In 1989, the cellular industry began the task of migrating cellular
from an analog technology to one of several digital technologies,
primarily to increase capacity in several cities that
were in danger of running out of voice capacity (as in New York
and Los Angeles). Data was not the overriding concern for the
standard bodies, and unfortunately, not every region adopted
the same migration path. This created a challenge to the network
designers working to maintain uniformity of operation.
The European community chose collectively to migrate
their existing networks to Global System for Mobile
Communications (GSM) for their first-generation digital networks.
Meanwhile North America chose to develop a digital
standard in two parts. The first was referred to as Interim
Standard-54 (IS-54) or North American Digital Cellular. This
standard, based on a version of Time Division Multiple Access
(TDMA), is similar to GSM but incompatible. IS-54 was
developed during the early 1990s and was soon followed with
IS-136. The difference between the two was that IS-54 continued
to use analog control channels and used both analog
and digital traffic channels. IS-136 contained both digital and
analog channels for control and traffic. IS-54 was not widely
popular because it lacked clear advantages to the user. The
promise of greater battery life with IS-136 alone was inducement
enough to win customers over even had it lacked other
advantages.
Having two different network architectures wasn’t too bad
but wait—there’s a new show in town. Here comes a company
out of San Diego that no one has ever heard of before, and
they claim to have a better solution to digital cellular. The
company was Qualcomm and the solution proposed was Code
Division Multiple Access (CDMA). Today, Europe still has
GSM and North America has TDMA, CDMA, and a little
GSM for variety. By 2001, GSM occupied about 65 percent of
the worldwide cellular market and CDMA held about 17 percent
market share.
As far as wireless data is concerned, we have only three
choices: CDPD on an analog channel, Short Message Service
(SMS) if it is available, or an internal modem in the phone or
device. Each choice has its pros and cons. Short Message
Service is just that—short—so speed is very important to the
user. The rate for CDPD is 19.2 Kbps, which is fine for certain
text applications, and because it is packet-based, valuable spectrum
is not wasted. The third option is a built-in modem in the
phone that connects to a laptop computer by either cable or
infrared. Speeds with an internal modem range from 8 Kbps to
9.6 Kbps. The data simply replaces the voice traffic transmitted
by the phone; the connection is circuit-switched, so spectrum
is wasted. None of these options is satisfactory for
real-time access to the Internet or streaming video. 43
IT Certification CCIE,CCNP,CCIP,CCNA,CCSP,Cisco Network Optimization and Security Tips
TRENDS IN NEXT-GENERATION MOBILE COMMUNICATIONS
Shortly after cellular first launched, third-party entrepreneurs
began offering modems for cellular data transmission. These
modems resemble the standard analog modems circa 1985.
They transmitted data at 300 baud, used a special cellular protocol
called MNP-10, and an AT command set. MNP-10 made
these modems different from regular modems because they
had to be fault-tolerant to cellular hand-offs and the in-band
signaling tones used in analog cellular. One such modem was
created by a Dallas, Texas company, Spectrum Cellular, that
actually consisted of a modem set or pair. The land or fixed side
modem was installed at the cellular switch. The mobile half
was connected to the mobile phone and computer. The connection
was circuit-switched, which meant that the phone was
connected as long as data was transmitted and the cellular traffic
channel was dedicated to that one user.
The next milestone for data over cellular was Cellular
Digital Packet Data (CDPD) in 1992. An industry consortium
of leading wireless communications companies set out to
develop the CDPD specification. Their design objectives were
to send digital data over the existing AMPS wireless infrastructure
without major changes to the AMPS infrastructure, with
reasonable performance (19.2 Kbps), high reliability, and security;
and to support seamless roaming. CDPD also had to coexist
with voice traffic. Because it was based on standard
Internet TCP/IP protocols, service providers that do not have
next-generation digital solutions for consumers today can still
use CDPD as an Internet connection. The CDPD market is
alive for the time being, but this may change as next-generation
networks become active.
began offering modems for cellular data transmission. These
modems resemble the standard analog modems circa 1985.
They transmitted data at 300 baud, used a special cellular protocol
called MNP-10, and an AT command set. MNP-10 made
these modems different from regular modems because they
had to be fault-tolerant to cellular hand-offs and the in-band
signaling tones used in analog cellular. One such modem was
created by a Dallas, Texas company, Spectrum Cellular, that
actually consisted of a modem set or pair. The land or fixed side
modem was installed at the cellular switch. The mobile half
was connected to the mobile phone and computer. The connection
was circuit-switched, which meant that the phone was
connected as long as data was transmitted and the cellular traffic
channel was dedicated to that one user.
