Addressing Measurement Challenges of 160 MHz 802.11ac MIMO · Addressing Measurement Challenges of...

© 2012 Agilent Technologies

Wireless Communications

Greater insight. Greater confidence. Accelerate next-generation wireless.

Addressing Measurement Challenges of 160 MHz 802.11ac MIMO

Presented by: Ron Harrison and Jake Sanderson, Agilent Technologies



2 © 2012 Agilent Technologies



About this Webcast

Objectives:

1. Discuss test and measurement architectures, both hardware and

software, for next generation MIMO wireless test including 802.11ac

2. Understand how to configure MIMO measurement technology

3. Learn to make and interpret key measurements for 802.11ac

www.agilent.com/find/wirelesswebcasts

LTE and Wireless - Webcast Series (Live and On-Demand Webcasts)

http://www.agilent.com/find/wirelesswebcasts




2 1

Related Webcasts in Series

Introduction to 802.11ac WLAN

Technology and Testing

Next Generation Very High

Throughput: 802.11ac WLAN MIMO

Design & Test Challenges

• Introduction to 802.11ac standard

• Understand how standard addresses

“very high throughput”

• Design & test challenges of standard

• Integrating simulation in system design

• Simulation to model design

performance

• System performance budget trade-offs

• Hardware-in-the-loop & MIMO

www.agilent.com/find/wirelesswebcasts

3

http://www.agilent.com/find/webcasts






Agenda

1. Market Drivers and Resulting Design & Test Challenges

2. Quick Review: What is MIMO?

3. Introduction to PCI Extensions for Instrumentation (PXI)

4. Software solutions for PXI instrumentation

5. Configuring PXI instrumentation

6. Making and interpreting key measurements for 802.11ac






New Applications for WLAN

Higher data rates are needed for new applications

outside “traditional” email and browsing

Key new features for increasing data throughput:

• Wider channel bandwidths: mandatory 20, 40, and 80

MHz; optional 160 MHz and 80+80 MHz (not necessarily

contiguous)

• Higher order modulation: optional support for

256QAM

• More spatial streams and antennas (up to 8) and

multi-user MIMO (MU-MIMO)

• Up to 6.93 Gbps best case (160 MHz, 8 Tx antennas,

MCS9, short guard interval)






Enhancements for 802.11ac

6

Feature Mandatory Optional

Channel frequency 2.4 GHz, 5.8 GHz

Channel bandwidth 20, 40, 80 MHz 160, 80+80 MHz

FFT size 64, 128, 256 512

Data subcarriers / pilots 52 / 4, 108 / 6, 234 / 8 468 / 16

Modulation types BPSK, QPSK, 16, 64 QAM 256 QAM

MCS supported 0 to 7 8 and 9

Spatial streams and MIMO 1 2 to 8 Tx beamforming, STBC

Multi-user MIMO (MU-MIMO)

Operating mode / PPDU format Very high throughput / VHT



WHAT IS MIMO?

7




Transmit

Antennas

Receive

Antennas

SISO

The Radio

Channel

MISO

Single Input Single Output

Multiple Input Single Output

(Transmit diversity)

Receive

Antennas

Transmit

Antennas

MIMO

The Radio

Channel

SIMO

Single Input Multiple Output

(Receive diversity)

Multiple Input Multiple Output

(Multiple data streams)

MIMO: Increased Capacity

(and Test Complexity)

8






Diversity

Improve robustness

Spatial Expansion

(Transmit Diversity)

Receive Diversity

Multiple Antenna Techniques in

802.11ac

Space-time block

coding (STBC)

X1, X2

-X2, X1*

y1, y2

Spatial division multiplexing

(direct mapping) Multi-user MIMO

Transmit Beamforming

Spatial multiplexing

Improve user throughput

Multi-user Increase system

efficiency

MIMO

MIMO (4x2)

