ADVANCEMENTS TOWARDS 4G

A SEMINAR REPORT

In partial fulfillment for the award of the degree

Of

BACHELOR OF TECHNOLOGY
In
COMPUTER SCIENCE & ENGINEERING

NOVEMBER 2013

ABSTRACT

Currently 2G Technology (GSM), or second generation

technology, is
Widely used worldwide for cell phone networks. The problem
with 2G
Technology is that the data rates are limited. This makes it inefficient for
data
Transfer applications such as video conferencing, music or video
downloads.
To increase the speed, various new technologies have been in development.
One of these, 4G technology, is mainly made up of high-speed
wireless
Networks designed to carry data, rather than voice or a mixture of the
two.

4G transfers data to and from mobile devices at broadband speeds

up
To100 Mbps moving and 1Gbps while the phone is stationary. In addition
to
High speeds, the technology is more robust against interference and tapping
Guaranteeing higher security. This innovative technology functions with the
Aid of VoIP, IPv6, and orthogonal frequency division
multiplexing
(OFDM).
To cater the growing needs of 4G, mobile data communication
providers
Will deploy multiple antennas at transmitters to increase the data rate.
Unlike
The 3G networks, which are a mix of circuit switched and packet switched
Networks, 4G will be based on packet switching only (TCP/IP). This
will
Allow low-latency data transmission. Furthermore, the use of IP to transfer
Information will require IPv6 to facilitate the use of more cell phone
devices.
During the presentation, an overview of the various generations of mobile
Device technologies preceding 4G would be followed by technical aspects
of

4G and how it functions, as well as the way it can lead to future

innovations
In cellular and communication technology.

TABLE OF CONTENTS
CH.

TITLE

PAGE NO.

NO.
LIST OF TABLES
LIST OF FIGURES

iii
iv

1.

INTRODUCTION

01

2.

HISTORY

02

3.

VISION OF 4G

06

3.1. Objectives of 4G

07

3.2. An All IP Network

08

3.3. Developments

09

4.

KEY 4G TECHNOLOGIES

11

4.1. Access Schemes

11

4.2. OFDMA

12

4.2.1. OFDMA Advantages

4.3. MIMO
4.3.1. Functions of MIMO

13
14
14
1

4.4. IPV6

15

4.5. VoIP

16

4.5.1. Functionality

17

4.6. Software Defined Radio

18

5.

QUALITY OF SERVICE

20

6.

COMPTING TECHNOLOGIES

21

7.

6.1. UMB

21

6.2. 3GPP LTE

22

6.3. Wi MAX Enhanced

23

BENFITS

25

7.1. Convergence of Cellular Networks and WLANs

8.

9.

25

7.2. Convergence of Mobile Communications and Broadcasting

25

7.3. Convergence Benefits

26

APPLICATIONS

27

8.1 Multimedia Video Services

27

8.2 Multiple Operators and billing system

28

CONCLUSION

29

REFERENCES

30
2

LIST OF TABLES
2.1 Wireless System Evolution

LIST OF FIGURES
4

Figure 3.1. Seamless Connection of Networks

07

Figure 6.1. Wi MAX Architecture

24

1. INTRODUCTION

4G (also known as Beyond 3G), an abbreviation for Fourth-Generation, is a

term used to describe the next complete evolution in wireless communications. A
4G system will be able to provide a comprehensive IP solution where voice, data
and streamed multimedia can be given to users on an "Anytime, Anywhere" basis,
and at higher data rates than previous generations.
As the second generation was a total replacement of the first generation
networks and handsets; and the third generation was a total replacement of second
generation networks and handsets; so too the fourth generation cannot be an
incremental evolution of current 3G technologies, but rather the total replacement of
the current 3G networks and handsets. The international telecommunications
regulatory and standardization bodies are working for commercial
deployment of 4G networks roughly in the 2012-2015 time scale. At that point it is
predicted that even with current evolutions of third generation 3G networks, these
will tend to be congested.
There is no formal definition for what 4G is; however, there are certain
objectives that are projected for 4G. These objectives include: that 4G
will be a fully IP-based integrated system. 4G will be capable of providing
between 100 Mbit/s and 1 G bit/s speeds both indoors and outdoors, with premium
quality and high security. Many companies have taken self-serving definitions and
distortions about 4G to suggest they have 4G already in existence today, such as
several early trials and launches of Wi Max, which is part of the formal ITU
6

standard for 3G. Other companies have made prototype systems calling those 4G.
While it is possible that some currently demonstrated technologies may become part
of 4G, until the 4G standard or standards have been defined, it is impossible for any
company currently to provide with any certainty wireless solutions that could be
called 4G cellular networks that would conform to the eventual international
standards for 4G. These confusing statements around "existing" 4G have served to
confuse investors and analysts about the wireless industry.

