Wireless 2002IEEE Seattle Section

Communications Society

Computer Society

Electromagnetic Compatibility

Microwave Theory and Techniques

Agenda

• Introduction to Wireless Technology

• Bluetooth™ Application Development

• Rationalizing Bluetooth™ in a Wireless World

• Antenna Design for Wireless Products

• Physical Layer Overview of Wireless LAN Modems and RF Testing

• Bluetooth™ Compliance Testing

Introduction to Wireless Technology

Joe Decuir

Chair, Seattle Section

IEEE Communications Society

Agenda• Wireless technologies

– WAN, LAN, PAN– Some detail on Cellular

• Scenarios

• Design issues– Software– Radios/modems– Antennas– Testing and Certification

Todays’ Questions

• For designers of devices and systems– Where would wireless technology help my

product?– What kind of wireless technology would fit?– What are the design issues?– Where can I find solutions?– Where can I find more information?– How do I get my product tested and certified

to sell?

Why Wireless?• Wires are fast• Wires are secure• Wires conserve powerBut:• Wires have to be made• Wires have to be installed• Wires may have to be removed• Wires are often in the way• Wires may be too short

Wireless Radio Types

• There are several general classes of wireless radios, trading off range, power and data rate:– Satellite: video distribution, GPS, paging– Wide Area Networking: cellular, fixed wireless– Local Area Networking: e.g. 802.11– Personal Area Networking: e.g. Bluetooth™

• Today’s focus: WAN, LAN and PAN

Wide Area Wireless Uses• The driving applications are paging and

mobile telephony.

• Paging is one-way, with simple low power receivers, low bit rate and limited uses.

• The cellular networks were built and maintained to support two-way voice.

• Like the Public Switched Telephone Network, the cellular networks have been extended to support new data services.

Early Cellular Systems

• Because the mobile unit has to transmit, power is restricted, and therefore range.

• A huge infrastructure of base stations had to be constructed to make the system viable. The pattern of coverage cells gives it these systems their name.

• The early systems were voice only, with FM voice modulation and frequency division between callers.

Cellular System Evolution

• The success of early systems came at a tremendous cost: all those base stations

• The second generation systems all use digital techniques to reduce the amount of spectrum, time and power required to support telephony services.

• The direct benefit to the service providers is to serve many more subscribers with the same number of cell towers.

Digital Cellular: TDMA

• The air link uses digital modulation, with some error control on that link.

• Voice is compressed to between 14 and 5 kbit/s using DSPs in the phones.

• The earlier designs used time division (TDMA) to serve several individual phones in each frequency band pair formerly used to serve one voice caller. Examples: IS-136 TDMA, GSM

• Advantages: relative simplicity, easy migration from analog cellular technologies

TDMA parameters

• 30 KHz channels (like analog & CDPD)• 20 msec speech frames• 24.3 kbaud symbol rate• 3 time-slots/users• 7.4 kbps ACELP speech coding• 1/2-rate channel coding on important bits

interleaved over 2 bursts in 40 msec• Differential pi/4-QPSK modulation

Digital Cellular: CDMA

• Code Division Multiplexed Access• Qualcomm and other companies had

developed Spread Spectrum techniques for communication. Advantages:– Resistance to interference– Secure, difficult to eavesdrop– Can support multiple non-interfering users in

the same chunk of spectrum. – Theoretically, more users/Hz than TDMA.

Why CDMA?• Higher capacity• Improved performance in multipath by diversity• Lower mobile transmit power = longer battery life

– Power control– Variable transmission rate with voice activity detection

• Allows soft handoff• Sectorization gain• High peak data rates can be accommodated• Combats other-user interference = lower reuse

factors

Digital Services on Cellular

• The first add-on service to the PSTN was data, using a succession of modems, from Bell 103 and V.21 all the way to V.90.

• Data modems were tried on analog cellular, but performance was poor.

Cellular Digital Packet Data

• As a first step to offer packet data, some analog cellular providers developed a technique to grab bursts of unused capacity in the dead time available between calls, at 19.2kbps.

• CDPD was offered. It is useful, where available.

• Its success was impaired by the need to deploy new infrastructure, new mobile hardware, and connect that to useful applications. Digital cellular improvements will make it obsolete.

Digital Cellular Data Services• Traditional PSTN data modems can not work on

digital cellular at all, but the need for data services was recognized.

• All three types of digital cellular systems included provisions to offer modem-style circuit mode data services:– Add PSTN modem pools between the cell base stations

and the PSTN– The modem’s logical serial port is stretched over the

digital air link– The cell phone exposes a standard modem command

language through an attached cable.

