Testing Wireless Devices and Systems

Session 1: Introduction

9-July-2012

Fanny MlinarskyoctoScope, Inc.

1

Contents

Evolution of wireless technologyTest challengesTest applications

2

Wire

less

cap

acity

/ th

roug

hput

1970 1980 1990 2000 2010

First cell phones

GSMCDMA

802.11a/b/g802.16e

LTE

Increasing throughput and capacityWCDMA/HSxPA2G2G

3G3G

4G4G

IEEE 802IEEE 802

Brief History of Wireless

TACS AMPS NMT

IS-54IS-136

GPRS

AnalogAnalog

G = generation

LTE-A802.11n/ac

5G5G

Key wireless technologies

2015

3

OFDM (Orthogonal Frequency Division Multiplexing)

• OFDM is the most robust signaling scheme for a hostile wireless channel– Works well in the presence of multipath thanks to multi-tone signaling and

cyclic prefix (aka guard interval)• OFDM is used in all new wireless standards, including

– 802.11a, g and draft 802.11ac, ad– 802.16d,e; 802.22– DVB-T, DVB-H, DAB

• LTE is the first 3GPP standard to adopt OFDM

Multiple orthogonal carriers

Frequency

Vol

tage

4

DVB = digital video broadcastingDVB-T = DVB terrestrialDVB-H = DVB handheldDAB = digital audio broadcastingLTE = long term evolution

FDMA vs. OFDMA• OFDMA is more frequency efficient

than traditional FDMA– Orthogonal subcarriers require no guard bands

FDMAFDMA OFDMAOFDMA

ChannelGuard band

5

OFDMATi

me

Frequency allocation per user is constant vs. time

Frequency per user is dynamically allocated vs. time slots

User 1 User 2 User 3 User 4 User 5

Tim

e

OFDM = orthogonal frequency division multiplexingOFDMA = orthogonal frequency division multiple access

6

LTE

Resource Block (RB)

LTE Resource Block

7

1 slot, 0.5 ms

1 subcarrier (15 kHz)Resource Element1 subcarrierQPSK: 2 bits16 QAM: 4 bits64 QAM: 6 bits

Resource block 12 subcarriers

Time

Subc

arrie

r (fr

eque

ncy)

…

…

……v

A resource block (RB) is a basic unit of access allocation. RB bandwidth per slot (0.5 ms) is 12 subcarriers times 15 kHz/subcarrier equal to 180 kHz.

Multiple Antenna Techniques• SISO (Single Input Single Output)

Traditional radio

• MISO (Multiple Input Single Output)Transmit diversity (STBC, SFBC, CDD)

• SIMO (Single Input Multiple Output)Receive diversity, MRC

• MIMO (Multiple Input Multiple Output)SM to transmit multiple streams simultaneously; can be used in conjunction with CDD; works best in high SNR environments and channels de-correlated by multipathTX and RX diversity, used independently or together; used to enhance throughput in the presence of adverse channel conditions

• Beamforming SM = spatial multiplexingSFBC = space frequency block codingSTBC = space time block codingCDD = cyclic delay diversityMRC = maximal ratio combiningSM = Spatial MultiplexingSNR = signal to noise ratio

8

MIMO vs. SISO Throughput

Draft 802.11n vs. Legacy - Office

020406080

100120140160180

6 ft 40 110 150 180 200

feet

Mb

ps

Draft-802.11n Legacy 802.11g

Draft 802.11n vs. Legacy - Home

02040

6080

100120

140160180

25 35 45 50feet

Mb

ps

Draft-802.11n Legacy 802.11g

9

Vendor 1Vendor 1 Vendor 2Vendor 2

MIMO = multiple input multiple outputSISO = single input single output

Measured by octoScope

IEEE 802.11a,b,g,n Data Rates

SGI = short guard interval

10

802.11ac – Next Generation Wi-Fi

• Up to 6.9 Gbps of PHY data rate • Higher order MIMO (> 4x4)• 8 spatial streams• Multi-user (MU) MIMO

– Up to 4 users; up to 4 streams per user• Higher bandwidth channels (20, 40, 80,

80+80 and 160 MHz)

11

MU-MIMOMultiple beamformed

streams in the same channel

Wireless Topologies• 2G/3G/LTE and most Wi-Fi

networks are infrastructure based

• Mesh networks (e.g. 802.11s) are sometimes used to interconnect APs or base stations to the central carrier or corporate network or to the internet

• With the spread of LTE, the trend is towards smaller base stations and smaller cells interconnected via microwave (sometimes Wi-Fi) mesh networks

• Wireless backhaul is starting to displace traditional expensive fiber or copper cabling

Mesh networkInfrastructure network

Small 2G/3G/LTE base stations are interconnected via microwave links.

