Mobile WiMAX Workshop -802.16e-2005 OFDMA

					    802.16e-2005 OFDMA   Mobile WiMAX Workshop

                         August 2006




                                          Mobile WiMAX Workshop

Page 1                                              August 2006
Agenda

Introduction and Scope
What is Mobile WiMAX?
Key Measurements and Challenges
Overview of Agilent Solutions
Hands-On/Demo
Wrap-Up




                                  Mobile WiMAX Workshop

Page 2                                      August 2006
Introduction and Scope

Our objective today is to arm you with basic knowledge:
    –    Refresher on OFDMA technology
    –    Update on the 802.16e-2005 standard
    –    PHY-layer measurement applications and procedures


So that you can make informed decisions about what RF test
equipment is needed to support your mobile WiMAX R&D Effort!

This workshop is not meant to provide in-depth training on
OFDMA. It is also not going to focus on MAC-layer and
Protocol Test solutions. It will focus on PHY-layer applications.


                                                             Mobile WiMAX Workshop

Page 3                                                                 August 2006
Agenda

Introduction and Scope
What is Mobile WiMAX?
Key Measurements and Challenges
Overview of Agilent Solutions
Hands-On/Demo
Wrap-Up




                                  Mobile WiMAX Workshop

Page 4                                      August 2006
     What are WiMAX and 802.16?
    WiMAX Forum: An industry organization to promote the IEEE
    802.16 standard for Broadband Wireless Access (BWA) and promote
    interoperability
    WiMAX Forum is establishing a certification process that includes
    conformance and interoperability testing for both protocol and
    physical layer testing (like the WiFi Alliance for WLAN).
    “Profiles” are used to define key attributes of a subset of
    applications and the corresponding tests required
    Mobile WiMAX certification profiles under discussion now
    Radio Conformance Tests (RCT) are also in process and are
    targeted for completion by end of July/Aug 2006
    First Mobile WiMAX Certification lab will be setup in Q3/Q4
    2006. Wave 1 Certification testing targeted to start at end of
    October 2006


    Agilent is a Principal member of the WiMAX Forum, and our test
    equipment is used in the certification process for WiMAX

                                                                        Mobile WiMAX Workshop

Page 5                                                                            August 2006
     802.16(e), WiBro, and OFDMA
     IEEE 802.16: An IEEE specification targeted at Broadband Wireless Access
     opportunities not addressed by other standards like 802.11 (WLAN). Latest full
     revision of the standard is 802.16-2004.
     802.16e-2005 – an amendment to the 802.16-2004 standard focusing on the
     OFDMA physical layer to allow mobility up to 120 km/hr

     • Allows 128, 512, 1024, or 2048 sub-carriers in 1.25, 5, 10, or 20 MHz BWs
       respectively. Additional BWs (e.g. 3.5, 5.5, 7 MHz) may be used for Europe.
     • Focus on licensed frequencies < 4 GHz (standard allows 2-11 GHz)


     WiBro (Wireless Broadband) - began a few years ago as a proprietary TTA
     standard for Korea, formerly called HPI (High-speed Portable Internet)
     •   Now merged into 802.16e standard as one of the system profiles
     •   1024 subcarriers in 8.75 MHz BW in 2.3-2.4 GHz band only
     •   Development is more advanced than 802.16e: tested at speeds up to 120 km/hr
     •   Commercial service expected to be launched in April 2006


                                                                               Mobile WiMAX Workshop

Page 6                                                                                   August 2006
Current 802.16e Band Classes / Certification Profiles
(Subject to Change)

Band Class 1: 2.3 - 2.4 GHz
• 5/10/8.75 MHz, 512/1024/1024 FFT TDD (Time-Division Duplex)
Band Class 2: 2.305 - 2.320, 2.345 – 2.360 GHz
• 5/10 MHz, 512/1024 FFT TDD
Band Class 3: 2.496 - 2.69 GHz
• 5/10 MHz, 512/1024 FFT TDD
Band Class 4: 3.3 - 3.4 GHz
• 5/7/10 MHz, 512/1024/1024 FFT TDD
Band Class 5: 3.4 - 3.8 GHz
• 5/7/10 MHz, 512/1024/1024 FFT TDD
                                                Source: WiMAX Forum

                                                            Mobile WiMAX Workshop

Page 7                                                                August 2006
WiMAX Technology: OFDM Basic Concepts

• OFDM = orthogonal frequency division multiplexing
• Data is transmitted on multiple subcarriers for each symbol
• Subcarriers are spaced so that at each subcarrier peak, all other
  subcarriers have nulls. This creates orthogonality of the subcarriers.
• Transmitting on multiple carriers allows slower symbol rate for same data
  throughput (bits/sec/Hz)
• Less susceptible to narrowband interference and multipath



                             ...           ...



