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16 DEVICE ALTERNATIVES 16.1 INTRODUCTION: COMBINATIONS AND PERMUTATIONS A bewildering array of subscriber unit options are available for wireless data rangingfrom fully integrated termin

V PUTTING IT TOGETHERCopyright © 1999 John Wiley & Sons, Inc.

ISBNs: 0-471-31651-2 (Hardback); 0-471-22458-8 (Electronic)

16

DEVICE ALTERNATIVES

16.1 INTRODUCTION: COMBINATIONS AND PERMUTATIONS

A bewildering array of subscriber unit options are available for wireless data rangingfrom fully integrated terminal/modem/radio units to multibox combinations of PCs,external modems, cellular transceivers, and portable faxes A (too) simplerepresentation of some of the terrestrial variations is illustrated in Figure 16-1.This convoluted collection of hardware alternatives is extraordinarily volatile It isnot uncommon for a monthly trade magazine to publish reviews of a product only tohave some details revealed as outdated by the vendor’s new ad in the same issue Anup-to-the-minute review of the wide range of product possibilities makes little sensefor a book with an even slower publishing schedule

There is also the question of personal choice in devices For some users “carrying

an extra bag isn’t as comfortable as putting a palmtop in their pocket.”1 Users with asimilar profile require at least a notebook because they cannot tolerate the smallkeyboard, hard-to-read display, or Windows incompatibility2 of some palmtops Stillothers will carry the latest “desktop replacement” notebook PC even if it weighs 9pounds

The key trends for pivotal segments that permit the devices to communicatewirelessly is clear:

1 Universal adoption of the PC Card, Type II format radio modems, withmultiprotocol capability These are most often seen in notebook/laptop PCs

2 Integration of radio modems within devices, especially for custom designed,

“rugged” terminals However, full integration also extends to pagers as well asvoice handsets

Copyright © 1999 John Wiley & Sons, Inc.

ISBNs: 0-471-31651-2 (Hardback); 0-471-22458-8 (Electronic)

Figure 16-1 Device combinations and permutations.

3 Relentless attempts to introduce useful, well-packaged radio modems for palmPCs.

16.2 MODEM COMPLEXITY

Wireless modems have four levels of hardware sophistication:

1 No hardware consideration for errors With data over cellular this class ofmodem is usually limited to very low speed (300–1200 bps) where errortolerance is high Error control rests with simple communications protocolssuch as Xmodem3 (and its variants), Kermit,4 and Zmodem.5 These modems arevirtually an extinct breed, but the overlay protocol Zmodem is stillrecommended by BCTEL6 because of its ability to resume the transfer at thepoint of disconnect

2 Error detection mechanisms, combined with ARQ techniques, and oftenaccompanied by packet resizing to optimize performance These units tend to

be moderate speed (2400 bps) since longer burst errors can now be tolerated.The foremost examples are Microcom units and their many MNP cousins.These moderate-bit-rate protocols are being relegated to history, appearing only

as artifacts in multiprotocol modems

3 Trellis-coded modulation to provide initial error correction capability at higherbit rates (5–20 kbps) This more reliable data transmission technique is usuallycombined with error detection, usually V.42, and ARQ to improve the chances

of successful message delivery On cellular these modems are increasinglyequipped with signal shaping and hand-off detection technology to reduce theoccurrence of cellular “incidents.” On packet systems such as Motorola’sRD-LAP, the bit stream is interleaved to spread burst errors

4 The use of more powerful error correction coding techniques, deliberatelysacrificing airlink capacity, in an attempt to deliver a clean message withoutretransmission The most well known example of this class of modems areCDPD units

Wireless modems can be packaged as stand-alone units or, increasingly, integratedinto paging devices, laptops, or cellular phones Years of ground-laying packagingdevelopment for PC Cards has made fully integrated units a very powerful option.When modems are used on circuit switched cellular vendor variations on thecellular instruments often force the need for an adaptive device, now a “smart” cable,between modem and cellular radio These adapters mimic wireline dial operations forcommunications software Increasingly, adapters are being integrated into eithermodem or cellular phone

Some modems contain the radio transceiver Packet switched radio modemsintegrated into custom devices have been available from Motorola for more than a

decade Both Motorola and Ericsson began to deliver external radio modems atmanageable price levels in 1992–1993.

