Cellular and PCS telephones will be the predominant mobile
communications technologies for the foreseeable future. This
does not mean to imply that cellular is superior to other technologies,
only that it is more prevalent. With nearly 1 billion
users worldwide, there is no close second. These mobile technologies
are currently facing a major evolution in many areas,
however, including the technical and business sectors, because
they provide the economical means for realization of not only
mobile computing, but also many other applications ranging
from financial and retail communications to remote control
and signaling.
Recent technology, whether it’s TDMA, CDMA, or GSM
has experienced severe physical layer and user interface constraints.
Wireless data transmission is limited to relatively low
speeds, 19.2 Kbps or less. Cellular display applications for data
are limited to text messaging through SMS or WAP. There is a
wide disparity between browser applications. Some simple
graphics can be accomplished with WAP applications on some
phones, whereas i-Mode in Japan offers extensive graphics
including color displays on PDC phones,* even though the
data rates are similar. As GPRS is launched on GSM networks,
users will finally be able to access data at speeds superior to
traditional dial-up Internet service, approaching 115 Kbps.
With the launch of next-generation cellular systems and 3G
systems, users will have greater choice for data communications.
New modems will be commercially available to take
advantage of higher bandwidth networks, and packet data will
replace circuit-switched data. Choices will include either SMS
or a wireless modem using packet data at higher speeds. New
high-speed data capabilities will provide the platform for
mobile multimedia services, access to corporate LANs, and
financial transactions from a mobile terminal. The type of service
will determine the best data service to use. Many applications
will find SMS satisfactory even if a modem is available for
high data-rate service. And those that must use analog cellular
will still have CDPD.
Other devices such as PDAs and Pocket PCs as shown in
Figure 2-1 may use cellular networks or proprietary networks.
(Some cellular manufacturers have integrated PDAs into their
phones.)
Some cellular-based products will bear little resemblance to
a cellular phone at all, such as PCMCIA modems that incorporate
a cellular phone without voice capabilities. In addition
to standard products, custom products will be available for
wireless remote data and control applications. Examples are
shown in Figure 2-2.