2. HISTORY
The history and evolution of mobile service from the 1G (first generation) to
fourth generation are discussed in this section. Table 1 presents a short history of
mobile telephone technologies. This process began with the designs in the 1970s
that have become known as 1G. The earliest systems were implemented based on
analog technology and the basic cellular structure of mobile communication. Many
fundamental problems were solved by these early systems.
Numerous incompatible analog systems were placed in service around
the world during the 1980s.The 2G (second generation) systems designed in the
1980s were still used mainly for voice applications but were based on digital
technology, including digital signal processing techniques. These 2G systems
provided circuit-switched data communication services at a low speed. The
competitive rush to design and implement digital systems led again to a variety of
different and incompatible standards such as GSM (global system mobile),
mainly in Europe; TDMA (time division multiple access) (IS-54/IS-136) in the
U.S.; PDC (personal digital cellular) in Japan; and CDMA (code division multiple
access) (IS-95), another U.S. system. These systems operate nationwide or
internationally and are today's mainstream systems, although the data rate for users
in these system is very limited. During the 1990s, two organizations worked to
define

the

next,

or

3G,

mobile system, which would eliminate previous

incompatibilities and become a truly global system. The 3G system would have
higher quality voice channels, as well as broadband data capabilities, up to
2

Mbps.

Unfortunately, the two groups could not reconcile their

differences, and this decade will see the introduction of two mobile standards for
3G. In addition, China is on the verge of implementing a third 3G system. An
interim step is being taken between 2G and 3G, the 2.5G. It is basically an
enhancement of the two major 2G technologies to provide increased capacity on the
2G RF (radio frequency) channels and to introduce higher throughput for data
service, up to 384 kbps. A very important aspect of 2.5G is that the data channels
are optimized for packet data, which introduces access to
the Internet from mobile devices, whether telephone, PDA (personal digital
assistant), or laptop. However, the demand for higher access speed multimedia
communication in today's society, which greatly depends on computer
communication in digital format, seems unlimited. According to the historical
indication of a generation revolution occurring once a decade, the present appears
to be the right time to begin the research on a 4G mobile communication system.

2.1. Wireless System Evolution

Table2.1.ShortHistory
of MobileTelephone
Technologies

Legend:
1xRTT = 2.5G CDMA data service up to 384 kbps
AMPS = advanced mobile phone service
CDMA = code division multiple access
EDGE = enhanced data for global evolution
FDMA = frequency division multiple access
GPRS = general packet radio system
GSM = global system for mobile
NMT = Nordic mobile telephone
PDC = personal digital cellular
PSTN = public switched telephone network
TACS = total access communications system
TDMA = time division multiple access
4

WCDMA = wideband CDMA

First generation: Almost all of the systems from this generation were analog
systems where voice was considered to be the main traffic. These systems could
often be listened to by third parties. Some of the standards are NMT, AMPS, HI
cap, CDPD, Mobitex , DataTac,
TACS and ETACS.

Second generation: All the standards belonging to this generation are

commercial centric and they are digital in form. Around 60% of the current market
is dominated by European standards. The second generation standards are
GSM, iDEN, D-AMPS, IS-95,
PDC, CSD, PHS, GPRS, HSCSD, and Widen.
Third generation: To meet the growing demands in network capacity, rates
required for high speed data transfer and multimedia applications, 3G standards
started evolving. The systems in this standard are essentially a linear enhancement
of 2G systems. They are based on two parallel backbone infrastructures, one
consisting of circuit switched nodes, and one of packet oriented nodes. The ITU
defines a specific set of air interface technologies as third generation, as part of the
IMT-2000 initiative. Currently, transition is happening from 2G to
3G systems. As a part of this transition, numerous technologies are being
standardized.
Fourth generation: According to the 4G working groups, the infrastructure and
the terminals of 4G will have almost all the standards from 2G to 4G implemented.
Although legacy systems are in place to adopt existing users, the infrastructure for 4G
will be only packet-based (all-IP). Some proposals suggest having an open
platform where the new innovations and evolutions can fit. The technologies which
are being considered as pre-4G are the following: WiMax, WiBro, iBurst, 3GPP Long
Term Evolution and 3GPP2 Ultra
Mobile Broadband.
5

3. VISION OF 4G
This new generation of wireless is intended to complement and
replace

the

3G systems, perhaps in 5 to 10 years. Accessing information

anywhere, anytime, with a seamless connection to a wide range of information and

services, and receiving a large volume of information, data, pictures, video, and so
on, are the keys of the 4G infrastructures. The future 4G infrastructures will consist
of a set of various networks using IP (Internet protocol) as a common protocol so
that users are in control because they will be able to choose every application
and environment.

