Industrial Wireless Guidebook

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About Moxa

Moxa: Your Trusted

Partner in AutomationFounded in 1987, Moxa is now one of theleading manufacturers of industrial networking,

computing, and automation solutions.

Moxa provides thousands of hardware and

software products and draws upon 25 years of

accumulated expertise. Moxas products reflect

our constant zeal for improvement, keen eye for

innovation, and respect for proven solutions and

expertise. We harness these qualities to create

solutions that deliver a competitive edge for

our customers and partners in adapting to fast-

changing network and market environments.

Moxa delivers network-centric automation

solutions that integrate automation and IT

systems into a single network platform that

simplifies management, reduces costs, and

achieves greater reliability and efficiency.

A Leader and Partnerin Automation

Solutions

Moxas commitment to execution,

innovation, and collaboration with our

partners has fueled our transformative

journey to leadership as a solution

provider and partner in automation.

Mission and Vision

As a world-class leader and a trustedpartner in industrial-grade device

networking solutions for automation, Moxa

proudly provides quality products and

value-added service to establish win-win

business relationships based on mutual

trust and integrity. Moxa works closely with

customers, channel-partners, and solution-

partners to achieve and share success.

Delivering onCommitmentsMoxas talented design team, which is

experienced in networking technology

and solution development, offers quick,

flexible, and comprehensive R&D service

to meet customers specific expectations

and exacting requirements. Moxa

collaborates closely with customers to

drive advancements and achieve a faster

time-to-market, and these partnerships keep

Moxa in touch with emerging technologies

and ensure that new developments and

successes are shared with all of Moxas

partners.


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www.moxa.com e-mai l : [email protected]

Integrating Automation by Enabling Convergence

Moxa offers a wide array of devicenetworking products that feature anopen Ethernet infrastructure, industry-

proven standards, extended temperature

tolerance, environmental protection, and

network redundancy to ensure network

availability and reliability. Product lines

range from edge-to-core industrial

Ethernet switches, industrial wireless

devices, serial cards, serial device servers,

and embedded device servers, to USB

and fieldbus components. All of our

products are designed to stand up to harsh

environments and are ideal for deploying

mission critical applications in fields

such as maritime, oil and gas, power and

utilities, rail, and factory automation.

Moxas industrial embedded solutionsare used to construct powerful front-end controllers that can execute onsite

data collection and control at widely

distributed remote sites through industrial

Ethernet or wireless backbones. All of

the computers feature rugged reliability

and fanless operations with a wide

operating temperature range of -40 to

85C. Our products feature a user-friendly

environment that makes application

development easy. Moxa provides prompt

and extensive customization services in

addition to a wide selection of ready-to-run

products such as industrial computers,

wireless computers, and wide temperature

computers.

Moxas remote automation solutions empowercontrol and monitoring systems in remotelocations with the latest technology and industry

expertise. Our product portfolio includes

programmable RTU controllers, remote I/O

devices, IP surveillance solutions, and easy-to-

configure automation and video software. Both

network and cellular communication interfaces

are available to meet the needs of a variety of

applications and to simplify long-range host-

to-device communications around a standard

industry protocol. Including Moxas SCADA-

compatible IP surveillance solutions that enable

your network video monitoring system, Moxas

remote automation solutions enhance the safety

and security of remote industrial facilities. Withtheir robust, wide temperature design, all of

the products can be used in harsh, industrial

environments.

Industrial Networking Solutions Industrial Computing Solutions Remote Automation Solutions

Industrial automation users have long anticipated the integration of computer, controller,

I/O, video, and audio systems into a single easy-to-manage network. This vision of network-centric automation is possible today, thanks to Moxas two decades of accumulated

knowledge in industrial networking and wide selection of

automation solutions that enable the convergence of I/O, audio,

and video data over Ethernet networks. Improve the efficiency

and reliability of your industrial process by transforming a

hodgepodge of controller-centric

operations into a single network-

centric operation. Moxa provides

communication interoperability

across the full range of automation

devices and modules to seamlesslyintegrate them with industrial

Ethernet networks.


4/563 Industrial Wireless Guidebook

About Moxa ......................................................................................................................1

Table of Contents ............................................................................................................3

Chapter 1 Wireless Landscape

1-1 Overview ................................................................................................................................................................5

Introduction

TechnologyMap

1-2 WLAN Basics ..........................................................................................................................................................6

IEEE802StandardsintheOSIReferenceModel

HistoryofWLANStandards

WirelessSecurity

1-3 WWAN(Cellular) Basics ................................................................ ................................................................. .........9

Introduction

EvolutionoftheCellularNetwork

1-4 WPAN Basics ........................................................................................................................................................14

IEEE802.15StandardsforWPAN

IEEE802.15.4LowRateWPAN

ZigBee

ZigBeeSolution

Chapter 2 Understanding Wireless Technology

2-1 Radio System Concepts ............................................................... ................................................................. .......17

HowRadioWorks

WhatYouNeedtoKnowaboutaRadioSystem

2-2 WLAN Antennas ...................................................................................................................................................24

WhyUsingtheRightAntennaisImportant

AntennaParameters

AntennaTypes

2-3 Cables ...................................................................................................................................................................28

RFCables

EthernetCables

Table Of Contents

Table Of Contents


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2-4 Connectors ...........................................................................................................................................................31 AntennaConnectors

EthernetConnectors

Chapter 3 Industrial Wireless

3-1 Industrial Design Concepts .................................................................................................................................33

Introduction

IndustrialHazards

3-2 Robust Wireless Concepts ........................................................... ................................................................. .......35 Introduction

ConcernsforWirelessLocalAreaNetworks

ConcernsforWirelessWideAreaNetworks

Chapter 4 Standards

4-1 IEEE 802 Standards ..............................................................................................................................................38

IEEE802.3Ethernet

IEEE802.11WirelessLocalAreaNetwork IEEE802.15WirelessPersonalAreaNetwork

4-2 Safety and Certifications .....................................................................................................................................41

Moxas Wireless Product Selection Guide ..................................................................43

Glossary .........................................................................................................................49



Wireless Landscape

Wireless Landscape

Introduction

Wirelesstechnologieshavebecomeincreasinglypopularin

industrialautomationasgrowingnumbersofsystemintegrators,

governmentagencies,andindustrialoperatorscontinuetoturnto

wirelesssolutionsfortheirapplications.Wirelessnetworkscanbe

quicklydeployedtotransmitdatatoareaswithoutexistingcable

infrastructures.Forhard-to-wirelocationsandworksitelandscapes

thatconstantlychange,wirelesstechnologiesareidealforproviding

highlyflexibleandefficientnetworkconnectivity.Inadditiontomobile

versatility,wirelesstechnologiescanofferreal-timecommunication

formission-criticalapplications,highbandwidthforvideo

transmission,andalowtotalcostofownership.

However,sincewirelesscommunicationsrelysolelyontheemission

ofelectromagneticwavestotransmitdata,networksecurity

Technology Selection

WWAN (Wireless Wide Area Network) WLAN (Wireless Local Area Network) WPAN (Wireless Personal Area Network)

Characteristics h Wideareacoverageh Longdistancecommunicationh Hightransmissionlatencyh Mediumtransmissionbandwidthh On-goingdatatransmissioncosth Basestationrestriction

h Localareacoverageh Long/mediumdistancecommunicationh Lowtransmissionlatencyh Hightransmissionbandwidthh InitialAPsetupcost

h Smallareacoverageh Shortdistancecommunicationh Lowtransmissionlatencyh Lowtransmissionbandwidthh Lowpowerconsumption

Applications h Highwaysignalingcontrolsystemh Remotemonitoringsystemh

Nationwideenvironmentalmonitoring

h Traintogroundcommunicationformissioncriticaldatah HighthroughputforvideotogroundtransmissionhDatabridgingfordevicemonitoring

h Streetlightcontrolh PersonneltrackinghShortdistancedataacquisition

Technology Map

Sincetheinventionofradiotransmission,manytypesof

wirelesstechnologiesandstandardshavebeendevelopedto

meettherequirementsofvariouswirelessapplications.Forthe

developmentofeverywirelessstandard,twomajorvariables

wereconsidered:coveragearea(distance)anddatarate

(bandwidth).

Wirelesstechnologiescanbedividedintothreecategories:

WWAN,WLAN,andWPAN.

isanimportantfactorforadministratorstoconsider.Another

majorconcerniselectromagneticinterference(EMI),whichcan

disruptdatatransmission,severelyreducedatathroughput,and

compromisenetworkreliability.Withover25yearsofindustrial

automationexperience,Moxaofferssecureandreliableindustrial

wirelesssolutions,suchascellular,Wi-Fi,andZigBeeformission-

criticalapplicationsthatdemanddependableanduninterrupted

systemoperation.

Wehopethisguidebookwillprovideyouwithamorecomprehensive

understandingofindustrialwirelesstechnologiesandserveasyour

mosttrustedguidetogettingun-wired.

Itstimetogowireless!

1-1 Overview

Coverage

Low Data Rate

(>10 Mbps)

Glgabits

(>1 Gbps)

Medium Data Rate

(10 to 100 Mbps)

High Data Rate

(100 Mbps to 1 Gbps)

Nationwide(> 1,000 m)

Local Area(500 m)

Short Distance(10 m)

WLAN

WWAN

WPAN

Data Rate

Satellite

RFID

BlueTooth

Zigbee

UWB

2G/2.XG

GSM/GPRS/EDGE

Pre4G/4G

LTE/WiMAX/LTE-A

3G

UMTS/HSPA(+)CDMA2000 EV-DO

Cellular Technology

802.11b 802.11a/g 802.11n 802.11ac

802.11 Family

(Commonly known as Wifi)


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W

irelessLandscape

1

History of WLAN Standards

ForWLANapplications,theIEEEfirstpublishedthe802.11standard

in1997.ThreeMACsub-layersandthreedifferentphysical(PHY)

layersareaddressedforthe802.11standard.FrequencyHopping

SpreadSpectrum(FHSS)andDirectSequenceSpreadSpectrum

(DSSS)aretwomethodsoffrequencyspreadingforthe2.4GHzISM

bandthatprovidedataratesof1and2Mbps.

IEEE802.11wasnotwidelyacceptedforuseuntiltherelease

of802.11a/bin1999.IEEE802.11ausesthe5GHzbandwith

orthogonalfrequency-divisionmultiplexing(OFDM)modulationtoprovidedataratesofupto54Mbps.IEEE802.11bstillusesthe2.4

GHzISMbandtoprovidedataratesofupto11MbpsusingDSSS

modulation,whichallowsintegrationofotherDSSS-basedIEEE

802.11systems.FHSS-based802.11systems,however,cannotbe

integrated.

Themostwidely-adoptedvariationoftheIEEE802.11protocolsuite

isIEEE802.11g,whichwasanimprovementupontheexistingIEEE

802.11bstandard.Usingthesame2.4GHzband,OFDMmodulation

allowsdataratesofupto54Mbps.

