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    4G WIRELESS COMMUNICATION



                                             Presented by

                                       MOHAN.S (FINALCSE)

                                       HARI.R (FINALCSE)

E-mail id: mohancse77@yahoo.com        Contact no: 9381443702
           harrie16cse@gmail.com                  9994740740
                                    ABSTRACT:
       In this present world, Science and technology shows a remarkable growth in all
fields one such field is wireless technology. Now the world is marching towards a new
era in wireless communication that is 4th generation. The 4th generation overcomes the
problem faced by the 3rd generation to a considerable extent. It adds up the greater
transmission rate, with high bit rate, greater design flexibility, with greater security since
security is much important in this advanced world.
       This paper presents an overall vision of the Fourth Generation (4G) features,
framework and integration of mobile communication. The features of 4G systems might
be summarized with one word-integration. The 4G systems are about seamlessly
integrating terminals, networks and applications to satisfy increasing user demands.
       The term 4G is used broadly to include several types of broadband wireless access
communication systems, not only cellular telephone systems. One of the terms used to
describe 4G is MAGIC—Mobile multimedia, anytime anywhere, Global mobility
support, Integrated wireless solution, and Customized personal service. As a promise for
the future, 4G systems, that is, cellular broadband wireless access systems have been
attracting much interest in the mobile communication arena. The 4G systems not only
will support the next generation of mobile service, but also will support the fixed wireless
networks.
       The approaching 4G mobile communication systems are projected to solve still-
remaining problems of 3G (third generation) systems and to provide a wide variety of
new services, from high-quality voice to high-definition video to high-data-rate wireless
channels. 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.
       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, Personal Digital Assistant (PDA), and laptop to seamlessly access the voice
communication, high-speed information services, and entertainment broadcast services.
The continuous expansion of mobile communication and wireless networks shows
evidence of exceptional growth in the areas of mobile subscriber, wireless network
access, mobile services, and applications.
       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.


       Key words: MAGIC, Wireless Internet and PDA.
INTRODUCTION
4G (or 4-G) is short for fourth-generation the successor of 3G and is a wireless
access technology. It describes two different but overlapping ideas.



   1. 4G technology stands to be the future standard of wireless devices. The Japanese
       company NTT DoCoMo is testing 4G communication at 100 Mbit/s while
       moving, and 1 Gbit/s while stationary. NTT DoCoMo plans on releasing the first
       commercial network in 2010. Despite the fact that current wireless devices
       seldom utilize full 3G capabilities, there is a basic attitude that if you provide the
       pipeline then services for it will follow.
   2. Pervasive networks. An amorphous and presently 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 UMTS, EDGE or any other future access technology.

      Ideally, 4G would provide users with on demand high quality video and audio.
The killer application of 4G is not clear, but video is one of the big differences between
4G and 3G. 4G may use OFDM (Orthogonal Frequency Division Multiplexing), and also
OFDMA (Orthogonal Frequency Division Multiple Access) to better allocate network
resources to multiple users. 4G devices may use SDR (software-defied radio) receivers
which allows for better use of available bandwidth as well as making use of multiple
channels simultaneously.

       Unlike the 3G networks which are a complex circuit switched and packet
switched networks, 4G will be based on packet switching only. This will allow low-
latency data transmission.
 ABOUT PREVIOUS GENERATION
         The history and evolution of mobile service from the 1G(first generation) to fourth
generation are discussed in this section.
         This process began with the designs in the 1970s that is termed 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) in the U.S.; and CDMA
(code division multiple access) 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.
          Table presents a short history of mobile telephone technologies.




Legend:
1xRTT = 2.5G CDMA data service up to 384 kbps GSM = global system for mobile
AMPS = advanced mobile phone service             NMT = Nordic mobile telephone
CDMA = code division multiple access              PDC = personal digital cellular
EDGE = enhanced data for global evolution         PSTN = pubic switched telephone
FDMA = frequency division multiple access         network
GPRS = general packet radio system                WCDMA = wideband CDMA
TACS = total access communications system
TDMA = time division multiple access
Motivation for 4G Research Before 3G Has Not Been Deployed?

      3G performance may not be sufficient to meet needs of future high-performance
       applications like multi-media, full-motion video, wireless teleconferencing. We
       need a network technology that extends 3G capacity by an order of magnitude.
      There are multiple standards for 3G making it difficult to roam and interoperate
       across networks. We need global mobility and service portability
      3G is based on primarily a wide-area concept. We need hybrid networks that
       utilize both wireless LAN concept and cell or base-station wide area network
       design.
      We need wider bandwidth
      Researchers have come up with spectrally more efficient modulation schemes that
       can not be retrofitted into 3G infrastructure
      We need all digital packet networks that utilizes IP in its fullest form with
       converged voice and data capability.
      Support interactive multimedia services: teleconferencing, wireless Internet, etc.
      Wider bandwidths, higher bit rates.
      Global mobility and service portability.
      Low cost.
      Scalability of mobile networks.

What's New in 4G

      Entirely packet-switched networks.
      All network elements are digital.
      Higher bandwidths to provide multimedia services at lower cost (up to 200Mbps).
      Tight network security.
Comparison of 3G and 4G
                 3G                                            4G

                                                  Extend 3G capacity by one order of
   Back compatible to 2G.
                                                  magnitude.
   Circuit and packet switched networks.          Entirely packet switched networks.
   Combination of existing & evolved
                                                  All network elements are digital.
   equipment.
                                                  Higher          bandwidth            (upto
   Data rate (up to 2Mbps).
                                                  200Mbps).


