Many digital phones are advertised as Internet-ready, coming
with a browser or a connectivity kit. Advertising for Wireless
Internet modems or Internet-ready phones can be very deceiving,
however. If the ad mentions a data rate of 19.2 Kbps, then
it’s CDPD. The phone may be CDMA or TDMA but the data
connection is through either an internal or external CDPD
modem connected to an analog channel. If a TDMA or CDMA
phone has a data connectivity kit, such as a cable to connect
the phone and a laptop, and it does not mention the data rate,
or if the phone has an internal browser, the modem is integrated
into the phone and probably uses the rate of the traffic
channel, 8 Kbps for TDMA and 9.6 or 14.4 Kbps for CDMA.
GSM phones have long used data capabilities built into the
phones so that they connect to a laptop by cable or include
built-in modems to send data in the traffic channel at 9.6
Kbps. In all of these cases except CDPD, the connection is still
circuit-switched for 2G networks.
A second type of modem is essentially a phone without
voice capabilities on a PCMCIA card. There are modems of
this type for every technology. They have an antenna integrated
into them or are connected by a short cable to an antenna.
Again, if the data rate is specified as 19.2 Kbps, it’s CDPD. If
the rate is not specified, it’s probably using a traffic channel.
Some PCMCIA modems offer a data rate of 56 Kbps and mention
wireless in the same sentence. These actually combine two
modems in one: a 56K landline modem and a wireless traffic
channel modem.
With the launch of 2.5G and 3G networks, modems will
become available having much higher data rates. They will fall
into the same two categories: internal to a phone with a cable
connection to a laptop or as a PCMCIA card. GPRS technology
is just being launched in Europe but as with all new technologies,
GPRS modems are still scarce. The United States will see next
generation modems for CDMA and TDMA phones by 2002. The
CDMA phones will use 1xRTT technology, and the TDMA
phones will use GPRS. The CDMA standard 1xEV, with data
rates up to 2.4 Mbps, will not be available until later. Products for
W-CDMA will become available later in 2002 or 2003. 65
IT Certification CCIE,CCNP,CCIP,CCNA,CCSP,Cisco Network Optimization and Security Tips
CDPD MODEMS
Early cellular manufacturers and operators recognized the
need for data communications, and the first modems were very
similar to standard modems used in homes and offices.
However, cellular uses a valuable, shared commodity—spectrum.
(Fixed telephone lines or wires may be shared, but they
can always be increased in number if necessary.) CDPD was
created as a digital packet data service over an analog cellular
telephone: It uses the same analog channels as voice, but with
different modulation applied to the air interface. Traffic channels
not being used for voice calls may be used for CDPD calls.
CDPD was the first digital data application to use packet data
for cellular, and it is still very much in use today by carriers
such as AT&T Wireless Services.
CDPD is fully compatible with analog cellular and is colocated
with AMPS systems. Therefore, the analog infrastructure,
such as frequency spectrum, cell sites, towers, and antennas,
can be shared. The CDPD network elements overlay parallel to
the analog infrastructure (see Figure 2-3). Analog voice or analog
data using an AMPS modem or digital data using a CDPD
modem shares the same frequency spectrum. External modems
are most common for CDPD communications, typically existing
as PCMCIA cards for laptop computers, as accessories for PDA
devices, or as external modems for connection to an analog
phone. Some manufacturers actually include CDPD modems
into their cellular telephone. This makes a 2G digital phone
“Internet ready” because all TDMA and CDMA phones also
include AMPS analog compatibility, and CDPD is carried on
AMPS channels.
Two key design criteria were used to develop the CDPD
protocol. From its inception, it was designed to use TCP/IP, the
Internet protocol, making it transparent to Internet data. It was
also designed to overlay an AMPS network, taking advantage of
existing infrastructure. These design goals make CDPD very
attractive to any carrier that manages an AMPS network. This
becomes even more important when a carrier lacks true 2.5G
or 3G capabilities and finds itself at a competitive disadvantage.
CDPD can make any TDMA or CDMA phone “Internet
ready” with 19.2 Kbps data rates by using TCP/IP in a packetdata
network instead of on a circuit-switched connection.
As of the end of the February 2000, CDPD was available in
184 markets in the United States covering 56 percent of the
United States population and 60 international markets.* As
2.5G and 3G cellular networks launch, CDPD will begin to
fade, but as long as there are 2G or analog phones, CDPD will
retain its usefulness. And although it may compete with SMS
for short text messages, it still has one advantage—CDPD
works across networks with different physical layers. A CDPD
modem in a laptop using CDMA can still send an email to a
phone across the country, which is using TDMA.
need for data communications, and the first modems were very
similar to standard modems used in homes and offices.
However, cellular uses a valuable, shared commodity—spectrum.
(Fixed telephone lines or wires may be shared, but they
can always be increased in number if necessary.) CDPD was
created as a digital packet data service over an analog cellular
telephone: It uses the same analog channels as voice, but with
different modulation applied to the air interface. Traffic channels
not being used for voice calls may be used for CDPD calls.