1-2 WLAN Basics

OSI Model

Layer Functions

(7)ApplicationUserapplicationinteractionProcess-to-processcommunication

(6)PresentationDatatransformation/reformattingDatacompression/encryption

(5)SessionEstablishcommunicationbetweenendsystemsManageuserconnections

(4)Transport Errordetection/recoveryNetworkconnectionflowcontrol

(3)NetworkManagenetworkpathconnectionsDatarouting/relay

(2)DataLinkAccess/error/flowcontrolMACaddressing

(1)PhysicalControlsrawbit-streamtransmissionElectricalsignaling

IEEE 802 Standards in the OSI Reference ModelIEEE802specificationsareonlyaddressedforlayer1(physical)

andlayer2(datalink)oftheOpenSystemsInterconnection(OSI)

referencemodelbytheInternationalOrganizationforStandardization

(ISO).Thedatalinklayeriscomposedof2sub-layers:MediaAccess

Control(MAC)andLogicalLinkControl(LLC).TheLLCsub-layer

manageserror/flowcontrolandisessentiallythesameforallIEEE

802standards.TheMACsub-layerisforphysicaladdressingand

managesmediaaccesscontrol.IEEE802.3specificationsreferto

accessforEthernetandIEEE802.11specificationsrefertoaccess

forwirelessLANs.

LLC 802.2

IEEE 802 WLAN802.11

Ethernet802.3

TheIEEE802.11hstandardisanamendmentoftheIEEE802.11a

standard.TransmissionPowerControl(TPC)andDynamicFrequency

Selection(DFS)areappliedatthePHYlayertomeetEuropean

regulationsandallowcompatibilitywithotherstandardsinthe5GHz

band.

ThenewestspecificationtotheIEEE802.11protocolsuiteisIEEE

802.11ac,whichisbackwards-compatiblewithother802.11n

networksusingthe5GHzrange.ItprovidesWLANthroughput

ofgreaterthan1Gbpsonthe5GHzband,offersupto8MIMOstreamswithupto160MHzbandwidtheach,anduseshigh-density

modulationofupto256QAM.

Thetablebelowillustratesthedevelopmenthistoryof802.11and

thedifferencesbetweenthevariousversionsof802.11network

standards.



Wireless Landscape

Wireless Security

802.11networksuseradiosignalbroadcaststocommunicateand

anyonewithacompatiblewirelessnetworkinterfacecardcanaccess

theWLAN.SecuritymeasurestoverifyWLANaccessarecriticalto

preventunauthorizedaccesstonetworkdevicesandresources.

TwomaintypesofsecuritymeasuresareavailableforWLANs:

Authentication:User/deviceidentityisverifiedbeforenetwork

accessisgranted.

Encryption:DataexchangedbetweenWLANnodesshouldbe

encryptedtomakeintercepteddataunreadable.

Variouscombinationsofauthenticationandencryptionmethods

arecommonlyusedtoprovidedifferentlevelsofWLANsecurity.

InadditiontothreemajortypesofWLANsecurity(WEP,WPA,

andWPA2),theIEEE802.1Xprotocolalsoprovidesarobust

authenticationschemeforeverysingleWLANconnection.

WLAN Security Protocols

Security Protocol Features

WEP(WiredEquivalentPrivacy)

RC4dataencryption

Nouser/passwordauthentication

WPA(Wi-FiProtectedAccess)

TKIP+802.1X+MICSupportsRADIUSauthenticationBackwardscompatiblewithallsystems

WPA2 WPA+AEScipher

802.11 Standards

Protocol Released Frequency (GHz) Bandwidth (MHz) Data Rate (Mbps) MIMO (max.) Modulation Compatibility

802.11 1997 2.4 20 1,2 1 DSSS,FHSS 802.11

802.11b 1999 2.4 20 1,2,5.5,11 1 DSSS 802.11b

802.11a 1999 5 20 6to54 1 OFDM 802.11a

802.11g 2003 2.4 20 6to54 1 DSSS,OFDM 802.11b/g

802.11n 2009 2.4&52040

6.5to28.813.5to600

4 OFDM 802.11a/b/g/n

802.11ac 2013 5

204080160

6.5to693.613.5to160029.3to3466.458.5to6933.6

8 OFDM 802.11ac/n

WEP

WiredEquivalentPrivacy(WEP)isalow-levelsecuritymeasure

toprovidedataconfidentialityforwirelesscommunication.Static

sharedkeys(fixed-lengthalphanumericstrings)areusedtoencrypt

dataandaremanuallydistributedtoallwirelessstationsonthe

wirelessnetwork.

In2001,WEPwasfoundtobehighlyvulnerabletopassiveattacks

thatcancompromisethe24-bitRC4encryptionkeyandisnot

recommendedforhigh-levelsecuritynetworks.Forwirelesssecurity

thatismorerobust,Wi-FiProtectedAccess(WPAorWPA2)offers

improveddataencryptionanduserauthentication.

WPA

Wi-FiProtectedAccess(WPA)wascreatedinresponsetothe

flawsfoundinWEP.Itwasdesignedasatemporarymeasureuntil

developmentsin802.11isecuritymeasureswereready.Whenused

withRADIUSandVPNauthenticationmethods,WPAisgenerally

acceptableasaneffectivemethodofWLANsecurity.

WPA2

WPA2isanupdatetotheencryptiontechnologyofWPA.WPA

usesTemporalKeyIntegrityProtocol(TKIP)for128-bitdata

encryption,whileWPA2usesAdvancedEncryptionStandard(AES),

asubstitution-permutationnetworkencryptiondesignthatissuitable

forWLANsthatrequirehighly-secureaccesscontrol.


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W

irelessLandscape

1

802.1X

802.1Xisaport-basedauthenticationmethodthatprevents

unauthorizedaccesstothenetwork.ItisusedwithWPAtoforma

completeWLANsecuritysystem.Onmanywirelesssystems,users

canlogintoindividualaccesspointsbutcannotgetfurtherwithout

Method Client Support Considerations

Open Nospecialrequirementh Canbeinstalledandusedquicklyh Bringshighriskandmaydamagethenetworksecurity

WEP Built-insupportforall802.11a,802.11b,and802.11gdevicesh Providesweaksecurityh Requiresmanualkeymanagement

WPA RequiresWPA-enabledsystemandnetworkcarddriver

h Providesdynamicallygeneratedkeysthatareperiodicallyrefreshedh Providessimilarsharedkeyuserauthenticationh Providesrobustsecurityforsmallnetworks

WPA2 RequiresWPA-enabledsystemandnetworkcarddriver

h Providesrobustsecurityforsmallnetworksh Requiresmanualmanagementofpre-sharedkeyh WirelessstationsmayrequirehardwareupgradetobeWPA2-compliant

802.1X RequiresWPA-enabledsystemandnetworkcarddriver

h Providesdynamicallygeneratedkeysthatareperiodicallyrefreshedh RequiresconfiguredRADIUSserverh ProvidesbackwardscompatibilitywiththeoriginalWPA

Choosing the Right Level of WLAN Security

Therightbalancebetweensecurity,transparency,andcost

effectivenessisimportantwhendeterminingthetypeofsecurityto

implementontheWLAN.Factorssuchasthetargetenvironment,

compatibletypesofsecuritylevels,andthepossibleimpacton

networkperformancewhenusingmoresophisticatedsecuritymethodsshouldallbetakenintoconsideration.

HereareafewkeyquestionsforevaluationofWLANsecurityoptions:

Doestheenvironmentrequirehigh-levelsecurity?IftheWLAN

willtransmitinformationsuchasmedicalrecords,thehighest

levelofsecurityshouldbeapplied.However,iftheWLANwill

onlybeusedtocommunicateenvironmentalmonitoringdata,

alowerlevelofsecurityshouldbeappliedtooptimizeWLAN

performance.

Whatlevelsofsecuritycanthenetworkenvironmentsupport?

WPAandWPA2encryptiontechnologiesprovidereliablesecurity,

butcantheclientdevicessupportthem?Also,if802.1X

authenticationistobeimplemented,isaRADIUSserveravailable

ontheWLAN? Willhigh-levelsecurityhaveanundesirableimpactonthe

performanceoftheWLAN?Howwilltheperformanceofwireless

devicesontheWLANbeaffectedifencryptionisenabled?

Encryption/decryptioncanrequiresignificantCPUresourcesfor

processing.CanallWLANdevices,includingthedeviceservers,

handletheadditionalloadfordataprocessing?

Thefollowingtablesummarizestheconsiderationsfor

implementationandclientrequirementsforWLANsecuritymethods.

additionalauthentication.802.1Xrequiresuserstoauthenticate

withthewirelessnetworkitself,nottoindividualAPsoraVPN

connection.ThisprovideshigherWLANsecurity,asunauthorized

trafficcanbedeniedrightattheAP.

Open

Applies no wireless

security

Provides quick deployment

and easy-to-use access

Makes the entire network

system vulnerable

Can be augmented with

VPN in enterprise and

high-traffic environments

WEP

Supported by most

existing hardware

Offers sufficient security

for home use, but may be

cracked in a few minutes

Can be augmented with

VPN in enterprise and

high-traffic environments

WPA2

Adopts the final 802.11i

standard (2004)

Uses the new AES cipher

Provides pre-authentication

and PMK caching

Most products are

backwards compatible

with WPA

WPA

Replaces WEP by using

TKIP for encryption

Provides a standard

handshake procedure

for determination/

transmission of the

session key

Incorporates key

features of pre-802.11i

Low Security Level High



Wireless Landscape

IntroductionAWWAN(wirelesswide-areanetwork)canincludevarioustypes

ofmobilecommunicationnetworks,suchastraditionalmicrowave

transmission,satellitecommunication,andnowadayscellular

networktechnology.Allofthesenetworksofferawidecoverage

areaandcanevenbeusedforglobaltransmissionofdigitaldata.

Incellularcommunication,3Gnetworksservedmorethan1.5

billionsubscribersin2013andthenumberofusersisforecasted

toincreaseto3.5billionby2015.However,LTEtechnology(4G)is

showingrapidgrowthandisexpectedtoreplace3Gtechnologyas

theleadingstandardfornextgenerationcellularcommunication.

Majorconcernsregardingtheuseofcellularnetworksfordata

exchangeincludebandwidth,IPmanagement,andhighoperational

cost(suchassatellitecommunication).However,astechnologies

advancetoprovidemoreefficientservice,cellularnetwork

infrastructurescanbedeployedatlowercoststopotentially

replacetraditionalmicrowave,RF(radiofrequency),andsatellite

communications.

