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The evolving wireless environment

Learning objective
After completing this topic, you should be able to recognize potential future developments in wireless
services.

1. User demands and wireless technologies

The advance of wireless technologies from Second Generation (2G) is being driven by a wide range of
user demands.
For example, with voice communication, there is a demand for enhanced Quality of Service (QoS)
from wireless networks so that sound quality is clearer and any delays are avoided. There is also
demand for integrated wideband multimedia services such as e-mail access and software
downloading.
It was thought that 3G and 3.5G would meet these demands. However, this has not been the case and
it is now expected that a new set of technologies, 4G, will do this.
The International Telecommunication Union - Radiocommunication Standardization Sector (ITU-R)
predicts trends in the evolution of wireless technologies. It suggests that existing radio access
networks will continue to evolve as they have and that, with the arrival of 4G, we will see a fusion of
the existing elements of cellular systems with newly developed ones.
It also expects nomadic wireless access systems to be more prevalent, allowing roaming and more
mobility in offices.

It also predicts that wireless systems will have more in common with each other and that seamless
internetworking will be the norm.
The main user requirements driving the development of current wireless systems are
• global mobile access
• higher QoS
• increased access to multimedia services
• ubiquity and diversity
global mobile access
Current users expect that 4G wireless services will be global, allowing enhanced terminal and
personal mobility throughout the world.
higher QoS
The quality of wireless communications is increasing all the time and, with 4G, users will expect
that the QoS for wireless services will be characterized by better coverage, more intelligible
sound, no drop, and lower call blocking and latency.
increased access to multimedia services
Current user needs for more complex wideband multimedia services and the continued
convergence of information technology (IT) and telecommunications mean that mobile users of
the future will want to be able to download software, access e-mail, upload files, and talk on the
phone, all from a single terminal.
ubiquity and diversity
Users demand both ubiquity and diversity from wireless communications. They need phone
 networks to be ubiquitous so they can travel anywhere, at any time, and access the network.
However, they will also need the systems to be versatile in order to make customized services
based on diverse individual needs available.

These two demands are, in many ways, conflicting, so it's important for 4G systems to be
flexible so that they can meet them simultaneously.

Question
Which user needs are driving the development of 4G technologies?
Options:
1. Access to multimedia services
2. Global mobile access
3. Higher QoS
4. Ubiquity and homogeneity

Answer
Global mobile access, higher QoS, and access to multimedia services are the user needs driving the
development of 4G technologies.
Option 1 is correct. Current users expect easy and simple access to multimedia services for voice,
data, message, video, and the Web via a single user terminal.
Option 2 is correct. It is expected that 4G wireless services will be global, allowing enhanced terminal
and personal mobility throughout the world.
Option 3 is correct. Current wireless users expect a higher QoS from mobile communications. They
expect better coverage and more intelligible sound. They also expect lower drop, call blocking, and
latency, which is related to delay, data rate, and bit error requirements.
Option 4 is incorrect. Although it's true that current users want mobile access to be ubiquitous, this
conflicts somewhat with a different demand - diversity. It's more likely that mobile communications of
the future will try and meet these two demands so that technologies will tend towards diversity rather
than homogeneity.

2. Shortcomings of 3G and 3.5G

Many of the things that current users of wireless technologies expect are not being met by 3G and
3.5G technologies.
Some of the shortcomings of 3G and 3.5G include
• the cost of deployment and upgrade
• a lack in system integration and QoS
• unsuitability for high-performance applications
• an excess of standards
• a network design that is too basic
• bandwidth that is too narrow
• incompatibility with new modulation schemes
the cost of deployment and upgrade
One of the main problems associated with 3G is that, even though it comprises advanced
wireless technologies that provide multimedia data services, comprehensive wireless networks
have yet to become widely available. This is because it's expensive to deploy them or to
 upgrade existing system equipment.
a lack in system integration and QoS
System integration is a problem for 3G and 3.5G technologies. Disparate technologies still exist,
such as GPRS, CDMA2000, and WLAN, which need to be unified into a single wireless access
system. When 4G is fully implemented, it is expected that the Internet will act as the core
network for wireless networks.

Wireless network architecture will consist of a set of overlapping wireless Internet access
domains, such as WPAN, WLAN, WMAN, and WWAN, and a mobile host will have multimode
wireless interfaces to connect to different wireless networks. 3G is currently not equipped in this
way.
unsuitability for high-performance applications
User demands for full-motion video, wireless teleconferencing, and other multimedia
experiences require a high performance that 3G and 3.5G technologies are unable to provide.
4G systems will provide a network technology that extends 3G capacity by an order of
magnitude.
an excess of standards
Because there are many different standards for 3G, it's difficult to roam and interoperate across
networks. To achieve global mobility and service portability, these need to be unified.
a network design that is too basic
The 3G and 3.5G network is based primarily on a wide area concept and is too basic - 4G
requires hybrid networks that utilize both wireless LANs (WLANs) and cell or base station Wide
Area Network (WAN) design.
bandwidth that is too narrow
With users demanding more from their wireless technologies, data rates must increase.
However, there isn't enough bandwidth in 3G and 3.5G technologies to transfer large e-mail
attachments quickly, or to stream audio or video at broadcast quality.
incompatibility with new modulation schemes
In recent years, new modulation schemes for wireless technologies have been developed that
make more efficient use of the radio spectrum. Unfortunately, these can't be retrofitted into the
existing 3G or 3.5G infrastructure.

Another problem associated with 3G and 3.5G is that it has the wrong kind of network architecture if
you want to use the Internet as the core network.

Voice signals are carried on a circuit-switched infrastructure that 3G inherited from 2G, as opposed to
using the Internet Protocol (IP). And, although the 3G architecture is centralized, it has a complex and
expensive infrastructure and is strictly based on hierarchical networks.