CDPD was the first digital data application to use packet data
for cellular, and it is still very much in use today by carriers
such as AT&T Wireless Services.
CDPD is fully compatible with analog cellular and is colocated
with AMPS systems. Therefore, the analog infrastructure,
such as frequency spectrum, cell sites, towers, and antennas,
can be shared. The CDPD network elements overlay parallel to
the analog infrastructure (see Figure 2-3). Analog voice or analog
data using an AMPS modem or digital data using a CDPD
modem shares the same frequency spectrum. External modems
are most common for CDPD communications, typically existing
as PCMCIA cards for laptop computers, as accessories for PDA
devices, or as external modems for connection to an analog
phone. Some manufacturers actually include CDPD modems
into their cellular telephone. This makes a 2G digital phone
“Internet ready” because all TDMA and CDMA phones also
include AMPS analog compatibility, and CDPD is carried on
AMPS channels.
Two key design criteria were used to develop the CDPD
protocol. From its inception, it was designed to use TCP/IP, the
Internet protocol, making it transparent to Internet data. It was
also designed to overlay an AMPS network, taking advantage of
existing infrastructure. These design goals make CDPD very
attractive to any carrier that manages an AMPS network. This
becomes even more important when a carrier lacks true 2.5G
or 3G capabilities and finds itself at a competitive disadvantage.
CDPD can make any TDMA or CDMA phone “Internet
ready” with 19.2 Kbps data rates by using TCP/IP in a packetdata
network instead of on a circuit-switched connection.
As of the end of the February 2000, CDPD was available in
184 markets in the United States covering 56 percent of the
United States population and 60 international markets.* As
2.5G and 3G cellular networks launch, CDPD will begin to
fade, but as long as there are 2G or analog phones, CDPD will
retain its usefulness. And although it may compete with SMS
for short text messages, it still has one advantage—CDPD
works across networks with different physical layers. A CDPD
modem in a laptop using CDMA can still send an email to a
phone across the country, which is using TDMA.
CELLULAR DATA MODEM TECHNOLOGIES
Today’s cellular technology offers several different methods for
data communications—an internal modem with built-in browser,
an internal modem with an external port for connection (typically
RS-232 or infrared (IR) to computer, or internal SMS
messaging.
Modems fall into two categories: CDPD or traffic channel.
CDPD offers true packet data communications at 19.2 Kbps
whereas modems using the traffic channels are limited to the
maximum rate for a traffic channel ( 14.4 Kbps, depending on
the standard). Future 2.5G and 3G networks will differ in two
distinct ways: Traffic channel rates will be higher, from 64
Kbps to 2.4 Mbps, and all data will be either packet-based or
high speed circuit-switched.
data communications—an internal modem with built-in browser,
an internal modem with an external port for connection (typically
RS-232 or infrared (IR) to computer, or internal SMS
messaging.
Modems fall into two categories: CDPD or traffic channel.
CDPD offers true packet data communications at 19.2 Kbps
whereas modems using the traffic channels are limited to the
maximum rate for a traffic channel ( 14.4 Kbps, depending on
the standard). Future 2.5G and 3G networks will differ in two
distinct ways: Traffic channel rates will be higher, from 64
Kbps to 2.4 Mbps, and all data will be either packet-based or
high speed circuit-switched.
CELLULAR AND PCS-BASED TECHNOLOGIES
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.
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.
DRIVING TECHNOLOGIES: COMPETING AND COMPLEMENTARY
Numerous technologies fuel Wireless Internet development,
some associated with the terminals and some with the network
infrastructure equipment. Many of these diverse technologies
are related by the wireless access method used,
whether it’s GPRS or CDPD for example. We cover technologies
related to terminal devices and network infrastructure in
this chapter:
• Access technologies
• Application protocols and languages
• IP network design and equipment
Many technologies are used on multiple platforms, so
applications must be device independent to be successful.
Applications cannot be customized for a dozen different protocols
or operating systems. If a Wireless Internet application is
to be truly mobile, it must also function ubiquitously as the
user moves from one location to another. This requires IP
mobility over multiple access methods. Cellular users should
be able to go indoors and on to a WLAN seamlessly. Therefore,
wireless LANs should not compete with cellular or PDA wireless
access, rather they should complement or extend its usefulness.
Some of the leading WLAN technologies also will be
discussed.
some associated with the terminals and some with the network
infrastructure equipment. Many of these diverse technologies
are related by the wireless access method used,
whether it’s GPRS or CDPD for example. We cover technologies
related to terminal devices and network infrastructure in
this chapter:
• Access technologies
• Application protocols and languages
• IP network design and equipment
Many technologies are used on multiple platforms, so
applications must be device independent to be successful.
Applications cannot be customized for a dozen different protocols
or operating systems. If a Wireless Internet application is
to be truly mobile, it must also function ubiquitously as the
user moves from one location to another. This requires IP
mobility over multiple access methods. Cellular users should
be able to go indoors and on to a WLAN seamlessly. Therefore,
wireless LANs should not compete with cellular or PDA wireless
access, rather they should complement or extend its usefulness.
