12 Computer

T raditionally, the word “net-working” has evoked images ofyards of spaghetti-like wiring inwalls, on floors, and hangingfrom the backs of computers

and peripherals.However, several trends in the com-

puter industry are rapidly driving thedevelopment and adoption of newerwireless networking technologies, whichlink devices to each other and to corpo-rate LANs, primarily via radio-frequency(RF) technology.

These trends include the increase inhome networking; the rapidly growinguse of networkable portable devices—such as smart phones, personal digitalassistants, and laptops—by a mobilework force; and the desire by companiesto operate networks in historic, leased,or temporary buildings in which wiringis impractical, prohibited, or expensive.

Moreover, there is a demand for wire-less networking by industries, such asmedicine, in which employees must com-municate with central networks but aretoo mobile to use wired devices.

Meanwhile, improved radio and net-working technologies have increased theperformance, reliability, and desirabilityof wireless networking.

To maximize the usefulness of wirelessLANs, vendors want technology basedon open standards rather than on pro-prietary technologies, which have beenused during the past 10 years.

With this in mind, the IEEE and twoindustry consortia have developed threemajor wireless LAN standards: IEEE802.11, HiperLAN, and HomeRF.

And another industry consortium hasdeveloped Bluetooth, which manyexperts consider to be wireless PAN (per-sonal area network) technology. (See thesidebar “Bluetooth: The Wireless PAN.”)

Major vendors are beginning todevelop products using these standards,and a number of vendors are workingwith more than one of the technologies.

And now, faster and otherwiseimproved versions of wireless LAN stan-dards are being prepared for release.

“We’ve been touting wireless LANsfor six or seven years, and they just havenot taken off,” said Eric Thompson,senior analyst with the Gartner Group,a market research firm.

However, said Peter Hortensius, direc-tor of technology development for IBM’spersonal system group, the IEEE 802.11standard, backed by established compa-nies, has begun to move wireless LANsinto the mainstream. Bluetooth andHomeRF are following in a similar path,he said. HiperLAN appears aimed prin-cipally at the high-end corporate market,primarily in Europe.

The technologies are not well estab-lished yet, though, and they still face suchchallenges as high costs. Meanwhile, themarket has not determined whether oneor all of the technologies will succeed.

WIRELESS LAN TECHNOLOGIESSeveral companies developed wireless

LAN technology about a decade ago. Forexample, said John Barr, Motorola’sdirector of systems architecture and tech-nology for PANs, Motorola developedAltair, one of the first commercial wire-less LAN systems.

Early wireless LANs were expensive,their data rates were low, they wereprone to signal interference, and most ofthem were based on proprietary RF andinfrared technologies.

IEEE 802.11bThe recently adopted IEEE 802.11b is

the newest IEEE 802.11 wireless LANstandard. IEEE developed the 802.11standards to provide an Ethernet-likewireless networking technology.

The European TelecommunicationsStandards Institute (ETSI) is looking intoadopting IEEE 802.11 standards, whichwould enhance the technology’s interna-tional interoperability.

The technology. The technology permitstransmission speeds of up to 11 Mbits persecond, which makes it considerablyfaster than the original IEEE 802.11,which sends data at up to 2 Mbps, and abit faster even than standard Ethernet.

IEEE 802.11b permits devices to estab-lish either peer-to-peer networks or net-works based on fixed access points withwhich mobile nodes can communicate.

IEEE 802.11 operates in the unlicensed2.4-GHz so-called industrial, scientific,and medical frequency band, which hasbecome popular for worldwide wirelesscommunications because it is globallyavailable.

On the physical layer, the originalIEEE 802.11 uses either FHSS (fre-quency-hopping spread spectrum) orDSSS (direct-sequence spread spectrum)technologies.

With both technologies, transmissionsregularly shift frequencies, which reducesinterference and efficiently uses the avail-able bandwidth. However, DSSS sends

Exploring the WirelessLANscape Linda Dailey Paulson

I N D U S T R Y T R E N D S

transmissions over a wider channel (11MHz) than FHSS (1 MHz) and thusoffers greater transmission speeds over

longer distances. However, wider chan-nels also mean that DSSS offers fewerpotential channels and less scalability. In

addition, DSSS uses more power and ismore expensive to build.

IEEE 802.11b uses complementary

October 2000 13

Bluetooth has been one of the hotteststories in computer technology, eventhough vendors have only just begunreleasing products.

Ericsson developed the wireless net-working technology in 1994 to replacethe cables used to link computers andtelephones. The technology has garneredstrong industry support, with about2,000 companies, universities, and otherorganizations joining the BluetoothSpecial Interest Group (http://www.bluetooth.com). And many vendors—including Intel, Lucent Technologies, andMicrosoft—have invested in the tech-nology.