The next milestone for data over cellular was Cellular
Digital Packet Data (CDPD) in 1992. An industry consortium
of leading wireless communications companies set out to
develop the CDPD specification. Their design objectives were
to send digital data over the existing AMPS wireless infrastructure
without major changes to the AMPS infrastructure, with
reasonable performance (19.2 Kbps), high reliability, and security;
and to support seamless roaming. CDPD also had to coexist
with voice traffic. Because it was based on standard
Internet TCP/IP protocols, service providers that do not have
next-generation digital solutions for consumers today can still
use CDPD as an Internet connection. The CDPD market is
alive for the time being, but this may change as next-generation
networks become active.
WIRELESS COMMUNICATIONS DEVICES
Today’s wireless communications devices are not your father’s
car phone of yesterday. Mobile telephones in the 1980s were big
and heavy. A phone’s weight was measured in pounds instead of
ounces. Those that were hand transportable were referred to as
“luggable.” They were limited to low resolution character display.
Cellular phones today are portable, hand-held devices
smaller in overall size than yesterday’s mobile phones. Personal
Digital Assistant (PDAs) are more closely related to a small
computer than a cellular phone. Some include a proprietary
radio frequency modem for wireless communications whereas
others simply connect to a cellular phone through a serial
cable, radio link, or infrared port.
Figure 1-4 is a picture of an older “portable,” large by today’s
standards. Yet the first portable or “luggable” device were many
times larger and heavier than today’s handhelds. One of the earliest
units was consisted of a full three-watt mobile like the ones
installed in car trunks, a phone handset almost the size of a
home phone and a twelve-pound nickel-cadmium battery. The
whole unit was mounted in a heavy-duty transportation briefcase
and tipped the scales at forty-five pounds!
Figure 1-5 shows several manufacturers’ wireless PDAs and
Pocket PCs while Figure 1-6 illustrates some manufacturers’
current models of handheld cellular phones.
Tomorrow will bring many new wireless devices that communicate
over commercial cellular or within their own
assigned frequency bands. An example might be a smart or
Internet appliance that communicates warranty information to
the manufacturer or requests service. This will all be done over
the Internet, with a message returned to the end user to notify
him that the appliance has reported a malfunction and will
require service or that a software upgrade was completed and
no further action needs to be taken.
No matter what the end application, two things are rather
clear:
1. Any information presented across the Internet to or from
wireless devices will be limited by network bandwidth and
the display capabilities of the terminal device. To the end
user, bandwidth is the quantity of information transmitted
per second. In the wireless world, this is limited by the size
and efficient use of spectrum. A wireless device will not
display all of the information that a traditional Web site
may contain. Either some type of filtering will be applied to
convert Web site content to a suitable size, or other user
interfaces will be developed—such as text-to-voice translation
or a dedicated wireless Web site.
2. The projected number of personal computers connected to
the Internet will be exceeded by the number of Webenabled handsets by about 2003, see Figure 1-7 (600 million
wireless Internet users: source Dataquest).
car phone of yesterday. Mobile telephones in the 1980s were big
and heavy. A phone’s weight was measured in pounds instead of
ounces. Those that were hand transportable were referred to as
“luggable.” They were limited to low resolution character display.
Cellular phones today are portable, hand-held devices
smaller in overall size than yesterday’s mobile phones. Personal
Digital Assistant (PDAs) are more closely related to a small
computer than a cellular phone. Some include a proprietary
radio frequency modem for wireless communications whereas
others simply connect to a cellular phone through a serial
cable, radio link, or infrared port.
Figure 1-4 is a picture of an older “portable,” large by today’s
standards. Yet the first portable or “luggable” device were many
times larger and heavier than today’s handhelds. One of the earliest
units was consisted of a full three-watt mobile like the ones
installed in car trunks, a phone handset almost the size of a
home phone and a twelve-pound nickel-cadmium battery. The
whole unit was mounted in a heavy-duty transportation briefcase
and tipped the scales at forty-five pounds!
Figure 1-5 shows several manufacturers’ wireless PDAs and
Pocket PCs while Figure 1-6 illustrates some manufacturers’
current models of handheld cellular phones.
Tomorrow will bring many new wireless devices that communicate
over commercial cellular or within their own
assigned frequency bands. An example might be a smart or
Internet appliance that communicates warranty information to
the manufacturer or requests service. This will all be done over
the Internet, with a message returned to the end user to notify
him that the appliance has reported a malfunction and will
require service or that a software upgrade was completed and
no further action needs to be taken.
No matter what the end application, two things are rather
clear:
1. Any information presented across the Internet to or from
wireless devices will be limited by network bandwidth and
the display capabilities of the terminal device. To the end
user, bandwidth is the quantity of information transmitted
per second. In the wireless world, this is limited by the size
and efficient use of spectrum. A wireless device will not
display all of the information that a traditional Web site
may contain. Either some type of filtering will be applied to
convert Web site content to a suitable size, or other user
interfaces will be developed—such as text-to-voice translation
or a dedicated wireless Web site.