Data Service Speed Limits• The circuit mode data rates are

constrained to the rates allocated to the phone to carry voice: 9600-14400 bps.

• These rates support the kinds of applications common when the systems were designed: e.g. text-based email.

• By the time these services were deployed, Web access had become the dominant data application; these rates are too slow.

Migration to Packet-Based Service• Common data applications are not

continuous, they are bursty.

• Circuit mode services spends transmit power, and cell tower time, sustaining connections that are used in bursts.

• The control channels included in the digital cellular air interfaces make small packet traffic easy to add, such as the popular Short Messaging Services (SMS).

Speeding up Cellular Data• Step one: add packet-based service, with

rapid fine grained allocation of spectrum, time slots, code space, e.g.– GPRS = General Packet Radio Service– Cdma2000 1xRTT– EDGE

• Step two: Redesign as a high bandwidth packet-based service– “3G Cellular”

Wide-Area Wireless SummaryWide Area WirelessWide Area Wireless

US SummaryUS SummaryMobitex 8, DataTAC 19.2 PacketMobitex 8, DataTAC 19.2 Packet

CDPD 19.2 PacketCDPD 19.2 PacketGSM 9.6 Circuit-SwitchedGSM 9.6 Circuit-Switched

iDEN - Nextel - 9.6 Packet and iDEN - Nextel - 9.6 Packet and Circuit-SwitchedCircuit-Switched

cdmaOne Circuit-SwitchedcdmaOne Circuit-Switched14.4 - IS-95A14.4 - IS-95A

cdma2000 1XRTTcdma2000 1XRTT153 Kbps - Packet153 Kbps - Packet

GSM GPRS TechnologiesGSM GPRS Technologies

EDGEEDGE384 Kbps Packet384 Kbps Packet

Trials StartTrials Start

General DeploymentGeneral Deployment

TrialsTrialsVerizonVerizonSprintSprint

General DeploymentGeneral Deployment

Trials Trials Start Start

Limited DeploymentLimited Deployment

General DeploymentGeneral Deployment

Trials Trials Start Start

19.2 Rx/9.6 Tx19.2 Rx/9.6 Tx

38.4 Rx/9.6 Tx38.4 Rx/9.6 Tx

57.6 Kbps57.6 Kbps

Trials Start Trials Start Limited DeploymentLimited Deployment

General DeploymentGeneral Deployment

19991999 20002000 20012001 20022002 20032003Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4

WLAN Applications

• The original application is to allow office (or home) networking, with file, printer and internet access sharing.

• Industrial applications, networking factory or hospital devices without wires in the way.

• The emerging application is public access to the Internet

Early Wireless LAN Technologies• Proprietary schemes were developed in

the early 1990s to extend the advantages of LANs without running wires.

• After early work on radio technology in the TIA, the work moved from to the P802 committee of the IEEE

• HiperLAN was developed in ETSI, with support for voice and other isochronous services as well as packets.

IEEE 802.11 Progress• IEEE generated 802.11, using the 2.4GHz

ISM band, first at rates of 1 and 2 Mbps.• “HomeRF” was a short lived attempt to

cost reduce 802.11.• 802.11a was standardized for rates up to

54Mbps using the 5 GHz band.• 802.11b was standardized for 11Mbps on

the original 2.4GHz band.• 802.11g is in development, to add rates up

to 54Mbps in the 2.4GHz band.

Local-Area Wireless Summary

Local Area NetworkLocal Area Network

TechnologyTechnology

802.11 (FHSS) 2.4 GHz802.11 (FHSS) 2.4 GHz

1 Mbps1 MbpsFreq. Hopped Spread SpectrumFreq. Hopped Spread Spectrum

802.11 (DSSS) 2.4 GHz802.11 (DSSS) 2.4 GHz

1 or 2 Mbps1 or 2 Mbps

Direct Sequence Spread Spectrum Direct Sequence Spread Spectrum

HiperlanHiperlan23.5 Mbps23.5 Mbps

High Performance Radio LANHigh Performance Radio LAN

P802.11b (DSSS) 2.4 GHzP802.11b (DSSS) 2.4 GHz

11 Mbps11 Mbps

Direct Sequence Spread SpectrumDirect Sequence Spread Spectrum

P802.11a 5 GHzP802.11a 5 GHz

InitialInitialShipmentsShipments

InitialInitialShipmentsShipments

FinalFinalSpecificationSpecification

SpecificationsSpecificationsApprovedApproved

Initial MobileInitial MobileShipmentsShipments

19991999 20002000 20012001 20022002 20032003Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4

54 Mbps54 MbpsDirect Sequence Spread SpectrumDirect Sequence Spread Spectrum

Short range wireless: IrDA• Early work centered on InfraRed, given the

availability of IR used in remote controls.• InfraRed Data Association developed

specifications:– Serial port emulation at 115.2kbps– Upgrade to 4Mbps

• It is fast, directional, and depends on unobstructed line of sight.