Question
3G and 3.5G technologies are unsuitable for meeting the needs of future high-performance
applications.
Identify the elements that 4G will need that are currently not provided by 3G and 3.5G.
Options:
1. A centralized infrastructure
2. Global mobility
3. Hybrid networks

Answer
Global mobility and hybrid networks are two elements needed by 4G that are not being provided by
3G.
Option 1 is incorrect. Although 3G architecture is actually centralized, it's not centralized on the
Internet, which is what 4G aims to be. Instead, 3G has an expensive, circuit-switched infrastructure
and is strictly based on hierarchical networks.
Option 2 is correct. As of yet, 3G systems aren't global. It is expected that 4G wireless services will be
global, allowing enhanced terminal and personal mobility throughout the world.
Option 3 is correct. 4G systems need to make use of hybrid networks that combine cellular systems
with WLAN technologies, which 3G systems currently don't do.

3. 4G and the future

In the future, mobile IT will play a key role in wireless communications. Computers, people, and cell
phones will communicate with each other through networks. Different communication relationships,
such as person to person, machine to machine, and machine to person, will exist.
This increase in complexity presents a number of challenges for 4G technologies.
The challenges for 4G are
• understanding the importance of wireless data
• developing new radio 4G technologies
• diversifying mobile devices
• providing open access to all Internet applications
• increasing bandwidth
• developing new wireless services
• meeting a wide range of QoS requirements
understanding the importance of wireless data
3G has met the need for an enhanced capacity for narrowband voice data. 4G services will be
expected to meet the need to transfer data just as quickly. Mobile data rates of 100 Mbps are
expected and these will be over IP rather than voice circuits.
developing new radio 4G technologies
New radio 4G technologies include Mobile Ad-Hoc Networks (MANETs), which are adaptable
wireless networks with no fixed infrastructure. Personal Area Networks (PANs) will also be
commonplace - these are short-range networks that allow devices in your home to communicate
with each other - for example, your PDA will be able to communicate with your fridge.

Wireless Sensor Networks (WSNs) will also emerge - these are networks of tiny devices
equipped with wireless communication. To achieve all this, IP will be used over every radio link.
diversifying mobile devices
With the arrival of 4G, there will be many new devices that will be wireless transmitters and
receivers, including watches, pagers, and pocket PCs – IP will be the standard on every mobile
device.
providing open access to all Internet applications
4G networks will allow open access to all IP applications, unlike 3G where Internet applications
are filtered or restricted by a service provider using Wireless Application Protocol (WAP) or
iMode.
increasing bandwidth
Because of the many emerging bandwidth-hungry applications, 4G systems will need to provide
more bandwidth than 3G.
developing new wireless services
New wireless services in 4G might include dynamic service creation and deployment and
programmable mobile networks.
meeting a wide range of QoS requirements
Various QoS requirements will need to be met, such as providing for real-time and non real-time
web data and microflows, continuous media, and bursty TCP data. All this will be over IP and
networks will be interconnected and have to deliver support to mixed media.

Question
What are some of the challenges facing 4G systems?
Options:
1. Meeting demands for increasingly complex communication relationships
2. Providing open access to Internet applications
3. To move away from a reliance on packet-switched technologies such as IP

Answer
Providing open access to Internet applications and meeting demands for increasingly complex
communication relationships are two of the challenges facing 4G.
Option 1 is correct. 4G will be characterized by an increased dependence on mobile IT to account for
more complex communication relationships. Computers, people, and cell phones will communicate
with each other through networks. Different communication relationships, such as person to person,
machine to machine, and machine to person, will exist.
Option 2 is correct. 4G networks will allow open access to all IP applications, as distinct from 3G
where Internet applications are filtered or restricted by a service provider using Wireless Application
Protocol (WAP) or iMode.
Option 3 is incorrect. IP will actually play a core role in 4G wireless networks.

Question
Identify the true statements about the development of wireless technologies from 2G to 4G.
Options:
1. A circuit-switched infrastructure will be employed
2. Current wireless technologies will need to be unified into a single wireless access system
3. New, more spectrally efficient modulation schemes for wireless technologies will be developed
and retrofitted into existing 3G or 3.5G infrastructures
4. Users expect comprehensive, global coverage with enhanced multimedia from a single
terminal
5. Various devices will act as wireless transmitters and receivers, and IP will be the standard on
all devices

Answer
4G will provide comprehensive, global coverage with enhanced multimedia from a single terminal.
Current wireless technologies, such as GPRS, CDMA2000, and WLAN, will be unified into a single
wireless access system. Watches, pagers, and pocket PCs will act as wireless transmitters and
receivers, and IP will be the standard on all devices.
Option 1 is incorrect. The current 2G circuit-switched system that is employed by 3G is insufficient to
meet user demands. The Internet will, instead, need to be used as a core network, and IP will be the
standard, rather than circuit-switching.
Option 2 is correct. It is expected that, by 4G, comprehensive system integration will have occurred.
Disparate technologies, such as GPRS, CDMA2000, and WLAN, will be unified into a single wireless
access system.
Option 3 is incorrect. More spectrally efficient modulation schemes have already been developed.
However, they are incompatible with 3G or 3.5G infrastructures and will work instead with new 4G
systems.
Option 4 is correct. It is expected that current user demands for an enhanced multimedia experience
from a single terminal as well as global availability of wireless services will be met by 4G.

4G systems will make this possible using overlapping wireless Internet access domains, such as
WPAN, WLAN, WMAN, and WWAN, and mobile hosts will have multimode wireless interfaces to
connect to different wireless networks.
Option 5 is correct. It will be possible for any electronic device to act as a wireless transmitter or
receiver. Because IP will be the standard, communication will be easy. New types of mini-networks,
such as MANETs, PANs, and WSNs, will help all these devices communicate at short range.

Summary
Users of wireless have various demands that need to be met by 4G technologies. For example, there
is a demand for enhanced Quality of Service (QoS) from wireless networks so that sound quality is
clearer and there's no delay. There is also a demand for integrated wideband multimedia services,
such as e-mail access and software downloading. The ITU-R predicts that existing radio access
networks will continue to evolve as they have and that, by 4G, we will see a fusion of the existing
elements of cellular systems with newly developed ones.