Evolution of the Cellular Network

1-3 WWAN (Cellular) Basics

Technology Multislot Class TDMA Timeslots allocatedDL+UL (Active TS)

Coding Schemes(Kbps per slot)

Download (Kbps) Upload (Kbps)

GPRS 10 4+1(5) CS-4(20Kbps) 4slots(80Kbps) 1slots(20Kbps)

GPRS 10 3+2(5) CS-4(20Kbps) 3slots(60Kbps) 2slots(40Kbps)

EDGE 10 4+1(5) MCS-9(59.2Kbps) 4slots(236.8Kbps) 1slots(59.2Kbps)

EDGE 10 3+2(5) MCS-9(59.2Kbps) 3slots(177.6Kbps) 2slots(118.4Kbps)

P.14

LTE-A

HSPA+

(UMTS)

2G 2.XG 3G 4G

GSM GPRS

W-CDMA

(UMTS)

HSPA

(UMTS)

EV-DO/Rev A/Rev B

(CDMA2000)CDMAOne

1x

(CDMA2000)

LTE

WiMAX

EDGE

Evolution of Digital Cellular Standards


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W

irelessLandscape

1

2G/2.XG Technology

Circuit-Switched Data for GSM Networks

GSM(GlobalSystemforMobileCommunications)isasetof

standardsformobilephonecommunicationon2Gdigitalcellular

networks.GSMwasdevelopedbytheEuropeanTelecommunications

StandardsInstitute(ETSI)andbecamethedefactostandardfor

mobilecommunicationtoreplacefirstgeneration(1G)analog

cellularnetworks.GSMusescircuit-switcheddata(CSD)forfull

duplexvoicetransmissionandthetechnologywasexpandedover

timetointroducedatacommunicationfirstviacircuit-switched

transmission,whicheventuallyevolvedintopacket-switched

technologiesandthenbyGPRS(GeneralPacketRadioServices)

andEDGE(EnhancedDatarateforGSMEvolution)fortransmitting

dataviaGPRS(GeneralPacketRadioServices)andEDGE(Enhanced

DataratesforGSMEvolution).

GPRS

GeneralPacketRadioService(GPRS)isapacket-switchedservice

forGSMtransmissionon2G/2.5Gnetworkstoallowsimultaneous

voiceanddatatransmissions.GPRScanbeusedforservices,

includingSMS,MMS,email,andinternetaccess.GPRSwasfirst

developedbytheEuropeanTelecommunicationsStandardsInstitute,

andisnowmaintainedbythe3rdGenerationPartnershipProject

(3GPP).

EDGE

EnhancedData-ratesforGSMEvolution,alsoknownasEnhanced

GPRS(EGPRS),IMTSingleCarrier(IMT-SC),orEnhancedDatarates

forGlobalEvolution,isanextensionofGSM.EDGEisapre-3Gdigital

mobilephonetechnologythatallowshigherdataratesthanGPRS,

withtransmissionratesofupto384kbps.

Additional Information

Thefollowingfiguregivesaroughideaofthroughputimprovement

overtimewithdifferent2Gtechnologies.

Furthermore,GSM,GPRS,andEDGEoperateonfourcommonGSM

bands:850MHz,900MHz,1800MHz,and1900MHz.However,

sincedifferentregulationsareusedindifferentcountries,acommon

GSMfrequencyisnotusedaroundtheworld.Theaccompanying

tablegivesabriefoverviewoftheGSMbandsusedinanumberof

countries.

Continent Country850MHz

900MHz

1800MHz

1900MHz

America

Brazil

Canada

UnitedStates

EuropeFrance Germany

UnitedKingdom

Africa SouthAfrica

Asia

China

India

Russia

Taiwan

OceaniaAustralia

NewZealand

Note1:Forthelatestbandusage,pleasecontactlocalcarriers.Note2:Forcellulardevicecompatibilitywithaparticularcarrier,pleasecheckCarrierApprovalwithyourcellulardevicevendor.

GSM Frequency Band Usage Overview

(Based on major carriers)

1990 Timeline 20132003

GSM

Circuit-SwitchedData

GPRS

UL:20kbps

DL:80kbps

EDGE

UL:59.2kbps

DL:236.8kbps



Wireless Landscape

3G Technologies

3GPPFrom UMTS to HSPA+

UMTS

TheUniversalMobileTelecommunicationsSystem(UMTS)isaGSM-based3Gtechnologyformobilecellularnetworksdevelopedbythe

3rdGenerationPartnershipProject(3GPP).UMTSusesWideband

CodeDivisionMultipleAccess(W-CDMA)andcombinesboth

wirelessandsatellitecellulartechnologiestotransmitupto2Mbps

ofdatatoprovidegreaterspectrumefficiencyandbandwidth.

HSPA (HSDPA/HSUPA/HSPA+)

HighSpeedPacketAccess(HSPA)isthetermforUMTS-based3GcellularnetworksthatsupportbothHSUPA(HighSpeedUplink

PacketAccess)andHSDPA(HighSpeedDownlinkPacketAccess)

datatocommunicateviaW-CDMAprotocolstoprovidedownload

ratesofupto14.4Mbpsanduploadratesofupto5.8Mbps.A

newerversion,EvolvedHSPA(alsoknownasHSPA+),wasreleased

in2008andiscapableofprovidingdataratesofupto42Mbpsfor

downloadingand22Mbpsforuploading.

2001 Timeline 2013

UMTS

UL:64kbps

DL:2MbpsHSPA

UL:5.8Mbps

DL:14.4Mbps

HSPA+

UL:22Mbps

DL:42Mbps

HSDPA

DL:14.4Mbps

HSUPA

UL:5.8Mbps


Thefollowingfiguregivesaroughideaofthethroughputimprovementovertimewithdifferent3G-UMTStechnologies.

Furthermore,thereare5commonlyusedUMTSfrequencies:800,850,900,1900,and2100.TheUMTSfrequencyusageisdifferentfordifferent

operators.ThefollowingtablegivesaroughoverviewoftheUMTSbandselectionforseveralmajoroperatorsaroundtheworld.

Continent Country 850 MHz 900 MHz 1700 MHz 1900 MHz 2100 MHz

America

BrazilTIMBR

Vivo

CanadaBellMobility

RogersWireless

UnitedStatesAT&TMobility

T-MobileUS

Europe

FranceOrange

SFR

GermanyO2

Vodafone

UnitedKingdomT-Mobile

Vodafone

Africa SouthAfricaMTNSA

Vodacom

AsiaChina ChinaUnicom

Taiwan ChunghwaTelecom

Oceania

Australia Telstra

NewZealandTelecomNZ

VodafoneNZ

Note1:Forthelatestbandusage,pleasecontactlocalcarriers.Note2:Forcellulardevicecompatibilitywithaparticularcarrier,pleasecheckCarrierApprovalwithyourcellulardevicevendor.

UMTS Frequency Band Usage Overview



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W

irelessLandscape

1

3GPP2From CDMA2000 to EV-DO

CDMA2000,alsoknownasIMTMulti-Carrier(IMT-MC),isanIMT-

2000-basedstandardofCode-DivisionMultipleAccess(CDMA)that

wasdevelopedbytheITUforsendingdatabetweenmobilephones

andcelltowers(orBST,BaseTransceiverStation).CDMA2000and

W-CDMAarecompetingstandardsinthecellularcommunication

networkmarket.

CDMA2000actuallydenotesafamilyofstandardsthatrepresentthe

successive,evolutionarystagesoftheunderlyingtechnology.The

differentvariationsareallapprovedradiointerfacesforIMT-2000

andarelistedbelowinchronologicalorder:

4G Technologies

Pre-4G vs. True 4G

Today'soperatorsrefertoLTEandWiMAXtechnologiesasfourth

generationcellulartechnologies(4G).However,accordingtothe

InternationalTelecommunicationUnion,True4Gtechnology

shouldprovideGigabit-leveldatarateswhenstationary,andapeak

rateof100Mbpsforhighlymobileapplicationsandothercriteria

(detailsgivenbelow).Thissectiongivesabriefintroductiontopre-4G

technology(LTE),andtrue-4Gtechnology(LTE-A).

Requirements of IMT-Advanced (4G)

ThecandidateRadioInterfaceTechnology(RIT)shallbebasedon

anIP-basedpacketswitchednetwork.

ThecandidateRITshallprovideanominaldatarateof100Mbps

whentheclientisphysicallymovingathighspeedsrelativetothe

basetransceiverstation(BST),and1Gbpsforlow-speedmobility

orrelativelyfixedpositions.

ThecandidateRITshallbeabletodynamicallyshareandusethe

networkresourcestosupportmoresimultaneoususerspercell.

ThecandidateRITshallbeabletousedifferentbandwidth

allocationstosupportascalablebandwidthofupto(and

including)40MHz.

ThecandidateRITshallhaveaminimumdownlinkpeakspectral

efficiencyof15bits/s/Hz,andaminimumuplinkpeakspectral

efficiencyof6.75bits/s/Hz.

Forindoorenvironments,thecandidateRITshallhaveacellspectralefficiencyofupto3bits/s/Hz/cellfordownlinkand2.25

bits/s/Hz/cellforuplink.

ThecandidateRITshallprovideseamlesshandoversandglobal

roamingacrossmultipleheterogeneousnetworks.

ThecandidateRITshallofferahighqualityofservicefornext

generationmultimediaservices.

2000 Timeline 2013

CDMA20001X

UL:153kbps

DL:153kbps

1xEV-DORel.0

UL:153kbps

DL:2.4Mbps

1xEV-DORev.A

UL:1.8Mbps

DL:3.1Mbps

EV-DORev.B

UL:5.4Mbps

DL:14.7Mbps

DOAdvanced

UL:12.4Mbps

DL:32Mbps

1XEnhancements

EVRC-B+QLIC+QQF

UL:153kbps

DL:153kbps

1XAdvanced

NEWCHANNELCARD

UL:307kbps

DL:307kbps



Wireless Landscape

LTE Data Speeds

LTE

PeakDownload 100Mbps

PeakUpload 50Mbps

Long Term Evolution (LTE)

Thepre-4G3GPPLongTermEvolution(LTE)technologyisoften

branded4G-LTE,butthefirstLTEreleasedoesnotfullycomply

withtheIMT-Advancedrequirements.LTEhasatheoreticalnetbit

ratecapacityofupto100Mbpsinthedownlinkand50Mbpsin

theuplinkifa20MHzchannelisused,andmoreifmultiple-input

multiple-output(MIMO),i.e.,antennaarrays,areused.Thefollowing

tablegivesatheoreticalmeasurementoftheLTEdatarate.

LTE Advanced Data Speeds

LTE Advanced

PeakDownload 1Gbps

PeakUpload 500Mbps


LTEin2013isstillagrowingtechnology,andfrequencyusageorregulationisstillevolvingovertime.ThefollowingtablegivesasnapshotofLTE

frequencyusagein2013.ForthelatestinformationpleasecontactyourlocalLTEserviceprovider.

Continent Country 700 MHz 800 MHz 850 MHz 900 MHz 1700 MHz 1800 MHz 2100 MHz 2300 MHz 2600 MHz

America

Brazil

Canada

UnitedStates

Europe

France

Germany

UnitedKingdom

Africa SouthAfrica

AsiaJapan

SouthKorea

OceaniaAustralia

NewZealand

Note1:Forthelatestbandusage,pleasecontactlocalcarriers.Note2:Forcellulardevicecompatibilitywithaparticularcarrier,pleasecheckCarrierApprovalwithyourcellulardevicevender.

