Wireless 2002 IEEE 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 power But: 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 –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: bps. These rates support the kinds of applications common when the systems were designed: e.g. text-based . 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 Summary Wide Area Wireless US Summary Mobitex 8, DataTAC 19.2 Packet CDPD 19.2 Packet GSM 9.6 Circuit-Switched iDEN - Nextel Packet and Circuit-Switched cdmaOne Circuit-Switched IS-95A cdma2000 1XRTT 153 Kbps - Packet GSM GPRS Technologies EDGE 384 Kbps Packet Trials Start General Deployment Trials Verizon Sprint General Deployment General Deployment Trials Start Limited Deployment General Deployment Trials Start 19.2 Rx/9.6 Tx 38.4 Rx/9.6 Tx 57.6 Kbps Trials Start Limited Deployment General Deployment Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4

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 Progress IEEE generated , using the 2.4GHz ISM band, first at rates of 1 and 2 Mbps. “HomeRF” was a short lived attempt to cost reduce a was standardized for rates up to 54Mbps using the 5 GHz band b was standardized for 11Mbps on the original 2.4GHz band g is in development, to add rates up to 54Mbps in the 2.4GHz band.

Local-Area Wireless Summary Local Area Network Technology (FHSS) 2.4 GHz 1 Mbps Freq. Hopped Spread Spectrum (DSSS) 2.4 GHz 1 or 2 Mbps Direct Sequence Spread Spectrum Hiperlan 23.5 Mbps High Performance Radio LAN P802.11b (DSSS) 2.4 GHz 11 Mbps Direct Sequence Spread Spectrum P802.11a 5 GHz Initial Shipments Initial Shipments Final Specification Specifications Approved Initial Mobile Shipments Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 54 Mbps Direct 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 Wireless Local Area Network Technology Bluetooth 721 Kbps Initial Shipments Integrated Handsets PC Card and CF Module Computer Integrated Products Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4 IrDA 4Mbps

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, Notebooks TVs, games Phones, Pagers PC companions Books, tablets, handheld PCs Many diverse devices to be connected

A Connected Home xDSLCableSatellite POTS, ISDN ResidentialGateway 1394 STB Phone Ethernet/1394b PLC IrDA Bluetooth Internet

A Connected Small Office T1, T3, … Edge Server Phone SmallBusinessServer Ethernet Internet Bluetooth

Enterprise Information at your fingertips –At meetings, in the office, on the road –Reliable, secure, multimedia LAN T1, T3, … Proxy Server IrDA GPRS Web Server Ethernet GPRS Bluetooth GPRS Internet

An ISP Connected Public Space Discovery of proximity services (flight schedules at airport, mall directories, …) T1, T3, … Proxy Server Phone Bluetooth IrDA GPRS Web Server Ethernet Internet

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 for cellularhttp:// for http://