Based on the developing trends of mobile

communication,
4G will have broader bandwidth, higher data rate, and smoother and
quicker handoff and will focus on ensuring seamless service across a multitude of
wireless systems and networks. The key concept is integrating the 4G capabilities
with all of the existing mobile technologies through advanced technologies.
Application adaptability and being highly dynamic are the main features of 4G
services of interest to users.
These features mean services can be delivered and be available to the personal
preference of different users and support the users' traffic, air interfaces, radio
environment, and quality of service. Connection with the network applications can
be transferred into various forms and levels correctly and efficiently. The dominant
methods of access to this pool of information will
PDA,

and

laptop

to

seamlessly

access

the

be

the

mobile

telephone,

voice communication, high-

speed information services,

and entertainment broadcast services. Figure 1 illustrates elements and techniques
to support the adaptability of the 4G domain. The fourth generation will encompass
all systems from various networks, public to private; operator-driven broadband
networks to personal areas; and ad hoc networks. The 4G systems will interoperate
with 2G and 3G systems, as well as with digital (broadband) broadcasting systems.
In addition, 4G systems will be fully IP-based wireless Internet. This allencompassing integrated perspective shows the broad range of systems that the
fourth generation intends to integrate, from satellite broadband to high altitude
7

platform to cellular 3G and 3G systems to WLL (wireless local loop) and FWA
(fixed wireless access) to WLAN (wireless local area network) and PAN (personal
area network),all with IP as the integrating mechanism. With 4G, a range of new
services and models will be
Available. These services and models need to be further examined for their
interface with the design of 4G systems. Figures 2 and 3 demonstrate the
key elements and the seamless connectivity of the networks.

Figure 3.1: Seamless Connection of Networks

3.1. Objectives of 4G
4G is being developed to accommodate the quality of service (QoS)
and rate requirements set by forthcoming applications like wireless broadband
8

access, Multimedia Messaging Service

(MMS),

video chat,

mobile TV,

HDTV content, Digital Video

Broadcasting (DVB), minimal service like voice and data, and other streaming
services for "anytime-anywhere". The 4G working group has defined the following as
objectives of the
4G wireless communication standard:

A spectrally efficient system (in bits/s/Hz and bits/s/Hz/site),

High network capacity: more simultaneous users per cell,

A nominal data rate of 100 Mbit/s while the client physically moves at high speeds
relative to the station, and 1 Gbit/s while client and station are in relatively fixed
positions as defined by the ITU-R,

A data rate of at least 100 Mbit/s between any two points in the world,

Smooth handoff across heterogeneous networks,

Seamless connectivity and global roaming across multiple networks,

High quality of service for next generation multimedia support (real time audio, high
speed data, HDTV video content, mobile TV, etc.)

Interoperability

with

existing wireless standards, and

An all IP, packet switched network.

In summary, the 4G system should dynamically share and utilize network resources to
meet the minimal requirements of all the 4G enabled users.

3.2. An "All IP Network" (AIPN)

A
that

they

characteristic

of

so-called

"4G"

networks

such

as

LTE

is

are fundamentally based upon TCP/IP, the core protocol of the

Internet, with higher level services such as voice, video, and messaging,
built on top of this. In 2004, the 3GPP proposed this as the future of UMTS
and began feasibility studies into the so-called All IP
9

Network (AIPN.) These proposals, which included recommendations in

2005 for 3GPP Release 7 (though some aspects were in releases as early as 4),
form the basis of the effort to build the higher level protocols of evolved UMTS.
The LTE part of this effort is called the
3GPP System Architecture Evolution.
At a glance, the UMTS back-end becomes accessible via a variety of means,
such as
GSM's/UMTS's own radio network (GERAN, UTRAN, and E-UTRAN), WiFi, and
even competing legacy systems such as CDMA2000 and WiMAX. Users of nonUMTS radio networks would be provided with an entry-point into the IP network,
with different levels of security depending on the trustworthiness of the network being
used to make the connection. Users of GSM/UMTS networks would use an integrated
system where all authentication at every level of the system is covered by a single
system, while users accessing the UMTS network via WiMAX and other similar
technologies would handle the WiMAX connection one way (for example,
authenticating themselves via a MAC or ESN address) and the UMTS link-up another
way.

3.3. Developments

The Japanese company NTT DoCoMo has been testing a 4G communication

system prototype with 4x4 MIMO called VSF-OFCDM at 100 Mbit/s while
moving, and 1 Gbit/s while stationary. NTT DoCoMo recently reached 5 Gbit/s
with 12x12 MIMO while moving at 10 km/h,and is planning on releasing the first
commercial network in 2010.

10

Dig web, an Irish fixed and wireless broadband company, has announced that
they have received a mobile communications license from the Irish Telecoms
regulator, ComReg. This service will be issued the mobile code 088 in Ireland and
will be used for the provision of 4G Mobile communications.

Pervasive networks are an amorphous and at present entirely hypothetical

concept where the user can be simultaneously connected to several wireless access
technologies and can seamlessly move between them. These access technologies can
be Wi-Fi, UMTS, EDGE, or any other future access technology. Included in this
concept is also smart-radio (also known as cognitive radio technology) to efficiently
manage spectrum use and transmission power as well as the use of mesh routing
protocols to create a pervasive network.
Sprint plans to launch 4G services in trial markets by the end of 2007 with
plans to deploy a network that reaches as many as 100 million people in 2008.... And
has announced WiMax service called Xohm. Tested in Chicago, this speed was
clocked at 100 Mbit/s.
Verizon Wireless announced on September 20, 2007 that it plans a joint effort with
the Vodafone Group to transition its networks to the 4G standard LTE. The time of
this transition has yet to be announced.
The German WiMAX operator Deutsche Broadband Dienste
(DBD) has launched WiMAX services (DSLonair) in Magdeburg and Dessau. The
subscribers are offered a tariff plan costing 9.95 euros per month offering 2 Mbit/s
download / 300 kbit/s upload connection speeds and 1.5 GB monthly traffic. The
subscribers are also charged a 16.99 euro one-time fee and 69.90 euro for the
equipment and installation. DBD received additional national licenses for WiMAX
in December 2006 and have already launched the services in Berlin,
Leipzig and Dresden.
11