3G and 3.5G systems are insufficient to meet the demands of wireless users. Their shortcomings are
the cost of deployment and upgrade, a lack in system integration and QoS, unsuitability for high-
performance applications, too many standards, too basic a network design, too narrow a bandwidth,
and incompatibility with new modulation schemes.

In the future, mobile IT will play a key role in wireless communications and an increase in complexity
presents a number of challenges for 4G technologies. For 4G, data rates of 100 Mbps are expected.
New radio 4G technologies, such as MANETs and PANs, will be developed, as will new wireless
devices, such as pocket PCs and watches that can communicate with other devices. Open access to
all Internet applications will be available and there will be an increase in bandwidth. New wireless
services will be developed and 4G will also focus on meeting a wide range of QoS requirements.

Table of Contents
| Top of page |
| Learning objective |
| 1. User demands and wireless technologies |
| 2. Shortcomings of 3G and 3.5G |
| 3. 4G and the future |
| Summary |
Copyright © 2004 SkillSoft. All rights reserved.
SkillSoft and the SkillSoft logo are trademarks or registered trademarks
of SkillSoft in the United States and certain other countries.
All other logos or trademarks are the property of their respective owners.
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The elements of 4G

Learning objective
After completing this topic, you should be able to identify the characteristics and benefits of the
principal and enabling technologies of 4G.

1. Characteristics of 4G
4G technologies are designed to meet the needs of users who want to access multimedia, make
phone calls, and have the same level of service wherever they are located.
The defining features of 4G networks are
• high speed
• high network capacity
• fast and seamless handovers across multiple networks
• next-generation multimedia support
high speed
On average, 4G systems will have a speed of 20 Mbps when traveling and 100 Mbps when the
user is stationary.
high network capacity
4G is expected to have a much higher capacity than 3G - at least ten times the capacity, in fact.
This means, for example, that a 10 Mb file, which takes 200 seconds to download now, would
take only one second on a 4G device. One use of this feature would be the streaming of high-
definition video on phone handsets.
fast and seamless handovers across multiple networks
With global roaming, quick and imperceptible handovers as a traveling user goes from one
wireless network to another will become the norm.
next-generation multimedia support
It will be possible for large volumes of multimedia data to be transmitted over 4G networks at a
low cost.

Although 4G's infrastructure is, as yet, not finalized, a consensus has been reached on the
technologies that will be used to implement it. In order to provide seamless transition for cell phone
users between different network types, for example, one possible setup would provide mediation in an
intermediate network called an overlay access network.
Operational parameters, such as frequency, channel information, and interface technologies, would be
set up in the overlay access network to be in harmony so that the cell phone, once on the access
network, doesn't have to concern itself with mediation when changing between the different network
types.
Another way of setting up the network architecture would be to have no intermediate network, in which
case the cell phone itself would need to do all mediation.
When a user changes from one network type to the other, the phone would negotiate the handover
and agree all the new operational parameters. This model would require significant processing power
on the part of the cell phone.
Question
Identify the defining characteristics of 4G services.
Options:
1. Ability to download a 10 Mb file in one second
2. A peak speed of more than 200 Mbps in stationary mode
3. Global roaming support across multiple mobile networks

Answer
Downloading a 10 Mb file in one second and global roaming support across multiple mobile networks
will be two of the features of 4G.
Option 1 is correct. 4G systems will have a much higher capacity than 3G. A 10 Mb file will typically
take only one second to download on a 4G device.
Option 2 is incorrect. On average, 4G systems will have a speed of 20 Mbps when traveling and 100
Mbps when the user is stationary.
Option 3 is correct. For global roaming, quick and imperceptible handovers as a traveling user goes
from one wireless network to another will become the norm.
One problem with high data rates is the interference that results from it, known as intersymbol
interference (ISI). 4G technologies aim to limit this and to use the available bandwidth in a spectrally
efficient manner. The technologies in contention to do this are
• Code-Division Multiple Access (CDMA)
• Orthogonal Frequency Division Multiplexing (OFDM)
Code-Division Multiple Access (CDMA)
CDMA is in common use and is well-known. It is a spread spectrum technology and uses a code
- as opposed to time divisions - to regulate the flow of packets of information in a wireless
connection.
Orthogonal Frequency Division Multiplexing (OFDM)
OFDM is a multi-carrier (MC) technique that will be used for WLANs and large city networks. It
cancels out distortion in a way that makes best use of the radio spectrum and doesn't require
multiple local oscillators.

4G systems will combine CDMA and OFDM and apply this combination, OFDM-CDMA, to a wide-area
environment. This will allow large throughputs per user.
Various types of OFDM and CDMA combinations have been proposed or are being put into use to
counteract interference. For example, MCDS-CDMA combines DS-CDMA and OFDM. Other examples
of combinations are MC-CDMA, MCDS-CDMA, TFL-CDMA, and VSF-OFCDM.

Question
Identify the characteristics of OFDM.
Options:
1. It's a spread spectrum technology
2. It can be combined with DS-CDMA
3. It can cancel multipath distortion in a spectrally efficient manner

Answer
OFDM can cancel multipath distortion in a spectrally efficient manner and can be combined with DS-
CDMA.
Option 1 is incorrect. OFDM is a multi-carrier technique although it can be combined with spread
spectrum techniques, such as CDMA.
Option 2 is correct. OFDM can be combined with DS-CDMA - where MCDS-CDMA is the result. Other
combinations of OFDM and CDMA include OFDM-CDMA, MC-CDMA, MCDS-CDMA, TFL-CDMA, and
VSF-OFCDM.
Option 3 is correct. OFDM cancels out distortion in a way that makes best use of the radio spectrum
and doesn't require multiple local oscillators.