• This is widely supported in PDAs, cameras and some cell phones

Short range radio wireless

• The cell phone manufacturers found that attaching serial cables to cell phones was cumbersome and consumed a lot of pins.

• Being radio experts, they looked for a convenient radio-based solution.

• Ericsson, Nokia and other interested manufacturers formed the Bluetooth™ Special Interest Group.

Bluetooth Wireless Technology

• The prospect of short ranged radio to replace cables attracted a lot of companies with a variety of applications.

• The Bluetooth Specifications support a number of Profiles: sets of specifications on how the applications should use the air interface.

• Several speakers will address Bluetooth technical issues today in detail.

Primary Bluetooth Applications• Cable replacement:

– Serial modem access to a DTE– Wireless Headsets

• Data exchange between personal devices– OBEX

• Ad Hoc networking amongst personal devices• Internet Access• Other device access:

– Printers, speakers, etc

Personal Area WirelessLocal Area NetworkLocal Area NetworkTechnologyTechnology

BluetoothBluetooth721 Kbps721 Kbps

Initial ShipmentsInitial ShipmentsIntegrated HandsetsIntegrated HandsetsPC Card and CF ModulePC Card and CF Module

Computer Integrated ProductsComputer Integrated Products

19991999 20002000 20012001 20022002 20032003Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4 Q1Q1 Q2Q2 Q3Q3 Q4Q4

IrDAIrDA

4Mbps4Mbps

Common Wireless Trends• IP networks• Always connected• Increased bandwidth• Convenience• Moving from vertical market to horizontal markets• Moving from proprietary to standards based• Proliferation of smart devices• New scenarios enabled• Outsourcing• Adhoc networks

Ad Hoc Networks

Desktops, Desktops, NotebooksNotebooks

TVs, TVs, games games

Phones, PagersPhones, PagersPC companionsPC companions

Books, tablets, Books, tablets, handheld PCshandheld PCs

Many diverse Many diverse devices to be devices to be connectedconnected

A Connected Home

xDSLxDSLCableCable

SatelliteSatellitePOTS, ISDNPOTS, ISDN ResidentialResidential

GatewayGateway

13941394

STBSTB

PhonePhone

Ethernet/1394bEthernet/1394b

PLCPLC

802.11802.11

IrDAIrDA

BluetoothBluetoothInternetInternet

A Connected Small Office

T1, T3, …T1, T3, …

Edge ServerEdge Server

PhonePhone

SmallSmallBusinessBusiness

ServerServer

EthernetEthernet

InternetInternet BluetoothBluetooth802.11802.11

Enterprise• Information at

your fingertips – At meetings, in the office, on

the road

– Reliable, secure, multimedia LAN

T1, T3, …T1, T3, …

Proxy ServerProxy Server

802.11802.11

IrDAIrDAGPRSGPRS

Web ServerWeb Server

EthernetEthernet

GPRSGPRS

BluetoothBluetooth

GPRSGPRS

InternetInternet

An ISP Connected Public Space

• Discovery of proximity services (flight schedules at airport, mall directories, …)

T1, T3, …T1, T3, …

Proxy ServerProxy Server

802.11802.11

PhonePhone

BluetoothBluetooth

IrDIrDAA

GPRSGPRS

Web ServerWeb Server

EthernetEthernet

InternetInternet

Wireless Architecture Requirements

• “Just works”

• Always connected

• Unified transport: IP

• Mobility

• Unified security model

• Adhoc

• QoS

• Performance

Designer Issues Addressed Today• What is Bluetooth technology?

– Tim Reilly, Stonestreet One, next speaker

• What are all the Bluetooth Protocols?– Andy Glass, Microsoft

• How do I deal with antennas?– Kerry Greer, Skycross

• How do WLANs work, how to test them?– Todd Stockert, Agilent

• How do I get my product tested and certified?– Karsten Beckman, Rohde & Schwartz

Web References• http://www.wow-com.com/ for cellular• http://www.bluetooth.com• http://www.wi-fi.com for 802.11• http://www.irda.org• http://www.stonestreet.com• http://www.microsoft.com/hwdev/wireless• http://www.microsoft.com/hwdev/bluetooth• http://www.skycross.com• http://www.rohde-schwarz.com