American WiMAX services provider Clearwire made its debut on Nasdaq in

New
York on March 8, 2007. The IPO was underwritten by Merrill Lynch, Morgan
Stanley and JP Morgan. Clearwire sold 24 million shares at a price of $25 per share.
This adds $600 million in cash to Clearwire, and gives the company a market
valuation of just over $3.9 billion.

4. KEY 4G TECHNOLOGIES

4.1. Access schemes

12

As the wireless standards evolved, the access techniques used also exhibited
increase in efficiency, capacity and scalability. The first generation
wireless standards used plain TDMA and FDMA. In the wireless channels,
TDMA proved to be less efficient in handling the high data rate channels as it
requires large guard periods to alleviate the multipath impact. Similarly, FDMA
consumed more bandwidth for guard to avoid inter carrier interference. So in
second generation systems, one set of standard used the combination of
FDMA

and TDMA and the other set introduced a new access scheme called

CDMA. Usage of CDMA increased the system capacity and also placed a soft limit
on it rather than the hard limit. Data rate is also increased as this access
scheme is efficient enough to handle the multipath channel. This enabled the
third generation systems to used CDMA as the access scheme IS- 2000, UMTS,
HSXPA, 1xEV-DO, TD-CDMA and TD-SCDMA. The only issue with
CDMA is that it suffers from poor spectrum flexibility and scalability.
Recently, new access schemes like Orthogonal FDMA (OFDMA), Single
Carrier FDMA (SC-FDMA), Interleaved FDMA and Multi-carrier code division
multiple access
(MC-CDMA) are gaining more importance for the next generation systems. WiMax
is using OFDMA in the downlink and in the uplink. For the next generation UMTS,
OFDMA is being considered for the downlink. By contrast, IFDMA is being
considered for the uplink since OFDMA contributes more to the PAPR related
issues and results in nonlinear operation of amplifiers. IFDMA provides less
power fluctuation and thus avoids amplifier issues. Similarly, MCCDMA is in the proposal for the IEEE 802.20 standard. These access schemes offer
the same efficiencies as older technologies like CDMA. Apart from this, scalability
and higher data rates can be achieved.
The other important advantage of the above mentioned access techniques is that
they

13

Require less complexity for equalization at the receiver. This is an added advantage
especially in the MIMO environments since the spatial multiplexing transmission of
MIMO systems inherently requires high complexity equalization at the receiver.
In addition to improvements in these multiplexing systems,
improved modulation techniques are being used. Whereas earlier standards
largely used Phase-shift keying, more efficient systems such as 64QAM are being
proposed for use with the 3GPP Long Term
Evolution standards.

4.2. OFDMA: Orthogonal Frequency Division Multiple Access

Orthogonal Frequency-Division Multiple Access (OFDMA) is a multi-user version
of the popular Orthogonal frequency-division multiplexing (OFDM) digital
modulation scheme. Multiple access is achieved in OFDMA by assigning
subsets of subcarriers to individual users as shown in the figure below. This allows
simultaneous low data rate transmission from several users.
Based on feedback information about the channel

conditions,

adaptive user-to- subcarrier assignment can be achieved. If the assignment is done

sufficiently fast, this further improves the OFDM robustness to fast fading and
narrow-band cochannel interference, and makes it possible to achieve even better
system spectral efficiency.

Different number of sub-carriers can be assigned to different users, in view to

support differentiated Quality of Service (QoS), i.e. to control the data rate and error
probability individually for each user.

14

OFDMA resembles code division multiple access (CDMA) spread spectrum,

where users can achieve different data rates by assigning a different code spreading
factor or a different number of spreading codes to each user.
OFDMA can also be seen as an alternative to combining OFDM with time
division

multiple access

(TDMA)

or

time-domain

statistical multiplexing,

i.e.

packet mode communication. Low-data-rate users can send continuously with

low transmission power instead of using a "pulsed" high-power carrier. Constant
delay, and shorter delay, can be achieved.

However, OFDMA can also be described as a combination of frequency

domain and time domain multiple access, where the resources are partitioned in the
time-frequency space, and slots are assigned along the OFDM symbol index as well
as OFDM sub-carrier index.
OFDMA is considered as highly suitable for broadband wireless networks, due
to advantages including scalability and MIMO-friendliness, and ability to take
advantage of channel frequency selectivity.

4.2.1. Claimed OFDMA Advantages

Flexibility of

deployment

across

various

frequency

bands

with

little

needed modification to the air interface.

Averaging interferences from neighboring cells, by using different basic carrier

permutations between users in different cells.

