The Wireless Internet is not just wireless communications across
town or the country. It is also local—sometimes in a home or
office building. Wireless LANs are just becoming popular with
economically priced wireless Ethernet equipment. Standards
such as IEEE 802.11, HiperLAN2, and Home RF are leading the
way to untethered communications in-building or outside over
small areas. Another important development is the Personal Area
Network, also known as Bluetooth. Let’s take a look at each of
these to see how they further promote Wireless Internet sessions. 90
IT Certification CCIE,CCNP,CCIP,CCNA,CCSP,Cisco Network Optimization and Security Tips
OMNISKY
OmniSky’s Wireless Internet service uses the CDPD packetbased
network, encompassing over 172 million people. The
first service began in May 2000. Data rates are 19.2 Kbps and
users are offered a flat-rate monthly fee for unlimited service.
Much of Omnisky’s success can be attributed to the partners
it has chosen to work with: Palm, Handspring, HP, and
Compaq. However, Omnisky should be feeling the competition
when cellular begins next-generation service.
network, encompassing over 172 million people. The
first service began in May 2000. Data rates are 19.2 Kbps and
users are offered a flat-rate monthly fee for unlimited service.
Much of Omnisky’s success can be attributed to the partners
it has chosen to work with: Palm, Handspring, HP, and
Compaq. However, Omnisky should be feeling the competition
when cellular begins next-generation service.
MOBITEX OR RAM MOBILE DATA
Mobitex enjoys wide acceptance as a global standard for wireless
data networks. This technology was originally developed by
Swedish Telecom as a private network similar in purpose to the
Ardis network. The network became commercial in 1986. Since
then, many networks have been deployed in Europe, the United
States, and Australia. The frequency varies by country but the
United States and Canada mainly use 900 MHz. In the United
States, Mobitex is operated by RAM Mobile Data, a subsidiary of
Bell South. There are over 1,200 base stations installed nationwide
with service in more than 7,700 cities and towns, covering
approximately 93 percent of America’s urban business population.
Mobitex technology offers six distinguishing features that
other networks lack:
• Transparent, seamless roaming
• Store-and-forward
• Dependability (99.99 percent)
• Interoperability and connectivity options
• Capacity to support millions of subscribers
• Security second to none
Channels use 12.5 kHz bandwidth and support a data rate
of 8 Kbps. The network operates in the United States at 935
MHz to 940 MHz for the downlink (base to mobile) and 896
MHz to 901 MHz for the uplink (mobile to base).
data networks. This technology was originally developed by
Swedish Telecom as a private network similar in purpose to the
Ardis network. The network became commercial in 1986. Since
then, many networks have been deployed in Europe, the United
States, and Australia. The frequency varies by country but the
United States and Canada mainly use 900 MHz. In the United
States, Mobitex is operated by RAM Mobile Data, a subsidiary of
Bell South. There are over 1,200 base stations installed nationwide
with service in more than 7,700 cities and towns, covering
approximately 93 percent of America’s urban business population.
Mobitex technology offers six distinguishing features that
other networks lack:
• Transparent, seamless roaming
• Store-and-forward
• Dependability (99.99 percent)
• Interoperability and connectivity options
• Capacity to support millions of subscribers
• Security second to none
Channels use 12.5 kHz bandwidth and support a data rate
of 8 Kbps. The network operates in the United States at 935
MHz to 940 MHz for the downlink (base to mobile) and 896
MHz to 901 MHz for the uplink (mobile to base).
RICOCHET
Ricochet is the only wireless packet data network today that
was built from the ground up to handle high speed data, up to
128 Kbps. Modems are available from third-party sources that
allow connection to laptop computers by at least one Pocket
PC. The network has about 41,000 customers in 15 markets as
of July 2001 but the parent company, Metricom, has filed for
Chapter 11 in bankruptcy court, so anything could happen to
Ricochet. On August 8, 2001, Metricom ceased operations of
Ricochet but the company is negotiating with third parties to
buy the Ricochet network. If a third party can buy the network
at a really good price, then Ricochet may continue in some
form. As of the publishing of this book, the outcome is
unknown. The high costs of building out a nationwide network
far exceeded the revenue, and current economic conditions
make financing very difficult.