Long Term Evolution Advanced (LTE-A)

LTE-Advanced(LongTermEvolutionAdvanced)wasformally

submittedbythe3GPPorganizationtoITU-Tinfall2009asa

candidatefortheIMT-Advancedstandardandisexpectedtobe

releasedin2013.LTE-Advancedisessentiallyanenhancement

totheexistingLTEtechnologyformobilenetworks.LTEandLTE-

Advancedalsomakeuseofadditionalspectrumsandmultiplexingto

allowhigherdataspeeds.CoordinatedMulti-pointTransmissionwill

alsoallowmoresystemcapacitytohelphandletheenhanceddata

speeds.Release10ofLTEisexpectedtoachievethedata-speed

requirementsofIMT-Advanced.Release8currentlyprovidesup

to300Mbpsofdatadownload,whichisstillinadequateforIMT-

Advancedstandards.

LTE Frequency Band Usage Overview



15/5614


W

irelessLandscape

1

1-4 WPAN Basics

IEEE 802.15 Standards for WPANWPAN(WirelessPersonalAreaNetwork)technologies,alsoknown

asIEEE802.15,weredevelopedbytheIEEEforpersonal-area

communicationacrossashort-distancewirelessnetwork,which

IEEE 802.15.4 Low Rate WPAN

IEEE802.15.4(LowRateWPAN)providesanuncomplicatedmethod

forlowdataratecommunicationbutwithaverylongbatterylife(low

powerconsumption).Thestandarddefineslayer1(physical)and

layer2(datalink)oftheOSIreferencemodel.Severalstandardized

andproprietaryprotocolscanbeusedforcommunicationon

802.15.4networks,suchasIEEE802.15.5,ZigBee,ISA100.11a,

6LoWPAN,andWirelessHART.

includeswirelesscommunicationbetweenmobilecomputers,and

devicessuchascellphones,laptops,andPDAs.Thetablebelow

compareskeyfactorsforvarioustypesofWPANtechnology.

SPAN (IEEE) Technology Data Rate Distance

IEEE802.15.1 Bluetooth 1Mbps10m(Class3)100m(Class1)

IEEE802.15.2 CoexistenceMechanismsbetweenWLANandWPAN

IEEE802.15.3 HighRateWPAN(UWB) 11,22,33,44,55Mbps 30to50m

IEEE802.15.3a Alternate15.3PHY >100Mbps 10m

IEEE802.15.4 LowRateWPAN(ZigBee) 250kbps 1to100m

IEEE802.15.4aLowRateAlternativePHYof802.15.4(UWB)

5Mbps



Wireless Landscape

ZigBee

Developedforlowcostandlowpowerconsumption,ZigBeeisa

globalstandardbasedonIEEE802.15.4formachine-to-machine

(M2M)networkcommunicationusingunlicensedbands(868MHz

inEurope,900MHzintheUS,and2.4GHzglobally).Therelatively

lowcostallowsZigBeetobewidelydeployedinwirelesscontrol

andmonitoringapplications,anditslowpowerrequirementsallows

nodestooperateformonths,andevenuptoafewyears,atatime

withouthavingtoreplacethebatteries.Meshnetworkingprovides

highreliability,extensivecoverageareas,andnetworkflexibility.Data

transmissionratescanrangefrom20kbps(868MHz)to250kbps

(2.4GHz).

TheZigBeenetworklayersupportsstar,tree,andmeshnetwork

topologies.Everynetworkmusthaveatleastonecoordinatordevice.

Withinstarnetworks,thecoordinatormustbethecentralnode.Both

treeandmeshnetworktopologiesallowtheuseofZigBeeroutersto

extendcommunicationatthenetworklevel.

Thespecificationgoesontocompletethestandardbyaddingfourmaincomponents:networklayer,applicationlayer,ZigBeedeviceobjects

(ZDOs),andmanufacturer-definedapplicationobjects,whichallowforcustomization,andfavortotalintegration.

ZigBeeisnotdesignedforpowerlinenetworkingbutisoftenusedinapplicationssuchasbuildingautomation,lightingcontrols,HVACcontrol,

medicaldevices,andwarehouseapplications.ZigBeenodesarehighlycosteffectiveandcanrecoverfromsleepmodeinlessthan30

millisecondstoprovidelowlatencynetworkcommunication.

Star Tree Mesh

Mobility L M H

Distance 100m 500m 1000m

Stability H M L

Efficiency H M L

Star

Coordinator

Router

End DeviceTree Mesh

Application (APL) Layer

Application Framework

Application Support Sublayer (APS)

SecurityServiceProvider

ZDOM

anagementPlane

Medium Access Control (MAC) Layer

Physical (PHY) Layer

ZigBee Device Object(ZDO)

ApplicationObject 240

APSDE-SAP

APS SecurityManagement

SecurityManagement

2.4 GHz Radio 868/915 MHz Radio

RoutingManagement

NetworkManagement

MessageBroker

APS MessageBroker

ReflectorManagement

APSDE-SAP

NLDE-SAP

IEEE 802.15.4 defined

ZigBee Alliance defined

End manufacturer defined

Layer function

Layer interface

NLME-SAP

MLME-SAP

PLME-SAP

NLME-SAP

PD-SAP

Endpoint 1APSDE-SAP

Endpoint 0APSDE-SAP

ZDOP

ublic

Interface

ApplicationObject 1


17/5616


W

irelessLandscape

1

TheIEEE802.15.4standardforZigBeenetworksisidealforWPANcommunicationinindustrialapplications.ZigBeenetworksprovidesimpleand

low-costwirelesscommunicationforserialdevices,suchassensors,meters,anddisplays,toprovideflexibledatacommunicationwithminimal

cablingrequired.AdditionalZigBeenetworkbenefitsinclude:

Meshnetworkscanextendupto120nodes

ConfigurableinStar,Tree,andMeshtopologies

Easyinstallationandlowpowerconsumptionreducestotalcostofownership

ZigBee Solution

TheZigBeeprotocolhasbeenacceptedbyover300companies

(knownastheZigBeeAlliance)acrosstheglobeasareliableopen

standardtoprovidealow-costpersonal-areainfrastructureforlow

data-ratecommunication.

AZigBeenetworkconsistsofthreetypesofdevices/nodes;the

ZigBeecoordinator(ZC),ZigBeerouter(ZR),andZigBeeenddevice

(ZED).

ZigBee Coordinator

EveryZigBeenetworkhasonecoordinatorfornetworkmanagement

anddatarouting.Thecoordinatorshouldbemains-poweredbecause

ZigBeenetworkcommunicationreliesontheZC.

ThefollowinggraphillustratesatypicalZigBeenetworktopology,

whichgenerallyincludesthreedevicetypes.Serialdevicescanbe

connectedtoanyZigBeedevicetypetoexchangedataviathePAN.

Autilityisusuallyprovidedbythedevicemanufacturertoconfigure

theZigBeenetwork.

ZigBeedevicesthatareconfiguredasthecoordinator(ZC)canhave

anEthernet-enabledinterfacetoprovideaccesstoanotherdevice,

Ethernet-basednetwork,ortheInternet.Thefollowinggraphshows

twosucharchitectures.

ZigBee Router

Routersforwarddataacrossthenetworkthroughmulti-hoprouting

andareusuallymains-powered.Otherthanconnectingtorouters,enddevicescanalsoconnectdirectlytothecoordinator.

ZigBee End Device

ZigBeeenddevicesaregenerallyconnectedtothenetworkthrough

routers.Inadditiontorelyingonmains-power,enddevicescan

bebattery-poweredtoobecauseoftheirlow-powerconsumption.

Mostly,enddevicessleeptoconservebatterypowerandwakeup

regularlytocollectandtransmitdata.

Coordinator Router End DeviceCoordinator Router End Device

Internet

Connection to a Host Uplink to a Network



Understanding Wireless Technology

2-1 Radio System ConceptsHow Radio Works

Electromagnetic Waves

DataistransmittedthroughtheairwithElectromagnetic(EM)waves,

whichareformedbyanalternatingcurrentthatisrapidlychanging

directiononaconductivematerial.Therapidoscillationofelectric

andmagneticfieldsaroundtheconductorprojectselectromagnetic

wavesintotheair(seetheaccompanyingfigure).Inorderforcurrent

toberadiatedintotheairintheformofelectromagneticwaves,

afewfactorsarecritical;namely,thelengthoftheconductor

andfrequencyoftheACcurrent.Ahigherfrequencyreducesthe

requirementforconductorlength.

Anantenna(alsocalledanaerial)isaconductordevicedesigned

totransmitand/orreceiveelectromagneticwavesduringwireless

communication.

Tx & Rx

Everyradiosetupincludestwomajorcomponents:

Transmitter(abbreviatedasTx)

Receiver(abbreviatedasRx)

Electromagneticwavesareradiatedfromatransmittertoareceiver.

Thetransmitterencodesvoice,video,anddataontoasinewave,

andtransmitsitviaradiowaves.Thereceiverreceivestheradio

wavesanddecodesthewavestoretrievetheinformation.Boththe

transmitterandreceiveruseantennastoradiateandcaptureradio

signals.Thefollowingfigureisanexampleofthesystemarchitecture

andblockdiagramofanIEEE802.11aradiounit.Youcanseethatthetransmitterandreceiverarebothfeaturedinthesameradio

unit.Theupperpath,fromtheantennaside(left)toadatastream

(right),showshowtheradiosignalistransferredtoadatastreamvia

areceiverandseveralfunctionalblockswhilethelowerpathshows

howtransmissionworks.Amultiplexerisusedtoselectapathfor

transmissionorreception.


Magnetic field

Electric field

Propagation

direction

Wavelength ()

I & Q

Modulator

Symbol

Shaping

FEC

Encoder

FEC

Decoder

Guard

Interval

Addition

Guard

Interval

Removed

Interleaving

and

mapping

Demapping

and

Deinterleaving

IFFT

FFT

MultiplexerAntenna

Switch

Automatic

Frequency

Control

Clock Recovery

I & Q

Demodulator

Receiver Level

Determination

11010111

01001011

Automatic Gain Control

AmplifierMixer

AmplifierMixer

Low Noise

Amplifier

Thesize(orlength)oftheantennaisdirectlyproportionaltoits

desiredtransmission/receptionfrequency.


19/5618


UnderstandingWirelessTechnology

2

Propagation

AsEMwavespropagatethroughtheair,theyexperiencethe

followingtypesofalterationsastheyencounterdifferenttypesof

obstacles:

Diffraction (Shadow Fading)

Signalstrengthisreducedafterexperiencingdiffraction.Obstacles

causingdiffractionusuallyhavesharpedgessuchastheedgesof

buildings.WhenEMwavesencounteranobstaclewithsharpedges

thatcannotbepenetrated,theEMwaveswraparoundtheobstacle

toreachthereceiver.

Scattering

WhenEMwavesencountermanysmallobstacles(smallerthanthe

signalwavelength),theEMwavesscatterintomanysmallreflective

wavesanddamagethemainsignal,causinglowqualityoreven

MIMO

MIMO(MultipleInput/MultipleOutput,commonlypronouncedmy-

mo)isatechnologythatusesmultipletransmittersandreceivers

(withmultipleantennas)toimprovetheperformanceofwireless

communication.Thefollowinglettersareusedtodescribesuch

aradiosystem:M=Multiple;S=Single;I=Input;O=Output.

TheM,S,I,andOrelatetowhatisdoneintheair,notthedevice.