Some of the leading WLAN technologies also will be
discussed.
SOFT SWITCHES AND MEDIA GATEWAYS.
Soft switches are
poised to replace the call processing functions of the Class 4 and
5 switches previously used by the telecommunications industry.
This new breed of switch is smaller, less expensive, less power
consuming, more reliable, more flexible, and more efficient than
its predecessors. A soft switch can be placed in a closet, whereas
the equivalent Class 5 switch functionality would fill a building
to achieve the same capacity. The proliferation of control
protocols makes soft switches the ideal solution for today’s market.
Because soft switches derive their name from the “soft” in
software, they can support many protocols at once.
By utilizing soft-switch technology along with a media gateway,
a simplified network architecture could be developed (see
Figure 1-12). A single core switching product is needed to support
both voice and data for 2G, 3G, and future all-IP networks.
The support for all three generations of networks is still a
requirement but the interfaces are much simpler.
The solution may be based on state-of-the art, high density,
scalable, soft-switch technology and utilize a multimedia
session initiation protocol (SIP) session manager as the basic
building block for services. This architecture is all-IP ready
and fully compatible with 2G, 2.5G, and 3G voice and data
specifications. It could support present operator needs yet
allow for seamless evolution to future technologies.
A soft-switch/media gateway product developed by Spatial
Wireless in shown in Figure 1-13. This product is designed for
next generation markets—packet-based core switching for the
GSM, CDMA, UMTS and All-IP wireless markets. These elements
enable unique voice/data converged services, help maintain
service transparency across different wireless generations,
and can result in more than 50 percent savings in capital and
operational expenditures. The Spatial’s Portico product is an
overlay gateway product that supports the introduction of
voice, data and converged services.
As we have seen in this overview of the history of modern communications,
competing standards and protocols both drive
and hinder the development of a truly ubiquitous Wireless
Internet. Chapter 2 explores the evolution of these technologies
in greater depth.
poised to replace the call processing functions of the Class 4 and
5 switches previously used by the telecommunications industry.
This new breed of switch is smaller, less expensive, less power
consuming, more reliable, more flexible, and more efficient than
its predecessors. A soft switch can be placed in a closet, whereas
the equivalent Class 5 switch functionality would fill a building
to achieve the same capacity. The proliferation of control
protocols makes soft switches the ideal solution for today’s market.
Because soft switches derive their name from the “soft” in
software, they can support many protocols at once.
By utilizing soft-switch technology along with a media gateway,
a simplified network architecture could be developed (see
Figure 1-12). A single core switching product is needed to support
both voice and data for 2G, 3G, and future all-IP networks.
The support for all three generations of networks is still a
requirement but the interfaces are much simpler.
The solution may be based on state-of-the art, high density,
scalable, soft-switch technology and utilize a multimedia
session initiation protocol (SIP) session manager as the basic
building block for services. This architecture is all-IP ready
and fully compatible with 2G, 2.5G, and 3G voice and data
specifications. It could support present operator needs yet
allow for seamless evolution to future technologies.
A soft-switch/media gateway product developed by Spatial
Wireless in shown in Figure 1-13. This product is designed for
next generation markets—packet-based core switching for the
GSM, CDMA, UMTS and All-IP wireless markets. These elements
enable unique voice/data converged services, help maintain
service transparency across different wireless generations,
and can result in more than 50 percent savings in capital and
operational expenditures. The Spatial’s Portico product is an
overlay gateway product that supports the introduction of
voice, data and converged services.
As we have seen in this overview of the history of modern communications,
competing standards and protocols both drive
and hinder the development of a truly ubiquitous Wireless
Internet. Chapter 2 explores the evolution of these technologies
in greater depth.
WIRELESS OPERATOR CHALLENGES.
The core switching network
elements found in current wireless networks are called
Mobile Switching Centers (MSC). In most cases, MSCs were
created by adding wireless-specific interfaces and mobility
management functions to existing circuit-switched Class 5 or
Class 4 switches. As a result, the incumbent MSC vendors are
also traditional switch vendors, such as Ericsson, Nortel,
Siemens, Nokia, Lucent, and Alcatel.
Because of the tremendous growth in the number of wireless
subscribers and their minutes of use, wireless carriers are continually
adding additional capacity to their voice networks. At the
same time, to provide data services, new elements (SGSN,
GGSN, etc.) are also being added to the network. Furthermore,
the evolution of wireless networks to 3G and packet networking—
and thereafter to all-IP networks—is leading to the addition
of more core switching network elements. The end result is
a very complex core network, as depicted in Figure 1-11.
Next generation networks will be comprised of really three
types—2, 2.5G, and 3G networks. Each network adds features
and therefore requires different interfaces. Compound this
with support for circuit switched and packet switched and you
have a major headache to connect.