AP = access pointLTE = long term evolution

12

Wireless Protocols and Applications

13

LTE, Wi-Fi, ...LTE, Wi-Fi, ...

EPCEPC

IMSIMS InternetInternet

IMS = IP multimedia subsystemEPC = evolved packet coreLTE = long term evolution

Voice, video, ...Voice, video, ...

Contents

Evolution of wireless technologyTest challengesTest applications

14

Many Things To Test

15

Lots of Knobs

16

Wireless Test Standards of Note2G/3G/LTE Wi-Fi Data transport Applications Smart Grid

3GPP RAN5 →ETSI →PTCRB/GCF (conformance, interoperability)

CTIA (TIS/TRPMIMO-OTASAR)

Wi-Fi Alliance (WMM, WPA, etc.)

IEEE 802.11.2 (range, throughput, latency)

IETF RFC 2285, 2544, 2889 (packet loss, latency, jitter)

ITU-T Voice Quality P.800 (MOS); P.862 (PESQ); G.107 (R-Factor)

IETF video quality RFC 4445 (MDI MLR, DF)

NIST SEP 2 interoperability

17

3GPP = 3rd generation partnership projectRAN = radio access networkIETF = internet engineering task forceRFC = request for commentsGCF = global certification forumITU = international telecommunication unionETSI = European Telecommunications Standards InstituteCTIA = cellular telecommunications internet association

TIS = total isotropic sensitivityTRP = total radiated powerMIMO = multiple input multiple outputOTA = over the airSAR = specific absorption ratioWMM = wireless multimediaWPA = wireless protected access

NIST = national institute of standard and technologySEP = smart energy profileMOS = mean opinion scorePESQ = perceptual speech quality measureR-Factor = rating factorMDI = Media Delivery Index MLR = media loss rateDF = delay factor

MIMO/OTA Test Standards• 3GPP (International)

– MIMO/OTA specification development – RAN WG4 in collaboration with CTIA & COST

• CTIA (US)– SISO OTA certification standard – MIMO/OTA Sub-Working Group (MOSG) is driving effort

to update current standard SISO TIS/TRP standard

• COST (Europe)– ICT COST IC1004 Action: “Cooperative Radio

Communications for Green Smart Environments”; Formerly COST 2100 Action: “Pervasive Mobile & Ambient Wireless Communications”

– Contributions driven by SWG2.2: “Compact Antenna Systems for Terminals”

MIMO = multiple input multiple outputOTA = over the air3GPP = 3rd generation partnership projectCTIA = cellular telecommunications industry associationCOST = European Cooperation in Science and Technology

3GPP Groups

• RAN1-4 develop the functionality standards

• RAN4 feeds RAN5 RF group with test requirements

• RAN1 feeds RAN5 RF group through RAN4• RAN2 feeds RAN5 Signaling group with

test requirements• ETSI develops TTCN code per RAN5

standards and makes code available as open source

• Test equipment manufacturers are active contributors to the TTCN effort

• TTCN makes signaling certification uniform; RF certification is different among test equipment vendors

RAN1TX/RX DSP

RAN4RF and channel

RAN2Signaling

RAN5Signaling Cert

RAN5RF Cert

ETSI(TTCN)

GCFPTCRB Te

st E

quip

men

teN

B em

ulat

ors

Now working on LTE-A

3GPP = 3rd generation partnership projectRAN = radio access networkGCF = global certification forumETSI = European Telecommunications Standards InstituteTTCN = Testing and Test Control Notation

19

SEP 2 Architecture

• SEP 2 was selected in 2009 by the NIST as a standard profile for smart energy • Smart Grid Interoperability Panel (SGIP) sets guidelines for smart grid testing and

certification programs.

20

SEP = smart energy profileNIST = national institute of standards and technology

IP layer

Smart Grid application 1 Smart Grid application 1 …

… Radio technologies

Applications

The interoperability test spec is targeted to be completed in Q4-2012

www.homeplug.org www.wi-fi.org www.zigbee.org

Contents

Evolution of wireless technologyTest challengesTest applications

21

Test ApplicationsR&D QA Production Deployment

RX sensitivityTX spectrumThroughput vs. rangeAdaptive modulationMIMO modesRoaming, handoverMesh algorithmsThroughputDelayPacket error rate

Test automationRegression testingConformanceInteroperabilityRegulatory complianceReproducing field failures

Parametric testing- Speed- Coverage- Yields

Pre-deployment lab testField surveyDeployment testMonitoring

22

Next Session

Part II: R&D Test

When: July 10th at 2 p.m.

Thank you!Please see more info and white papers at

www.octoscope.com

23