2. The projected number of personal computers connected to
the Internet will be exceeded by the number of Webenabled handsets by about 2003, see Figure 1-7 (600 million
wireless Internet users: source Dataquest).
WIRELESS COMMUNICATIONS DEVICES
Today’s wireless communications devices are not your father’s
car phone of yesterday. Mobile telephones in the 1980s were big
and heavy. A phone’s weight was measured in pounds instead of
ounces. Those that were hand transportable were referred to as
“luggable.” They were limited to low resolution character display.
Cellular phones today are portable, hand-held devices
smaller in overall size than yesterday’s mobile phones. Personal
Digital Assistant (PDAs) are more closely related to a small
computer than a cellular phone. Some include a proprietary
radio frequency modem for wireless communications whereas
others simply connect to a cellular phone through a serial
cable, radio link, or infrared port.
Figure 1-4 is a picture of an older “portable,” large by today’s
standards. Yet the first portable or “luggable” device were many
times larger and heavier than today’s handhelds. One of the earliest
units was consisted of a full three-watt mobile like the ones
installed in car trunks, a phone handset almost the size of a
home phone and a twelve-pound nickel-cadmium battery. The
whole unit was mounted in a heavy-duty transportation briefcase
and tipped the scales at forty-five pounds!
Figure 1-5 shows several manufacturers’ wireless PDAs and
Pocket PCs while Figure 1-6 illustrates some manufacturers’
current models of handheld cellular phones.
Tomorrow will bring many new wireless devices that communicate
over commercial cellular or within their own
assigned frequency bands. An example might be a smart or
Internet appliance that communicates warranty information to
the manufacturer or requests service. This will all be done over
the Internet, with a message returned to the end user to notify
him that the appliance has reported a malfunction and will
require service or that a software upgrade was completed and
no further action needs to be taken.
No matter what the end application, two things are rather
clear:
1. Any information presented across the Internet to or from
wireless devices will be limited by network bandwidth and
the display capabilities of the terminal device. To the end
user, bandwidth is the quantity of information transmitted
per second. In the wireless world, this is limited by the size
and efficient use of spectrum. A wireless device will not
display all of the information that a traditional Web site
may contain. Either some type of filtering will be applied to
convert Web site content to a suitable size, or other user
interfaces will be developed—such as text-to-voice translation
or a dedicated wireless Web site.
2. The projected number of personal computers connected to
the Internet will be exceeded by the number of Webenabled handsets by about 2003, see Figure 1-7 (600 million
wireless Internet users: source Dataquest).
car phone of yesterday. Mobile telephones in the 1980s were big
and heavy. A phone’s weight was measured in pounds instead of
ounces. Those that were hand transportable were referred to as
“luggable.” They were limited to low resolution character display.
Cellular phones today are portable, hand-held devices
smaller in overall size than yesterday’s mobile phones. Personal
Digital Assistant (PDAs) are more closely related to a small
computer than a cellular phone. Some include a proprietary
radio frequency modem for wireless communications whereas
others simply connect to a cellular phone through a serial
cable, radio link, or infrared port.
Figure 1-4 is a picture of an older “portable,” large by today’s
standards. Yet the first portable or “luggable” device were many
times larger and heavier than today’s handhelds. One of the earliest
units was consisted of a full three-watt mobile like the ones
installed in car trunks, a phone handset almost the size of a
home phone and a twelve-pound nickel-cadmium battery. The
whole unit was mounted in a heavy-duty transportation briefcase
and tipped the scales at forty-five pounds!
Figure 1-5 shows several manufacturers’ wireless PDAs and
Pocket PCs while Figure 1-6 illustrates some manufacturers’
current models of handheld cellular phones.
Tomorrow will bring many new wireless devices that communicate
over commercial cellular or within their own
assigned frequency bands. An example might be a smart or
Internet appliance that communicates warranty information to
the manufacturer or requests service. This will all be done over
the Internet, with a message returned to the end user to notify
him that the appliance has reported a malfunction and will
require service or that a software upgrade was completed and
no further action needs to be taken.
No matter what the end application, two things are rather
clear:
1. Any information presented across the Internet to or from
wireless devices will be limited by network bandwidth and
the display capabilities of the terminal device. To the end
user, bandwidth is the quantity of information transmitted
per second. In the wireless world, this is limited by the size
and efficient use of spectrum. A wireless device will not
display all of the information that a traditional Web site
may contain. Either some type of filtering will be applied to
convert Web site content to a suitable size, or other user
interfaces will be developed—such as text-to-voice translation
or a dedicated wireless Web site.