Forexample,regardingaMIMOradiosystem,MI(multipleinputs)

meansmultipletransmitterssendmultipledatastreamsintothe

air.MO(multipleoutputs)meansmultiplereceiversacquiremultiple

datastreamsoutoftheair.Notethatthetermsinputandoutput

refertotheradiochannelcarryingthesignal,nottothedeviceswith

antennas.

Whenmultipletransmittersandmultiplereceiversareused,simulta-

neousdatastreamscanbesent,whichincreasethedatarate.Inad-

dition,multiplereceiversallowgreatercoverageandlongerdistances

betweendevices.TheIEEE802.11nstandardusesMIMOtoincrease

speedto100Mbpsandbeyond.MIMOtechnologyisalsousedin

LTEandotherwirelessstandards.

RxTx

Tx Rx

RxTx

Tx Rx

brokenlinks.Suchobstaclesincluderoughsurfaces,rocks,sand,

dust,treeleaves,streetlights,etc.

ReflectionWhenEMwavesrunintolargeobstaclessuchastheground,walls,

orbuildings,theyreflectandchangetheirdirectionandphase.Ifthe

reflectedsurfaceissmooth,thereflectedsignalwilllikelyrepresent

theinitialsignalandnotbescattered.

Alloftheabovephenomenaresultinmultipathpropagationsonot

allsignalswillarriveatthereceiverantennaatthesametimedue

toobstaclesthatchangethesignalpaths.Whetheryouaresetting

upanoutdoororindoorapplication,multipathcanseverelyaffect

receivedsignalqualitybecausethedelayedsignalsaredestructiveto

themainsignal.ThemultipathissuecanusuallybecompensatedbyantennadiversityattheRFleveland/orbyOFDMatthebasebandlevel.

The various systems are illustrated below:

Single-inputsingle-output(SISO)

Multiple-inputsingle-output(MISO)

Single-inputmultiple-output(SIMO)

Multiple-inputmultiple-output(MIMO)




Transmit Power and Received SensitivityWhenaradiosignalisbeingtransmittedthroughtheair,itwill

experienceagreatlossinsignalstrength,knownasattenuation,

whilepropagatingthroughfreespace.Therefore,whenevaluating

awirelesssystem,oneneedstobeawareofthesignalpowerlevel

atthetransmitterendandatthereceiverend.Thesignalpower

receivedcannotbesoweakastobreakthecommunicationlink,or

toostrongastosaturatethereceiversamplifiers.

Theseconcernscallforestimatingthepowerbudgetofawireless

system.Powerbudgetestimationswillgiveanideaofhowfarto

extendthewirelesslinkwithoutlosingcommunication.Notethatthefollowingcalculationsaretheoreticalestimatesthatarenotmeantto

guaranteecommunicationdistance.TheformulascomefromtheFriis

EquationandarebasedontheideaofFreeSpaceLoss.

TheFriisTransmissionFormulaenablesustocalculatethepower

received(Pr)giventhataknownpower(P

t)isradiated.Friisassumes

thatbothantennasareisotropic,andFreespaceimpliesthatthere

arenoobjectspresenttoaffectpropagation.Thetheoreticalformula

maylooklikethis:

whereGtandG

rarethegainofthetransmittingandreceiving

antennas,isthewavelength,andRisthedistancefromtheradiator.

Since=c/F, where cisthespeedoflight(3x108m/s)andFis

thefrequencyinHz,wecansimplifytheformulaandrepresentthe

effectivetransmissiondistancer(inkm)asfollows

wherefisthefrequencyinMHz,ptandp

rareindBm,andg

tandg

r

areindBi.

Theseparametersareeasytoobtainfromthedesignortheproduct

specifications.Pluginthevaluesfortheseparameterstogetthe

effectivedistance.Inreality,duetosystemlossortheuseofnon-

isotropictransmittingandreceivingantennas,weusuallydivide

thetheoreticalresultbyafactorof4toobtainamorereasonable

distance.Infact,factorsof8orhighermaybeusedifthesystemand

environmentalconditionsarenotcontrollable.

(pt+gt+gr

_pr) /2010

r=41.88 fx

=GtGrPP ( )

2

4Rr

t

Signal Power

Radiosignalsaretransmittedatacertainpowerlevel,withpower

measuredinwatts.However,powerratingsforaWLANareusuallymeasuredinmilliwatts(mW).AcommercialwirelessAPtransmits

between30to100mWofpower,andabout50mWforwireless

adaptors(clients).Certainapplicationswillrequirehighertransmit

power(orTxpower)andmayattempttousepowerboostersor

customizedhigh-powermodulestoamplifythetransmitpower.

However,suchattemptsmustbeperformedwithcautionaspower

amplificationmaycausethesystemtoexceedthecountrysradio

emissionregulations(i.e.,FCCregulations).

PowermeasuredinmWishardonthemathwhendealingwith

extremelysmallpowerlevelsatthereceiverend.Therefore,insteadofusingabsolutevalues(milliwatts)weoftenconverttheminto

dBm.TheunitofdBmisalogarithmicrepresentationofmW.The

conversionsareasfollows:

What You Need to Know about a Radio System

ThedBmisanabsoluteunitwhichisreferencedtothemilliwatt.0

dBmequals1milliwatt.TheunitdBmisusedforameasurementofabsolutepower.Bycomparison,thedecibel(dB)isadimensionless

unit,usedforquantifyingtheratiobetweentwovalues.Roughly

speaking,a3-dBincreaserepresentsroughlydoublingthepower,

whilea3-dBdecreasemeansthatthepowerisreducedbyabout

onehalf.Hereisaquicktableshowingunitconversions:

dBm mW dBm mW dBm mW

-3 0.5 9 8 21 126-2 0.6 10 10 22 158-1 0.8 11 13 23 2000 1.0 12 16 24 2501 1.3 13 20 25 3162 1.6 14 25 26 3983 2.0 15 32 27 5004 2.5 16 40 28 6305 3.2 17 50 29 8006 4 18 63 30 10007 5 19 79 33 20008 6 20 100 36 4000

dB m logPmWP = 10

mWP = 10

dBmP

10( )


21/5620



2

Spread-spectrumtechniquesaremethodsfortransmittinga

radiosignaloverabandwidththatisconsiderablylargerthanthe

frequencycontentoftheoriginalinformation.Spread-spectrum

techniquesprovidethebenefitsofsecurecommunications,better

resistanceagainstinterference,noise,andjamming,andlimiting

thepowerfluxdensity.Tosimplifythisdiscussion,onlyspread-spectrumtechniquesthatpertaintotheradio-basedphysicallayers

inthe802.11standard,namelyFHSS,DSSS,andOFDM,willbe

discussed.

FHSS (Frequency Hopping Spread Spectrum, or FH)

Thisisoneofthemodulationtechniquesusedinspreadspectrum

signaltransmission.ItisalsoknownasFrequency-HoppingCode

DivisionMultipleAccess(FH-CDMA).Spreadspectrumenablesa

signaltobetransmittedacrossafrequencybandthatismuchwider

thantheminimumbandwidthrequiredbytheinformationsignal.The

transmitterspreadstheenergy,originallyconcentratedinanarrowband,acrossanumberoffrequencybandchannelsonawider

electromagneticspectrum.FHSShastheadvantagesofimproved

privacy,decreasednarrowbandinterference,andincreasedsignal

capacity.

DSSS (Direct Sequence Spread Spectrum, or DS)

DSSSdividesastreamofinformationtobetransmittedintosmall

pieces,eachofwhichisallocatedtoafrequencychannelacrossthe

spectrum.DSSSgeneratesaredundantbitpatternforeachbittobe

transmitted.Thisbitpatterniscalledachip(orchippingcode).Even

ifoneormorebitsinthechiparedamagedduringtransmission,

statisticaltechniquesembeddedintheradiocanrecovertheoriginal

datawithouttheneedforretransmission.Directsequencespread

spectrumisalsoknownasdirectsequencecodedivisionmultiple

access(DS-CDMA).Thismodulationtechniqueisofficiallyaccepted

andusedbytheIEEE802.11bandIEEE802.11gstandards.

Modulation and Spread Spectrum

Modulationistheprocessofconveyingamessagesignalbyvarying

oneormorepropertiesofaperiodicwaveform,calledthecarrier

signal,withamodulatingsignalthatencodestheinformationtobe

transmitted.Theactofextractingtheoriginalinformation-bearingsignalfromamodulatedcarrierwaveiscalleddemodulation.

TherearemanyRFmodulationtechniques.Theaccompanyingchart

categorizesdifferentdigitalmodulationtechniques.

Category Digital Modulation Technology

Phase-shiftkeying

BinaryPSK(BPSK)BinaryPSK(BPSK)QuadraturePSK(QPSK)DifferentialPSK(DPSK)

DifferentialQPSK(DQPSK)Multi-phaseshiftkeying(M-aryPSKorMPSK)/4QPSK

Frequency-shiftkeying

Audiofrequency-shiftkeying(AFSK)Multi-frequencyshiftkeying(M-aryFSKorMFSK)Dual-tonemulti-frequency(DTMF)

ComplementaryCodeKeying

ComplementaryCodeKeying(CCK)

Quadratureamplitude

MultipleQuadratureamplitudemodulation(M-aryQAM)

Continuousphase

Minimum-shiftkeying(MSK)

Gaussianminimum-shiftkeying(GMSK)Continuous-phasefrequency-shiftkeying(CPFSK)

Frequency-divi-sionmultiplexing

Orthogonalfrequency-divisionmultiplexing(OFDM)

Spread-spectrumDirect-sequencespreadspectrum(DSSS)Chirpspreadspectrum(CSS)Frequency-hoppingspreadspectrum(FHSS)

Theformulaalsoshowsthattherearemanyotherfactorsinvolved

thatwillaffecttransmissiondistance.Thereceiverssensitivityis

theminimumpowerlevelthatisrequiredforthereceivertoprocess

receiveddata.Thespecifiedsensitivityisnotthepowerdetectedby

thereceivingantenna,butthepowerpresentatthereceivermodule.Animportantpointtonotefromtheaboveequationisthatasthe

frequencyincreases,theeffectivedistancedecreases.Therefore,

the5GHzband-enabled802.11aand802.11nstandardswillyield

ashortercommunicationdistancethan2.4GHz-enabled802.11b/g

and802.11n.Userswhowishtocommunicateoverlongdistances

shouldthereforeselectthe2.4GHzbandandtake802.11b/g/nastheiroperatingstandard.




ISM and Unlicensed Bands

Unlicensedbandsarepartoftheradiospectrumthatcanbeused

byanybodywithoutapplyingforalicense.Awell-knownunlicensed

bandistheISM(industrial,scientific,andmedical)radioband,

whichisreservedinternationallyfortheuseofradiofrequency(RF)

energyforindustrial,scientific,andmedicalpurposesotherthan

communications.TheISMbandsaredefinedbytheITU-Rin5.138,

5.150,and5.280oftheradioregulations.ThreeISMbandsare

commonlyused:

902MHzto928MHz

2.400GHzto2.500GHz

5.725GHzto5.875GHz

Usageofthebandsdesignatedinthesesectionsmayvaryin

differentcountriesduetovariationsinnationalradioregulations.