Matrix

4 streams, 3 users X1

X2

y1

y2

Downlink only

Up to 4 users

Up to 4 streams/user

Total 8 streams max



INTRODUCTION TO PXI

10



Data &

Control

Bus

Processing Measurement Technology

Test & Measurement Equipment Consist of

Several Building Blocks

Baseband

Generators &

Analyzers

Converters &

Detectors

Control

System

Signal

Condioning

Host

Processors

Protocol &

Digital Signal

Processors

Data &

Control

Bus Test

Management &

Control System

11




Data &

Control

Bus

Processing Measurement Technology

Optimized Test & Measurement

Architecture for Multichannel and MIMO

Baseband

Generators &

Analyzers

Converters &

Detectors

Control

System

Signal

Condioning

Host

Processors

Protocol &

Digital Signal

Processors

Data &

Control

Bus Test

Management &

Control System

Chassis &

Backplane

Peripheral Modules Controller

• Test management,

control and processing

• Built on latest COTS

processors & software

• Upgradable hard drive

and memory

• Instant performance

upgrade by swapping

controller

• Modular measurement technology

• Build-up functional system

• Data and control bus

• Low latency

• High bandwidth

• Multiple peripheral

slots

12




PXI – Open Modular Platform

for Test & Measurement

PXI in Industry

1,500+ products

70+ vendors

100k+ systems deployed

• Capable T&M Platform

– Foundation adapted from consumer products

– Robust, mature technologies

• Current PXI Implementations

– PXI adopts CompactPCI and CompactPCI Express

– Engineering requirements for infrastructure

13






Strengths of PXI in

Shared Resources

• Instrumentation Clocks

– 10 MHz and 100 MHz

– Capable of High Quality

• Trigger Buses

– Parallel PXI_TRIG

– Matched STAR and DSTAR Lines

• Data Communication

– PCI Parallel Bus

– PCIe Point-to-Point Architecture




Importance of Bandwidth

and Latency in T&M Buses

1

10

100

1000

10000

Throughput Latency

0.1

1

10

100

1000

Maxim

um

Bandw

idth

(M

B/s

)

Appro

xim

ate

Late

ncy (

us)

• Latency: the amount of time it takes data to be received after it is transmitted

• Bandwidth: a measure of the rate of data transferred on a bus over time, measured in MB/s

Goal of System: ↑ bandwidth & ↓ latency

16




PCI Express (PCIe) links & lanes

17




PXIe Backplane

PCIe Gen 2 Switches (4 GB/s)