16.3 CELLULAR SPEARHEADS MODEM DEVELOPMENT

Multiple slow-speed modems capable of operating via circuit switched cellular wereannounced within a year of the initial cellular rollout in October 1983 Most werefailures, but all contributed to the relentless trend toward lower weight and smallerphysical volume These physical improvements ultimately made device integrationpossible

For nearly six years the cellular modem physical trends were pleasant: a 300-bpsmodem in 1984 weighed 20 ounces; in 1990 a 1200-bps unit weighed the same 20ounces; 300-bps units weighed 5 ounces This compound annual weight reduction of

~20% and a compound bit rate increase of ~25% per year seemed a new law of physicsand often appeared on forecast charts

The 1991 introduction of the Telebit QBlazer was the first break in the trend lines.This modem departed from the old modulation techniques, which were topping off at

4800 bps on wireline systems Telebit employed V.32 (9600-bps) TCM as well asrecovery strategies originally developed for wireline units With the transmissionspeed reduced, typically to 4800 bps, these techniques made a good fit for cellular.Raw bit rates thus rose by a factor of 8; weights/volumes fell to one-third of the priorbest: the V.32 Digicom 9624LE The unit had V.42 error detection, with ARQ, andV.42bis data compression, which had the potential for quadrupling throughput (seeSection 15.4)

This sharp break signaled the end of the medium-speed stand-alone modem.Excellent new units such as Microcom’s MP1042, in normal times a breakthroughunit, were doomed by the V.32 development Dozens of vendors7 began to produceV.32 and the even faster V.32bis pocket modems Nearly all included fax capability

as well This tight packaging was made possible by the advent of inexpensive chip setsfrom AT&T, Exar, Rockwell, and Sierra

Three years later the nails were hammered ever faster into the stand-alone modemcoffin V.32bis (14,400-bps) PC Card modems now weighed less than 35 grams—alittle over an ounce During much of this period list prices fell very slowly until theimpact of wireline V.32/V.32bis cellular-capable modems was felt In the first quarter

of 1985 Spectrum Cellular’s Bridge/Span units delivered 300 bps for $595: 1 bit persecond for ~$2 The coming of devices such as Megahertz’s PC Card cellular modempermitted theoretical speeds up to 14,400 bps for a list price of $459: 1 bit per secondfor $0.03 Further, the new modems included many extras, including fax capabilityand communications software for both data and fax In the first quarter of 1995 it wasroutine to find direct order retailers selling brand name cellular modems for $289: 1bit per second for ~$0.02 By the fourth quarter of 1997 V.34 modems with cellularsupport could be purchased for $50–$908: 1 bit per second for about a half cent This400-fold price-per-bps decline in just 12 years ranks with the best technology shifts

of the decade

16.4 VOICE/DATA PUSH–PULL

16.4.1 Positioning Tussles

During the transition from stand-alone modem to PC Card, vendors were able toproduce small OEM modems capable of being integrated into either data devices orcellular phones Hybrid solutions were developed for each alternative Thiscompetition over function placement, voice versus data centric, continues

16.4.2 Voice Devices Swallow Modems

In 1992 Mitsubishi integrated the Microcom 1042, a 2400-bps MNP10 modem, underthe covers of its 1500MOB series phones The resulting CDL300 was a 3-wattportable cellular phone with attractive physical characteristics for its time Withbattery, it weighed 4.3 pounds—not bad for such a high-transmit-power machine

In 1993 PowerTek announced its CMI-3000 cellular data link Rich withconnection options, the CMI-3000 contained a 3-watt transmitter and a V.32bis(14,400) bps data/fax modem using MNP10 correction and V.42bis compression Theidentical unit was also offered by Audiovox as the CDI-1000 To add interest to theMNP10-versus-ETC dispute, both PowerTek and Audiovox claimed a 96% first-timeconnect rate9 with MNP10 This may have reflected the high transmit power available

in these rather large units The PowerTek/Audiovox units made advertising claims forfull integration but, like Mitsubishi’s CDL300, the handset was distinctly separate

In 1994 Air Communications announced a product that truly was fully integrated.Weighing in at 1 pound, the modem section was multiprotocol, including V.32bis andfax The device used the proprietary AirTrue enhancements to improve the probability

of call connection as well as duration The battery permitted 2 hours of datatransmission When disconnected from a PC it operated as a conventional cellularphone, with features such as voice mail In this mode it served as an answeringmachine for incoming calls (16 minutes maximum time) Its storage capability alsopermitted it to hold up to 37 fax pages for later transmission to a fax machine The AirCommunicator was marketed by both Ameritech and Sprint Cellular, but in spite ofdiligent efforts, it failed