                                                     Frequency

                                                                    Mobile WiMAX Workshop

Page 8                                                                        August 2006
  Contrasting OFDMs — WLAN

    802.11 = Freq range: 2 - 6GHz Data rate: ≤ 54 Mbps Mobile/Fixed: Fixed

                                      4 BPSK Pilots,                 BPSK, QPSK, 16QAM, 64QAM
                                      fixed locations

   Carriers: 52
   Spacing: 312.5 kHz
                                                                                       802.11a (18 MHz)




                      Preamble                                         Payload
         Short Training         Chan. Estimation        Sig Symbol   Data 1   Data 2    ...        Data N
            2 sym                    2 sym                1 sym      1 sym     1 sym               1 sym

                          Payload – multi-symbol, one modulation type, no overlap

                                                                                            Mobile WiMAX Workshop

Page 9                                                                                                August 2006
Contrasting OFDMs — Fixed WiMAX

802.16 OFDM = Freq range: 2 - 11GHz Data rate: ≤ 70 Mbps Mobile/Fixed: Fixed
                                  8 BPSK Pilots,                  BPSK, QPSK, 16QAM, 64QAM
                                   fixed location

    Carriers: 200
    Spacing: 90 kHz
              .                                               .                          802.16d (28 MHz)
              .                                               .                                       :
              .                                               .                                   10 MHz
                                                                                                  7.0 MHz
    Carriers: 200                                                                                 3.5 MHz
    Spacing: 5.6 kHz                                                                                  :
                                                                                        802.16d (1.25 MHz)
                       Preamble                       Payload
                  Long synch Chan est.    FCH        Data 1       Data 2   ...    Data N
                    1 sym      1 sym      1 sym      N sym        N sym            N sym
                            Payload – multi-symbol, multi-modulation type, no overlap

                                                                                             Mobile WiMAX Workshop

Page 10                                                                                                August 2006
OFDMA — Mobile WiMAX 802.16e
 802.16e : Freq range: 2-6 GHz Data rate: ≤ 70Mbps Mobile/Fixed: Mobile (60kph)
                               166-240 BPSK Pilots,      QPSK, 16QAM, 64QAM
                                 variable location
   FFT:      2048
   Carriers: 1680
   Spacing: ~11 kHz
         •                                                           802.16e (20 MHz)
         •                      83-120 Pilots
         •
   FFT:      1024
   Carriers: 840
   Spacing: ~11 kHz
         •                            802.16e (10 MHz)
         •
         •               42-60 Pilots
   FFT:      512
   Carriers: 408
   Spacing: ~11 kHz
         •                            802.16e (5 MHz)
         •
         •
   802.16e (1.25 MHz, FFT: 128)
                                                                          Mobile WiMAX Workshop

Page 11                                                                             August 2006
Comparing 802.16 OFDMA vs. OFDM
          OFDM

  • In 802.16-2004 OFDM user data
    DO NOT overlap in time.               OFDMA Symbol Number




          OFDMA
• In OFDMA, data bursts overlap in time
   (MA – Multiple Access)

• Maximizes data capacity to many users

• Adds support for handovers to allow
  mobility in a complex environment
                                                  time


                                                                Mobile WiMAX Workshop

Page 12                                                                   August 2006
    802.16 OFDMA Concepts
    Subchannelization – Sharing the bandwidth

                                    • The carriers are organized into “logical
                                    subchannels”. To maintain good noise
                                    immunity the carriers are distributed
      Logical        Logical        randomly across the entire bandwidth.
      Subchannel 1   Subchannel 2
                                    • Number of subchannels varies based on
                                    zone type

                                    • Carrier assignment changes for every
                                    symbol (part of permutation formula)

                                    Permutation formula = pseudo-random
                                    sequence determined by preamble index,
                                    cell ID and segment number.




                                                                       Mobile WiMAX Workshop

Page 13                                                                          August 2006
OFDMA Terminology                                                         Slot (2 symbols x 1
                                                                          subchannel for DL-PUSC)

 There are many new terms being introduced to
 describe the new OFDMA PHY layer. Here are some




                                                        subchannels
 more key new terms and how they are related to
 each other.

  Slot – smallest data unit (n symbols x m logical
 subchannels); size depends on zone type
 • Data Burst – block of adjacent slots, assigned to                                                      symbols
                                                       Data Burst
 one user (or group of users)
 • Permutation Zone – group of adjacent slots,                                                   DL Subframe
 carriers, pilots, and subchannels controlled by the




                                                                                      FCH and DL Map




                                                                                                                        Optional FUSC
 same permutation formula (PRBS)




                                                                           Preamble



                                                                                                       PUSC

                                                                                                              FUSC



                                                                                                                                          AMC
 • PUSC / FUSC / AMC - some of the zone types:
          • PUSC = partial usage of subchannels
          • FUSC = full usage of subchannels
                                                                      A subframe can contain multiple zone types
          • AMC = adaptive modulation and coding
                                                                                                                     Mobile WiMAX Workshop

Page 14                                                                                                                                 August 2006
Detailed OFDMA Frame Structure

                           1st DL                                                                    UL Zone 1
                                   DL Zone 1
                         zone only                   DL Zone 2    DL Zone 3
                                         (PUSC)                                                       (PUSC)
                              UL-MAP
                              FCH




                                                                                                                                    FCH
                                                                                                      UL Burst 1
                                                                    DL Burst
   Logical Subchannels




                                        DL Burst 3   DL Burst 4
                                                                       7
                         Preamble




                                                                                                                               Preamble
                                                                                                      UL Burst 2
                             DL-MAP




                                                                                                                                   DL-MAP
                                                                                 DL Burst 9
                                                                    DL Burst 8
                                                     DL Burst 5
                                       DL Burst 1                                                     UL Burst 3

                                                                                                      UL Burst 4
                                                     DL Burst 6
                                       DL Burst 2
                                                                                                    Ranging Subchannel

                                                      Symbol #                                TTG                        RTG                time

                                                     Frame 1 (2 to 20 ms)
                                                                                                                               Frame 2

                                                                                                                          Mobile WiMAX Workshop

Page 15                                                                                                                                 August 2006
Agenda

Introduction and Scope
What is Mobile WiMAX?
Key Measurements and Challenges
Overview of Agilent Solutions
Hands-On/Demo
Wrap-Up




                                  Mobile WiMAX Workshop

Page 16                                     August 2006
Basic WiMAX OFDM Signal Creation

