Advancements Towards 4G

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Submitted by


in partial fulfillment for the award of the degree









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Certified that this is a bonafide record of the seminar work entitled


done by the following student


Of the VII th semester Computer Science and Engineering in the year 2008

in partial fulfillment of the requirements to the award of Degree of Bachelor

of Technology in Computer Science and Engineering of

Cochin University of Science and Technology

Mrs. Rahna P Muhammad Dr. David Peter S

Seminar Guide Head of the Department


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I thank my seminar guide Ms. Rehna, Lecturer, CUSAT, for her

proper guidance and valuable suggestions. I am greatly thankful to Mr.

David Peter, the HOD, Computer Science Division & other faculty members

for giving me an opportunity to learn and do this seminar. If not for the

above mentioned people, my seminar would never have been completed

successfully. I once again extend my sincere thanks to all of them.


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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


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.

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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.

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List of Tables iii

List of Figures iv



3. VISION OF 4G 06

3.1. Objectives of 4G 07

3.2. An All IP Network 08

3.3. Developments 09


4.1. Access Schemes 11

4.2. OFDMA 12

4.2.1. OFDMA Advantages 13

4.3. MIMO 14

4.3.1. Functions of MIMO 14

4.4. IPV6 15

4.5. VoIP 16

4.5.1. Functionality 17

4.6. Software Defined Radio 18



6.1. UMB 21

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6.2. 3GPP LTE 22

6.3. WiMAX Enhanced 23


7.1. Convergence of Cellular Networks and WLANs 25

7.2. Convergence of Mobile Communications and Broadcasting 25

7.3. Convergence Benefits 26


8.1 Multimedia Video Services 27

8.2 Multiple Operators and billing system 28



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2.1 Wireless System Evolution 3

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Figure 3.1. Seamless Connection of Networks 07

Figure 6.1. WiMAX Architecture 24

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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


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 Gbit/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 WiMax, which is part of the

formal ITU 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

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wireless industry.


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

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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

Table 2.1. Short History of Mobile Telephone Technologies


1xRTT = 2.5G CDMA data service up to 384 kbps

AMPS = advanced mobile phone service

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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 = pubic switched telephone network

TACS = total access communications system

TDMA = time division multiple access

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, Hicap, CDPD, Mobitex, DataTac,


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,


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

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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.

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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


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


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 be the mobile telephone, PDA, and laptop to seamlessly access the 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 all-encompassing integrated perspective shows

the broad range of systems that the fourth generation intends to integrate, from satellite

broadband to high altitude platform to cellular 3G and 3G systems to WLL (wireless

local loop) and FWA (fixed wireless access) to WLAN (wireless local area network) and

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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 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

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"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 utilise network resources to meet

the minimal requirements of all the 4G enabled users.

3.2. An "All IP Network" (AIPN)

A characteristic of so-called "4G" networks such as LTE is that they 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

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

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competing legacy systems such as CDMA2000 and WiMAX. Users of non-UMTS 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.

Digiweb, 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

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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 Breitband 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.

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.

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4.1. Access schemes

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, MC-CDMA 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

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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.

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

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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


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


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

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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.

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 all of the receive antenna and precoding is used. Note that precoding requires

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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


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 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 packet-switched

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

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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 3.4×1038) addresses, or

approximately 5×1028 (roughly 295) addresses for each of the roughly 6.5 billion (6.5×109)

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


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

address space to assure geographical saturation with usable addresses. Rather, the 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.

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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

(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; zero- or 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

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with VoIP. It is only necessary to encrypt and authenticate the existing data stream.

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 with other services available over the Internet, including 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


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


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, detectors. etc.) are instead implemented using software on 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. 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

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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


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

realizable, however.

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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.

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-


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.

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6.1. UMB: Ultra mobile broadband

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

improve the CDMA2000 mobile phone standard for next generation applications 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.

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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.

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

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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

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

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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 OFDM and MIMO antenna technologies.

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 WiMAX services competitively yet profitably. By selecting the right DSP

for their MAS-enabled mobile WiMAX products, systems designers can differentiate

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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


7.1. 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.


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

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:

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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 multi-media 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.

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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 today’s 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.

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.

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8.2. Multiple Operators and Billing System

In today’s 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.

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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 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.

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1. Advances in Wireless Networks, Yasushi Yamao

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

Web Links

1. Wikipedia- Title: 4G




3. International Telecommunications Union


4. 3GPP Partnership project


5. 3GPP2 Partnership project