This “patchwork” approach leads to duplicity of functional
blocks and unnecessary capital expense (CAPEX) and operation
expense (OPEX) costs for the operator. Furthermore, the
service logic of voice and data and 2G and 3G remain disparate;
this results in slow roll-out of new services. Separate
service logic for voice and data also makes it nearly impossible
to deliver hybrid multimedia services that require voice–data
service integration.
Incumbent core network vendors are not addressing adequately
the migration to 3G networks because all their 2G
products (as well as some of their 3G products) are still based
on old, highly proprietary platforms and their approach to
adding new functionality is evolutionary rather than revolutionary.
New products are needed to simplify and streamline the network.
A cohesive technology is required to build the next generation,
packet-based, unified core switching platform that will
satisfy all the voice and data core switching needs of the wireless
operator. This new network architecture will lead them to
profitability by significantly reducing OPEX and CAPEX and
enabling rapid deployment of unique new services.
elements found in current wireless networks are called
Mobile Switching Centers (MSC). In most cases, MSCs were
created by adding wireless-specific interfaces and mobility
management functions to existing circuit-switched Class 5 or
Class 4 switches. As a result, the incumbent MSC vendors are
also traditional switch vendors, such as Ericsson, Nortel,
Siemens, Nokia, Lucent, and Alcatel.
Because of the tremendous growth in the number of wireless
subscribers and their minutes of use, wireless carriers are continually
adding additional capacity to their voice networks. At the
same time, to provide data services, new elements (SGSN,
GGSN, etc.) are also being added to the network. Furthermore,
the evolution of wireless networks to 3G and packet networking—
and thereafter to all-IP networks—is leading to the addition
of more core switching network elements. The end result is
a very complex core network, as depicted in Figure 1-11.
Next generation networks will be comprised of really three
types—2, 2.5G, and 3G networks. Each network adds features
and therefore requires different interfaces. Compound this
with support for circuit switched and packet switched and you
have a major headache to connect.
This “patchwork” approach leads to duplicity of functional
blocks and unnecessary capital expense (CAPEX) and operation
expense (OPEX) costs for the operator. Furthermore, the
service logic of voice and data and 2G and 3G remain disparate;
this results in slow roll-out of new services. Separate
service logic for voice and data also makes it nearly impossible
to deliver hybrid multimedia services that require voice–data
service integration.
Incumbent core network vendors are not addressing adequately
the migration to 3G networks because all their 2G
products (as well as some of their 3G products) are still based
on old, highly proprietary platforms and their approach to
adding new functionality is evolutionary rather than revolutionary.
New products are needed to simplify and streamline the network.
A cohesive technology is required to build the next generation,
packet-based, unified core switching platform that will
satisfy all the voice and data core switching needs of the wireless
operator. This new network architecture will lead them to
profitability by significantly reducing OPEX and CAPEX and
enabling rapid deployment of unique new services.
NETWORK SWITCH REQUIREMENTS
Wireless operators are experiencing a rapid decline in their
average revenue per user (ARPU). Strong competition has generated
a need for differentiation in operator service offerings.
The advent of the Internet has created a tremendous new
and exciting business opportunity for wireless operators.
Operators are rushing to upgrade their networks with new
packet-based technologies that will allow them to offer innovative
wireless data services to their subscribers. This has triggered
an immense demand for highly scalable, low-cost, easily
maintainable, packet-based, unified, voice and data wireless
core switching products.
Wireless subscribers are far more sophisticated users today
than they were five years ago. They are no longer satisfied with
just placing a call; they require innovative ways to use the wireless
phone. New applications for enhanced services are very
important to wireless customers. Features such as Caller ID
and voice messaging are considered standard. New services
and features will become important differentiators in a competitive
service-provider market.
To provide these new services and features for the wireless
Internet, present-day equipment must give way to new technology.
New application protocols must be implemented to
work with packet networks.
average revenue per user (ARPU). Strong competition has generated
a need for differentiation in operator service offerings.
The advent of the Internet has created a tremendous new
and exciting business opportunity for wireless operators.
Operators are rushing to upgrade their networks with new
packet-based technologies that will allow them to offer innovative
wireless data services to their subscribers. This has triggered
an immense demand for highly scalable, low-cost, easily
maintainable, packet-based, unified, voice and data wireless
core switching products.
Wireless subscribers are far more sophisticated users today
than they were five years ago. They are no longer satisfied with
just placing a call; they require innovative ways to use the wireless
phone. New applications for enhanced services are very
important to wireless customers. Features such as Caller ID
and voice messaging are considered standard. New services
and features will become important differentiators in a competitive
service-provider market.
To provide these new services and features for the wireless
Internet, present-day equipment must give way to new technology.
New application protocols must be implemented to
work with packet networks.
SERVICE PROVISIONING
The whole concept of service provisioning for packet networks
and IP billing requires new technology to meet the needs of
service providers and customers. Initially, these new technologies
augmented those of circuit-switched equipment and later
supplanted them. Telecommunications based on Internet
Protocol (IP) allow carriers to create grades of service and variable
pricing to reflect real market conditions.