Interferences

within

the

cell

are

averaged

by

using

allocation

with

cyclic permutations.
15

Enables orthogonality in the uplink by synchronizing users in time and frequency.

Enables Single Frequency Network coverage, where coverage problem exists and
gives excellent coverage.

Enables adaptive carrier allocation in multiplication of 23 carriers = nX23 carriers up

to 1587 carriers (all data carriers).

Offers Frequency diversity by spreading the carriers all over the used spectrum.

Offers Time diversity by optional interleaving of carrier groups in time.

Using the cell capacity to the utmost by adaptively using the highest modulation a
user can use, this is allowed by the gain added when less carriers are allocated (up to
18dB gain for 23 carrier allocation instead of 1587 carriers), therefore gaining in
overall cell capacity.

4.3. MIMO: Multiple Input Multiple Output

In radio, multiple-input and multiple-output, or MIMO is the use of multiple
antennas at both the transmitter and receiver to improve communication performance.
It is one of several forms of smart antenna technology.
MIMO technology has attracted attention in wireless communications, since
it offers significant increases in data throughput and link range without
additional

bandwidth

or transmit power. It achieves this by higher spectral

efficiency (more bits per second per hertz of bandwidth) and link reliability or
diversity (reduced fading). Because of these properties,
MIMO is a current theme of international wireless research.

16

4.3.1 Functions of MIMO

MIMO can be sub-divided into three main categories, precoding, spatial
multiplexing, or SM, and diversity coding.
Precoding is multi-layer beamforming in a narrow sense or all spatial
processing at the transmitter in a wide-sense. In (single-layer) beamforming, the
same signal is emitted from each of the transmit antennas with appropriate phase
(and sometimes gain) weighting such that the signal power is maximized at the
receiver input. The benefits of beamforming are to increase the signal gain from
constructive combining and to reduce the multipath fading effect. In the absence of
scattering, beamforming results in a well defined directional pattern, but in typical
cellular conventional beams are not a good analogy. When the receiver has multiple
antennas, the transmit beamforming cannot simultaneously maximize the signal
level

at

precoding

all of the

receive

antenna

and

precoding

is

used.

Note

that

requires knowledge of the channel state information (CSI) at the

transmitter.
Spatial multiplexing requires MIMO antenna configuration. In spatial
multiplexing, a high rate signal is split into multiple lower rate streams and each
stream is transmitted from a different transmit antenna in the same frequency
channel. If these signals arrive at the receiver antenna array with sufficiently
different spatial signatures, the receiver can separate these streams, creating parallel
channels for free. Spatial multiplexing is a very powerful technique for increasing
channel capacity at higher Signal to Noise Ratio (SNR). The maximum
number of spatial streams is limited by the lesser in the number of antennas at the
transmitter or receiver. Spatial multiplexing can be used with or without transmit
channel knowledge.
Diversity coding techniques are used when there is no channel knowledge
at the transmitter. In diversity methods a single stream (unlike multiple
streams in spatial multiplexing) is transmitted, but the signal is coded using
17

techniques

called

space-time coding. The signal is emitted from each of the

transmit antennas using certain principles of full or near orthogonal coding.

Diversity exploits the independent fading in the multiple antenna links to enhance
signal diversity. Because there is no channel knowledge, there is no beamforming
or array gain from diversity coding.
Spatial multiplexing can also be combined with precoding when the channel is
known at the transmitter or combined with diversity coding when decoding reliability
is in trade-off.

4.4. IPv6 : Internet Protocol Version 6

Internet Protocol version 6 (IPv6) is an Internet Layer protocol for packetswitched internetworks.

The

Internet Engineering Task Force

(IETF)

has

designated IPv6 as the successor of IPv4, the first and still dominant version of
the Internet Protocol, for general use on the Internet.
IPv6 has a much larger address space than IPv4, which allows flexibility in
allocating addresses and routing traffic. The extended address length eliminates the
need to use network address translation to avoid address exhaustion, and also
simplifies aspects of address assignment and renumbering when changing
Internet connectivity providers.
The very large IPv6 address space supports 2128 (about 3.41038)
addresses, or approximately 51028 (roughly 295) addresses for each of the roughly
6.5 billion (6.5109) people alive today. In a different perspective, this is 252
addresses for every observable star in the known universe more than ten billion
billion billion times as many addresses as IPv4 supported.

18

While these numbers are impressive, it was not the intent of the designers of
the IPv6 address
addresses.

Rather,

space
the

to

assure

geographical

saturation

with

usable

large number allows a better, systematic, hierarchical

allocation of addresses and efficient route aggregation. With IPv4, complex

Classless Inter-Domain Routing (CIDR) techniques were developed to make the best
use of the small address space. Renumbering an existing network for a new
connectivity provider with different routing prefixes is a major effort with IPv4, as
discussed in RFC 2071 and RFC 2072. With IPv6, however, changing the prefix in
a few routers can renumber an entire network ad hoc, because the host
identifiers (the least- significant 64 bits of an address) are decoupled from the
subnet identifiers and the network provider's routing prefix. The size of each subnet
in IPv6 is 264 addresses (64 bits); the square of the size of the entire IPv4 Internet.
Thus, actual address space utilization rates will likely be small in IPv6, but network
management and routing will be more efficient.