                                                                                                     Pilots
                                                                                                                    1001    -0.32+j0.95


            PDU                                      FEC &                                           Map to
  101101                           Scrambling                                  Interleaver
           Creation                                Puncturing                                       Symbols
           Data put into                          Reed-Solomon                                      BPSK
           MAC PDUs                                Convolutional Coding                             QPSK
           (protocol data units)                   (RS-CC)                                          16QAM
                                                  Convolutional turbo coding                        64QAM




             OFDM
                                                              Insert                                          Upsampling/
           Subcarrier                      IFFT                                         Windowing
                                                           Cyclic Prefix                                          DAC
           Modulation


                                                                      CP

                                                          time             Useful symbol time
                                    freq




                                                                                                                    Mobile WiMAX Workshop

Page 17                                                                                                                       August 2006
Basic WiMAX OFDM Signal Creation
(For continued notes only)
                                                                                                     Pilots
                                                                                                                    1001    -0.32+j0.95


            PDU                                      FEC &                                           Map to
  101101                           Scrambling                                  Interleaver
           Creation                                Puncturing                                       Symbols
           Data put into                          Reed-Solomon                                      BPSK
           MAC PDUs                                Convolutional Coding                             QPSK
           (protocol data units)                   (RS-CC)                                          16QAM
                                                  Convolutional turbo coding                        64QAM




             OFDM
                                                              Insert                                          Upsampling/
           Subcarrier                      IFFT                                         Windowing
                                                           Cyclic Prefix                                          DAC
           Modulation


                                                                      CP

                                                          time             Useful symbol time
                                    freq




                                                                                                                    Mobile WiMAX Workshop

Page 18                                                                                                                       August 2006
  Key measurement challenges – where to start?

                               I                      I
                                    DAC                                                            PA
           FEC
       Interleaver   Encode                                              Σ    DAC
                                    DAC
                              Q                      Q             90º




  Digital                    Digital                Analog                   IF                           RF         SA Digital
Test Plane                Baseband I-Q           Baseband I-Q                                                         Outputs


   Logic Analyzers       Frequency Response       IQ Plane metrics:      Demod Meas             Measure ACPR         Spectrum
   Oscilloscopes           Baseband Filters             EVM            Wide Bandwidth       IMD/ Gain compression    Analyzers
                         Low frequency range   Freq, Mag, Phase Error Measure Phase Noise          Spurious
                                                   Magnitude Error      LO Feed through          Noise Figure
                              Digital IQ       Code Domain Analysis      Measure TOI             Phase Noise
                                                                         Measure Mod          Frequency Response
                                                                           accuracy          Gated Measurements


                                                                                                            Mobile WiMAX Workshop

 Page 19                                                                                                              August 2006
  Key measurement challenges – where to start?
  (For continued notes only)
                               I                      I
                                    DAC                                                            PA
           FEC
       Interleaver   Encode                                              Σ    DAC
                                    DAC
                              Q                      Q             90º




  Digital                    Digital                Analog                   IF                           RF         SA Digital
Test Plane                Baseband I-Q           Baseband I-Q                                                         Outputs


   Logic Analyzers       Frequency Response       IQ Plane metrics:      Demod Meas             Measure ACPR         Spectrum
   Oscilloscopes           Baseband Filters             EVM            Wide Bandwidth       IMD/ Gain compression    Analyzers
                         Low frequency range   Freq, Mag, Phase Error Measure Phase Noise          Spurious
                                                   Magnitude Error      LO Feed through          Noise Figure
                              Digital IQ       Code Domain Analysis      Measure TOI             Phase Noise
                                                                         Measure Mod          Frequency Response
                                                                           accuracy          Gated Measurements


                                                                                                            Mobile WiMAX Workshop

 Page 20                                                                                                              August 2006
    Physical Layer Measurement in the Standard
    Tx Signal Quality: Spectral Flatness
    “The absolute difference between
    each adjacent sub-carrier shall be no
    more than 0.1dB”
    +/-2 dB difference from average
    energy allowed for carriers closer to
    center
    +2/-4 dB difference from average
    energy allowed for carriers furthest
    from center
    3 different methods of
    measurement:
    • Using Time Gating + Markers
      with a Spectrum Analyzer
    • Demodulating and post
      processing with external SW
    • Direct demodulation analysis
      using Agilent VSA

                                            Mobile WiMAX Workshop

Page 21                                               August 2006
    Physical Layer Measurement in the Standard:
    Tx Modulation Quality: Relative Constellation Error
    RCE is the same
    measurement as Error
    Vector Magnitude (EVM),
    and requires the signal to
    be correctly demodulated
    RCE specification differs for
    each modulation and coding
    type
          E.g. QPSK ¾ is -18.5 dB
    When measuring, be certain
    the bursts are the same OR
    that the burst RCE
    measurements are separable


                                                    Mobile WiMAX Workshop

Page 22                                                       August 2006
    Physical Layer Measurement in the Standard:
    Rx: Receiver Sensitivity
    A BER/PER measurement vs. power
    level, with a unique spec for each
    channel BW, modulation type, and
    coding rate.
    Must have BER less than 10e-6 for                                          RF
    the specified power levels.
    Test messages are specially defined
    patterns: SBPSK, SQPSK, S16QAM, and      Radio Control
    S64QAM                                   and BER/PER             Radio
                                               Software             Receiver
    2 Test Methods:
    • Use signal from a “Golden Radio”
    • Test using a laboratory-grade signal
      generator
                                                     Radio Control and
                                                       payload data
                                                                         Mobile WiMAX Workshop

