, WEP
 –   EAP-TLS, PSK (pre-shared key)
 –   WPA Enterprise (TLS, PSK)
 –   WPA Personal (PSK)

• WPA2
 –   Entire 802.11i
 –   Superset of WPA
 –   AES support
 –   Pre-Authentication to help with 802.11r fast roaming




                                                            Slide 17
      WFA and IEEE Timeline
IEEE                            11e                                               11k                           11r        11n
Standards                                                                                                       11p        11s
Core Wi-Fi                                802.11a+b+g (basic wireless LAN IEEE Specs)
Functionality
                                                                  802.11h+d

                                                  WMM (802.11e-based QoS)

                                                                             WMM Scheduled Access
Multimedia
Enablers                                                                          WMM Power Save

                                                                 Consumer Electronics Framework phase 1

                                                                                  Consumer Electronics Framework phase 2

                                      Wi-Fi Protected Access (WPA) (802.11i-based Security)

                                                       WPA2 (full 802.11i)

Security                                                    Extended EAP (Enterprise)

                                                                                Public Access

                                                                                         Simple Configuration

Voice & Data                                                         Wi-Fi Cellular Convergence (WCC)
Convergence
                                                                                        Voice over Wi-Fi




                Q1/05   Q2/05    Q3/05           Q4/05           Q1/06          Q2/06            Q3/06          Q4/06

                                                                                                           Slide 18
15 minute break




                  Slide 19
Azimuth Automated
Test Family
AAT




               Slide 20
   Azimuth Automated Tests - AAT
   A Systematic Approach to Automation
  Precise control of physical                             Repeatability and real
     layer to effect motion                               device performance
    algorithms and motion
            protocol
                                 Motion
                                 Control      Isolation


                                                                    Automated
User programmable        Azimuth                                    configuration and
                                                  DUT Control
  multi-personality     testMAC™                                    control and
                                                    SDKs
              MAC                                                   automatic reporting


                                   TCL         testMAC™
                                               testMAC™
                                Automation   Programmable
                                             Programmable
                                  Engine       Extensions
                                               Extensions

Programmatic control of every                             User programmable packet-
 test system and DUT function                             level, protocol engine


                                                                            Slide 21
    Azimuth Automated Tests
    Automated Turnkey Test Solutions
                                           Azimuth W-Series
                                             Test Platform




              Performance Tests                                     Certification Tests




      Data
                          Voice Applications            Wi-Fi Alliance               Cisco CCX
    Application



             Infra-                     Infra-
 Client                  Handset                        Client and AP                     Client
           structure                  structure
Rate Vs.   Client        Range Vs.   Call Capacity     11a, b, g with WPA           CCX Version 3
Range      Capacity      MOS                           WPA2
Roaming    Assoc.        Roaming                       WMM
           Performance
           Forwarding
           Rate


                                                                                     Slide 22
  VoWiFi Call Capacity Test

Test Description: Capacity vs. QoS Performance of Wi-Fi infrastructure

                                          Features

                                           • Emulate voice traffic from multiple
                                             phones


                                           • Emulate background data traffic


                                           • Measure delay, jitter and packet
                                             loss* vs. number of calls and
                                             background traffic



    Test Diagram       Test Results
                                                      * Per IETF RFCs 2544, 2889

                                                                             Slide 23
    VoWiFi Call Capacity Test

Test Description: Capacity vs. QoS Performance of Wi-Fi infrastructure

                                          Features

                                           • Verifies the ability of infrastructure
                                             to prioritize voice traffic and to
                                             reject or redirect calls when
                                             capacity is reached
                                           • Test APs, wireless switches and
                                             other infrastructure devices
                                           • Measures infrastructure capacity
                                             vs. R-Factor and MOS quality
                                             scores computed from the
                                             measured packet loss rate, delay
+ click to enlarge
                                             and jitter
        Test Diagram   Test Results


                                                                      Slide 24
    VoWiFi Call Capacity Test

Test Description: Capacity vs. QoS Performance of Wi-Fi infrastructure

                                          Features

                                           • Verifies the ability of infrastructure
                                             to prioritize voice traffic and to
                                             reject or redirect calls when
                                             capacity is reached
                                           • Test APs, wireless switches and
                                             other infrastructure devices
                                           • Measures infrastructure capacity
                                             vs. R-Factor and MOS quality
                                             scores computed from the
                                             measured packet loss rate, delay
+ click to enlarge
                                             and jitter
        Test Diagram   Test Results