4.5. VoIP: Voice over IP

Voice-over-Internet protocol (VoIP) is a protocol optimized for the
transmission of voice through the Internet or other packet-switched networks. VoIP
is often used abstractly to refer to the actual transmission of voice (rather than the
protocol implementing it). This latter concept

is

also

referred

to

as

IP

telephony, Internet telephony, voice over broadband, broadband telephony, and

broadband phone.

VoIP providers

may

be

viewed

as commercial

realizations of

the

experimental Network Voice Protocol (1973) invented for the ARPANET providers.
Some cost savings are due to using a single network to carry voice and
data, especially where users have underused network capacity that can carry
VoIP at no additional cost. VoIP-to-VoIP phone calls are sometimes free, while
VoIP calls connecting to public switched telephone networks
19

(VoIP-to-PSTN) may have a cost that is borne by the VoIP user.

Voice-over-IP systems carry telephony signals as digital audio, typically

reduced in data rate using speech data compression techniques, encapsulated in a
data-packet stream over IP.
There are two types of PSTN-to-VoIP services: Direct inward dialing
(DID) and access numbers. DID will connect a caller directly to the VoIP user,
while access numbers require the caller to provide an extension number for the
called VoIP user.

4.5.1. Functionality

VoIP can facilitate tasks and provide services that may be more difficult to
implement or more expensive using the PSTN. Examples include:

The ability to transmit more than one telephone call over the same
broadband connection. This can make VoIP a simple way to add an extra
telephone line to a home or office.

Conference calling, call forwarding, automatic redial, and caller ID; zeroor near- zero-cost features that traditional telecommunication companies
(telcos) normally charge extra for.

Secure calls using standardized protocols (such as Secure Real-time

Transport Protocol.) Most of the difficulties of creating a secure
phone connection over traditional phone lines, like digitizing and digital
transmission, are already in place with VoIP. It is only necessary to encrypt
and authenticate the existing data stream.
20

Location independence. Only an Internet connection is needed to get a

connection to a VoIP provider. For instance, call center agents using VoIP
phones can work from anywhere with a sufficiently fast and stable Internet
connection.

Integration
including

with

other

services

available

over

the

Internet,

video conversation, message or data file exchange in parallel

with the conversation, audio conferencing, managing address books, and

passing information about whether others (e.g., friends or colleagues) are
available to interested parties.

Advanced

Telephony

features

such

as

call

routing,

screen

pops, and IVR implementations are easier and cheaper to implement and
integrate. The fact that the phone call is on the same data network as
a user's PC opens a new door to possibilities.

4.6. Software-Defined Radio (SDR)

SDR is one form of open wireless architecture (OWA). Since 4G is a
collection of wireless standards, the final form of a 4G device will constitute
various standards. This can be efficiently realized using SDR technology, which is
categorized to the area of the radio convergence.
A Software Defined Radio (SDR) system is a radio communication system
where components that have typically been implemented in hardware (i.e. mixers,
filters, amplifiers, modulators/demodulators,
implemented

using

software

on

detectors.

etc.)

are

instead

a personal computer or other embedded

computing devices. While the concept of SDR is not new, the rapidly evolving
capabilities of digital electronics are making practical many processes that
were once only theoretically possible.
A basic SDR may consist of a computer (PC) equipped with a sound card,
or other analog-to-digital converter, preceded by some form of RF front end.
21

Significant amounts of signal processing are handed over to the general purpose
processor, rather than done using special-purpose hardware. Such a design produces
a radio that can receive and transmit a different

form

of

radio

protocol

(sometimes referred to as a waveform) just by running different software.

Software radios have significant utility for the military and cell phone
services, both of which must serve a wide variety of changing radio protocols in real
time.
In the long term, software-defined radio is expected by its proponents to
become the dominant technology in radio communications. It is the enabler of the
cognitive radio.
The ideal receiver scheme would be to attach an analog to digital converter to
an antenna. A digital signal processor would read the converter, and then its software
would transform the stream of data from the converter to any other form the
application requires.

An ideal transmitter would be similar. A digital signal processor would

generate a stream of numbers. These would be sent to a digital to analog converter
connected to a radio antenna.

The ideal scheme is, due to the actual technology progress limits, not
completely realizable, however.

22

5.QUALITY OF SERVICE

Traffic generated by the different services will not onlyincrease traffic loads
on the networks, but will also require different quality of service (QoS)
requirements (e.g., cell loss rate, delay, and jitter) for different streams (e.g.,
video, voice, data).

Providing QoS guarantees in 4G networks is a non-trivial issue where both

QoS signaling across different networks and service differentiation between
mobile flows will have to be addressed.

23

One of the most difficult problems that are to be solved, when it comes to IP
mobility, is how to insure the constant QoS level during the handover.

Depending on whether the new access router is in the same or some

other subnetwork, we recognize the horizontal and vertical handover.