IntheU.S.,ISMbandusageisgovernedbyFCC(Federal

CommunicationsCommission)Part18,andPart15contains

regulationsforunlicensedcommunicationdevices(eventhosethat

shareISMfrequencies).InEuropeancountries,theuseoftheISM

bandiscoveredbyShortRangeDevice(SRD)regulationsissuedby

theEuropeanCommission,basedontechnicalrecommendationsby

CEPTandstandardsbyETSI.

Regulatoryauthoritiesmayallocatepartsoftheradiospectrumfor

unlicensedcommunicationsthatmayormaynotalsobeallocated

asISMbands.Forexample,theFCCregulatestheusablefrequency

bandsandthemaximumallowablepowerinthesefrequencybands

fortheUnitedStates.From1997,ithasaddedadditionalbands

inthe5GHzrangeunderPart15.407,knownastheUnlicensed

NationalInformationInfrastructure(U-NII)bandsforWLANusage.

U-NII band a.k.a. Frequency Bandwidth Usage DFSPower

Limitation

Max EIRP

(with 6 dBi Ant.)

Note

U-NII-1 U-NIILow 5.15to5.25GHz 100MHzIndoor

onlyNo 50mW

23dBm/200mW

U-NII-2AU-NIIMid,

U-NII-25.25-5.35GHz 100MHz

Indoor&Outdoor

Yes 250mW30dBm/

1W

U-NII-2B U-NIIUpper 5.35to5.47GHz 120MHz - - - - Notdeterminedyet

U-NII-2CU-NIIWorldwide,

U-NII-2e5.47to5.725GHz 225MHz

Indoor&Outdoor

Yes 250mW30dBm/

1W

Operationsonch120-128(5.6to5.65GHz)bandislimitedbecause

ofweatherradar

U-NII-3 U-NIIUpper 5.725to5.825GHz 100MHzIndoor&Outdoor

No 1W36dBm/

4WOverlapswiththeISMband

U-NII-4 U-NIIUpper 5.85to5.925GHz 75MHz - - - - Notdeterminedyet

OFDM (Orthogonal Frequency Division Multiplexing)

OFDMisamodulationschemethatdividesasingledigitalsignal

simultaneouslyacross1,000ormoresignalcarriers.Thesignals

aresentatrightangles(orthogonal)toeachothersotheydo

notinterferewitheachother.OFDMhastheabilitytoovercome

multi-patheffectsbyusingmultiplecarrierstotransmitthesame

signal.OFDMiscommonlyusedintheIEEE802.11aand802.11g

standards.Non/nearline-of-sightassociationscanalsobeachieved

byusingtheOFDMtechnique.

The802.11g(802.11bbackwardscompatible)standardisused

belowasanexampleforhowthetransmissiontypeofspread

spectrumandmodulationschemecorrespondstoeachdatarate:

Data Rate (Mbps)Transmission Type

of Spread SpectrumModulation Scheme

54 OFDM 64QAM

48 OFDM 64QAM

36 OFDM 16QAM

24 OFDM 16QAM

18 OFDM QPSK

12 OFDM QPSK

11 DSSS CCK

9 OFDM BPSK

6 OFDM BPSK

5.5 DSSS CCK

2 DSSS QPSK

1 DSSS BPSK


23/5622



2

Advantages and Disadvantages of Using Unlicensed Bands

ISMandU-NIIarebothunlicensedbands,whichallowanyoneto

transmitinthesebandswithoutalicensefromtheFCCorrelatedauthorities.Itistheopeningoftheseunlicensedbandsthathas

allowedtheWLANbusinesstogrowinsmallbusinessesandhomes.

However,thefreedomoftheselicense-freebandsalsomeans

agreatnumberofun-licensedusersmaybesharingthesame

bandwidth.Thepowerfulemissionsofthesedevicescancreate

electromagneticinterferenceanddisruptradiocommunicationusing

thesamefrequency,sothesedeviceswerelimitedtocertainbands

offrequencies.Ingeneral,communicationsequipmentoperatingin

theseunlicensedbandsmusttolerateanyinterferencegeneratedby

otherequipment,anditalsomeansthatusershavenoregulatory

protectionfromdevicesoperatingonunlicensedbands.

Letstakethe2.4GHzbandasanexample.Inthefollowingdiagram,

therearethreenon-overlappingchannelsforDSSSoperation(IEEE

802.11b).Whenchannel-bondingisappliedinIEEE802.11n,there

isonlyonenon-overlappingchannel(eitherch3orch11),which

meansthattheoperationofonedevicecaneasilyinterferewithother

devices,andviceversa.Thatiswhysomevendorsdonotprovide

channel-bondingfor2.4GHzbandoperation.

Inthefollowingsections,ourdiscussiononlyincludesthe2.4GHz

bandand5GHzbandbecausetheyarethemostcommonlyused

bandsinWLANapplications.InadditiontoIEEE802.11standards,

thetradeoffsbetweenthesetwobandsareusuallyconsideredwith

interference(almostentirelyinthe2.4GHzband)andrange(bigger

powerlossshortensthetransmissiondistanceinthe5GHzband).

902-928 MHz

2400-2500 MHz

U-NII-1 U-NII-2A U-NII-2B U-NII-3 U-NII-4U-NII-2C

ISM: 2.4 GHz

ISM: 900 MHz

ISM: 5.8 GHz

900

100 km

3 kHz

increasing wavelength

30 kHz 300 kHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz 300 GHz

10 km 1 km 100 m 10 m 1 m 10 cm 1 cm 1 mm

VLF

maritimenavigation

signals

navigational

aids

AM radio,

maritime radio

shortwave radio VHF television,

FM radio

UHF television,cellular phone,

GPS

space andsatellite

communications,microwavesystems

radio astronomy

LF MF HF VHF UHF SHF EHF

2400 2425 2450 2475

5100 5200 5300 5400 5500 5600 5700 5800 5900

2500

910 920 930 MHz

6000 MHz

MHz

increasing frequency

2.4 GHz

802.11b (DSSS) channel width 22 MHz

802.11n (OFDM) 44 MHz ch. width - 33.75 MHz used by sub-carriers

2.4835 GHz 2.5 GHz

Channel 1

2412 MHz

Channel 3

2422 MHz

Channel 11

2462 MHz

Channel 6

2437 MHz

Channel 11

2462 MHz

2.4 GHz 2.4835 GHz 2.5 GHz

ThefollowingdiagramshowsthespectrumoverviewoftheISMandU-NIIbands.




ChannelNumber

CenterFrequency

(MHz)

Regulatory Domain

US EU JP

8 2447 Yes Yes Yes

9 2452 Yes Yes Yes

10 2457 Yes Yes Yes

11 2462 Yes Yes Yes

12 2467 Yes Yes

13 2472 Yes Yes

14 2484 Yes*

ChannelNumber

CenterFrequency

(MHz)

Regulatory DomainChannelNumber

CenterFrequency

(MHz)

Regulatory Domain

US EU JP US EU JP

36 5180 Yes Yes Yes 116 5580 Yes Yes Yes

40 5200 Yes Yes Yes 120 5600 No** Yes Yes






64 5320 Yes Yes Yes 149 5745 Yes Yes*** No





**Thesechannelshavebeeneliminatedfrom2010toavoidinterferencewithTerminalDopplerWeatherRadar(TDWR)systems.***ThesechannelsareonlyrelatedtotheuseofShortRangeDevices(SRD)with25mWpowerlimitation.

ChannelNumber

CenterFrequency

(MHz)

Regulatory Domain

US EU JP

1 2412 Yes Yes Yes

2 2417 Yes Yes Yes

3 2422 Yes Yes Yes

4 2427 Yes Yes Yes

5 2432 Yes Yes Yes

6 2437 Yes Yes Yes

7 2442 Yes Yes Yes

2.4 GHz Band

802.11b/garethemostcommonlyusedWLANstandardstoday.The

2.4GHzISMbandissupportedbyalmosteverycountryworldwide.

Noteverycountrysupportsthesamechannelsinthe2.4GHzISM

band,sousersneedtomakesurethatthewirelessAPmatches

thesamestandardthatisbeingusedinthatcountry.Thefollowing

chartshowschannelsthataresupportedinthe2.4GHzISMband

5 GHz Band

802.11a/h/j/n/acusethe5GHzband.Comparedwiththe2.4GHz

band,the5GHzbandisconsideredtohavemoreclearoptions:

afullchannelwidthreservedwithoutoverlap,andlessnon-Wi-Fi

interferenceandtightercellpackingforhighercapacity.However,

everycountryappliesitsownradioregulationstoallocatethe

allowablechannelsandmaximumpowerlevelswithinthe5GHz

band.Networkoperatorsshouldconsultlocalauthoritiesasthese

regulationsaresubjecttochangeatanytimeandmaybeoutof

date.Seebelowforchannelssupportedinthe5GHzbandforthe

threeregulatorydomains.

fordifferentregulatorydomains.AlthoughtheISMbandisopen

between2.4to2.5GHz,IEEE802.11b/gstandardsonlyuse2.400

to2.4835GHz.Theminormismatchisduetochannelspacingand

providesabuffertopreventpowerfromleakingintothelicensed

bands.

*Ch14isvalidonlyforDSSSandCCKmodesinJapan.


25/5624



2

2-2 WLAN Antennas

Why Using the Right Antenna is Important

Antenna Parameters

FrequencyAnantennaisatransducerthatisdesignedtotransmitand/or

receiveelectromagneticwaves.Itislikeaconverterthatconverts

backandforthbetweenelectromagneticwavesandelectrical

currents.Differentwirelessdevicesusedifferentantennastooperate

indifferentfrequenciesandtoachieve,forexample,adesired

range.Themostimportantparameterofanantennaisitsworking

frequency.Forexample,a2.4GHzantennaswavelengthistooshort

tousewithIEEE802.11acommunicationandusinganantennawith

amismatchedfrequencywilllikelycauseaverypoorperformanceon

bothsignalradiationandactualdatathroughput.

Thetransmissionspeedofawirelessconnectionissignificantly

relatedtotheradiosignalstrengthofthetransmission.Selectingthe

appropriateantennasfortheapplicationenvironmentisthemost

importantsteptoensureastrongwirelesslink.

Thefigurebelowisasimpleillustrationofthewirelesssignal

transmission.Afterthedigitalsignalsgetconvertedintoanalog

LessDense

LessDense

MoreDense

MoreDense

IncidentPulse

TransmittedPulse

ReflectedPulse

form,thesignalgetsmixed,filtered,amplified,andfinallyreleased

totheatmosphere.Themainfunctionoftheantennaistocontrol

howtheenergyisreleasedandwhatkindofenergyfielditis

forming.Thischapterintroducesthekeyparametersforselecting

therightantennaforyourapplication,suchasantennafrequency,

impedancematching,voltagestandingwaveratio(VSWR),gain,and

polarization.

Impedance Matching

Maximumpowertransferfromthetransmittertotheantenna

requiresimpedancematchingoftheantennasystem.Thefigure

belowdemonstratesthereflectioneffectwhentheimpedancedoesn'tmatchbetweentwomediums.Mismatchedimpedance

willcauseenergylossandriskcircuitdamagefromthereflected

energypulse.Transmittersgenerallyhaveanoutputimpedanceof

50ohmsandthatneedstobematchedacrossthetransmission

linetotheantennainordertomaximizeoverallefficiency,eliminatelinevariationwithanequalvoltagestandingwaveratio(VSWR),and

reducetransmissionlinelosses.