                                                                      Slide 25
    VoWiFi Call Capacity Test

Test Description: Capacity vs. QoS Performance of Wi-Fi infrastructure

                                          Features

                                           • Verifies the ability of infrastructure
                                             to prioritize voice traffic and to
                                             reject or redirect calls when
                                             capacity is reached
                                           • Test APs, wireless switches and
                                             other infrastructure devices
                                           • Measures infrastructure capacity
                                             vs. R-Factor and MOS quality
                                             scores computed from the
                                             measured packet loss rate, delay
+ click to enlarge
                                             and jitter
        Test Diagram   Test Results


                                                                      Slide 26
    VoWiFi Call Capacity Test

Test Description: Capacity vs. QoS Performance of Wi-Fi infrastructure

                                          Features

                                           • Verifies the ability of infrastructure
                                             to prioritize voice traffic and to
                                             reject or redirect calls when
                                             capacity is reached
                                           • Test APs, wireless switches and
                                             other infrastructure devices
                                           • Measures infrastructure capacity
                                             vs. R-Factor and MOS quality
                                             scores computed from the
                                             measured packet loss rate, delay
+ click to enlarge
                                             and jitter
        Test Diagram   Test Results


                                                                      Slide 27
    VoWiFi Call Capacity Test

Test Description: Capacity vs. QoS Performance of Wi-Fi infrastructure

                                          Features

                                           • Verifies the ability of infrastructure
                                             to prioritize voice traffic and to
                                             reject or redirect calls when
                                             capacity is reached
                                           • Test APs, wireless switches and
                                             other infrastructure devices
                                           • Measures infrastructure capacity
                                             vs. R-Factor and MOS quality
                                             scores computed from the
                                             measured packet loss rate, delay
+ click to enlarge
                                             and jitter
        Test Diagram   Test Results


                                                                      Slide 28
Handset Range vs. Voice Quality

• Vary path loss between the
  phone and the AP


• Measure packet loss, delay
  and jitter of a phone-AP
  link as a function of path loss


• Use ITU-T E-Model to compute
  R-Factor and MOS vs. range




                                    Slide 29
VoWiFi Handset Range Test
Test Description: Quality of Voice Transmission over Wi-Fi as a
Function of Path Loss, Roaming and Traffic Load

                                         Features

                                          • Automatically validates Voice over
                                            Wi-Fi performance in minutes
                                          • Standard benchmark test to analyze
                                            rate adaptation of handset and AP pair
                                          • Shows R-Factor and MOS
                                            performance of real time voice stream
                                            - measures packet loss, delay and
                                              jitter to formulate MOS score
                                          • Precise RF control allows for
                                            measurement of true range
                                            performance based on actual WiFi-
                                            enabled handsets
    Test Diagram     Test Results


                                                                      Slide 30
 VoWiFi Handset Range Test
Test Description: Quality of Voice Transmission over Wi-Fi as a
Function of Path Loss, Roaming and Traffic Load

                                         Features

                                          • Automatically validates Voice over
                                            Wi-Fi performance in minutes
                                          • Standard benchmark test to analyze
                                            rate adaptation of handset and AP pair
                                          • Shows R-Factor and MOS
                                            performance of real time voice stream
                                            - measures packet loss, delay and
                                              jitter to formulate MOS score
                                          • Precise RF control allows for
                                            measurement of true range
+ click to enlarge                          performance based on actual WiFi-
                                            enabled handsets
      Test Diagram   Test Results


                                                                      Slide 31
 VoWiFi Handset Range Test
Test Description: Quality of Voice Transmission over Wi-Fi as a
Function of Path Loss, Roaming and Traffic Load

                                         Features

                                          • Automatically validates Voice over
                                            Wi-Fi performance in minutes
                                          • Standard benchmark test to analyze
                                            rate adaptation of handset and AP pair
                                          • Shows R-Factor and MOS
                                            performance of real time voice stream
                                            - measures packet loss, delay and
                                              jitter to formulate MOS score
                                          • Precise RF control allows for
                                            measurement of true range
+ click to enlarge                          performance based on actual WiFi-
                                            enabled handsets
      Test Diagram   Test Results


                                                                      Slide 32
 VoWiFi Handset Range Test
Test Description: Quality of Voice Transmission over Wi-Fi as a
Function of Path Loss, Roaming and Traffic Load

                                         Features

                                          • Automatically validates Voice over
                                            Wi-Fi performance in minutes
                                          • Standard benchmark test to analyze
                                            rate adaptation of handset and AP pair
                                          • Shows R-Factor and MOS
                                            performance of real time voice stream
                                            - measures packet loss, delay and
                                              jitter to formulate MOS score
                                          • Precise RF control allows for
                                            measurement of true range
+ click to enlarge                          performance based on actual WiFi-
                                            enabled handsets
      Test Diagram   Test Results