However, the mobile terminal can not receive IP packets while the
process of handover is finished. This time is called the handover latency.

Handover latency has a great influence on the flow of multimedia applications

in real- time.

Mobile IPv6 have been proposed to reduce the handover latency and the
number of lost packets.

The field Traffic Class and Flow Label in

IPv6 eader enables the

routers to secure the special QoS for specific packet series with marked
priority.

6.COMPETING TECHNOLOGIES

24

6.1. UMB: Ultra mobile broadband

UMB (Ultra Mobile Broadband) is the brand name for the project within
3GPP2 to improve
generation

the

applications

CDMA2000

mobile

phone

standard

for

next

and requirements. The system is based upon Internet

(TCP/IP) networking technologies running over a next generation radio system,

with peak rates of up to 280 Mbit/s. Its designers intend for the system to be
more efficient and capable of providing more services than the technologies
it replaces. Commercialization is unlikely as Qualcomm, its main developer,
3GPP2 and major CDMA carriers are concentrating on LTE instead.
UMB uses OFDM , advanced antenna techniques such as MIMO and
SDMA and IP based

architecture.

To

support

ubiquitous

and

universal

access, UMB supports inter- technology hand-offs and seamless operation with
existing CDMA2000 1X and 1xEV-DO systems. UMB offers high-speed data:
Peak download and upload speeds of 288 Mbps and 75 Mbps, respectively, in a
mobile environment with a 20 MHz bandwidth. It also supports increased VoIP
Capacity: Up to 1000 simultaneous Voice over IP (VoIP) users within a single
sector, 20 MHz of bandwidth .
To provide compatibility with the systems it replaces, UMB supports
handoffs with other

technologies

including

existing

CDMA2000

1X

and

1xEV-DO systems. However 3GPP2 added this functionality to LTE, allowing

LTE to become the single upgrade path for all wireless networks.

According to the technology market research firm ABI Research,

Ultra-Mobile Broadband might be "dead on arrival". No carrier has announced
plans to adopt UMB, and most CDMA carriers in Australia, USA, China, Japan
and Korea have already announced plans to adopt HSPA or LTE.

25

6.2. 3GPP Long Term Evolution

3GPP LTE (Long Term Evolution) is the name given to a project within the
Third Generation Partnership Project to improve the UMTS mobile phone standard
to cope with future technology evolutions. Goals include improving spectral
efficiency, lowering costs, improving services, making use of new spectrum and
refarmed spectrum opportunities, and better integration with other open standards.
The LTE air interface will be added to the specification in Release 8 and can be
found in the 36-series of the 3GPP

specifications. Although an evolution of

UMTS, the LTE air interface is a completely new systems based on OFDMA in
the downlink and SC-FDMA (DFTS-FDMA) in the uplink that efficiently
supports multi-antenna techologies (MIMO). The architecture that will result from
this work is called EPS (Evolved Packet System) and comprises E-UTRAN
(Evolved UTRAN) on the access side and EPC (Evolved Packet Core) on the core
side.
While 3GPP Release 8 has yet to be ratified as a standard, much of the
standard will be oriented around upgrading UMTS to a so-called fourth generation
mobile communications technology, essentially a wireless broadband Internet system
with voice and other services built on top.

The standard includes:

Peak download rates of 326.4 Mbit/s for 4x4 antennas, 172.8 Mbit/s for 2x2
antennas for every 20 MHz of spectrum.

Peak upload rates of 86.4 Mbit/s for every 20 MHz of spectrum.

5 different terminal classes have been defined from a voice centric class up to
a high end terminal that supports the peak data rates. All terminal will be able
to process 20 MHz bandwidth.

At least 200 active users in every 5 MHz cell. (i.e., 200 active data clients)

Sub-5ms latency for small IP packets

26

Increased spectrum flexibility, with spectrum slices as small as 1.5 MHz (and
as large as 20 MHz) supported (W-CDMA requires 5 MHz slices, leading to
some problems with roll-outs of the technology in countries where 5 MHz is a
commonly allocated amount of spectrum, and is frequently already in use with
legacy standards such as 2G GSM and cdmaOne.) Limiting sizes to 5
MHz also limited the amount of bandwidth per handset

Optimal cell size of 5 km, 30 km sizes with reasonable performance, and up

to 100 km cell sizes supported with acceptable performance

Co-existence with legacy standards (users can transparently start a call or

transfer of data in an area using an LTE standard, and, should coverage be
unavailable, continue the operation without any action on their part using
GSM/GPRS or W-CDMA-based UMTS or even 3GPP2 networks such as
CDMA or EV-DO)

Supports MBSFN (Multicast Broadcast Single Frequency Network). This

feature can deliver services such as Mobile TV using the LTE infrastructure,
and is a competitor for DVB-H-based TV broadcast.

A large amount of the work is aimed at simplifying the architecture of the

system, as it transits from the existing UMTS circuit + packet switching combined
network, to an all-IP flat architecture system.
Preliminary requirements have been released for LTE-Advanced, expected to be
part of 3GPP Release 10. LTE-Advanced will be a software upgrade for LTE
networks and enable peak download rates over 1Gbit/s that fully supports the 4G
requirements as defined by the ITU-R. It also targets faster switching between power
states and improved performance at the cell edge. A first set of requiremens has been
approved in June 2008.