Page 23                                                                            August 2006
Signal Generation: Two Major Challenges

      1: Creating & Measuring Spectrally and Statistically Correct Signals
      • Used in testing Receiver sensitivity and in doing channel
        emulation for component & subsystem testing

      2: Creating & Measuring Fully-Compliant Signals
      • Create compliant signals for testing your receiver
      • Provide reference signal to compare with your transmitter
      • Certification: Conformance testing
      • Margin analysis: how much signal degradation can be tolerated




                                                                    Mobile WiMAX Workshop

Page 24                                                                       August 2006
Signal Analysis: Two Major Challenges

      1: Testing the transmitter at different points in the block diagram
      with confidence (various signal types)
      • Digital or analog baseband, analog IF and RF signals
      • Confidence you are measuring the device and not your
        measurement hardware!
      2: Successfully demodulating a complex OFDMA signal
      • DL and UL MAP information is critical to successfully
        demodulating a WiMAX signal (must be provided)
      • May not have stable DSP software (prototype Baseband FW)
        when performing system-level tests or RF Front End tests
      • Uncover issues such as incorrect PRBS that may prevent
        successful demodulation


                                                                   Mobile WiMAX Workshop

Page 25                                                                      August 2006
Agenda

Introduction and Scope
What is Mobile WiMAX?
Key Measurements and Challenges
Overview of Agilent Solutions
Hands-On/Demo
Wrap-Up




                                  Mobile WiMAX Workshop

Page 26                                     August 2006
Agilent’s Solutions for WiMAX R&D




Signal Analysis Tools
RF/BB PHY Parametric test                            EDA Tools
• Spectrum/Power                                     Design Libraries
• Modulation Quality
                                                     • Works within Agilent ADS
• Burst and Zone analysis
                            Signal Creation Tools    • Uses Ptolemy simulator
                                                     • Streamlines design and
                            RF and BB test signals
                                                     verification
                            • Uplink and Downlink
                                                     • Test “Benches”
                            • Multiple zone types
                            • Supports AWGN



                                                                     Mobile WiMAX Workshop

Page 27                                                                        August 2006
Agilent’s 802.16e Product Portfolio for
Measurements


                                       • E4438C Signal Generator


                             LAN,                              DUT
                             GPIB


  • 89601A VSA Software,
     Opt B7Y – 802.16 OFDMA analysis   • PSA-series Signal Analyzer
  • N7615A Signal Studio for           • Infiniium-series Oscilloscopes
     802.16 OFDMA signal creation      • 89600-series VXI modules
                                       • 16900-series Logic Analyzers
                                                                   Mobile WiMAX Workshop

Page 28                                                                      August 2006
Signal Creation




                  Mobile WiMAX Workshop

Page 29                     August 2006
    N7615A Signal Studio for 802.16 OFDMA
    Supports OFDMA physical layer in IEEE 802.16-2004
    and 802.16e standards
    • Creates arbitrary waveform files for use with E4438C
    • Generates up to 16 frames (same configuration with
      incrementing frame number and continuing data in MAC
      PDUs)
    • Fixed data patterns, PN9 or PN15 sequences, or user
      data files
    • Supports 512, 1024, and 2048 FFTs with variable
      bandwidths
    • Automatically generates FCH, DL-MAP, and UL-MAP for
      receiver test
    • Create downlink or uplink subframes, TDD or FDD
    • Supported zone types: DL-PUSC, DL-FUSC, UL-PUSC,
      UL-OPUSC
    • Flexible configuration of zones, bursts, and MAC PDUs
    • Add real-time AWGN when used with E4438C option 403



                                                              Mobile WiMAX Workshop

Page 30                                                                 August 2006
Signal Studio User Interface: Project Parameters

                                              Parameter
                                              checker and
                                              user hints

Set OFDMA
system                                        Convenient
parameters                                    signal
                                              generator
Configure                                     settings
waveform
parameters
                                               Configure
                                               AWGN
                                               settings
                                               (requires
                                               E4438C
                                               option 403)

                                            Mobile WiMAX Workshop

Page 31                                               August 2006
Signal Studio User Interface: Downlink


                                         Flexible burst
                                         configuration
                                            (auto or
                                            manual)


                                         Include FCH,
                                         DL-MAP, UL-
Add zones                                    MAP



                                         Zone layout
                                           display


                                          Mobile WiMAX Workshop

Page 32                                             August 2006
Signal Studio User Interface: Uplink




Add one or
more MAC
PDUs in
each burst
                                         Automatic
                                         or manual
                                         burst
                                         allocation




                                       Mobile WiMAX Workshop

Page 33                                          August 2006
User Interface: Waveform Generation Log
                        Displays raw data generated,
                        including contents of DLFP (FCH),
                        DL-MAP, UL-MAP, and data bursts
                        with MAC headers and CRC.