Currently, data from switches is formatted into billable
event detail records through a mediation function. The big difference
between the circuit-switched and the IP network is
that IP billing must handle many more variables. Just as circuit-
switched billing is derived from call detail records
(CDRs), IP-based billing is derived from Internet usage
records (IURs). However, IURs must contain far greater information.
Future bills will include usage-based billing based on
IP information.
Customers can receive value-added information and services
with real-time billing. Provisioning of services can take place
online for wireless users, satisfying the customer who wants
added services. It also benefits the service provider by adding
incremental revenue for a given customer and by providing
more accurate and timely billing.
To implement IP billing, however, techniques must be
developed to retrieve and analyze IP data. Because this holds
true whether it’s wired or wireless IP, many companies are
working on solutions to this problem today.
and IP billing requires new technology to meet the needs of
service providers and customers. Initially, these new technologies
augmented those of circuit-switched equipment and later
supplanted them. Telecommunications based on Internet
Protocol (IP) allow carriers to create grades of service and variable
pricing to reflect real market conditions.
Currently, data from switches is formatted into billable
event detail records through a mediation function. The big difference
between the circuit-switched and the IP network is
that IP billing must handle many more variables. Just as circuit-
switched billing is derived from call detail records
(CDRs), IP-based billing is derived from Internet usage
records (IURs). However, IURs must contain far greater information.
Future bills will include usage-based billing based on
IP information.
Customers can receive value-added information and services
with real-time billing. Provisioning of services can take place
online for wireless users, satisfying the customer who wants
added services. It also benefits the service provider by adding
incremental revenue for a given customer and by providing
more accurate and timely billing.
To implement IP billing, however, techniques must be
developed to retrieve and analyze IP data. Because this holds
true whether it’s wired or wireless IP, many companies are
working on solutions to this problem today.
INFRASTRUCTURE CHALLENGES CIRCUIT-SWITCHED VS. ALL-IP
Today’s Internet is a packet-based network with an always-on
connection. There are very fundamental differences between circuit-switched connections and packet networks. Circuitswitched
connections require a real time end-to-end session,
whether the transmission is a voice conversation or a data
transfer session. Whatever goes into one end always comes out
the other in the same order. It may be degraded by static or
noise, but its original order is maintained. If there is a loss of
voice or data, a repeat transmission can take place instantly to
guarantee the reliability of the connection.
Internet Protocol (IP) works entirely differently in the
transmission of data, whether using Voice-over-IP (VoIP) or a
binary data file. The data is broken up into small entities called
packets and each one carries a sequence number so that if they
arrive out of sequence, they can be reassembled. They can also
take different paths to the final destination, so there may be
delays in the arrival.
We do not wish to imply that packet is better than circuit
switched. The method selected depends on the application.
HSCSD allows wireless data to be transmitted at up to 38.4
Kbps or more over GSM networks by allocating multiple
time slots to a user. Although this is better than today’s average
data rate over most Wireless Internet access methods, it
will not really support true multimedia content. HSCSD,
however, is well suited for time-sensitive, real-time services
such as large file transfers. Packet is well suited to short file
transfers, messaging, or for longer file transfers where time
is not critical.
IP packet-switched networks operate as distributed networks—
after all, that was the reason for the creation of the
Internet in the beginning. Distributed networks allow for the
decentralized control of key elements required of a network
such as applications, management, and billing. Packet networks
are typically connectionless networks. The path that a
packet takes through the network can vary from packet to packet.
Circuit-switched networks are connection oriented. A connection
is set at the beginning of a session and remains until
the session ends. From a network point of view, connectionless
is a far more efficient use of the network resources because
resources are shared with all users dynamically. Circuitswitched networks use distance, location, and time as yardsticks
to measure the billing rate for sessions. In packet networks,
distance, time, and location are not as important as the
number of packets transferred through the network.
Usage billing becomes far more important in packet networks.
Circuit-switched networks are generally more proprietary,
legacy-based systems, whereas packet networks are much
less complex. Service provisioning is far more difficult for circuitswitched networks.
connection. There are very fundamental differences between circuit-switched connections and packet networks. Circuitswitched
connections require a real time end-to-end session,
whether the transmission is a voice conversation or a data
transfer session. Whatever goes into one end always comes out
the other in the same order. It may be degraded by static or
noise, but its original order is maintained. If there is a loss of
voice or data, a repeat transmission can take place instantly to
guarantee the reliability of the connection.
Internet Protocol (IP) works entirely differently in the
transmission of data, whether using Voice-over-IP (VoIP) or a
binary data file. The data is broken up into small entities called
packets and each one carries a sequence number so that if they
arrive out of sequence, they can be reassembled. They can also
take different paths to the final destination, so there may be
delays in the arrival.
We do not wish to imply that packet is better than circuit
switched. The method selected depends on the application.