Anders Edlund, Ericsson MobileCommunication’s marketing directorfor Bluetooth, said “We don’t considerBluetooth to be a wireless LAN. It ismore like a personal network.”

Bluetooth personal area networks(PANs) link enabled devices—such asPCs, laptops, smart phones, and personaldigital assistants—into mininetworks viaradio signals operating in the 2.4-GHzspectrum. Bluetooth can also linkmininetworks to form a piconetwork.However, the technology is primarilydesigned to replace wiring betweendevices that are close together, ratherthan create data or voice networks.

Edlund said Bluetooth functions overdistances of 10 meters or 100 meters,depending on the power of the radiotransceiver being used. The technologypermits net throughputs of up to 721Kbps upstream and 56 Kbps downstream.

Bluetooth works with a wireless sys-tem packed onto a chip that can be inte-grated into computers, phones, andother devices.

Ericsson has released a wireless cellu-lar headset and two types of cellularphones, all equipped with Bluetooth.Meanwhile, other vendors plan toimplement Bluetooth in their upcomingcellular phone releases.

Bluetooth: The Wireless PAN

14 Computer

HiperLANETSI developed the HiperLAN (high

performance radio LAN) standard. The HiperLAN Alliance (http://www.hiperlan.com) designed the initial versionof the technology, HiperLAN1; theHiperLAN2 Global Forum (http://www.hiperlan2.com) is working on a fasterversion.

HiperLAN1 offers up to 23.5 Mbpsthroughput, the highest performance oftoday’s wireless LAN technologies.

The technology. The keys to Hiper-LAN’s high data rate include its efficientpower amplifier and its use of the 5-GHzfrequency band. Within the 5-GHzband, providers have larger frequencyranges and, therefore, higher bandwidthto work with than providers using tech-nology in the 2.4-GHz band.

On the physical layer, HiperLAN1 usesGaussian Minimum Shift Keying, arobust technique for modulating data sig-nals by shifting transmitter frequencies.

HiperLAN1 supports quality of ser-vice in some implementations. In addi-tion, the technology supports encryption,including the WEP algorithm, as shownin Figure 1.

The market. HiperLAN offers greatpromise because of its high data rates,according to Jeff Orr, product managerfor Proxim, a manufacturer of broad-band wireless networking products anda member of the HiperLAN Alliance.

code-keying DSSS, which permits fastertransmission speeds than the originalDSSS used in IEEE 802.11.

For security, IEEE 802.11b supportsauthentication and encryption, including128-bit wired equivalent privacy (WEP)cryptography.

The market. Apple Computer was thefirst company to market IEEE 802.11bsystems, via its AirPort technology. Air-Port is implemented via add-on cardsand, in some cases, base stations that letup to 10 devices form networks. Othercompanies, including Cisco Systems and3Com, also offer IEEE 802.11b prod-ucts, such as network cards and chips.

Gartner’s Thompson predicts that mostwireless LAN vendors will invest in 802.11-based technology. Corporate users like802.11 because of its range, security, andreliability, he said.

In addition, IEEE 802.11 offers quality-of-service capabilities, according to BarryDavis, Intel’s strategic marketing man-ager for wireless LAN operations.

“The [big] advantage,” Thompsonsaid, “is that it has a very strong pushfrom the industry and is standards based.It’s absolutely brought vendors togetherand given them a target for interoper-ability.”

“It is a little more expensive thansome of the other wireless technologiestoday, but the price is coming down,”he said.

Potential commercial applications ofthe high-speed technology include med-ical imaging, video training, or remotesurveillance.

However, HiperLAN has not hit themarketplace yet, as vendors have focusedmore on IEEE 802.11 thus far.

“HiperLAN is fancy and it’s new,”said Barry Davis, strategic marketingmanager for wireless LAN operations atIntel, “but products have never shipped.”

Although HiperLAN has been seen asprimarily a technology for the Europeanmarket, it can be used in other areas. Forexample, the US Federal Communica-tions Commission (FCC) has allocatedspectrum for its use.

HomeRFHomeRF is based on the shared wire-

less access protocol (SWAP), which theHomeRF Working Group (http://www.homerf.org) adopted in late 1998.

The technology, including a fasterWideband HomeRF currently underdevelopment, is designed for use primar-ily in homes and small offices.

The technology. SWAP lets up to 127PCs, peripherals, cordless telephones,and other devices with a network stackshare and communicate data. SWAP alsopermits up to six voice connections.

A HomeRF system can operate eitheras an ad hoc network of devices, whichsupport only data communications, or asa managed network under the control ofa central connection point. For trans-missions that won’t tolerate latency, suchas voice communications, a connectionpoint is required to coordinate the sys-tem. The connection point can also sup-port power management for prolongedbattery life by scheduling device wake-up and polling.