2. Adaptive modulation
Radio signals can take different paths to reach their destination and, as a result, phase modulated
radio signals have a signal-to-noise ratio (SNR) that's sometimes very good and other times very poor.
The current, fixed modulation scheme accepts the worst-case scenario for the bit error rate (BER)
that's required. Because of this, a poor SNR may be the end result despite the fact that other, better
signal rates are also occurring. This isn't a particularly efficient use of the spectrum.
Although combining OFDM with CDMA allows 4G systems to be more spectrally efficient than
previous systems, this can be further enhanced by setting up the digital modulation format so that it
changes depending on the condition of the channel. This is known as adaptive modulation. You would
usually employ a modulation scheme like this in order to maintain a particular BER.
For example, the modulation scheme order would be higher if channel conditions were good, whereas
it would be lower if conditions were poor.
The result is a higher data throughput in favorable conditions and a lower data throughput in less
favorable conditions - but the average throughput is higher than with present schemes.
Different adaptive modulation schemes that are currently being developed adapt the transmission
power, data rate, coding schemes, or modulation schemes - or a combination thereof - to maintain a
constant BER and achieve a good SNR.
There are also other, alternative methods for performing adaptive modulation, depending on the
requirements. For example, one way of performing adaptive modulation is the burst-by-burst Adaptive
Quadrature Amplitude Modulation (AQAM) method. This method is suitable when a fixed BER is not a
priority, but a certain data throughput is. For example, this may be useful for videoconferencing, in
which case speech and video information is transported.
Other techniques based on signaling, channel estimation, and channel coding have also been
proposed.
For an adaptive modulation scheme to work, you need to
• estimate the channel quality
• ensure that the receiver is aware of the parameters used
estimate the channel quality
An adaptive modulation scheme needs to be able to reliably predict the channel quality during
an upcoming timeslot in which data is transmitted. This is so that the correct transmission
parameters are employed for the transmission and that the appropriate modulation scheme is
used for the subcarriers.
ensure that the receiver is aware of the parameters used
The receiver of information needs to know what transmission parameters are being employed by
the sender of data packets. Some adaptive modulation schemes ensure this by conveying the
information within the packet itself - despite the fact that this may take up valuable bandwidth.
Other schemes estimate the parameters using blind detection mechanisms.
Question
What does adaptive modulation offer for 4G?
Options:
1. It always varies the BER
2. It provides a higher data throughput in favorable conditions
3. It reduces throughput in worsening conditions
4. It varies the transmission parameters

Answer
Adaptive modulation provides a higher data throughput in favorable channel conditions and a reduced
throughput in less favorable conditions. It also varies the transmission parameters.
Option 1 is incorrect. In most cases, adaptive modulation aims to achieve a fixed BER. There are
cases when having a fixed BER isn't a priority but in those cases, a fixed data throughput is ensured
instead.
Option 2 is correct. Adaptive modulation schemes ensure a higher data throughput in favorable
conditions instead of accepting the worst-case scenario for the BER that's required.
Option 3 is correct. Adaptive modulation has reduced data throughput in less favorable channel
conditions. This is balanced by a higher throughput during more favorable conditions.
Option 4 is correct. Adaptive modulation varies transmission power, data rate, coding schemes, or
modulation schemes - or a combination thereof - to maintain a constant BER and achieve a good
SNR.
Additional technologies that will be employed in 4G are
• software-defined radios (SDRs)
• smart antennas
• open platform architectures
software-defined radios (SDRs)
SDRs are personal devices, such as cell phones, PDAs, or PCs, that use software to perform
wireless operations. For example, you can control, via software, modulation techniques,
wideband or narrowband operations, communication security, and waveforms. Or your SDR may
scan the wireless environment to find the cheapest or most convenient method of transmitting
data.

SDRs may also perform the operations presently performed by hardware, such as generating a
radio signal.
smart antennas
Smart antennas, such as multiple-input, multiple-output (MIMO) systems, respond automatically
to received signals according to a predefined algorithm. This means that the antenna "focuses"
on the signal and not the surrounding noise and interference. This reduces the number of
dropped calls, improves call quality, and keeps the communication channel free of unnecessary
data.
open platform architectures
Open platform architectures, such as Open Wireless Architecture (OWA), will provide a common
communication model whereby different standards, including TDMA, CDMA, and OFDM, and
technologies, such as cell phones, cordless phones, and WLANs, can be combined and
complement each other.

For the users, this means global access to wireless services and the resulting mobility that this
 affords, as well as comprehensive access to multimedia, such as video, the Web, and GPS,
from a single terminal.

Question
Match each 4G technology with its description.
Options:
1. Open platform architectures
2. Smart antennas
3. Software-defined radios (SDRs)
Targets:
1. Personal devices that perform wireless operations
2. Provide a common communication model whereby different standards and technologies can
combine and complement each other
3. Respond automatically to received signals according to a predefined algorithm

Answer
SDRs will be personal devices that perform wireless operations, smart antennas will respond
automatically to received signals according to a predefined algorithm, and open platform architectures
will provide a common communication model for different standards and technologies.
Open platform architectures, such as Open Wireless Architecture (OWA), will provide a common
communication model whereby different standards, including TDMA, CDMA, and OFDM, and
technologies, such as cell phones, cordless phones, and WLANs, can be combined and complement
each other.
Smart antennas will respond automatically to received signals according to a predefined algorithm
thus reducing the number of dropped calls and improving call quality.
SDRs will be devices, such as cell phones, PDAs, or PCs, that use software to perform wireless
operations.