                                                  Mobile WiMAX Workshop

Page 34                                                     August 2006
RF, Digital & Analog Baseband Outputs:
Flexibility For An Evolving World
                                                 Flexible Configuration
          High Performance RF




                                                                          N5102A

                                                                          PCB Adapter


                                     RF
                                                         ADC              Baseband
                                 translation



   Standard Compliant SW        Standard feature:          Ready for the future:
   Highly configurable          Analog Differential IQ     Digital Interfaces

                                                                            Mobile WiMAX Workshop

Page 35                                                                               August 2006
  N5102A Digital Signal Interface Module (DSIM)

                         Key features
                         • Delivers ESG/PSG digital baseband
                           signals to DUT
                         • Matches digital signal to DUT
                           – Serial or parallel
                           – LV TTL, LV CMOS (3.3V, 2.5V, 1.8V, 1.5V),
                             or LVDS
                           – IQ or IF (digital IF = ¼ clock rate)
                           – 2’s complement or offset binary
                           – MSB or LSB
                           – 4 to 16-bit words
                           – 1 to 100 MHz sample rate
                           – Internal/external clock source to 400 MHz
                           – Up to 4 clocks per sample
                           – Adjustable clock-to-data skew
                         • Simple, direct connectivity
                           – Direct ESG/PSG cable connection
                           – Six connector types supported (on supplied
                             breakout boards) for connection with DUT



                                                             Mobile WiMAX Workshop

Page 36                                                                August 2006
    Baseband Studio Digital Signal Interface Module
    Configuration Requirements


                                                            N5102A Baseband Studio Digital
                                                            Signal Interface Module (DSIM)



                                         Digital Bus

Built-in user     E4438C                                                                        DUT
interface
                                                       Breakout board
                E4438C ESG with:                       of your choice
          Internal Baseband Generator
              (E4438C-601 or 602)                                           Digital IQ output
           Digital output connectivity
                  (E4438C-003)                           Breakout boards (included):
                                                   • 68-pin mini-D sub “SCSI-style”
                                                   • 38-pin dual AMP Mictor
                                                   • 100-pin dual Samtec ASP-65067-1
                                                   • 20-pin dual 0.1 inch header
                                                   • 40-pin dual 0.1 inch header
                                                   • Z-DOC+ spare mating connector


                                                                                                Mobile WiMAX Workshop

Page 37                                                                                                   August 2006
Signal Analysis




                  Mobile WiMAX Workshop

Page 38                     August 2006
VSA Software and acquisition hardware
Benefits/Advantages:
- Consistent VSA software can be used with
  different acquisition hardware as required
- Import test setups (Including MAP info) directly
  from our Signal Creation tool
- Synergy with Design Tools (ADS)
- Comprehensive and Flexible yet Easy to Use
- High Performance with PSA or VXI-based
  signal acquisition instruments


- Up-to-Date and Expandable
- Mature – Agilent has OFDM/OFDMA experience
  dating back to 2003




                                                     Mobile WiMAX Workshop

Page 39                                                        August 2006
Comprehensive OFDMA Signal Analysis
    Vector Signal Analysis Software:
    89601A/AN Option B7Y: 802.16e OFDMA
    modulation analysis (v6.2 now Shipping!)
    • Zone types: UL/DL, PUSC, OPUSC, FUSC,
      OFUSC, AMC
    • Supports all FFT lengths: 128, 512, 1024, 2048
    • Bandwidths: 1.25-28MHz (preset & manual)

    • Features/advantages
      – Zone level & data burst level analysis
      – Market leading EVM spec (PSA)
      – Displays more than one modulation type at a
        time
      – Supports ratified standard & pre-ratified
        standard
      – PRBS status indicator
      – CPE trace and parametric measurement
      – 6 trace display


                                                       Mobile WiMAX Workshop

Page 40                                                          August 2006
    802.16 OFDMA modulation analysis
   RF engineers designing power amps
   and other components needing complex
   stimulus/ response testing

   What Agilent provides:
   •Easy one-box check to set up uniform
   zone analysis (all subcarriers and all
   symbols within a zone have the same
   modulation format).




                                            Mobile WiMAX Workshop

Page 41                                               August 2006
    802.16 OFDMA modulation analysis


Constellation,
BPSK to                                Overall error
64QAM                                  statistics


   Spectrum,
   now with                            CCDF to determine
   limit lines                         amplifier headroom


Error Vector
Time to                                Channel
verify EVM                             equalizer
across                                 response for
symbols                                linearity testing




                                            Mobile WiMAX Workshop

Page 42                                               August 2006
    802.16 OFDMA modulation analysis
   RF and baseband engineers designing
   at module/subsystem level who need
   to perform multi-burst OFDMA analysis
   What B7Y provides:
   •Graphical GUI or user map file to
   input burst parameters
   •Timing diagram to easily set up
   measurements within a frame




                                           Mobile WiMAX Workshop

Page 43                                              August 2006
    802.16 OFDMA modulation analysis

   RF and baseband engineers designing at module/subsystem level who need
   multi-burst analysis



   Constellation, BPSK to
   64QAM, color-coded by burst                          EVM across carriers or
                                                        symbols, color-coded
                                                        by burst




                                                               Overall error
                                                               statistics, color-
                                                               coded by burst

                     New data burst info
                     summary giving
                     power and EVM for
                     individual burst
                                                                   Mobile WiMAX Workshop

Page 44                                                                      August 2006
Selecting the Acquisition Hardware
89601A Measurement Platforms
   Choices: VXI, PSA, ESA, Scopes, Logic Analyzers
   Basis for selecting the right platform
          1. Frequency range – Operating frequency, harmonics/spurs
          2. Signal bandwidth required
          3. EVM (or dynamic range) spec required



                     802.16e       PSA              VXI      ESA         Scopes*
                   OFDMA spec
     Frequency     Up to 6 GHz Up to 40GHz    Up to 6 GHz   Up to 26   Up to 13 GHz
     range                                      (BBIQ)        GHz         (BBIQ)
     Bandwidth     5,10,20 MHz   40, 80 MHz     36 MHz      10 MHz     Up to 13 GHz
     EVM             -31.4 dB      -49dB         -46dB       -39dB       <-35 dB



                                                                        *Not specified
                                                                           Mobile WiMAX Workshop

Page 45                                                                              August 2006
Consistent Measurement SW = Correlation of
Results across the block diagram