Baseband

InputAmplifier Amplifier

RFOutput

MixerFilter

VCO

Baseband

Output

Amplifier Amplifier

RFInput

MixerFilter

VCO




Polarization

Polarizationreferstothedirectioninwhichtheelectricfieldlines

pointasthesignalradiatesawayfromtheantenna.Thesimplest

andmostcommontypeislinearpolarization.Animproperantenna

installationwilldecreasesignalreceptionquality.Forexample,a

perfectlyalignedhorizontal(sidetoside)antennawillnotreceiveany

signalssentfromaperfectlyalignedvertical(upanddown)antenna.

Gain

Thegainofeachantennaspecifiesitsdirectivityandelectrical

efficiency.Ingeneral,thelowerthegain,themoreevenlydistributed

inalldirectionstheradiationwillbe.Highgainantennas,onthe

otherhand,emitradiationinamorespecificdirection.Thegain

definesitspowergainordirectivegainintermsoftheratioofthe

intensity,orpowerperunitsurface.Ingeneral,whenwechoose

anantenna,thelongerthetransmissiondistance,thehigherthe

antennagainmustbe.Atthesametime,wemustsacrificeomni-

directionalcoverage.

Anantennaata45alignment(skewpolarization)however,can

receivesignalssentfrombothhorizontalandverticalantennas,

butatreducedsignalstrengths(dB).Itisimportanttoknowthe

polarizationoftheantennasintheWLANtomakesurethatsignals

arebeingsentandreceivedunderoptimalconditions.Thefigures

belowarethevisualizationofthehorizontalandverticallinear

polarizations.

HorizontalLinearPolarization VerticalLinearPolarization

0

30

60

90

120

150

180

210

240

270

300

330

-

0

30

60

90

120

150

180

210

240

270

300

330

Useofdirectorsmakesanglesmallerandgainhigher


27/5626



2

H-Plane

E-Plane

Antenna Radiation Patterns (E-plane and H-plane)

HPBW

Half-powerbeamwidth,alsocalledthe3-dBbeamwidth,istheangular

measurementofthemainlobedirectivityontheantennaradiationpattern

wherethesensitivity(gain)isone-half(or-3dB)ofthemaximumvalue.

SometimesitisalsocalledFWHM(thefullwidthofthebeamathalfits

maximumintensity).The3-dBbeamwidthmeasurementiscommonlyused

todefinetheverticalandhorizontalanglesofaparticularantenna.

Asasidenote,anantennaisapassivecomponent,whichmeansitdoesnot

increasetheoverallinputenergyinanyway.Inordertoachievelongerdistance

transmission,itcompressestheenergyfieldtomakeitleanerandlonger.Therefore,ahighergainantennatendstocomewithanarrowerbeamwidth.

VSWR

Thevoltagestandingwaveratio(VSWR)istheratioofthemaximum

voltagetotheminimumvoltageonthetransmissionline(cable)used

tomeasureantennaefficiency.Whenthetransmittersendssignals

forwardthroughthetransmissionlinetotheantenna,aportionofthe

signalwillbouncebackacrossthetransmissionlineiftheantennais

atadifferentimpedance,andmixwithoncomingforwardsignalsto

createavoltagestandingwavepattern.

A1:1VSWR(orjust1)indicatesthatpowerisbeingfullyabsorbed

bytheantenna(becauseantennaimpedanceisalsothesameasthe

impedanceonthetransmissionline)andnopowerisbeingreflected

backtothetransmitter,butthisisverydifficulttoachieve.For

example,a50-ohmradiowithanantennaimpedanceof75ohmswill

haveatheoreticalVSWRof1.5:1onthetransmissionline.Fortypical

antennasystems,aVSWRof1.2:1canbeconsideredtobemore

thanacceptable.AVSWRof2:1,whichiscommonformanyantenna

systems,meansthatroughly10%oftheforwardsignalsarebeing

reflectedfromtheantenna.AhigherVSWRmeanslowertransmissionefficiencyandcanresultinheatedtransmissionlinesanddamaged

transmitters.

Mainlobemaximumdirection

Mainlobe

1.0

0.5

Half-powerpoint(right)

Half-powerpoint(left)

Minorlobes

Half-powerbeamwidth(HP)

Muchaboutanantennasperformancecanbelearnedfrom

itsradiationpattern.Theantennaradiationpatternisathree-

dimensionalillustrationofhowtheantennaemitsandreceivesradio

signals(seefigureontheright)duringcommunication.

Aradiationpatternisessentiallytheelectromagneticfield,which

consistsofanelectricfield(E-plane)andamagneticfield(H-plane).

Theelectricfieldandmagneticfieldpropagatetowardthesame

generaldirection,butthepolarizationoftheirwavesarealways

perpendicular(90angle)toeachother.Radiationpatternsare

differentforvarioustypesofantennas.E-planeandH-plane

diagramsprovideatwo-dimensionalviewofhowelectricand

magneticfieldsbehaveforaparticularantenna.

VSWR Efficiency Chart

VSWR Efficiency Loss

1 100% 0.00dB

1.3 98.3% 0.08dB

1.5 96.0% 0.18dB

1.8 91.8% 0.36dB

2 88.9% 0.51dB

2.5 81.6% 0.86dB

3 75.0% 1.25dB

3.5 69.1% 1.61dB

4 64.0% 1.94dB

5 55.6% 2.55dB




Sample Antenna Spec

Omni-directional Antennas Antenna Patterns: E-Plane for 2.4 GHz Antenna Patterns: H-Plane for 2.4 GHz

0

30

60

90

120

150

180

210

240

270

300

330

0

30

60

90

120

150

180

210

240

270

300

330

Antenna Types

TherearetwobasictypesofantennasforWLANproducts,categorizedbythedirectioninwhichtheybeamradiosignals:omni-directionaland

directional.

Sample Antenna Spec

Directional Antennas Antenna Pattern: E-Plant for 2.4GHz Antenna Pattern: H-Plant for 2.4GHz

0

30

60

90

120

150

180

210

240

270

300

330

0

30

60

90

120

150

180

210

240

270

300

330

Directional Antennas

Directionalorpatchantennasprovideamorefocusedsignalthan

omni-directionalantennas.Signalsaretypicallytransmittedinan

oval-shapedpatternwithabeamwidthofapproximately30degrees.

Thistypeofantennaisalsoidealforofficelocations.Forexample,an

accesspointwithasemi-directionalantennacanbeplacedinone

Omni-directional Antennas

Omni-directionalantennasaredesignedtoradiatesignalsequally

inall360degrees.Usethistypeofantennaifyouneedtotransmit

fromacentralnode,suchasanaccesspoint,tousersscatteredall

aroundthearea.Inasmallofficewiththreeorfourrooms,anaccess

pointwithanomni-directionalantennashouldbeabletoprovide

sufficientcoverageforallwirelessstationsinallrooms.

cornerofaroomtoprovidereliablecoverageforitsentirelength.

Directionalantennascanalsobeusedoutdoorstoprovideshort

distancepoint-to-pointlinksorasthecustomerendofapoint-to-

multipointnetwork.


29/5628



2

2-3 Cables

RF CablesRFcable,alsocalledcoaxialcable,isthemostcommontype

ofcableusedtoconnectanRFtransmitter(orreceiver)tothe

antenna.Thecoreandwovenshieldaregenerallymadeofcopper,

andthedielectricinsulatoriscommonlymadeofsolidorfoamed

polyethylene.SomeRFcablesalsoincludeafoillayerbetweenthe

shieldandthedielectrictofurtherreduceloss.

Typically,themetallicshieldisatgroundpotentialandthevoltageis

appliedtothemainconductortotransmitsignals.Themainbenefit

ofusinganRFcableisthatelectromagneticfieldsarekeptwithin

thedielectricinsulatorwithverylittleradiatedloss.Inaddition,the

dielectricinsulatorprotectsthetransmissionlineagainstsourcesof

externalinterference.

plastic jacket

dielectric insulator

metallic shield

central core

Key Parameters

Impedance Matching

Thisisthesameprincipleintroducedintheantennasection.Tohave

thebesttransmissionefficiency,theconnectedmediums,suchasRFcable,antenna,connector,andsourcetransmitter,musthavea

matchingimpedance.

Attenuation

EveryRFcablehassignalloss,whichisreferredtoasattenuation

andismeasuredindecibels(dB)per100feet.AttenuationofRF

signalswillincreaseathigherfrequenciesbecauseRFcurrenttravels

mostlyontheoutersurfacelayer(skineffect)ofthecoreconductor

andsurfaceresistancewillincreaseathigherfrequencies.Skin

effectlossesonthecoreconductorcanbereducedbyincreasing

thediameterofthecable.Doublingthecablediameterwillreducetheskineffectresistanceinhalf(notincludingdielectricandshield

losses).

Bending Radius

Thebendingradiusistheminimummeasureoftheinsidecurvature

thatacablecanbebentwithoutcausingitphysicaldamage,reducingitsperformance,orshorteningitsusefullife.Thefigure

belowillustratesacablewithabendingradiusof3centimeters.

3cm

Cable




Common Coaxial Cables

Ethernet Cables

Category5(Cat5)isthefifth-generationstandardfortwisted-pair

EthernetcablesestablishedbytheElectronicIndustriesAssociation

andTelecommunicationsIndustryAssociation(EIA/TIA).Cat5

cablescontain4pairsofwiresbutuseonly2pairs(ratedat100

MHz)for10BASE-Tand100BASE-TX(FastEthernet)transmission.

Anenhancedversion,CAT5e,imposesmorerestrictedcross-talk

specificationstoensurethestabilitywhenusingallfourpairsfor

1000BASE-T(GigabitEthernet)communication.Cat5/5ecables

generallyhaveatransmissiondistancelimitationof100meters.

Category6(Cat)isanothercommonlyusedstandardforGigabit

Ethernettransmission.ItisbackwardscompatiblewithCat5andCat

5e,butatthesametime,itallowshighertransmissionfrequency

upto250MHz.Itissuitablefor10BASE-T,100BASE-TX(Fast

Ethernet),1000BASE-T/1000BASE-TX(GigabitEthernet),and

10GBASE-T(10-GigabitEthernet).

TypeImpedance

(ohms)Core

DielectricType

Dielectric VF Dielectric mm OD mmMax. Attenuation

@ 750 MHz dB/100 ft

LMR-100 50 2.79 20.725

LMR-195 50 4.95 10.125

LMR-200

50 1.12mmCu PF 0.83 2.95 4.95 9.035HDF-200

CFD-200

LMR-400

502.74mm

(Cu-cladAl)PF 0.85 7.24 10.29 3.544HDF-400

CFD-400

LMR-600 50

4.47mm

(Cu-cladAl) PF 0.87 11.56 14.99 2.264

LMR-900 506.65mm(BCtube)

PF 0.87 17.27 22.1 1.537


PF 0.88 23.37 30.48 1.143


PF 0.89 34.29 42.42 0.844


31/5630



2

Key Parameters

Bending Radius

MostCategory5cablescanbebentatanyradiusexceeding

approximatelyfourtimesthediameterofthecable.