Question
Identify the true statements about 4G technologies.
Options:
1. 4G systems will apply various combinations of OFDM and TDMA to a wide-area environment
2. 4G systems will be faster and have a higher capacity for data and voice
3. In 4G, the mobile device itself will need to perform all mediation when a user goes from one
area to another
4. Transmission power, data rate, coding schemes, and modulation schemes will fluctuate in one
call
5. There will be devices that can scan the airwaves for the cheapest call and antennas that
ensure better call quality

Answer
4G systems will be faster and have a higher capacity for data and voice. Transmission power, data
rate, coding schemes, and modulation schemes will fluctuate in one call. And devices will be able to
scan the airwaves for the cheapest call and smart antennas will ensure better call quality.
Option 1 is incorrect. 4G systems will combine CDMA, not TDMA, with OFDM and apply this
combination to a wide-area environment.
Option 2 is correct. 4G systems will have a speed of 20 Mbps when traveling, 100 Mbps when the
user is stationary, and will have 10 times the capacity of current systems.
Option 3 is incorrect. The architecture of 4G systems is not yet decided and, although it may be the
case that mobile devices will perform all the mediation, an overlay access network may be set up to
provide this instead.
Option 4 is correct. Adaptive modulation will be employed in 4G systems. Depending on the scheme
used, transmission power, data rate, coding schemes, and modulation schemes - or a combination
thereof - will be modified to ensure a fixed BER and a good SNR.
Option 5 is correct. SDRs are devices, such as PDAs or cell phones, that use software to scan the
airwaves to find the cheapest call or the best connectivity. Smart antennas will also be employed in
4G. These can adapt according to an algorithm thus ensuring good quality calls and fewer calls being
dropped.

Summary
The defining features of 4G networks are high speed, high network capacity, fast and seamless
handovers across multiple networks, and next-generation multimedia support. 4G's infrastructure is,
as yet, not finalized. 4G technologies aim to limit intersymbol interference (ISI) by combining CDMA
with OFDM and applying this to a wide-area environment.

Adaptive modulation schemes are currently being developed that adapt the transmission power, data
rate, coding schemes, or modulation schemes - or a combination thereof - to maintain a constant BER
and achieve a good SNR. The result is a higher data throughput in favorable conditions and a lower
data throughput in less favorable conditions. Additional technologies that will be employed in 4G are
software-defined radios (SDRs), smart antennas, and open platform architectures.

Table of Contents
| Top of page |
| Learning objective |
| 1. Characteristics of 4G |
| 2. Adaptive modulation |
| Summary |
Copyright © 2004 SkillSoft. All rights reserved.
SkillSoft and the SkillSoft logo are trademarks or registered trademarks
of SkillSoft in the United States and certain other countries.
All other logos or trademarks are the property of their respective owners.

This page contains a JavaScript function that prints out the current frame document. To print out the
document without using JavaScript, you need to press Control P.
| Print | Contents | Close |

4G applications and services

Learning objective
After completing this topic, you should be able to identify the system and service architecture issues
for 4G networks and their solutions.

1. From 1G to 4G
The progression of wireless technologies from 1G through 3G and beyond has been characterized by
a progression in services.
Each of these generations has its own set of applications and services:
• 1G
• 2G
• 3G
• Beyond IMT-2000 to 4G
1G
The First Generation of wireless technologies were analog and their networks were circuit
switched. They provided basic voice telephony - they had a low capacity and were unsuitable for
multimedia. The coverage they provided was limited to regions that were local to the user.
2G
The Second Generation of wireless technologies were digital but still used circuit-switched
networks. In addition to voice telephony, they provided basic data applications although the data
speed was low. Some efforts were made to provide packet-switched networks and higher data
rates, as well as transnational and global roaming.
3G
The Third Generation of wireless technologies were entirely digital. It was intended for 3G to be
entirely based on packet-switched networks, but this was not entirely realized - 3G networks use
both packet-switched and circuit-switched technologies.

They also provide some data and multimedia streaming, and data rates are higher than 2G.
Global roaming and coverage are the norm with 3G.
Beyond IMT-2000 to 4G
It is the intention for technologies from IMT-2000 onwards – namely, 4G - to be entirely digital
and based on packet-switched networks. They'll all be IP-based and provide a variety of more
advanced multimedia applications, which the user will be able to control from a single terminal.

They will operate on a flexible platform that is usable by a number of access systems. Data rates
will be high and there will be an improved Quality of Service (QoS). Global coverage and
roaming will continue to be available.

Question
Match the features with the wireless technology that provides them.
Options:
1. First Generation
2. Second Generation
3. Third Generation
4. Fourth Generation
Targets:
1. Analog and circuit switched
2. Digital, all packet switched, and IP based, with advanced multimedia
 3. Digital, both packet and circuit switched, with some multimedia
4. Digital, circuit switched, with low data rates

Answer
First Generation technologies are analog and circuit switched. Second Generation technologies are
digital and circuit switched, with low data rates. Third Generation technologies are digital, both packet
and circuit switched, with some multimedia. And Fourth Generation technologies will be digital, all
packet switched, and IP based, with advanced multimedia.
1G technologies were analog and their networks were circuit switched. They provided basic voice
telephony - they had a low capacity and were unsuitable for multimedia.
2G technologies were digital but they still used circuit-switched networks. In addition to voice
telephony, they provided basic data applications although the data speed was low.
3G technologies are entirely digital and 3G networks use both packet-switched and circuit-switched
technologies. They also provide some data and multimedia streaming.
4G will be entirely digital and based on packet-switched networks. They'll all be IP based and provide
a variety of more advanced multimedia applications, which the user will be able to control from a
single terminal.
4G technologies will be centered on the user, providing users with more intuitive control over
applications, services, and devices.
It will be possible to personalize 4G services and applications given that they will be more adaptive.
Their availability will be ubiquitous.
One of the main aims of 4G is to provide a high QoS and seamless handovers to users, groups of
users, communities, and devices, regardless of where they are or what network they're in.
Another aim is to allow users, application developers, service and content providers, and
manufacturers to create their own services based on the 4G architecture.

Question
What features will 4G applications provide to facilitate the user?
Options:
1. Adaptive services
2. Intuitive applications
3. Seamless handovers between circuit-switched networks
4. Ubiquitous personalized applications and services

Answer
Adaptive services, intuitive applications, and ubiquitous personalized applications and services will all
be features of 4G applications and services that facilitate the user.
Option 1 is correct. 4G services and applications will be more adaptive, so it will be possible for the
user to personalize them and for developers, manufacturers, and content providers to create their own
services.
Option 2 is correct. 4G will provide users with more intuitive control over applications, services, and
devices.
Option 3 is incorrect. Although seamless handovers will be a feature of 4G systems, this will not be
over circuit-switched networks, but over packet-switched networks.
Option 4 is correct. It will be possible to personalize 4G services and applications, and their availability
will be ubiquitous.