•30W per slot

•13 signal PXI local bus

•Length-matched Star Trigger

•8 signal TTL trigger bus

18



DIFFERENCES BETWEEN PXI &

STANDALONE BOX INSTRUMENTS

19



Differences Between

PXI and Standalone Box

Modular

• Greater flexibility/scalability

• Integrated system

• Higher throughput

• Smaller footprint

• Lower power

• More cost effective

Standalone Box

•Interactive measurement

•Time to first measurement

•Predictable system performance

•Lower software investment

•No infrastructure investment

20



PXI ARCHITECTURAL

STRUCTURES FOR 802.11AC

21






3-Channel Wideband MIMO PXI VSA

• M9202A IF Digitizer

• Resolution: 12 bit

• Sample Rate: 2 GS/s

• Bandwidth: 800 MHz

• Nominal residual EVM -43 to -46

dB for 80 MHz BW signals

M9362A-D01

4 Ch Down-

converter

3 x

M9202A

Digitizer

M9352A

Amp

Atten

• M9362A-D01 4-channel Downconverter

• 1.5 GHz BW

• 10 MHz – 26.5 GHz

• M9352A Amp/Attn

• 1 GHz analog bandwidth

• 36 dB Maximum Gain

• ½ dB attenuation Steps

Key building blocks enable outstanding performance






23

Building Blocks of a Wideband

Measurement Solutions

M9362A-D01

Downconverter

100 MHz Out1

100 MHz Out2

Video Trigger This Channel

M9352A

Amp Attenuator M9168C uW

Attenuator






24

Building Blocks of a Wideband

Measurement Solutions

M9362A-D01

Downconverter

100 MHz Out1

100 MHz Out2

Video Trigger This Channel

M9352A

Amp Attenuator M9168C uW

Attenuator

M9202A Digitizer /

Digital IF Module •12 bit resolution

•2 GS/s max sample rate

•1 GHz max BW

•Hardware digital

downconversion

•High speed data upload

M9352A Quad IF

Amplifier/Attenuator •Fast IF power control with 31.5 dB

solid state IF attenuator with 0.5 dB steps

•Analog Bandwidth (3dB) : 1 GHz

•≥ 5 dB Minimum Gain (nominal)

•≥ 36 dB Maximum Gain (nominal)

M9362A Quad

Downconverter Module •10 MHz to 26.5 GHz

•4 CH Synchronous

•IF BW = 1.5 GHz

M9168C Programmable

Step Attenuator •0.03 dB insertion loss

repeatability

•0 to 101 dB, 1 dB steps

•+0.4 dB flatness @ 26.5 GHz

M9302A LO Module •Supplies LO to downconverters

•Supplies 100 MHz reference to

digitizer for sampling clock generation



SOFTWARE SOLUTIONS FOR

PXI INSTRUMENTATION

25






Software Platforms for PXI

• Agilent Connection Expert

• List and configure instruments

Configuration Utility

• Natural instrument interface

• Quickly launch and debug

• Ensure proper setup

Soft Front Panels

• LabVIEW

• MATLAB

• LabWindows/CVI

• Visual Studio C#, C/C++, VB.NET

• VEE

Application Programming Interface (API)

• Signal Studio

• Waveform Editing

• Jitter Generation

• Digital Debug

• Waveform Analysis

• SystemVue

• 89600A/B VSA Measurement Applications

IVI-C/COM, .NET, LabVIEW G drivers, Calibration, IO Libraries

Measurement Science



CONFIGURING PXI EQUIPMENT

DEBUGGING W/ SOFT FRONT PANELS

Demo 1

27






Transmitter Tests

Section 22.3.19 in 802.11ac Standard

1. Transmit spectrum mask

2. Spectral flatness

3. Transmit center frequency tolerance

4. Packet alignment

5. Symbol clock frequency tolerance

6. Modulation accuracy

– Transmit center frequency leakage

– Transmitter constellation error (EVM)

28



USING 89600 VSA SOFTWARE

W/ PXI INSTRUMENTS

Demo 2

29




Agilent Multi-channel Signal Analyzer Solutions

~ $138,000 ~ $113,500 (~$138,500 for 3 channels)

Wideband MIMO PXI

VSA

Dual channel PXI

VSA

90000SeriesScopes PXA Signal Analyzer N7109A

Applications 80 + 80 MHz and 160 MHz

802.11ac R&D / DVT, MIMO

Environment recording with

wide bandwidths and

multichannel to support 80 +

80 MHz 802.11ac

2 to 4 Channel MIMO

802.11ac, LTE, WiMAX

Beamforming R&D

Troubleshoot multichannel

timing errors, GP debug

802.11ac, LTE-Advanced 802.11n, WiMAX,

LTE Advanced, MIMO,

Beamforming R&D

Freq Range 2.25 GHz to 26.5 GHz

(lower with external LO)

50 MHz to 26.5 GHz DC to 33 GHz

(IQ and IF/RF)

3 Hz to

3.6/8.4/13.6/26.5/44/50 GHz

(IQ and IF/RF)

20 MHz to 6 GHz

# Channels/Chassis 2 to 4 channels (1 chassis)

Up to 8 channels (2 chassis)

1 or 2 channels 4 phase coherent channels 1 (up to 160 MHz BW)

2 (up to 40 MHz BW) [H2’12]