HSCSD allows wireless data to be transmitted at up to 38.4
Kbps or more over GSM networks by allocating multiple
time slots to a user. Although this is better than today’s average
data rate over most Wireless Internet access methods, it
will not really support true multimedia content. HSCSD,
however, is well suited for time-sensitive, real-time services
such as large file transfers. Packet is well suited to short file
transfers, messaging, or for longer file transfers where time
is not critical.
IP packet-switched networks operate as distributed networks—
after all, that was the reason for the creation of the
Internet in the beginning. Distributed networks allow for the
decentralized control of key elements required of a network
such as applications, management, and billing. Packet networks
are typically connectionless networks. The path that a
packet takes through the network can vary from packet to packet.
Circuit-switched networks are connection oriented. A connection
is set at the beginning of a session and remains until
the session ends. From a network point of view, connectionless
is a far more efficient use of the network resources because
resources are shared with all users dynamically. Circuitswitched networks use distance, location, and time as yardsticks
to measure the billing rate for sessions. In packet networks,
distance, time, and location are not as important as the
number of packets transferred through the network.
Usage billing becomes far more important in packet networks.
Circuit-switched networks are generally more proprietary,
legacy-based systems, whereas packet networks are much
less complex. Service provisioning is far more difficult for circuitswitched networks.
TERMINAL TECHNOLOGIES
Early attempts at data transmission used either an analog
modem or CDPD, but these never really proved financially
rewarding to the carriers. The analog modems are very slow and
do not warrant further discussion. CDPD transmitted packet
data over an analog network. It was a niche market rather than
a mass market: Data rates were moderate (19.2 Kbps), phones
and modems were expensive, applications were very limited,
and most people never even knew that it existed. CDPD is still
in use as a slow-speed (by today’s standards), Wireless Internet
connection on analog and dual-mode phones.
Newer equipment and protocols have resulted in many
wireless transmission schemes, some competitive (directly or
indirectly) and some complementary to the others. For limited
mobility applications, we have wireless local and personal area
networks (WLANs and PANs) with standards such as Home
RF, IEEE 802.11, or Bluetooth. Mobile data networks such as
Mobitex and Ardis, for public or private wide area networks are
used mostly for dispatch and service industries. Wireless PDAs
(Palm, Handspring, etc.) and Pocket PCs (Compaq, HP, etc.)
have their own data networks such as OmniSky or they use a
cellular phone with a modem. In the cellular networks themselves,
SMS, WAP, I-Mode, and J2ME compete as data application
platforms. GPRS competes with CDPD or other modem
technology on cellular phones. Yet, all of these technologies are
needed to make wireless mobility truly ubiquitous. (A more indepth
description of the technical characteristics of these significant
technologies follows in Chapter 2.)
With the proliferation of so many standards as shown in
Figure 1-10, there is an increasing need for convergence. Users
will demand that their Wireless Internet service be simple, fast
and uninterrupted. Many locations such as inside buildings are
very difficult for wireless carriers to provide adequate coverage.
One possible solution maybe the construction of public
WLANs. Wireless LANs are currently being built because the
technology is fast, proven, inexpensive and available. Wireless
Internet users who operate within a WLAN environment can
get better coverage than that promised by 3G. The bandwidth available is up to 11 Mbps with 802.11b. Other technologies
could result in even higher bandwidths. Solutions will be created
that make the experience as simple as possible for both
the users and the wireless providers. If billing is handled by the
wireless provider on the users existing account, incremental
income is realized and the carriers like that rather than viewing
the WLAN as a competitor.
modem or CDPD, but these never really proved financially
rewarding to the carriers. The analog modems are very slow and
do not warrant further discussion. CDPD transmitted packet
data over an analog network. It was a niche market rather than
a mass market: Data rates were moderate (19.2 Kbps), phones
and modems were expensive, applications were very limited,
and most people never even knew that it existed. CDPD is still
in use as a slow-speed (by today’s standards), Wireless Internet
connection on analog and dual-mode phones.
Newer equipment and protocols have resulted in many
wireless transmission schemes, some competitive (directly or
indirectly) and some complementary to the others. For limited
mobility applications, we have wireless local and personal area
networks (WLANs and PANs) with standards such as Home
RF, IEEE 802.11, or Bluetooth. Mobile data networks such as
Mobitex and Ardis, for public or private wide area networks are
used mostly for dispatch and service industries. Wireless PDAs
(Palm, Handspring, etc.) and Pocket PCs (Compaq, HP, etc.)
have their own data networks such as OmniSky or they use a
cellular phone with a modem. In the cellular networks themselves,
SMS, WAP, I-Mode, and J2ME compete as data application
platforms. GPRS competes with CDPD or other modem
technology on cellular phones. Yet, all of these technologies are
needed to make wireless mobility truly ubiquitous. (A more indepth
description of the technical characteristics of these significant
technologies follows in Chapter 2.)
With the proliferation of so many standards as shown in
Figure 1-10, there is an increasing need for convergence. Users
will demand that their Wireless Internet service be simple, fast
and uninterrupted. Many locations such as inside buildings are
very difficult for wireless carriers to provide adequate coverage.