2. The projected number of personal computers connected to
the Internet will be exceeded by the number of Webenabled handsets by about 2003, see Figure 1-7 (600 million
wireless Internet users: source Dataquest).
WIRELESS COMMUNICATIONS DEVICES
Today’s wireless communications devices are not your father’s
car phone of yesterday. Mobile telephones in the 1980s were big
and heavy. A phone’s weight was measured in pounds instead of
ounces. Those that were hand transportable were referred to as
“luggable.” They were limited to low resolution character display.
Cellular phones today are portable, hand-held devices
smaller in overall size than yesterday’s mobile phones. Personal
Digital Assistant (PDAs) are more closely related to a small
computer than a cellular phone. Some include a proprietary
radio frequency modem for wireless communications whereas
others simply connect to a cellular phone through a serial
cable, radio link, or infrared port.
Figure 1-4 is a picture of an older “portable,” large by today’s
standards. Yet the first portable or “luggable” device were many
times larger and heavier than today’s handhelds. One of the earliest
units was consisted of a full three-watt mobile like the ones
installed in car trunks, a phone handset almost the size of a
home phone and a twelve-pound nickel-cadmium battery. The
whole unit was mounted in a heavy-duty transportation briefcase
and tipped the scales at forty-five pounds!
Figure 1-5 shows several manufacturers’ wireless PDAs and
Pocket PCs while Figure 1-6 illustrates some manufacturers’
current models of handheld cellular phones.
Tomorrow will bring many new wireless devices that communicate
over commercial cellular or within their own
assigned frequency bands. An example might be a smart or
Internet appliance that communicates warranty information to
the manufacturer or requests service. This will all be done over
the Internet, with a message returned to the end user to notify
him that the appliance has reported a malfunction and will
require service or that a software upgrade was completed and
no further action needs to be taken.
No matter what the end application, two things are rather
clear:
1. Any information presented across the Internet to or from
wireless devices will be limited by network bandwidth and
the display capabilities of the terminal device. To the end
user, bandwidth is the quantity of information transmitted
per second. In the wireless world, this is limited by the size
and efficient use of spectrum. A wireless device will not
display all of the information that a traditional Web site
may contain. Either some type of filtering will be applied to
convert Web site content to a suitable size, or other user
interfaces will be developed—such as text-to-voice translation
or a dedicated wireless Web site.
2. The projected number of personal computers connected to
the Internet will be exceeded by the number of Webenabled handsets by about 2003, see Figure 1-7 (600 million
wireless Internet users: source Dataquest).
car phone of yesterday. Mobile telephones in the 1980s were big
and heavy. A phone’s weight was measured in pounds instead of
ounces. Those that were hand transportable were referred to as
“luggable.” They were limited to low resolution character display.
Cellular phones today are portable, hand-held devices
smaller in overall size than yesterday’s mobile phones. Personal
Digital Assistant (PDAs) are more closely related to a small
computer than a cellular phone. Some include a proprietary
radio frequency modem for wireless communications whereas
others simply connect to a cellular phone through a serial
cable, radio link, or infrared port.
Figure 1-4 is a picture of an older “portable,” large by today’s
standards. Yet the first portable or “luggable” device were many
times larger and heavier than today’s handhelds. One of the earliest
units was consisted of a full three-watt mobile like the ones
installed in car trunks, a phone handset almost the size of a
home phone and a twelve-pound nickel-cadmium battery. The
whole unit was mounted in a heavy-duty transportation briefcase
and tipped the scales at forty-five pounds!
Figure 1-5 shows several manufacturers’ wireless PDAs and
Pocket PCs while Figure 1-6 illustrates some manufacturers’
current models of handheld cellular phones.
Tomorrow will bring many new wireless devices that communicate
over commercial cellular or within their own
assigned frequency bands. An example might be a smart or
Internet appliance that communicates warranty information to
the manufacturer or requests service. This will all be done over
the Internet, with a message returned to the end user to notify
him that the appliance has reported a malfunction and will
require service or that a software upgrade was completed and
no further action needs to be taken.
No matter what the end application, two things are rather
clear:
1. Any information presented across the Internet to or from
wireless devices will be limited by network bandwidth and
the display capabilities of the terminal device. To the end
user, bandwidth is the quantity of information transmitted
per second. In the wireless world, this is limited by the size
and efficient use of spectrum. A wireless device will not
display all of the information that a traditional Web site
may contain. Either some type of filtering will be applied to
convert Web site content to a suitable size, or other user
interfaces will be developed—such as text-to-voice translation
or a dedicated wireless Web site.
2. The projected number of personal computers connected to
the Internet will be exceeded by the number of Webenabled handsets by about 2003, see Figure 1-7 (600 million
wireless Internet users: source Dataquest).
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