4TH GENERATION
       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 be the mobile telephone,
PDA, and laptop to seamlessly access the voice communication, high-speed information
services, and entertainment broadcast services. The fourth generation will encompass all
systems from various networks, public to private and operator-driven broadband
networks to personal areas. 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 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.
       This Figure illustrates elements and techniques to support the adaptability of the
4G domain.




                                Figure: 4G Visions
The following Figures demonstrate the key elements and the seamless connectivity
                                of the networks.




                                                                                   \
                 Figure: Key Elements of 4G Vision
                Figure: Seamless Connections of Networks



       GSM is a circuit-switched system that divides each 200 kHz channel into eight
25 kHz time-slots. GSM operates in the 1.9GHz PCS band in the US.

       CDMA operates in the 800MHz band and 1.9GHz PCS band and supports data
        transfer speeds of up to 14.4 kbit/s.
       TDMA, used as a digital upgrade for analog cellular, it divides each cellular
        channel into three time slots, tripling the data capacity from analog technology.
       Cellular Digital Packet Data (CDPD): A wireless data-only packet overlay for
        the existing analog AMPS network in the U.S., CDPD shunts data over unused
        intervals in the voice channels. It has a data transfer rate of 19.2 kbit/s.
3G Evolution
       Cellular providers use two frequencies in all their "evolutions" to 3G. Some
wireless network providers like Sprint PCS and Verizon Wireless use CDMA, while
Nextel is based on iDEN technology. AT&T Wireless, Cingular and Voice Stream are the
three TDMA/GSM carriers. To reach 3G status, all three GSM carriers will have to
upgrade their networks in stages, from GPRS (general packet radio service) to EDGE
(enhanced data for GSM evolution) to the eventual 3G destination, UMTS (universal
mobile telecommunications system).


Community LANs
       Community LANs, using the unlicensed 2.4 and 5 GHz bands, are restricted in
power and bandwidth and are more prone to interference since the frequencies are
available for anyone. The 2.4 GHz band has "only" 85 MHz while 5 Ghz band has a total
of 300 MHz - although only 5.25-5.35 and 5.725-5.825 (200 MHz total) can be used
outdoors. The 5.8 GHz band may have the most potential to deliver "backbone" service
because more power is allowed (up to 200 watts - EIRP). Combined with "smart
antennas" and "mesh" networking, many companies are convinced that the unlicensed 5
GHz will provide the most cost/effective solution for community networks.




DIFFERENCE BETWEEN CDMA AND W-CDMA
TDMA

      Time division multiplexing use a single channel to communicate - Time Division.
This works fine for data but is problematic for voice. With enough speed, however, the
two-way voice is possible. Time Division Duplexing (TDD) provides a scheme where a
single channel is used for both upstream and downstream transmissions. A TDD system
can dynamically allocate upstream and downstream bandwidth depending on traffic
requirements.

          Instead of needing two spectrum channels (one for transmit and one for receive),
companies like Arraycomm can do both over one. TDD is well suited to Internet access
as there is much downloading and little uploading, but problematic for voice - where the
split is more even. The use of this technique saves 3G bidders precious cash as they bid
for less spectrum. That was what brought Arraycomm to Australia. Australia let
Arraycomm bid on only "half" on the 3G spectrum. Most "4G" systems intend to use
licensed frequencies, usually in the 2.5 GHz MMDS band. But the unlicensed 5.8 GHz
band could become the proving ground for a range of last mile services.

Nextel May Try "4G"

          In the United States, Nextel may be planning to use Flarion's system before the
end of the year. Nextel is already testing Flarion's equipment.

   Nextel's spectrum realignment plan is being deliberated by the FCC. The proposal
calls for Nextel to exchange 16 megahertz of spectrum spread around the 700 MHz, 800
MHz and 900 MHz bands for 6 megahertz in the upper 800 MHz band and 10 megahertz
in the 2.1 GHz band. If approved, this would leave Nextel with 16 megahertz of
contiguous spectrum in the upper 800 MHz band, on which the carrier could continue to
offer its voice service, and 10 megahertz in the 2.1 GHz band to offer 3G services in the
future.
Expect 4G telephony in 2012

       Probably, in 2012 there would be 4G products on the market. 4G is a mobile
telephony work at a data rate of 100Mbps globally, that is, between any two points in the
world. Locally, 1G bps will be possible. Transmitting a hundred megabits per second
between two points at short range is not difficult. We can do that now. What's hard is to
make it work between any two points on the globe.
        New mobile telephony systems were launched about every 10 years, What took
time was not just developing the technology: It was necessary to find available radio
frequencies for the new systems, preferably the same frequency everywhere. The costs of
adapting technology to different local systems were becoming less and less acceptable.




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
PCC (personal computing and communication)—a vision that affordably provides high
data rates everywhere over a wireless network.


REFERENCES
1. B. G. Evans and K. Baughan, "Visions of 4G,"
Electronics and Communication Engineering
Journal, Dec. 2002.
2.T.Rappaport,”wireless communication”.2w222

				
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