The Ricochet radio network utilizes several elements
including microcell radios and wired access points. This provides
true Wireless Internet access to information—regardless
of where it resides either on the Web or the intranet, in an
email message or a video clip.
In many ways the Ricochet network functions similarly to a
wireless Ethernet network. Acquisition is a necessary first step
for each radio on the network. The user radio, when first turned
on, must locate neighboring radios and Ricochet modems by
sending out synchronization packets. On acknowledgment from
neighboring radios, it must then get the authorization from the
name server. Only then does it join the network.
The network operates in two Industrial, Scientific, Medical
(ISM) bands of regulated, unlicensed spectrum, the 900 MHz
band and the 2.4 GHz band, in addition to the licensed 2.3
GHz Wireless Communications Systems (WCS) spectrum. The
physical layer uses Frequency Hopping Spread Spectrum
(FHSS) technology.
was built from the ground up to handle high speed data, up to
128 Kbps. Modems are available from third-party sources that
allow connection to laptop computers by at least one Pocket
PC. The network has about 41,000 customers in 15 markets as
of July 2001 but the parent company, Metricom, has filed for
Chapter 11 in bankruptcy court, so anything could happen to
Ricochet. On August 8, 2001, Metricom ceased operations of
Ricochet but the company is negotiating with third parties to
buy the Ricochet network. If a third party can buy the network
at a really good price, then Ricochet may continue in some
form. As of the publishing of this book, the outcome is
unknown. The high costs of building out a nationwide network
far exceeded the revenue, and current economic conditions
make financing very difficult.
The Ricochet radio network utilizes several elements
including microcell radios and wired access points. This provides
true Wireless Internet access to information—regardless
of where it resides either on the Web or the intranet, in an
email message or a video clip.
In many ways the Ricochet network functions similarly to a
wireless Ethernet network. Acquisition is a necessary first step
for each radio on the network. The user radio, when first turned
on, must locate neighboring radios and Ricochet modems by
sending out synchronization packets. On acknowledgment from
neighboring radios, it must then get the authorization from the
name server. Only then does it join the network.
The network operates in two Industrial, Scientific, Medical
(ISM) bands of regulated, unlicensed spectrum, the 900 MHz
band and the 2.4 GHz band, in addition to the licensed 2.3
GHz Wireless Communications Systems (WCS) spectrum. The
physical layer uses Frequency Hopping Spread Spectrum
(FHSS) technology.
ARDIS (DATATAC)
Advanced Radio Data Information Services (Ardis) sometimes
referred to as the DataTAC network, is a two-way radio service
that is based on Motorola’s RD-LAP technology. It was originally
created and jointly owned by Motorola and IBM to serve
IBM field technicians. Coverage includes about 90 percent of
the urban business population in the U.S with more than 400
metropolitan areas in the United States, Puerto Rico, and the
Virgin Islands.
The network is based on packet-data transfer using data
rates as high as 19.2 Kbps. Some areas may not offer rates as
high as 19.2 Kbps if they are not enhanced with RD-LAP.
Frequencies and protocols are proprietary to Motorola.
Modulation at the physical layer is Gaussian Frequency Shift
Keying (GFSK).
referred to as the DataTAC network, is a two-way radio service
that is based on Motorola’s RD-LAP technology. It was originally
created and jointly owned by Motorola and IBM to serve
IBM field technicians. Coverage includes about 90 percent of
the urban business population in the U.S with more than 400
metropolitan areas in the United States, Puerto Rico, and the
Virgin Islands.
The network is based on packet-data transfer using data
rates as high as 19.2 Kbps. Some areas may not offer rates as
high as 19.2 Kbps if they are not enhanced with RD-LAP.
Frequencies and protocols are proprietary to Motorola.
Modulation at the physical layer is Gaussian Frequency Shift
Keying (GFSK).
Subscribe to:
Posts (Atom)