                           DUT

             DSP



          Digital (SSI)   BB (I-Q)          IF/RF




Logic Analyzer            Oscilloscope   Signal Analyzer




                                                           Mobile WiMAX Workshop

Page 46                                                              August 2006
Digital Signal Analysis vs. Vector Signal Analysis

    The digital BB engineer wants to:
    •       Analyze many signals
    •       Understand the timing relationships among
            signals
    •       Trigger on patterns and/or sequences of
            events
    The RF engineer wants to:
        •   See the spectrum and time domain, and
            verify quality
        •   Demodulate the signal and look for errors
            (EVM, etc)
        •   Trigger on power levels



                                                        Mobile WiMAX Workshop

Page 47                                                           August 2006
Logic Analyzer to VSA SW (89601) Interface
how it works…




                             COM

                             Data




   Configure the LA measurement BEFORE starting VSA measurement

                  LA passes data to VSA software


                                                        Mobile WiMAX Workshop

Page 48                                                           August 2006
Logic Analyzer – Probing
Designed In or an Afterthought?                                Connect


Designed In
(Connectorless or Connectors):
Signals are brought out to pads or
connectors for debug.




Flying Leads: Probe signals from dispersed locations or when
a connection has not been designed in.




                                                           Mobile WiMAX Workshop

Page 49                                                              August 2006
EDA Tools for Simulation and Modeling




                                        Mobile WiMAX Workshop

Page 50                                           August 2006
Example: Connecting it all together
ADS – WiMAX Connected Solution
                                 PC Workstation with ADS
                                 Signal Generation Equipment
                                 Signal Analysis (VSA SW and
                                 Acquisition hardware)
                                 Device Under Test




                                                     Mobile WiMAX Workshop

Page 51                                                        August 2006
Agilent EEsof Communication System Design Flow
                         Wireless Standards Specification
                                      Wireless Libraries
                                               `
          Fully coded signal source      DUT         Receiver   Measurement

System-Level




Circuit-Level




   Transistor-
      Level




Hardware-Level

                                                                              Mobile WiMAX Workshop

Page 52                                                                                 August 2006
                      ADS 802.16e Wireless Library:
                      OFDMA Downlink Transceiver
User 0
          FEC Encoding     Subcarrier Bit Allocation
           Interleaving         And mapping


User 1 FEC Encoding       Subcarrier Bit Allocation
        Interleaving           And mapping                            OFDM Modulation            RF
                                                       Multiplexer
                                                                      (IFFT, insert CP)      Up-converter
                      …




User
K-1       FEC Encoding     Subcarrier Bit Allocation
           Interleaving         And mapping




     FEC Decoding         Equalization and       OFDM Demodulation    Timing and frequency        RF
     DeInterleaving         Demapping             (FFT, remove CP )      synchronization     Down-converter




                              Channel
                             Estimation



                                                                                                 Mobile WiMAX Workshop

Page 53                                                                                                     August 2006
               ADS 802.16e Wireless Library:
          Use Template to Create Top-Level Design




                                  Specify parameters such as gain and
                                        1dB compression point
                                    Specify phase noise (dBc/Hz) vs.
                                            frequency offset

                                                               Mobile WiMAX Workshop

Page 54                                                                  August 2006
          System Design EVM with Behavioral Models




                                         EVM is 3.1%




                                                       Mobile WiMAX Workshop

Page 55                                                          August 2006
Agenda

Introduction and Scope
What is Mobile WiMAX?
Key Measurements and Challenges
Overview of Agilent Solutions
Hands-On/Demo
Wrap-Up




                                  Mobile WiMAX Workshop

Page 56                                     August 2006
Measurement & Troubleshooting Trilogy
3 Steps to successful Signal Analysis



Step 1                   Step 2                     Step 3

          Frequency,              Basic                 Advanced &

   Frequency & Time         Digital Demod             Specific Demod


   Get basics right,          Signal quality             Find specific
   find major problems   numbers, constellation,      problems & causes
                         basic error vector meas.



                                                                Mobile WiMAX Workshop

Page 57                                                                   August 2006
 Step 1: Performing frequency & time measurements
                                                      preamble
                                     Power vs. Time
                                     with time gate



          Spectrum with                                Time
          occupied BW                                  Gate
             marker
            Spectrogram




          Power vs. Time   Trigger
               CCDF        control

                                                      Preamble’s
                                                       spectrum




                                                                   Mobile WiMAX Workshop

Page 58                                                                      August 2006
Measurement & Troubleshooting Process
3 Steps to successful Signal Analysis



Step 1                   Step 2                     Step 3

          Frequency,              Basic                 Advanced &

   Frequency & Time         Digital Demod             Specific Demod


   Get basics right,          Signal quality             Find specific
   find major problems   numbers, constellation,      problems & causes
                         basic error vector meas.