One possible solution maybe the construction of public
WLANs. Wireless LANs are currently being built because the
technology is fast, proven, inexpensive and available. Wireless
Internet users who operate within a WLAN environment can
get better coverage than that promised by 3G. The bandwidth available is up to 11 Mbps with 802.11b. Other technologies
could result in even higher bandwidths. Solutions will be created
that make the experience as simple as possible for both
the users and the wireless providers. If billing is handled by the
wireless provider on the users existing account, incremental
income is realized and the carriers like that rather than viewing
the WLAN as a competitor.
ONWARD TO 2.5G AND 3G
The next step to higher data rates for each technology was
dubbed 2.5G and was to be closely followed by 3G. (The “G”
of course stands for “generation.”) 3G is not just a standard for
higher data rates: It is also meant to bring global standardization
to cellular. Our choice of words here is very deliberate:
“closely followed” has been defined by some as within two
years of 2.5G, whereas others say that the two standards are
practically on top of one another. The simple fact is that it
costs a lot of time and money to upgrade a cellular system and
it may make more business sense to skip interim steps. Just as
IS-54 was quickly replaced by IS-136, carriers may find 2.5G
unpalatable financially. In other words, they may skip 2.5G and
go directly to 3G. That makes sense but what happens when
industry skips an interim solution or worse yet, adds another?
Do we add a 2.75G?
The truth is that in the interests of harmonizing all of the
different proposals for 3G, the cellular industry has skipped
some steps or in some cases, changed direction altogether. Like Qualcomm, NTT DoCoMo, the Japanese telecommunications
giant, has proposed a new standard altogether, Wideband Code
Division Multiple Access (WCDMA). Three years ago, the
roadmaps for GSM, CDMA, and TDMA were clear. GSM
would become GSM Phase 2+ with improvements and the
addition of High-speed Circuit Switch Data (HSCSD) and
rates up to 144 Kbps. Later, it would migrate to Enhanced
Data Rate for Global Evolution (EDGE). GPRS would be
added along with a more robust modulation scheme; rates of
384 Kbps would offer wireless multimedia IP-based services
and applications. At that time there would be an “alignment”
with TDMA; each would have an EDGE physical layer. Figure
1-9 shows the most recent roadmap for 3G.
Meanwhile, TDMA would become IS-136 Plus with the
addition of HSCSD. It would then migrate to IS-136HS
(EDGE) just like its cousin, GSM. (Not all EDGE is created
equal: The European version of EDGE and the North
American version share a common standard but different frequencies.
A “world” phone would have to cover more bands in
order to roam.) The roadmap for GSM and TDMA primarily
increases data capabilities, not voice. It is expected that voice
transmission would migrate to Voice-over-IP in the future.
Until that happens, EDGE is split into two component networks,
one for voice and one for data.
The CDMA side was also quite clear three years ago. IS-
95A would become IS-95B with HSCSD up to 64 Kbps. Later
IS-95C and IS-95D (sometimes referred to as IS-2000 Phase I
and II) would increase data rates to about 307 Kbps. IS-95C
was also referred to as 1xRTT, and IS-95D referred to as
3xRTT. Just to confuse things a little, another standard was
created to overlay the other two. High Data Rate (HDR) could
go as high as 2.4 Mbps. (The latest acronym for 1xRTT combined
with HDR is 1xEV.)
Well, today most of this has changed. NTT DoCoMo proposed
a new Wideband CDMA. When the technical and political
ramifications were viewed, deals were made between
proponents of each standard. GSM Phase II+ survived but IS-
136 Plus didn’t. For CDMA, 1xRTT survived but IS-95B didn’t
and 3xRTT will most likely be delayed as long as HDR meets
users’ needs. As for WCDMA, it will become a component
overlaying GSM networks, transforming those networks into
Universal Mobile Telephone Service (UMTS).
The last three years have been very confusing to those following
the standards process. The only things that remain clear
are that CDMA will launch 1xRTT with an HDR overlay to
support date rates from 144 Kbps to over 2 Mbps. Both data
and voice capacity will benefit from 1xRTT.
Europe will launch EDGE with WCDMA overlaid. Data
rates will run from 384 Kbps to over 2.5 Mbps. Both data and
voice capacity will be improved. In the United States, the IS-
136 component of EDGE may be eliminated in favor of the
European version of EDGE and WCDMA. AT&T Wireless has
announced a decision to do exactly that: overlay the old IS-136
network with a GSM/EDGE/WCDMA version.
In the United States, a fourth cellular technology is
deployed by Nextel. It uses a proprietary technology developed
by Motorola called iDEN. The Nextel system works as a hybrid
design between cellular and dispatch technologies. Calls may
be connected like cellular, or members of a group can be connected
together in a way similar to two-way radio, without dialing.
For roaming outside the United States, Nextel offers a dual
mode—iDEN and GSM—phone. For data applications, the
Nextel phones include a Java 2 Micro-edition (J2ME) environment
and transmit data on a packet network.
