Wireless Communications

Pocket PC users have a myriad of wireless communications choices available to them. Unfortunately, most of these choices are imperfect. The not-so-well-kept secret of wireless data communication is that it doesn't work all that well. Even the all-pervasive cellular networks in this country have gaps in coverage. We've all experienced dropped calls, intolerable interference, and more. Why should we expect wireless data communications over many of these same networks to work any better?

So, what to do? Should we simply throw up our hands in despair and go back to writing on birch bark? Well, not quite yet. There's a rising star on the wireless data planetarium wall, and it's called "3G." But is 3G just another over-hyped and under-performing technology destined to further disappoint and confuse mobile professionals? Or, is there something really there for the Pocket PC user?

Wireless networks through the "ages"

In the early to mid 90's, the most popular option for wireless data communications with mobile devices was the Advanced Mobile Phone System (AMPS) cellular telephone network. This still-very-popular analog-only network can be used with a traditional external or PC Card modem to translate the bits pushed out the device's serial port into the analog signal expected by the cell phone. Users could expect blistering data throughputs on the order of 4.8 kbps, and lots of dropped calls (unless specialized error-correcting cellular protocols were used to maintain connectivity in roaming situations). AMPS is an example of what the industry calls a "1st Generation" or "1G" network.

The digital cellular network revolution in the mid to late 90's allowed users to eliminate the expensive, battery-hungry modem from the loop. Instead of an external modem, digital networks use native modulation techniques inside the telephone itself. This allowed companies such as Socket Communications (http://www.socketcom.com/)  to offer their Digital Phone Card product that provides a direct conduit through your Pocket PC's CompactFlash slot to your digital cell phone without the need for a modem.

Moreover, in contrast to the older analog AMPS networks, reliability and data throughput are better on these "2nd Generation" ("2G") digital networks (somewhere on the order of 14.4 kbps for CDMA networks such as that offered by Sprint PCS). Other digital providers such as AT&T and Verizon offer similar (though technologically incompatible) digital networks to keep your Pocket PC connected wirelessly to the Internet.

Besides the ubiquitous hybrid voice/data 2G networks, there is a veritable "alphabet soup" of acronyms for technologies which provide data-only networks for the use of Pocket PC owners. For example, AT&T and other companies offer an analog/digital technology called Cellular Digital Packet Data (CDPD). CDPD improves throughput slightly (to 19.2 kbps) but at the expense of higher latency than with hybrid voice/data digital networks. Latency is the delay that occurs after pressing a key or tapping on a link on a Web page while the wireless network moves the bits from your Pocket PC to the server and back again.

Other data-only 2G networks include two-way paging technologies such as REFLEX, whose very high 25–30 second latency would make interactive applications such as the Web intolerable for most users. Pocket PC users are also able to use packet radio networks such as Bellsouth Wireless Data's Mobitex infrastructure (this network makes most of those nifty RIM interactive pagers and Palm VII's communicate). The problems with all of these systems are high latency (12–15 seconds) and low throughput (8 kbps). Users are bound to get frustrated with the performance and reliability of most of these existing 2G solutions.

Other companies, such as Metricom, offer higher-performance wireless LAN technologies (up to 128kbps in some cities); however, coverage is again a big issue—currently the service is only available in 11 cities. Moreover, in those cities where there are quite a few hills (such as San Diego), coverage will continue to be a problem for many users.

If You Build the Wireless Web, Will They Come?