2. The 4G infrastructure
The architecture that 4G technologies will use will integrate different technologies in order to provide
the breadth of adaptable services to users.
4G architecture will be layered to support global roaming across multiple wireless and mobile networks
- for example, from a cellular network to a satellite-based network to a high-bandwidth wireless LAN.
The 4G architecture will be centered on an IP core and will have the following hierarchy of layers:
• Global layer
• Regional layer
• National layer
• Local Area layer
• Personal Network layer
Global layer
The Global layer will employ a global QoS scheme and will encompass existing and emerging
satellite networks and technologies, such as Satellite Code Division Multiple Access (SAT-
CDMA) and Satellite Wideband Code Division Multiple Access (SW-CDMA).
Regional layer
The Regional layer will consist of regional broadcast networks and will utilize technology such as
Digital Audio Broadcasting (DAB) and Digital Video Broadcasting - Terrestrial (DVB-T).
National layer
The National layer will overlap somewhat with the Regional layer and will encompass 2G and 3G
cellular networks.
Local Area layer
The Local Area layer will consist of wireless LANs and will utilize "hot spot" technologies.
Personal Network layer
The Personal Network layer will consist of small, Personal Area Networks (PANs) and will be
mainly concerned with short-range communication over individual links.

Question
Match the 4G architecture layers with their associated technology.
Options:
1. Global layer
2. Local Area layer
3. National layer
4. Personal Network layer
5. Regional layer
Targets:
1. 2G and 3G cellular networks
2. DAB and DVB-T technologies
3. PANs
4. Satellite networks
5. WLANs
Answer
The Global layer will include satellite technology, the Regional layer will use DAB and DVB-T
technologies, and the National layer will encompass the 2G and 3G cellular networks. The Local Area
layer will include WLANs and the Personal Network layer will contain PANs.
The Global layer will employ a global QoS scheme and will encompass existing and emerging satellite
networks and technologies, such as SAT-CDMA and SW-CDMA.
The Local Area layer will encompass WLANs and utilize "hot spot" technologies.
The National layer will encompass 2G and 3G cellular networks.
The Personal Network layer will contain PANs and will be mainly concerned with short-range
communication over individual links.
The Regional layer will use broadcast technologies, such as DAB and DVB-T.
To support better user mobility on a variety of mobile terminals, without compromising QoS, a number
of different technologies need to be integrated, including WPAN, WLAN, MANET, 2G, 2.5G, 3G,
satellite, DAB, and DVB-T.
A number of research projects are currently taking place throughout the world in an effort to integrate
different wireless technologies effectively as part of the 4G architecture. These include
• ETSI BRAN/3GPP
• WINE GLASS
• MOBY DICK
• SUITED
• BRAIN and MIND
ETSI BRAN/3GPP
The ETSI/BRAN project seeks to integrate Universal Mobile Telecommunications System
(UMTS) and HIPERLAN/2 (H/2) technologies.

One strand of the research, focused on loose coupling, provides centralized authentication and
signaling to the user but doesn't provide seamless handover. The other strand, focused on tight
coupling of the standards, allows for seamless internetworking although it makes signaling more
complex.
WINE GLASS
The Wireless IP Network as a Generic Platform for Location Aware Service Support (WINE
GLASS) project uses enhanced IP-based techniques to incorporate WLAN and UMTS in a
wireless IPv6 architecture.
MOBY DICK
The Mobility and Differentiated Services in a Future IP Network (MOBY DICK) project seeks to
find out if the IPv6 architecture will adequately replace the existing connection-oriented mobile
networks. It tests mobility on a heterogeneous network that supports QoS as well as
authentication, authorization, and accounting.
SUITED
The Multi-Segment System for Broadband Ubiquitous Access to Internet Services and
Demonstrator (SUITED) project is creating an integrated system - the Global Mobile Broadband
System (GMBS). This contains UMTS, GPRS, and WLAN components, and is IP based. It
consists of a multisegment infrastructure.
BRAIN and MIND
The Broadband Radio Access for IP-based Networks and Mobile IP-based Network
Developments (BRAIN and MIND) projects aim to provide customized broadband multimedia to
users by utilizing different wireless technologies, such as PANs, ad hoc networks, GPRS, UMTS,
and WLAN.
Some additional research projects on integrating wireless technologies in a 4G architecture include
• TRUST and SCOUT
• MOBIVAS
• FLOWS
• FuTURE
TRUST and SCOUT
The Transparently Re-configurable Ubiquitous Terminal (TRUST) and Smart User-centric
Communication environment (SCOUT) projects address integration by utilizing reconfigurable
wireless access networks and tight coupling. This provides seamless internetworking, improved
QoS, and better mobility, although high levels of signaling are necessary.
MOBIVAS
The Mobile Value-Added Services (MOBIVAS) project provides a middleware platform that
resides on an IP backbone outside an access network, such as a GPRS or UMTS network.
Value-added services are provided to the user – for example, personalized downloadable
applications and user profile management.
FLOWS
The Flexible Convergence of Wireless Standards and Services (FLOWS) project uses an IP-
based network on which a number of wireless access points are deployed, using GSM, UMTS,
or H/2. It focuses on the business needs of users and uses a variety of standards. It generally
focuses more on terminal and radio access systems, rather than plan for an integrated global
system.
FuTURE
The Future Technology for Universal Radio Environment (FuTURE) project is taking place in
China and is investigating various physical layer technologies, such as WLAN, ad hoc networks,
MIMO, and RF. It has proposed a number of possible handover methods and access schemes –
for example, Large Area Synchronized CDMA (LAS-CDMA), developed by FuTURE, has been
accepted by 3GPP2 as a candidate for their B3G air interface standard.