                                                                Mobile WiMAX Workshop

Page 59                                                                   August 2006
89601 OFDMA demodulation set-up

Zone set-up
•Table entry or mouse-based
• All zone types
• All burst types (FCH, map,
normal)
• Both burst shapes
  (rectangular, non-rectangular)
• New/edit old
OR
• Recall setup file saved in Agilent
Signal Studio! (.xml file )



                                       Mobile WiMAX Workshop

Page 60                                          August 2006
    Step 2: Performing basic demodulation

                              Compound constellation
                              • Demodulates and displays all
                              mod types in subframe in one
                              measurement
                              • Color coded by DATA BURST



                                   FCH
                                          ULMap    Burst 2

                                  DLMap            Burst 3


                                              Burst 1




                                                             Mobile WiMAX Workshop

Page 61                                                                August 2006
   Step 2: Results of OFDMA basic demodulation
   Symbol / Error table
   (subframe)
   •RCE (EVM) parameters
   •I/Q parameters
   •Sync Correlation: Preamble
   match to std pattern*
   •PRBS – measures permutation
   formula “seed” info*
   •Raw bits (color coded by data
   burst)



* Common problem with new designs, if
these are bad the signal will not demodulate

                                               Mobile WiMAX Workshop

 Page 62                                                 August 2006
Measurement & Troubleshooting Process
3 Steps to successful Signal Analysis



Step 1                   Step 2                     Step 3

          Frequency,              Basic                 Advanced &

   Frequency & Time         Digital Demod             Specific Demod


   Get basics right,          Signal quality             Find specific
   find major problems   numbers, constellation,      problems & causes
                         basic error vector meas.



                                                                Mobile WiMAX Workshop

Page 63                                                                   August 2006
  Step 3: Performing advanced demodulation
                               Error Vector Spectrum (subframe)
          (normal view)        • Shows the EVM for every carrier at
                               every symbol time along with:
                               average/min/peak EVM of every carrier
                               (R&S).
                               • Arbitrary zoom (marker based)
                               • Color code relates EVM reading to data
                               burst

                                         peaks
            (zoomed view)
                                                           average




                            minimums
                                                            Mobile WiMAX Workshop

Page 64                                                               August 2006
 Step 3: Performing advanced demodulation
            Error vector spectrum    Analysis by data burst and zone
            (assigned logical sub-
                channels only)       • Tracks and measures only the logical sub-
                                     carriers and symbols in target data burst
                                       Color code = data burst
                                       Full marker support
                                     • The user defines the target data burst,
                                     preamble index, cell ID and segment number
                                     (Map file or graphically)
                                     • Data burst info table gives mod type, size,
                                     power, RCE of every data burst defined by
                                     the user




          User defines target
              data burst
                                            Data burst info table

                                                                     Mobile WiMAX Workshop

Page 65                                                                        August 2006
  Step 3: Performing advanced demodulation

  Adjacent Carrier Difference


  • Shows magnitude delta
  between adjacent carriers




  • Use display zoom and
  marker functions to measure
  magnitude delta between
  specific carriers


                                             Mobile WiMAX Workshop

Page 66                                                August 2006
  Step 3: Performing advanced demodulation
Tools work together
        • Color coding ties
 measurements directly to
    responsible data burst




      • Coupled markers track
            problem between
               measurements

                                             Mobile WiMAX Workshop

Page 67                                                August 2006
Measurement and Troubleshooting Process
Key Steps to successful Signal Creation
          Step 1                   Step 2                          Step 3

             Connect                     Create                   Configure OFDMA
                                        Waveform                      Downlink



   Set up connection to            Set up waveform and signal      Choose subchannels used,
   signal generator                   generator parameters.              add zone(s).
            Step 4                          Step 5

             Configure Zones                      Configure                 Download
                                                  Data Bursts               waveform
                                                                            and GO!


                     Set up waveform and signal      Choose subchannels used,     Mobile WiMAX Workshop

Page 68
                        generator parameters.              add zone(s).                     August 2006
Step 1 and 2:
Key Steps to use Signal Studio to Create OFDMA Waveforms

1. Set up connection to signal    2. Set up waveform and signal
   generator (“Instruments” page)    generator parameters on
                                     “Project” page




                                                                ESG settings (set at
 NOTE: Detailed example/tutorial is       OFDMA system and
                                                                download, can be
                                          waveform parameters
 available in N7615A’s online help.                             changed from ESG’s
                                                                front panel)

                                                                     Mobile WiMAX Workshop

Page 69                                                                        August 2006
Step 3: Configure OFDMA Downlink

3. Choose subchannels used, add zone(s).

                                           Choose Preamble Index (sets
                                           Segment Index and ID Cell)



                                           Choose groups (subchannels)
                                           to assign to this downlink
                                           (default: all subchannels used)

                                           Add PUSC or FUSC zone


                                            Designate number of
                                            symbols in zone




                                                              Mobile WiMAX Workshop

Page 70                                                                 August 2006
Step 4: Configure Zone

4. Configure zone and data burst allocations.


                                           Enter number of symbols for zone


                                           Choose auto allocation on or off



                                             Choose whether to include
                                             FCH, DL-MAP, UL-MAP




                                                If auto allocation is off,
                                                configure layout of data
                                                bursts in table



                                                                   Mobile WiMAX Workshop

Page 71                                                                      August 2006
Step 5: Configure Data Bursts

5. Add MAC PDUs to each burst and configure data contents.
                                   Select coding type, modulation
                                   and coding rate, and other
                                   burst parameters


                                   Add MAC PDUs (protocol data units)


                                    Choose data type




                                                              Mobile WiMAX Workshop

Page 72                                                                 August 2006
Step 6: Check Parameters, Download Waveform
             Check setup parameters
                                                     Download waveform
                                                     to signal generator
                                 Generate waveform




 Display CCDF,
 power, I/Q, or
 spectrum
 graphs




                                                                           Mobile WiMAX Workshop

Page 73                                                                              August 2006
Agenda

Introduction and Scope
What is Mobile WiMAX?
Key Measurements and Challenges
Overview of Agilent Solutions
Hands-On/Demo
Wrap-Up




                                  Mobile WiMAX Workshop

Page 74                                     August 2006
Agilent’s WiMAX Test Solutions History
First-to-market with OFDM and OFDMA test tools and expertise!