2, 4, or 8 channels

Maximum Analysis

BW

800 MHz 250 MHz DC to 33 GHz 160 MHz (1-ch)

40 MHz (2-ch) [H2’12]

40 MHz

Ind. Channel Tuning Only within IF bandwidth Across RF Freq Range N/A N/A (Single Channel) Across RF Freq Range

Minimum Frequency

for Widest BW

2.25 GHz M9302A PXI LO

10 MHz with External LO

2.25 GHz DC 3 Hz 20 MHz

(always up to 40MHz BW)

89600 VSA Support Digitizer Control Only Full Hardware Support Full Hardware Support Full Hardware Support Full Hardware Support

Swept Measurements No (except VSA macros) No (except VSA macros) N/A Yes No (except VSA macros)

Streaming Support Yes (Up to 100 MHz) Yes (Up to 100 MHz) No No 132MSa capture

Typical EVM

(w/ EQ set to preamble,

pilots, data )

-44 to -46dB, 80MHz BW

-41 to -43dB, 160MHz BW


-41 to -43dB, 160MHz BW

~ -40dB, 80MHz BW

~ -40dB, 160MHz BW


-47 to -51dB, 160MHz BW

-43 to -47dB

depending on signal

Synchronization/

phase coherent

Synchronized

(not phase coherent)

Synchronized

(not phase coherent)

Yes Yes Yes, also

independently tunable

Pricing 2- ch $113K

3-ch $138K

4-ch $163K

2-ch $138K 13 GHz Model, 4 ch $123K 8.4 GHz Model

1-ch $ 60K

2-ch $120K

2-ch $ 84.9K

4-ch $105.5K

8-ch $208.5K

30

http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&nid=-34711.749314&imageindex=1



New Agilent RF Vector Signal Generators

N5172B EXG

• 9 kHz to 6 GHz

• Up to 512 MSamples baseband memory

• 120 MHz modulation BW with internal baseband

generator

• Opt. 012 provides LO in/out for phase coherency

for MIMO

• Excellent EVM: ~0.35% or -49 dB for 80 MHz

802.11ac signal

• 9 kHz to 6 GHz

• Up to 1 GSamples baseband memory

• 160 MHz modulation BW with internal

baseband generator

• Opt. 012 provides LO in/out for phase

coherency for MIMO

• Enhanced phase noise option

• Excellent EVM: ~ 0.4% or -47 dB for 160 MHz

802.11ac signal

N5182B MXG

EVM measured with equalizer training on preamble only

• Industry-leading performance • Advanced real-time applications and waveform playback for cellular, wireless connectivity,

and digital audio/video format signals with Signal Studio applications • Lower cost of ownership

31




Agilent: First to Market with

802.11ac Test Solutions

89600 VSA Software

EXG/MXG Signal Generator

E4438C ESG Signal Generator

N5106A PXB Baseband Generator and Channel

Emulator

PXA/MXA/EXA Signal Analyzers

N7109A Multi-Channel Signal

Analysis System

Infiniium & Infiniivision

Oscilloscopes

N7617B Signal Studio

81180A Wideband AWG

M8190A Wideband AWG

Signal

Creation SW

Signal Analysis

Hardware

32

Signal Generation

Hardware

Signal

Analysis SW

Configurations available for: • 20, 40, 80, 80+80, or 160 MHz channel bandwidth

• Single channel, 2x2, 3x3 or 4x4 MIMO.

Wideband MIMO PXI VSA

X-series Embedded Application

SystemVue W1917 WLAN Library W1716 DPD Builder

SystemVue W1917 WLAN Library






Summary:

Addressing Measurements Challenges

of 802.11ac Using PXI Scalable Architecture

1. MIMO and multichannel technologies pushing limits on standalone box architectures

2. PXI is an industry standard high-performance, scalable measurement platform

3. Combined with 89600 VSA software, PXI multichannel solutions can address latest challenges of 802.11ac

Agilent applies common measurement science across platforms

from standalone boxes to handhelds and modular delivering

consistent, reliable measurements across the design flow

from R&D to Manufacturing




Learn More

Literature on Agilent.com

• M9392A data sheet, brochure & config guide

• M9362A-D01 configuration guide

• Wideband MIMO PXI Vector Signal Analyzer page:

www.agilent.com/find/pxi-vsa-MIMO

Application Note - Overview:

