Mobile Computing Networks
Note: If you came to our site looking for information on
hardware components for designing your wireless networks (e.g. radio antennas,
RF wireless circuits, components, etc), we are sorry we do not carry this information. Please go to Wireless Design and Development Online site.
for this type of information.
There are a number of ways of providing connectivity to
mobile workers, telecommuters and remote workers. Following types of networks are
the most common methods of mobile connectivity:
Temporary or Switched Connection via Wireline WAN
Permanent connection between a mobile user and information
source is not only expensive but is not always practical because mobile users are
constantly on the move. Therefore, the ">most popular (though not most ubiquitous or
pervasive or persistent - using the new lingo) method of providing connectivity to mobile
workers continues to be one of a temporary wireline connection for a specific use and a
required period of time. This can be achieved by using a dial-up connection on a
traditional public telephone or cellular network. You call it switched because you
switch a circuit from one user to another user for the duration of the call. You
may have a switched wireline connection directly between a remote location where the user
is at a given moment and the information server or indirectly through the Internet. In
either case, you still need to locate a telephone jack of one kind or another. Go to
PSTN, ISDN, ADSL, or VPNs (Internet based Virtual Private Networks) for further information on these
temporary connections for mobile workers.
Wireless PANs (Personal Area Networks)
These are wireless networks that can be installed in a small
office or home within 5-15 metre distances. Two technologies being used for this purpose
are IrDA which is based on line of sight requirement within two devices, usually a few
feet apart. For more details on IrDA, please go to IrDA site.
The second technology is Blue Tooth. Blue tooth technology supports multipoint
connection without line of sight requirement. Go to Blue Tooth topic under "Hot
Topic" menu item on our site's home page.
Where the movement is within a contained geographical area,
you can provide mobility by implementing a wireless LAN and equipping your mobile device
with a corresponding wireless adapter - a PC card variety that goes into a notebook,
hand-held PDA, a Windows CE-compatible device or Palm Pilot organizer. Go to Wireless LANs page for more info.
Wireless MAN (Metropolitan Area Network)
Metricom's Ricochet, a specialized wireless network is available at 128 kbps,
24 hours 7 days always on, in the following major metropolitan areas: Atlanta, Baltimore, Dallas, Denver, Detroit,
Houston, Los Angeles, Minneapolis St. Paul, New York City, Philadelphia, Phoenix, San Francisco Bay Area and San Diego and 15 airports
nationwide. These areas join the Washington DC and Seattle 28.8 kbps service areas. The service is offered through
WWC, Worldcom, Earthlink, GoAmerica and Juno for $79.95/month and under. " (circa Spring 2001).
Go to Metricom
network description on this site for more.
Wireless WAN - Private or Public
Once we move out of the limited geography of a wireless LAN
in a campus or factory setting, we have to utilize wide area wireless network. These
networks may be private or public. Large organizations, such as Fedex or public safety
agencies, have implemented private CDPD or SMR networks to give wireless connectivity to
courier drivers and police officers. However, the current trend is to move towards
shared public networks, such as Motient or BellSouth (ex RAM Mobile Data - called Mobitex in
Europe and Canada). Go to wireless WANs for more
Even wireless wide area networks may not provide coverage in
extremely remote areas, because networks can not justify the economics of installing a
base station everywhere. True universal coverage for these types of mobile users is
possible only through wireless networks based on satellites. There are several GEOS,
LEOS, and MEOS satellite-based networks that transmit from different heights from the
surface of the earth. Refer to these terms in the glossary.
The Last Mile Problem for Wireless Networks
One thing worth noting is that it is only the last mile (or
so!) where we need wireless or radio-frequency-based connection. Once we reach a
terrestrial network, we can utilize the bandwidth of traditional wireline permanent
connections. By the same token, once we reach the Internet Service Provider through
a wireless hub or concentrator, we can be home free for riding high-speed connection to
the universal information highway.
Emerging Wireless Networks