There are a number of requirements that must be met at the network, terminal, user, and service level
before a truly integrated 4G architecture can be achieved.
At the network level, mobility and security need to be managed in a uniform way. When a user is
roaming between physical areas, they will need sessions to continue without disturbance. End-to-end
QoS and authentication, authorization, and accounting (AAA) systems in different networks also need
to be able to cooperate and exchange information.
Routing is another issue that needs to be considered because ad hoc networks, mobile wireless, and
wired networks all have different requirements.
For terminals, support for a number of different communication modes will be necessary, and terminals
will also need to be adaptable and reconfigurable. Terminals will need to be always best connected
(ABC). A user connected to applications with an ABC-enabled terminal should be able to roam
between wireless networks without losing data or having to restart the application.
There will also be some requirements for users. For example, user profiles with individual users'
preferences will need to be managed. Users will need to each have a unique identifier that is
independent of the terminal, location, or network that the user is usually in.
With 4G, services will need to be flexible and fast. Service advertisement, continuity, and adaptability
are all issues that need to be considered as well. For example, services will need to adapt to
limitations of certain networks and terminals. Service deployment and delivery will also need to be
managed so that the diversity of infrastructures is not a problem.
Security and privacy need to be considered for every layer of a 4G system. One proposed method is
for users to authenticate themselves using smart cards that contain credit card details. Terminals
would contain a public key encryption system.
Another proposed security measure is the provision of end-to-end security services for user
applications. Robust and flexible encryption methods would be used to secure communication, as well
as stored data and removable memory.

Question
Identify the correct description of the FuTURE project.
Options:
1. It allows centralized authentication and signaling information related to a user
2. It focuses on the physical layer architecture of future wireless systems
3. Its framework consists of an integrated system known as the Global Mobile Broadband System
(GMBS)
4. It takes advantage of the reconfigurability of wireless access networks to provide a high level of
integration
5. It will establish whether IPv6 is a suitable replacement for connection-oriented mobile networks

Answer
The FuTURE project focuses on the physical layer architecture of future wireless systems.
Option 1 is incorrect. One strand of the ETSI/BRAN project allows centralized authentication and
signaling information related to a user.
Option 2 is correct. The FuTURE project focuses on the physical layer architecture of future wireless
systems.
Option 3 is incorrect. The SUITED project's framework consists of an integrated system known as the
Global Mobile Broadband System (GMBS).
Option 4 is incorrect. The TRUST project uses the reconfigurability of wireless access networks to
provide a high level of integration.
Option 5 is incorrect. The MOBY DICK project will establish whether IPv6 is a suitable replacement for
connection-oriented mobile networks.

Summary
From 1G through 4G, each generation of wireless technologies has its own set of applications and
services. 1G technologies are analog and circuit switched and 2G technologies are digital and circuit
switched, with low data rates. 3G technologies are digital and packet and circuit switched, with some
multimedia, and 4G technologies will be digital, all packet switched, and IP based, with advanced
multimedia. 4G applications will facilitate the user by providing adaptive services, intuitive applications,
and ubiquitous personalized applications and services.

The 4G architecture will be centered on an IP core and will have a hierarchy of layers – a Global layer,
a Regional layer, a National layer, a Local Area layer, and a Personal Network layer. A number of
research projects are currently taking place in an effort to integrate wireless technologies effectively in
a 4G architecture, such as ETSI/BRAN, WINE GLASS, and FuTURE. However, there are a number of
requirements that must be met at the network, terminal, user, and service level before a truly
integrated 4G architecture can be achieved.

Table of Contents
| Top of page |
| Learning objective |
| 1. From 1G to 4G |
| 2. The 4G infrastructure |
| Summary |
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Recognizing the properties of 4G

Learning objective
After completing this topic, you should be able to recognize the properties and technologies of 4G.

Exercise overview
In this exercise, you're required to analyze the issues associated with changing from 3G to 4G
wireless technology.
This involves the following tasks:
• identifying the benefits of changing to 4G technology
• identifying 4G technologies
You work as a consultant in the area of wireless service provision.

You are currently working with a client who is considering whether to roll out 3G or 3.5G services in
their network now or wait until 4G services become available in the future.

Task 1: Identifying the benefits of changing to 4G

First you need to advise your client about some potential shortcomings of 3G and 3.5G technologies.

Step 1 of 2
Which aspect of 3G makes it difficult to roam and interoperate across networks?
Options:
1. 3G has an unsuitable service architecture
2. 3G has multiple standards
3. 3G is based primarily on a WLAN concept
4. 3G is not backward compatible with earlier technologies

Result
Because there are many different standards for 3G, it's difficult to roam and interoperate across
networks.
Option 1 is incorrect. Global roaming and coverage are possible within the 3G service architecture.
Option 2 is correct. Because there are many different standards for 3G, it's difficult to roam and
interoperate across networks. To achieve global mobility and service portability, these need to be
unified.
Option 3 is incorrect. 3G uses different air interface standards such as CDMA2000 and WCDMA.
However, the 3G specification does not include WLAN.
Option 4 is incorrect. 3G has, in fact, many things in common with earlier technologies, such as 2G,
and uses many of the same networks as 2G so global roaming that was available with 2G is still
possible with 3G.

Step 2 of 2
Which properties characterize 4G?
Options:
1. Circuit-switched technology
2. Consistent Quality of Service (QoS)
3. Limited global coverage
4. Multiple access technologies

Result
Consistent Quality of Service (QoS) and multiple access technologies will be characteristic properties
of 4G.
Option 1 is incorrect. 4G will use a packet-switched, not a circuit-switched system.
Option 2 is correct. One of the aims of 4G development is to provide consistent QoS, as well as more
multimedia, seamless handovers, and higher data rates.
Option 3 is incorrect. With 4G, global coverage will be comprehensive and global roaming will be
possible.
Option 4 is correct. Current 4G research is focusing on new multiple access technologies that will
enhance the overall bandwidth efficiency and fit the all-IP wireless applications. For example, 4G
systems will combine current CDMA and OFDM technologies and apply this combination, OFDM-
CDMA, to a wide-area environment.