                        Pilot                                 RF/BB Parametric
                                                                Test Systems
                        Production
                                                              1st OFDMA SG
                                                             Signal Generator
                                                   1st OFDMA VSA
                                                   Signal Analyzer
                                          1st OFDM SG
                                        Signal Generator

    R&D                         1st OFDM VSA
                               Signal Analyzer

    2004                             2005                                   2006
                                                              First Certifications*
             R&D/Design Validation                  Pilot Production
                                                                          *802.16-2004

                                                                             Mobile WiMAX Workshop

Page 75                                                                                August 2006
Summary

Agilent has been involved with 802.16-2004 OFDM and now 802.16e
OFDMA signal generation and troubleshooting from the beginning, working
with the WiMAX Forum and customers around the globe since 2002/2003.

Agilent’s flexible signal creation and vector signal analysis solutions
provide the most current, comprehensive “end to end” signal generation
and analysis capability in the market today. Our VSA and Signal
Generator have been chosen by CETECOM in support of their WiMAX
certification program1

Agilent is committed to supporting the development and commercial
success of 802.16e technology, and our test solutions will continue to be
expanded and matured as WiMAX moves from R&D into trials, validation
and certification, volume production and ultimately full-scale deployment.

1 Agilent/CETECOM   press release

                                                                    Mobile WiMAX Workshop

Page 76                                                                       August 2006
            THANK YOU!

          For More Information:

          www.agilent.com/find/wimax
          www.agilent.com/find/webcasts




                                          Mobile WiMAX Workshop

Page 77                                             August 2006
        Frequency,                                           Basic                                           Advanced &
     Frequency & Time                                    Digital Demod                                      Specific Demod
                                                       Signal quality
      Get basics right,                                                                                      Find specific
                                                  numbers, constellation,
    find major problems                                                                                   problems & causes
                                                  basic error vector meas.

Frequency & Time Measurements                     Constellation                                       Carrier-Specific Problems & Insights
• Center frequency, occupied bandwidth            • Successful demodulation?                          • Individual carriers or groups, band-edge
• Spurious, interference (all types)              • Correct modulation type(s)?                           problems, pilots vs. data carriers
• Amplitude--average, and variations during       • Indications of error?                             Time-Specific Problems & Insights
    burst (transients, drift)                     Symbols/Errors Table                                • Time interval or modulation type is cause of
• Turn-on & turn-off behavior, on/off ratio       • Relative constellation error (RCE)                    error
• Burst length, duty cycle, unanticipated         • Pilot & common pilot errors (CPE)                 • Identify impulsive, intermittent, or periodic
    frequency/time variations                                                                             error sources
                                                  • I/Q errors including gain imbalance,              • Turn on/off, power supply, settling, or thermal
• Band power measurements                              quadrature error, delay mismatch                   effects
                                                  Error Vector Spectrum                               Simultaneous Freq & Time-Specific Demod
Time-Gated Spectrum Measurements                  • Average vs. spread, data vs. pilots               Impairments Fixed by Pilot Tracking
• Spectrum vs. time, any spectrum artifacts       • Patterns/trends by carrier                        • Amplitude droop, variations
• Power changes during burst, CCDF                • Spurs (will affect individual carrier or few      • Phase noise, jitter, clock problems
    variations                                        carriers, for all symbols)                      • Timing uncertainties
• Carrier structure, missing or extra carriers,   Error Vector Time                                   Impairments Not Fixed by Pilot Tracking
    energy at exact CF                            • Average vs. spread vs. mod types
• Sidelobes (part of signal, not ACP),                                                                • Modulation-related compression or clipping
    symmetry                                      • Look for impulsive errors such as DSP,            • Non-narrowband phase noise
                                                      interference, clocks, power (will affect all
• Frequency accuracy, carrier spacing                 carriers for an individual symbol or group of   Linear Errors and Equalization
• Spurious, interference                              symbols)                                        • IF & modulation filtering errors sin(x)x
• Flatness, tilt/ripple                           Marker Coupling                                         compensation
• Preamble length, structure                      • Relation of error peaks (power, symbol            • Multipath
• Confirm sampling factor, guard interval             value or location, carrier, time)               • Preamble (training sequence) problems--
                                                  • Other relations discovered                            preamble vs. data-driven EQ


                                                                                                                                  Mobile WiMAX Workshop

Page 78                                                                                                                                     August 2006
Agilent Logic Analyzer Probes
                                                                                Connect

                Select                          If You Want
                               •Extremely Low Loading—<0.7pf

              Soft Touch       •Ability to Capture Very Fast Signals—1500Mb/s
             Connectorless     •Easy Flow Thru Routing
                Probe          •Differential Signaling
                               •The Joy of no connector on the board
                               •Very Low Loading—1.5pf
                               •Ability to Capture Very Fast Signals—1500Mb/s
           Samtec Connector •Flow Thru Routing
                Probe       •Differential Signaling
                               •High performance probe at a low price
                               •Low Loading—3.0pf
           Mictor Connector    •Ability to capture Fast Signals—600Mb/s
                Probe       •Common Probing
                               •Extremely Low Loading—As low As 0.9pf
                               •Ability to Capture Very Fast Signals—Up to
              Flying Lead      1500Mb/s
                 Probe         •Differential Signaling
                               •The Ultimate in probing Flexibility

                                                                             Mobile WiMAX Workshop

Page 79                                                                                August 2006

				
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Description: T o measure and characterize devices, California Eastern Laboratories (CEL) uses dif- ferent fixtures and calibration methods. One is the through- reflect-line, or TRL, which can be used to calibrate the HP8510 net- work analyzer.