• Accelerate Development of Next Generation

802.11ac Wireless LAN transmitters

Video

• 802.11ac video: See YouTube Playlist: Agilent PXI

Wideband Signal Analysis http://www.youtube.com/playlist?list=PL8E5DB371C1F8763C

34

http://www.agilent.com/find/pxi-vsa-MIMO





http://www.youtube.com/playlist?list=PL8E5DB371C1F8763C






Agilent Resources

• 802.11ac application and product info: www.agilent.com/find/802.11ac

• MIMO application and product info: www.agilent.com/find/mimo

• 89600 VSA product information: www.agilent.com/find/vsa

• Additional Webcasts and events: www.agilent.com/find/events

IEEE 802.11ac Standard

• Task group updates: http://www.ieee802.org/11/Reports/tgac_update.htm

• 802.11 working group project timelines:

http://www.ieee802.org/11/Reports/802.11_Timelines.htm

• 802.11ac working group documents:

https://mentor.ieee.org/802.11/documents?is_group=00ac

35

Learn More

http://www.agilent.com/find/802.11ac

http://www.agilent.com/find/mimo

http://www.agilent.com/find/vsa

http://www.agilent.com/find/events

http://www.ieee802.org/11/Reports/tgac_update.htm

http://www.ieee802.org/11/Reports/802.11_Timelines.htm

https://mentor.ieee.org/802.11/documents?is_group=00ac




36

• Introduction to 802.11ac WLAN Technology and Testing Webcast

• http://www.home.agilent.com/agilent/eventDetail.jspx?cc=US&lc=eng&ck

ey=2067515&nid=-11143.0.00&id=2067515

• Next Generation Very High Throughput: 802.11ac WLAN MIMO Design &

Test Challenges


ey=2113532&nid=-11143.0.00&id=2113532

• Innovations in EDA: High Performance Digital Pre-Distortion (DPD) for

Wideband Systems

• http://www.home.agilent.com/agilent/redirector.jspx?action=ref&lc=eng&

cc=US&nfr=-34867.0.08&ckey=2021229&cname=AGILENT_EVENT

• Accelerate 802.11ac/ad system-level design & verification for next-

generation WLAN


ey=2112408&nid=-52844.3383972.08&id=2112408

Learn More – Webcasts

http://www.home.agilent.com/agilent/eventDetail.jspx?cc=US&lc=eng&ckey=2067515&nid=-11143.0.00&id=2067515








http://www.home.agilent.com/agilent/redirector.jspx?action=ref&lc=eng&cc=US&nfr=-34867.0.08&ckey=2021229&cname=AGILENT_EVENT











37

• Tackling MIMO Design and Test Challenges for 802.11ac WLAN

– Microwave Journal

• http://www.microwavejournal.com/articles/17140-tackling-mimo-

design-and-test-challenges-for-802-11ac-wlan

• Wideband Digital Pre-Distortion with Agilent SystemVue and PXI

Modular Instrument

• http://cp.literature.agilent.com/litweb/pdf/5990-8883EN.pdf

• Accelerate Development of Next Generation 802.11ac Wireless

LAN Transmitters-Overview

• http://cp.literature.agilent.com/litweb/pdf/5990-9872EN.pdf

• Agilent’s WLAN 802.11ac Test and Design Home Page

• http://www.agilent.com/find/80211ac

Learn More – Articles & AN

http://www.microwavejournal.com/articles/17140-tackling-mimo-design-and-test-challenges-for-802-11ac-wlan





















http://cp.literature.agilent.com/litweb/pdf/5990-8883EN.pdf








http://www.agilent.com/find/80211ac




Thank You!

38




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