Maximum Cable Segment Length

TherecommendedlengthforaCAT5cablesegmentis100meters

(TIA/EIA568-5-A).Repeatersandswitchescanbeusedtoextend

thetransmissiondistance.Mediaconverters,suchasEthernet-to-

fiberconverters,canbeusedtosignificantlyextendtransmission

distance.

Straight-through vs. Cross-over

TwistedpairsofEthernetcablescanberearrangedtoprovide

connectivitybetweendifferenttypesofdevices.Atypicalstraight-

throughcable,alsocalledapatchcable,hasidenticaltwisted-pair

arrangementsonbothends(RJ45connector)andisusedtoconnect

acomputertoaswitchorrouter.Across-overcablehastheorange

twistedpaircrossedoverwiththegreentwistedpair,andisusedto

connecttwocomputersdirectlytoallowcommunication.However,

newernetworkinterfaceswithauto-MDIXportsarecapableof

detectingthetypeofconnectiontoautomaticallychooseMDIor

MDIXconfiguration,whicheliminatestheneedforcross-overcables.

10BASE-T and 100BASE-TX vs. 1000BASE-T

10BASE-Tand100BASE-TXEthernetconnectionsrequiretwo

cablepairs.1000BASE-TEthernetconnectionsrequirefourcable

pairs(8pins).Listedbelowarethepinassignmentsforthesethree

10/100BASE-TX MDI and MDI-X PORT PINOUTS

Pin MDI Signal Name MDI-X Signal Name

1 TransmitDataplus(TD+) ReceiveDataplus(RD+)

2 TransmitDataminus(TD-) ReceiveDataminus(RD-)

3 ReceiveDataplus(RD+) TransmitDataplus(TD+)

6 ReceiveDataminus(RD-) TransmitDataminus(TD-)

4,5,7,8 Notused Notused

1000BASE-T MDI and MDI-X PORT PINOUTS

Pin MDI Signal Name MDI-X Signal Name

1Bi-directionalPairAPlus(BI_DA+)

Bi-directionalPairBPlus(BI_DB+)

2Bi-directionalPairAMinus(BI_DA-)

Bi-directionalPairBMinus(BI_DB-)

3Bi-directionalPairBPlus(BI_DB+)

Bi-directionalPairAPlus(BI_DA+)

4Bi-directionalPairCPlus(BI_DC+)

Bi-directionalPairDPlus(BI_DD+)

5Bi-directionalPairCMinus(BI_DC-)

Bi-directionalPairDMinus(BI_DD-)

6Bi-directionalPairBMinus(BI_DB-)

Bi-directionalPairAMinus(BI_DA-)

7Bi-directionalPairDPlus(BI_DD+)

Bi-directionalPairCPlus(BI_DC+)

8 Bi-directionalPairDMinus(BI_DD-) Bi-directionalPairCMinus(BI_DC-)

1 2

Orangepair 1

Green pair 3

3 4 5 6 7 8

Bluepair 1

Brownpair 1

1 2

Orangepair 2

Green pair 3Straight-through

3 4 5 6 7 8

Bluepair 1

Brownpair 4

1 2

Orangepair 2

Green pair 3

3 4 5 6 7 8

Bluepair 1

Brownpair 4

1 2

Greenpair 3

Orange pair 2Cross-over

3 4 5 6 7 8

Bluepair 1

Brownpair 4

standards(10BASE-T,100BASE-TX,1000BASE-T)onbothMDI

(MediaDependantInterface)andMDI-X(MediaDependantInterface

cross-over).




2-4 Connectors

Beforeplacinganorderforantennasandcablesforyourwirelessdevice(s),theconnectortypesmustfirstbedetermined.Ingeneral,

termssuchasplug,pin,andprongrefertomaleconnectors,

andtermssuchasreceptacle,socket,andslotrefertofemale

Connector Frequency Range Male Connector Female Connector

SMA(Sub-MiniatureversionA)

DCto18GHz

RP-SMA(ReversePolaritySMA)

DCto18GHz

QMA(QuickSMA)

DCto18GHz

N-type(namedafterPaulNeill)

DCto11GHz

TNCDCto11GHz

Antenna Connectors

TherearevarioustypesofcoaxialRFantennaconnectorsdesignedfordifferentapplications.Thissectionintroducesseveralcommonly-usedantennaconnectortypesasaguidelineforidentifyingandselectingtheappropriateconnector.

connectors.Forelectricalconnectors,connectorgender(maleandfemale)isnotenoughtoidentifytherightconnector.Thischapter

providesseveralcommonlyusedconnectorsandtheirpicturesasa

referencetoyourselection.


33/5632



2

Connector Data Rate Distance Transceiver

SFP(SmallForm-factorPluggable)

155Mbpsto4.25Gbps



Industrial Wireless

Introduction

Wirelessfailuresathomeorintheofficewillbeaninconvenience

untilareplacementdeviceisinstalled.Wirelessnetworkfailuresin

industrialapplications,however,canjeopardizethesafetyofonsite

personnel,damageexpensivemachinery/equipment,andpossibly

translateintothousandsofdollarsperminuteinproductionlosses.

Industrial Hazards

Manyindustrialwirelessapplications,suchasthoseformining,

railway,andoil&gas,aredeployedinharshenvironments

andrequiretheuseofindustrial-gradedevices.Whilesome

environmentalfactorsareobvious,suchasextremetemperatures

andmoisture,thereareotherelementsthatarenotsoapparent

3-1 Industrial Design Concepts

Industrial Wireless

Electrical Interference

DescriptionTherearemanydifferentkindsofelectricalinterferenceinan

industrialenvironment:electrostaticdischargeaccumulatedona

humanbody,surgecausedbyindirectlightningstrikes,andbursts

generatedbyfactorygenerators.Failingtoproperlydesignyour

systemtoprotectagainstsuchinterferencecanresultinunstable

communications,orsometimesyourdevicecouldbepermanently

damaged,causingacompleteshutdownofyoursystem.

Inadditiontonetworkredundancy,industrialoperatorsmustalso

assesstheapplicationenvironmentforelementsthatcanimpact

networkperformance,compromisedevicereliability,andleadto

unplannedsystemdowntime.

butcanalsoquicklydisableanunprotecteddevice.Thischapter

introducesseveralexamplesofinterferencesandenvironmental

difficultiesthatarecommonlyseeninindustrialapplications.

Industrial SolutionIndustrial-gradedevicesaredesignedtoprotectinternal

components,andcircuitsarespeciallydesignedtobeable

towithstanddifferenttypesofinterference.Inaddition,the

manufacturerwilltesttheproductstomakesuretheycanoperate

reliablyinharshconditionssoend-userscanrestassuredthatthe

productswillbemorestable,morereliable,andhavealongerlife

thannon-industrialproducts.


35/5634


In

dustrialWireless

3

Radiated Electromagnetic Interference

Flammable Gases

Extreme Temperatures

Shock and Vibration

Description

Radiatedelectromagneticinterferenceismostobviousnearanelectricalsubstation.Thehigh

voltageandstrongcurrentflowcauseacouplingeffectwithnearbyelectricaldevices.Ifthe

devicesarenotproperlyprotected,theinternalcircuitsofthedevicescanwearoutmorequickly

orbepermanentlydamaged.Thesameeffectcanalsobeseennearfactorygeneratorsand

largetransformers.

Industrial Solution

Forindustrial-gradedevices,ametalcasingandproperlydesignedisolationcanovercomesuch

interference.

Description

Incertainindustries,theworkingenvironmentcouldbepermeatedwithflammablegasordust,andtopreventelectricalequipmentfromcausingafireorexplosion,strictregulationsarein

placetodefinewhatkindofdevicescanbeusedintheseextremehazardouslocations.

Industrial Solution

Differentlevelsofanti-explosivedesignarestipulated.Forexample,anencapsulationdesign

referstoadevicethatisairtight,orequivalentmethodsthatpreventsparksfromcominginto

contactwiththesurroundingflammablegases.Anintrinsicallysafedesignreferstoadevice

thatwillnotigniteflammablegasesunderanycircumstances,evenifthereisdirectcontact

betweenthedeviceandgas.

Description

Underahotsummersun,deviceslockedinsideanoutdoorcabinetcaneasilyreacha

temperatureof70C(158F),whereasasimilarcabinetlocatedatahighaltitudecould

experienceatemperatureof-30C(-22F)onacoldwinternight.Withoutaproperdesign,

electronicdevicesinsidethecabinetcouldeitherover-heat,orbeunabletobootupifthe

temperatureistoolow.

Industrial Solution

Twomajordesignfocusesforindustrial-gradeproductsareheat-dissipationandlow-

temperatureoperation.Byselectingtherightcomponentsandmechanicaldesign,engineers

canensurethatdeviceswillbeabletooperatereliablyinbothextremelyhotandextremelylow

temperatures.

Description

Wirelesstechnologyiswidelyusedinmobilecommunications.However,fordevicesinstalled

invehicleswithRJ45connectorsand/orstandardpowerjacks,thecontinuousvibrationofthe

vehiclecancausetheconnectionstowiggleloose.

Industrial Solution

Inordertoprovideamorereliableconnection,industrialproductsdesignedformobile

communicationsoftencomewithM12connectorsfordatacommunicationandterminalblocks

forpowerandDI/DOconnections.



Industrial Wireless

Omni-directional

Antenna

Standard Roaming

Connect to AP 1 Connect to AP 2

Lost AP1 signal,

disconnect to AP1

Scan for available AP and

re-establish the connection

Client

AP1 AP2

3-2 Robust Wireless Concepts

IntroductionEnsuringthestabilityandreliabilityofwirelessdevicesiscriticalfor

industrialdeployments.Withanindustrial-gradehardwaredesign,

wirelessdevicescanwithstandhigherlevelsofdisturbanceinharsh

industrialenvironments.However,tofurtherenhancethereliability

ofwirelessnetworkcommunicationformission-criticalapplications,

anindustrial-gradesoftwaredesignisalsorequired.Inthischapter,

wediscussseveralmajorindustrialconcernsforwirelesstechnology,

andintroducethecorrespondingsoftwaresolutionsdesignedto

answerthoseconcerns.

Concerns for Wireless Local Area Networks

Wi-Fi Mobile Communication: Roaming Break/Recovery Time

Standard Roaming

Thefollowingfigureillustratesthestandardroamingmechanismformostcommercial-gradewirelessdevices.Themovingclientdevice

willstayconnectedwiththecurrentAPuntilsignalsgettooweakto

maintainfurthercommunication.Itthendisconnectsfromthecurrent

Recentadvancesinwirelesstechnologyhavemadeitpossibleto

usewirelessformission-criticalmobileapplications,suchasrailway

(Train-to-Ground),buses(waysideAPcommunication),andfactory

AGV(AutomatedGuidedVehicle).Themostcrucialaspectofthese

mission-criticalwirelessapplicationsi

Documents

Industrial Wireless Guidebook