                                                                      Slide 33
 VoWiFi Handset Range Test
Test Description: Quality of Voice Transmission over Wi-Fi as a
Function of Path Loss, Roaming and Traffic Load

                                         Features

                                          • Automatically validates Voice over
                                            Wi-Fi performance in minutes
                                          • Standard benchmark test to analyze
                                            rate adaptation of handset and AP pair
                                          • Shows R-Factor and MOS
                                            performance of real time voice stream
                                            - measures packet loss, delay and
                                              jitter to formulate MOS score
                                          • Precise RF control allows for
                                            measurement of true range
+ click to enlarge                          performance based on actual WiFi-
                                            enabled handsets
      Test Diagram   Test Results


                                                                      Slide 34
 VoWiFi Handset Range Test
Test Description: Quality of Voice Transmission over Wi-Fi as a
Function of Path Loss, Roaming and Traffic Load

                                         Features

                                          • Automatically validates Voice over
                                            Wi-Fi performance in minutes
                                          • Standard benchmark test to analyze
                                            rate adaptation of handset and AP pair
                                          • Shows R-Factor and MOS
                                            performance of real time voice stream
                                            - measures packet loss, delay and
                                              jitter to formulate MOS score
                                          • Precise RF control allows for
                                            measurement of true range
+ click to enlarge                          performance based on actual WiFi-
                                            enabled handsets
      Test Diagram   Test Results


                                                                      Slide 35
VoWiFi Roaming Performance

• Emulate motion of the phone
  using programmable
  attenuators
• Monitor source and destination
  Wi-Fi channels and Ethernet
• Derive roaming time from data
  captures




                                   Slide 36
  Roaming Process

        AP1                                             AP2                              AP1
max
                                                                              Path to AP1

Atten

                                                                              Path to AP2
min
                                     Test cycle

                       Data rate transition




                                          t ASSOCIATE

                                                          t DATA
                t TRANSITION

                                       t SCAN
                                         t ROAM
              Last data packet                            First data packet
                  before roam                             after roam



                                                                              Slide 37
VoWiFi Roaming Test

Test Description: Roaming Performance of Wi-Fi Handsets

                                       Features

                                       • Measures the roaming time and
                                         quality of voice vs. roam
                                       • Detailed breakdown of the roaming
                                         time helps optimize roaming algorithm
                                       • Motion and fail-over roaming
                                         emulation of real world scenarios
                                       • Precise RF control and distributed
                                         monitoring present a wealth of
                                         information on handset performance
                                         as a function of motion

   Test Diagram     Test Results



                                                                   Slide 38
VoWiFi Roaming Test

Test Description: Roaming Performance of Wi-Fi Handsets

                                       Features

                                       • Measures the roaming time and
                                         quality of voice vs. roam
                                       • Detailed breakdown of the roaming
                                         time helps optimize roaming algorithm
                                       • Motion and fail-over roaming
                                         emulation of real world scenarios
                                       • Precise RF control and distributed
                                         monitoring present a wealth of
                                         information on handset performance
                                         as a function of motion

   Test Diagram     Test Results



                                                                   Slide 39
                     Sample Roaming Test Results
                                Fastest roaming client - test results reported by the Azimuth test script


                      0.2


                     0.18


                     0.16                                                                                   Assoc Resp > Data


                     0.14                                                                                   Assoc Req > Resp

                                                                                                            Auth Resp > Assoc Req
Roam Time, Seconds




                     0.12
                                                                                                            Auth Req > Resp

                      0.1
                                                                                                            Probe > Auth Req

                     0.08                                                                                   Data > First Probe


                     0.06


                     0.04


                     0.02


                       0
                            1      2            3           4            5            6           7
                                                       Roam Number


                                                                                                                        Slide 40
Cell-WiFi Handover Test

                          Complete WiFi and
                            VoWiFi
                            performance,
                            conformance
                            and certification


                          QoS vs. WiFi-to-cell
                            handover


                          Cellular test




                                    Slide 41
Wi-Fi is Proliferating

• Environments
   –   SOHO
   –   Enterprise
   –   Public access
   –   Outdoor campus
   –   MAN/WAN
   –   Transportation
   –   Military


• Applications
   – Data
   – Voice
   – Video




                         Slide 42
VoWiFi Call Capacity




                       Slide 43
VoWiFi Call Capacity




                       Slide 44
VoWiFi Call Capacity




                       Slide 45
VoWiFi Call Capacity




                       Slide 46
VoWiFi Call Capacity




                       Slide 47
VoWiFi Handset Range




                       Slide 48
VoWiFi Handset Range




                       Slide 49
VoWiFi Handset Range




                       Slide 50
VoWiFi Handset Range




                       Slide 51
VoWiFi Handset Range




                       Slide 52

				
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