Task 2: Identifying 4G technologies

Having identified some of the reasons for changing to 4G, you now need to identify some of 4G's
technologies.

Step 1 of 4
What are the principle contending multiple access technologies in 4G?
Options:
1. Code Division Multiple Access (CDMA)
2. Frequency Division Multiple Access (FDMA)
3. Orthogonal Frequency Division Multiplexing (OFDM)
4. Plain Old Telephone Systems (POTS)
Result
The contending multiple access technologies in 4G are CDMA and OFDM.
Option 1 is correct. CDMA is in common use, is well known, and is one of the contending technologies
for 4G. There are different types of CDMA such as DS-CDMA and MC-CDMA.
Option 2 is incorrect. FDMA is an analog system. It is expected that 4G will be entirely digital so it's not
likely that FDMA will be used.
Option 3 is correct. OFDM is a multi-carrier (MC) technique that will be used for WLANs and large city
networks. With 4G, it will be combined with CDMA to create a new technology, OFDM-CDMA.
Option 4 is incorrect. POTS is the original analog telephone system that uses telephone wires. It will
not be part of 4G systems.

Step 2 of 4
Your client has identified smart antennas as a possible 4G technology to invest in and has asked you
about the benefits of this technology.
Identify the features of smart antennas.
Options:
1. They may use multiple-input, multiple-output (MIMO) technology
2. They reduce the number of dropped calls and improve call quality
3. They respond automatically to received signals according to a predefined algorithm
4. They scan the wireless environment to find the cheapest or most convenient method of
transmitting data

Result
Smart antennas respond automatically to received signals according to a predefined algorithm. They
may use MIMO technology and they reduce the number of dropped calls and improve call quality.
Option 1 is correct. Many smart antennas use MIMO technology. Spectral efficiency is increased
through the use of multiple antenna arrays at both the transmitter and receiver.
Option 2 is correct. Smart antennas reduce the number of dropped calls and improve call quality by
keeping the communication channel free of unnecessary data.
Option 3 is correct. Smart antennas respond automatically to received signals according to a
predefined algorithm. They "focus" on the signal and not the surrounding noise and interference.
Option 4 is incorrect. Many personal devices, such as PDAs, PCs, and cell phones, will scan the
wireless 4G environment to find the cheapest or most convenient method of transmitting data.
Collectively, these are known as software-defined radios (SDRs). Smart antennas, however, will
enable SDRs to operate more efficiently in a changing network environment.

Step 3 of 4
One of the technologies you have identified as important to 4G is adaptive modulation.
How does adaptive modulation improve transmission rates?
Options:
1. By accepting the worst case scenario for the BER that's required
2. By adapting the transmission scheme to the current channel characteristics
3. By providing a constant BER, even when the SNR varies
 4. By providing a higher data throughput when the signal-to-noise ratio (SNR) on a channel is low

Result
Adaptive modulation improves transmission rates by adapting the transmission scheme to the current
channel characteristics thereby providing a constant BER, even when the SNR varies.
Option 1 is incorrect. Adaptive modulation doesn't accept the worst case scenario. In standard
modulation schemes, the BER is maintained at an acceptable level by assuming the channel
conditions are bad. Throughput is low in order to maintain the BER at an appropriate level.

In adaptive modulation, throughput is increased during good conditions while still maintaing the BER
thereby increasing spectral efficiency.
Option 2 is correct. Adaptive modulation automatically changes the transmission rates depending on
the conditions of the channel carrying the signal. For example, when the SNR is high, the transmission
rate is increased.
Option 3 is correct. The SNR on most radio channels varies constantly. Current modulation schemes
simply use the lowest SNR in order to get a constant BER. Adaptive modulation, on the other hand,
still achieves a constant BER by adapting the transmission rate to the SNR on the channel at any one
time.
Option 4 is incorrect. If the SNR is low, this means that a high data throughput is impossible. An
adaptive modulation scheme would accept a low data throughput in this instance and then increase
the transmission rate when conditions are more favorable - on average, the throughput would level off.

Step 4 of 4
Finally, you brief your client on some of the current research being carried out on 4G technologies.
Match the research projects with their descriptions.
Options:
1. BRAIN and MIND
2. ETSI BRAN/3GPP
3. TRUST and SCOUT
4. WINE GLASS
Targets:
1. Incorporates WLAN and UMTS in a wireless IPv6 architecture
2. Integrates UMTS and H/2 technologies
3. Provides customized broadband multimedia to users by utilizing different wireless technologies
4. Uses reconfigurable wireless access networks and tight coupling

Result
ETSI BRAN/3GPP integrates UMTS and H/2 technologies and BRAIN and MIND provide customized
broadband multimedia to users by utilizing different wireless technologies. WINE GLASS incorporates
WLAN and UMTS in a wireless IPv6 architecture and TRUST and SCOUT use reconfigurable wireless
access networks and tight coupling.
The BRAIN and MIND projects aim to provide customized broadband multimedia to users by utilizing
different wireless technologies such as PANs, ad hoc networks, GPRS, UMTS, and WLAN.
The ETSI BRAN/3GPP project seeks to integrate UMTS and H/2 technologies. It has two strands -
one is focused on a loose coupling and the other on a tight coupling of the standards.
The TRUST and SCOUT projects address integration by utilizing reconfigurable wireless access
networks and tight coupling thereby providing seamless internetworking, improved QoS, and better
mobility.
The WINE GLASS project uses enhanced IP-based techniques to incorporate WLAN and UMTS in a
wireless IPv6 architecture.

Table of Contents
| Top of page |
| Learning objective |
| Exercise overview |
| Task 1: Identifying the benefits of changing to 4G |
| Task 2: Identifying 4G technologies |
Copyright © 2004 SkillSoft. All rights reserved.
SkillSoft and the SkillSoft logo are trademarks or registered trademarks
of SkillSoft in the United States and certain other countries.
All other logos or trademarks are the property of their respective owners.