The radio in HomeRF systems has apower amplifier able to transmit at up to100 milliwatts, which permits the tech-nology to operate over distances up toabout 45 meters.

The market. HomeRF products havealready been released, including Intel’sAnyPoint home networking system, aswell as Compaq Computer’s Symphony-HRF USB dongle, PC cards for note-book computers, and PCI cards for PCs.

Wideband HomeRF, with its 10-Mbps

I n d u s t r y T r e n d s

Figure 1. In HiperLAN1’s implementation of wired equivalent privacy (WEP) cryptography, a ran-dom bit sequence called the initialization vector runs an XOR operation on the encryption key.The resulting value helps produce a stream cipher, which is used to encrypt the data. Packets—which include the key identifier, initialization vector, and data—are then sent to the recipient’ssystem, where decryption takes place.

Transmitter

HiperLANkey set

XOR

XORRandomsequencegenerator

Keyidentifier

Initializationvector Initialization

vector

Encrypteddata

Keyidentifier

Key

Seed

DataReceiver

HiperLANkey set

XOR

XORRandomsequencegenerator

Key

Seed

DataEncryptedtransmission

data rates, could be particularly appeal-ing in the residential marketplace. In thecorporate marketplace, however, itwould have to compete with faster ver-sions of other technologies.

THE WIRELESS LAN’S FUTUREThe widespread adoption of wireless

LANs has been limited by such issues asrelatively low data rates and a lack ofquality-of-service capabilities in sometechnologies.

Interoperability is also a potential issue.However, said Ben Manny, HomeRFWorking Group chair and director of res-idential wireless networking for Intel’sArchitecture Lab, “in the near future,you’ll start to see bridge products.”

These products—such as Proxim’sHarmony PC cards, access points, andaccess-point controllers—bridge LANsthat use different technologies, such asIEEE 802.11b and HomeRF.

The primary impediment to wider

adoption of wireless networking is thatcosts are still “too high relative toEthernet,” explained Peter Rysavy, pres-ident of Rysavy Research (http://www.rysavy.com), a communications-technol-ogy consultancy.

“The key new technology here isOFDM (orthogonal frequency divisionmultiplexing), which currently is expen-sive,” said Rysavy, “but vendors arelikely to make large strides in reducingproduct costs.”

Observers expect OFDM to be a keycomponent of next-generation, high-speed wireless networks. OFDM dividesthe available spectrum into multipletransmission channels. The technologypermits many channels and thus squeezesconsiderable performance out of thespectrum. OFDM places channels veryclose together and positions adjacentchannels orthogonal to each other tominimize interference that would other-wise occur.

OFDM is a key component of IEEE802.11a and HiperLAN2, both of whichare planned for release next year withthroughputs of up to 54 Mbps.

Meanwhile, the HomeRF WorkingGroup plans to release a 10-Mbps ver-sion of its technology, called WidebandHomeRF, early next year. A recent rulingby the FCC will enable the use of wide-band frequency-hopping systems in thedomestic 2.4-GHz frequency band. Thistechnology permits higher data rates byallowing more signal modulation withineach frequency hop, thus using radio fre-quencies more efficiently with less inter-ference.

Indicating how the wireless LAN mar-ket as a whole might grow, Figure 2shows that Gartner Group/Dataquestpredicts that the worldwide revenue fromsales of wireless NICs will increase from$187.9 million in 1998 to $648 millionin 2004, even as the average productprice drops from $340.20 to $180.

October 2000 15

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M any industry observers say thatHomeRF will be used more in thehome and small office, while

IEEE 802.11 and HiperLAN will be usedmore in the enterprise.

However, Thompson said, as pricesdrop for IEEE 802.11, home-networkingusers may well adopt this technology.

In the long run, said IBM’s Hortensius,“The dilemma is whether you need allthree [wireless LAN] technologies, andthat’s what the marketplace will tell us.There are not enough products [now] todecide. There could be a compelling casefor all three, or just one or two.” ✸

Linda Dailey Paulson is a freelance tech-nology writer based in Ventura, California.Contact her at ldpaulson@yahoo.com.

16 Computer

I n d u s t r y T r e n d s

Editor: Lee Garber, Computer, 10662 LosVaqueros Circle, PO Box 3014, Los Alamitos,CA 90720-1314; l.garber@computer.org

Figure 2. Gartner Group/Dataquest predicts that the number of network interface cards sold and the worldwide revenue they generate will steadily increase through 2004, even though theaverage product price will steadily fall.

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Source: Gartner Group/Dataquest