Regardless of the details of who implements what, three
important things should be remembered:
• High speed packet data will replace circuit-switched data.
• Internet Protocol (IP) will become the standard protocol for
all wireless traffic, voice, and data.
• A quasi-global standard will make international roaming easier.
These three changes to mobile communications will open
the door to the next generation of wireless applications.
dubbed 2.5G and was to be closely followed by 3G. (The “G”
of course stands for “generation.”) 3G is not just a standard for
higher data rates: It is also meant to bring global standardization
to cellular. Our choice of words here is very deliberate:
“closely followed” has been defined by some as within two
years of 2.5G, whereas others say that the two standards are
practically on top of one another. The simple fact is that it
costs a lot of time and money to upgrade a cellular system and
it may make more business sense to skip interim steps. Just as
IS-54 was quickly replaced by IS-136, carriers may find 2.5G
unpalatable financially. In other words, they may skip 2.5G and
go directly to 3G. That makes sense but what happens when
industry skips an interim solution or worse yet, adds another?
Do we add a 2.75G?
The truth is that in the interests of harmonizing all of the
different proposals for 3G, the cellular industry has skipped
some steps or in some cases, changed direction altogether. Like Qualcomm, NTT DoCoMo, the Japanese telecommunications
giant, has proposed a new standard altogether, Wideband Code
Division Multiple Access (WCDMA). Three years ago, the
roadmaps for GSM, CDMA, and TDMA were clear. GSM
would become GSM Phase 2+ with improvements and the
addition of High-speed Circuit Switch Data (HSCSD) and
rates up to 144 Kbps. Later, it would migrate to Enhanced
Data Rate for Global Evolution (EDGE). GPRS would be
added along with a more robust modulation scheme; rates of
384 Kbps would offer wireless multimedia IP-based services
and applications. At that time there would be an “alignment”
with TDMA; each would have an EDGE physical layer. Figure
1-9 shows the most recent roadmap for 3G.
Meanwhile, TDMA would become IS-136 Plus with the
addition of HSCSD. It would then migrate to IS-136HS
(EDGE) just like its cousin, GSM. (Not all EDGE is created
equal: The European version of EDGE and the North
American version share a common standard but different frequencies.
A “world” phone would have to cover more bands in
order to roam.) The roadmap for GSM and TDMA primarily
increases data capabilities, not voice. It is expected that voice
transmission would migrate to Voice-over-IP in the future.
Until that happens, EDGE is split into two component networks,
one for voice and one for data.
The CDMA side was also quite clear three years ago. IS-
95A would become IS-95B with HSCSD up to 64 Kbps. Later
IS-95C and IS-95D (sometimes referred to as IS-2000 Phase I
and II) would increase data rates to about 307 Kbps. IS-95C
was also referred to as 1xRTT, and IS-95D referred to as
3xRTT. Just to confuse things a little, another standard was
created to overlay the other two. High Data Rate (HDR) could
go as high as 2.4 Mbps. (The latest acronym for 1xRTT combined
with HDR is 1xEV.)
Well, today most of this has changed. NTT DoCoMo proposed
a new Wideband CDMA. When the technical and political
ramifications were viewed, deals were made between
proponents of each standard. GSM Phase II+ survived but IS-
136 Plus didn’t. For CDMA, 1xRTT survived but IS-95B didn’t
and 3xRTT will most likely be delayed as long as HDR meets
users’ needs. As for WCDMA, it will become a component
overlaying GSM networks, transforming those networks into
Universal Mobile Telephone Service (UMTS).
The last three years have been very confusing to those following
the standards process. The only things that remain clear
are that CDMA will launch 1xRTT with an HDR overlay to
support date rates from 144 Kbps to over 2 Mbps. Both data
and voice capacity will benefit from 1xRTT.
Europe will launch EDGE with WCDMA overlaid. Data
rates will run from 384 Kbps to over 2.5 Mbps. Both data and
voice capacity will be improved. In the United States, the IS-
136 component of EDGE may be eliminated in favor of the
European version of EDGE and WCDMA. AT&T Wireless has
announced a decision to do exactly that: overlay the old IS-136
network with a GSM/EDGE/WCDMA version.
In the United States, a fourth cellular technology is
deployed by Nextel. It uses a proprietary technology developed
by Motorola called iDEN. The Nextel system works as a hybrid
design between cellular and dispatch technologies. Calls may
be connected like cellular, or members of a group can be connected
together in a way similar to two-way radio, without dialing.
For roaming outside the United States, Nextel offers a dual
mode—iDEN and GSM—phone. For data applications, the
Nextel phones include a Java 2 Micro-edition (J2ME) environment
and transmit data on a packet network.
Regardless of the details of who implements what, three
important things should be remembered:
• High speed packet data will replace circuit-switched data.
• Internet Protocol (IP) will become the standard protocol for
all wireless traffic, voice, and data.
• A quasi-global standard will make international roaming easier.
These three changes to mobile communications will open
the door to the next generation of wireless applications.
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