The philosophy of these “voice-centric” products is shown in Figure 16-2 Thevoice handset is the key communications device The data user requires no modemwithin the laptop A regular RS-232 cable connects the laptop to the phone modem.This modem can sometimes connect to wireline networks via normal RJ11 cables.Principally, it uses the voice radio to make a circuit cellular, facsimile, and, now,CDPD connection

16.4.2.1 Voice Devices Try to Do It All In 1994 BellSouth announced IBM’sSimon, a cellular telephone with limited PDA functions such as appointmentscheduler and calendar, personal electronic directory, and calculator Simon used a

backlit liquid crystal display (LCD) screen as telephone keypad, pen annotation area,and computer display Its communication functions were limited:

1 E-mail Twenty messages could be received, but the data modem only operated

at 2400 bps There was no way to connect Simon to a PC and no wireline mode

2 Paging The coverage and costs were cellular based Nine phone numbers (notext) could be received and stored

3 Facsimile Three facsimiles could be viewed on the small screen and handannotated for retransmission

The BellSouth theme was “Simon Says Have It All.” Simon was occasionally spotted

in the movies, rarely in real life

Ignoring ill-fated detours such as the AT&T EO440/880 class devices, the newestdo-it-all unit is Qualcomm’s pdQ.10 Sometime in 1999 we will see this voice cellularphone wrapped around a 3Com Palm Pilot Two models were under test in the fourthquarter of 1998, an 800-MHz analog/digital voice version as well as a single-mode1900-MHz digital-only unit Three Qualcomm applications will exist to permitshort-messaging service (SMS), E-mail (likely Eudora), and Web browsing

The resulting device is odd looking and fairly large, though smaller than a palmPilot stuffed on top of a Minstrel modem I felt faintly embarrassed putting ademonstration unit up to my face to talk I also have trouble with the Palm Pilot as apen-based data entry device The pdQ price is unknown at this writing, so we mustsimply wait and see if the product(s) are successful

16.4.2.2 A Compromise: SmartPhones PCSI’s Unwired Planet Browser/HDML-based PALphone was the first example of what was immediately tagged a

“smartphone.” PDA functions are not integral to the phone instrument, as in Simon orthe pdQ, but are obtained from the network from a built-in “micro web browser.” Theaddress book and calendar (for example) can be located on your own personal Webpage, which the smartphone accesses

The notion behind the smartphone was that many users (perhaps most) were voicejunkies with a secondary need for data from the web or their own corporate network,especially one using Lotus Notes There is only a tertiary need for any data input other

Figure 16-2 Voice devices swallow modems.

than checklist yes/no responses Entering any real message of substance from atelephone keypad is time consuming and unusually annoying.

The PAL phone was, first and foremost, a cellular voice handset But it had a goodmultiprotocol modem under the covers for CDPD, circuit switched cellular andfacsimile It was all wireless, all the way; the RJ11 connection to wireline networksdid not exist Introduced in 1996, it was gone in May 1997,11 an obvious casualty ofthe death of PCSI

Before its end, there was a feeling that the PALphone did not quite measure up tothe smartphones that quickly followed, especially Samsung’s Duette12 and theMitsubishi MobileAccess 110.13 Initially priced at $500, they dropped to $300 by firstquarter of 1998.14 These units are now subsidized by the carriers In the fourth quarter

of 1998 AT&T Wireless offered units for $99 for those users subscribing to itsWorldNet E-mail service.15

AT&T Wireless bet heavily on these new devices with its PocketNet Service Theintroduction16 was all upbeat: “I truly believe (smartphones) will be one of the majorfactors that finally drives (wireless data) adoption—1996 and 1997 will be the yearswhen the curve did start to turn up.” But that hardly happened Within months somecustomers in pilot “opted to discontinue the service.”17 when they realized that “thetechnology requires an IS department or an application from one of the (softwaredevelopers) we’re working with.”18 AT&T Wireless was reasonably cautious about itsequipment orders, awarding Samsung an $18 million dollar contract in June

199719—20% of what BellSouth committed to RIM for two-way pagers

In 1988 Mitsubishi began to ship its MobileAccess 100 series cellular phones, agreatly improved technology advance over 1992’s 1500MOB phones Themultiprotocol MobileAccess phones have an extra cost PC/PalmPilot connection kit.20