6.3. Wi-MAX enhanced

27

WiMAX refers to broadband wireless networks that are based on the IEEE
802.16 standard, which ensures compatibility and interoperability between
broadband wireless access equipment. 802.16e is a new version of 802.16 standard
(WiMAX) which aims at a data speed of 1Gbps. It is also backward compatible
with existing WiMAX radios. It is based
on OFDMand MIMOantennatechnologies.

Figure 6.1: WiMAX Architecture

Mobile WiMAX is a major opportunity for systems designers who

understand the value of multi-antenna signal processing (MAS) technologies
such as multiple input/multiple output (MIMO) and adaptive antenna
systems. MAS technology addresses those service provider requirements by
extending cell radii, ensuring QoS and high throughput, and improving
network capacity, all of which reduce the need for additional BSs or
repeaters. These savings make the operator better able to price its mobile
28

WiMAX services competitively yet profitably. By selecting the right DSP for
their MAS-enabled mobile WiMAX products, systems designers can
differentiate their products (Figure 3.13). That ability is a major asset in a
market as crowded and competitive as WiMAX, where features and
performance are must-haves for standing out from the pack and justifying a
price premium

7.BENEFITS

7.1. Convergence of Cellular Mobile Networks and WLANs

Benefits for Operators:

Higher bandwidths.

Lower cost of networks and equipment.

The use of licence-exempt spectrum.

Higher capacity and QoS enhancement.

Higher revenue.

Users:

Access to broadband multimedia services with lower cost and where mostly needed.

Inter-network roaming.

7.2. Convergence of Mobile Communications and

Broadcasting From broadcaster point of view:
Introducing interactivity to their unidirectional point-to multipoint
29

Broadcasting systems. That is, a broadband downlink based on DAB/DVB-T

and a narrowband uplink based on 3G cellular systems.

From the cellular mobile operator point of view:

Providing a complementary broadband downlink in vehicular environments to
support IP- based multi-media traffic which is inherently asymmetrical.

7.3. Convergence Benefits

Broadcasters will benefit from the use of cellular

mobile systems to adapt the content of their multimedia services more rapidly in response to the
feedback from customers.

Cellular operators will benefit from offering their

customers a range of new broadband multi-media
services in vehicular environments.

Users will benefit from faster access to a range of

broadband multi-media services with reasonable
QoS and lower cost.

30

8.APPLICATIONS

Virtual Presence: This means that 4G provides user services at all times, even if the
user is off-site.

Virtual navigation: 4G provides users with virtual navigation through which a user
can access a database of the streets, buildings etc.

Tele-geoprocessing applications: This is a combination of GIS (Geographical

Information System) and GPS (Global Positioning System) in which a user can get
the location by querying.

Tele-Medicine and Educaton: 4G will support remote health monitoring of patients.

For people who are interested in life long education, 4G provides a good
opportunity.

Crisis management: Natural disasters can cause break down in communication

systems. In todays world it might take days or 7 weeks to restore the system. But in
4G it is expected to restore such crisis issues in a few hours.
31

8.1. MULTIMEDIA Video Services

4G wireless systems are expected to deliver efficient multimedia services at very high
data rates.

Basically there are two types of video services: bursting and streaming video services.

Streaming is performed when a user requires real-time video services, in which the
server delivers data continuously at a playback rate.

Bursting is basically file downloading using a buffer and this is done at the highest
data rate taking advantage of the whole available bandwidth.

8.2. Multiple Operators and Billing System

In todays communication market, an operator usually charges customers with

a simple billing and accounting scheme.

A flat rate based on subscribed services, call durations, and transferred data volume is
usually enough in many situations.

With the increase of service varieties in 4G systems, more comprehensive billing and
accounting systems are needed.

32

9.CONCLUSION
As the history of mobile communications shows,attempts have been made to
reduce a number of technologies to a single global standard. Projected 4G systems
offer this promise of a standard that can be
embraced worldwide through its key concept of integration. Future wireless
networks will need to support diverse IP multimedia applications to allow sharing
of resources among multiple users. There must be a low complexity of
implementation and an efficient means of negotiation between the end users and
the wireless infrastructure. The fourth generation promises to fulfill the goal of
33

PCC (personal computing and communication)a vision that affordably provides

high data rates everywhere over a wireless network.
4G is expected to be launched by 2010 and the world is looking forward for
the most intelligent technology that would connect the entire globe.

REFERENCES

1. Advances in Wireless Networks, Yasushi Yamao

2. The Next Generation Wireless Network, Cheng Cui & Zhiwei Li

34

Web Links
1. Wikipedia-

Title:

4G

http://en.wikipedia.org/wiki/4G
2. IEEE http://www.ieee.org
3. International Telecommunications Union
http://www.itu.org
4. 3GPP

Partnership

project

http://www.3gpp.org
5. 3GPP2

Partnership

project

http://www.3gpp2.org

35