It provides a 34-in cable and supporting software for Windows-based PCs, Palm III,PalmPilot Professional, and IBM WorkPads The phone thus can act as a radio modemfor connecting the data device to a variety of wireless (no wireline) options

16.4.2.3 Annoying Residual Problems The current smartphone offerings areexclusively loved by zealots Their voice clarity is only fair.21 The display screen, at

4 × 12 (really only 3 × 12 for received messages) characters, is incredibly limited.Entering data makes one want to throw the instrument on the ground Example: toenter the name DeRose (Nokia/Tegic T9 software is unlikely to find that name in alinguistic database) requires 18 key depressions and 6 pauses:

Do not bother to attempt numbers If you want to respond to the simple query “whattime shall we meet?” with the four-character reply 2:30, one practical keypadsequence is

2, 2, 2, 2, pause, softkey, softkey, 0, 0, 0, 0, 0, 0, 0, 0, pause, softkey, 3, 0, softkeyfor another 18 depressions and 2 pauses

Tethered data devices, especially PCs, eliminate this human data entry problem,but it is particularly difficult to juggle two boxes, linked by a yard of cable, on a citystreet

Battery life is also found wanting With the standard battery (when brand new), onecan only get an hour’s “talk” time; standby time is 9 hours As shown in Figure 16-3,

if the phone is on standby for, say, 3 hours, the usable time drops to 40 minutes Themessage: Always carry a spare battery and keep those chargers working every night.There are also qualitative problems with smartphones when using CDPD (at leastBAM’s version, Cellscape) Successful message transmission often takes 2–3 minutes

of fussing: much sending)))), network not responding, retry, sending)))))), gatewaynot responding, and so on

Once or twice I decided to torment a BAM Cellscape phone by sending a “long”(500-octet!) message to it from another device With BAM’s network settings onlyabout half the CDPD message is delivered initially To see the balance, one must hit

“MORE,” which results in the hateful sending))))) sequences If a really long message(say 1500 bytes) is attempted in a difficult area (Grand Central Station’s main

Figure 16-3 “Talk” vs standby time trade-off: PocketNet phones.

concourse is such a spot), you might as well buy a sandwich while you wait to readyour mail.

It is also extremely tedious to delete a received message: READ, ACT,sending))))), DELETE, sending))))), OK, sending))))), message deleted, OK,sending))))) Any one of the sending))))) sequences are vulnerable to

“network/gateway not responding” responses, forcing a retry After a while I simplygave up deleting messages and then gave up the phone

16.4.3 Data Devices Swallow the Radio

Data-centric devices containing the radio transceiver fall into three categories:

1 External radio modems for connection to the serial input–output (I/O) port ofthe terminal or PC

2 PC Card radio modems for laptops, PDAs, and custom devices Except inhigh-transmit-power applications, the PC Card radio modems have largelydriven out their external predecessors

3 Integrated units hidden under the covers of laptops or custom products Theseare becoming increasingly popular in high-production-run, application-specificdevices

An advantage often claimed for CDPD over competing alternatives is that there aremany multivendor radio modems to choose from.22 In truth, with the demise ofCincinnati Microwave and PCSI, the steady withdrawal of Coded Communications,Ericsson, IBM, and Motorola (for CDPD, for now), and the increasingmarginalization of suppliers such as Uniden, the total number of radio modemsuppliers for all carriers is remarkably small It is likely that six to eight manufacturersaccount for 95% of all shipments to date Of these, just seven vendors, four of themCanadian, dominate all current, in production, alternatives:

1 Dataradio: Has augmented its private radio offerings with its purchase of theMotorola R-net line in February 1998.23

2 Megahertz: Provides PC Card radio modems for BSWD

3 Metricom: Manufactures a line of external modems for cable connection tohand-held and notebook PC devices The modems are designed in Richmond,British Columbia, by ax-Motorola (MDI) engineers

4 Motorola: The only U.S vendor, it offers a full line of radiomodems—external, PC Card, other equipment manufacturer (OEM)modules—for RD-LAP/MDC4800 (ARDIS) and Mobitex (BSWD)

5 NovAtel: Concentrates on small external devices and OEM modules for CDPD

6 RIM: Specializes in integrated solutions, from OEM modules to customproducts, for ARDIS and BSWD