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									                                   4G WIRELESS NETWORKS

                        4G WIRELESS NETWORKS

Abstract                                             This paper explains, fundamentals of
       The Third-Generation (3G) wireless     4G and their various proposed architectures.
technologies offer wireless web, SMS,         In India it can be used to network rural and
MMS, EDGE, WCDMA, GPRS etc. 4G is a           urban areas, reduce cost of communication,
packet switched technology, uses bandwidth    flourish educational activities, facilitate
much more efficiently, allowing each user's   research and development, faster internet
packets to compete for available bandwidth.   connectivity, more cellular options, real time
It solves the non-standardization problems    information systems, crisis management,
associated with 3G. Data transfer rate will   Tele-medicines and many more. The present
be 20 to 100 Mbps, which is 10 to 50 times    3G networks need not to be discarded, and
than 3G and 10-20 times faster than ADSL.     can be used in conjunction with 4G
Operating frequency range will be 3 to 10     technology. There are various architectures
GHz and the IPv6 protocol will be used.
                                    4G WIRELESS NETWORKS

1. Introduction
       The fourth-generation wireless (4G)
technology implements designs that will                It will deliver superior quality video
take      the   wireless   telecommunication   and data, in addition to voice. It also solves
industry beyond 2010. The infrastructure of    the non-standardization problems associated
the 4G will function on top of the current     with 3G networks for voice, video and data
existing CDMA, GSM and TDMA. It                transmission. The data transfer rate is 20 to
extends the 3G capabilities These technical    100 Mbps, which will be 10 to 50 times
opportunities strengthen the user mobility     those offered by 3G links and 10-20 times
and encourage the deployment of the mobile     faster than standard ADSL (Asymmetric
technologies for the development of various    Digital Subscriber Line) services. The
(mobile) applications providing information,   operating frequency ranges between 3 to 10
orientation (routing) and other helpful        GHz and the IPV6 protocol used will be
services.                                      used.        High-definition          television
                                               programming through wireless broadband
                                               connections, Internet-based multi-channel
                                               video and higher mobile Internet will
                                 4G : 0.15     become a reality. The Defense Advanced
                       3G :      bits/sec/H
            2G :       0.30bit   z             Research Projects Agency (DARPA) in the
            0.15       s/sec/H   Adaptive
 1G :                                          US originally conceived of 4G.
            bits/sec   z         modulati
            /Hz        CDM       on
            Digital    A,        MIMO
 modu                                          2. Need of 4G:
            modula     Turbo     Adaptive
            tion       coding,   Modulati             3G performances insufficient to meet
                       wider     on
                       bandw                           high performance future needs.
                       idth      MC-                  Multiple    incompatible      standards.
                                 CDMA                  Global     mobility     and     service
                                                       portability required.
                                                      Need for hybrid networks for both
  Fig1. INCREMENTAL PROGRESS OF                        WLAN and cellular network design.
                                          4G WIRELESS NETWORKS

         Technology to utilize newly found
          modulation methods.                        4. Significance of 4G
         Need for All IP network with                      In 4G networks, users joining the
          converged voice and data capability.       network add mobile routers to the network

         Wider bandwidth.                           infrastructure.   Network      capacity     and
                                                     coverage     is   dynamically     shifted    to
                                                     accommodate       changing     user   patterns.

3. Characteristics                                   Wherever the concentration of people is

3.1 End-to-End Internet Protocol (IP):. It           more in one area, additional routes are

will provide access through a collection of          created, thus enabling additional access to

radio interfaces, seamless roaming/handover          network capacity. Users will automatically

and the best-connected service, combining            hop away from congested routes to less

multiple radio access interfaces (such as            congested routes. This permits the network

WLAN, Bluetooth and GPRS) into a single              to dynamically and automatically balance

network that subscribers may use. It allows          capacity and increase network utilization. As

any mobile device to seamlessly roam over            number of users increases, the service

different            wireless         technologies   improves for all users.

automatically, using the best connection
available for the intended use. Users will           5. Features of 4G
have access to different services, increased         High speed: 100 Mbps in stationary mode

coverage, the convenience of a single                with an average of 20 Mbps when traveling.

device, one bill with reduced total access           High network capacity: Should be at least

cost, and more reliable wireless access even         10 times that of 3G systems.

with the failure or loss of one or more              Fast/seamless handover across multiple
networks.                                            networks: 4G wireless networks should
                                                     support global roaming across multiple

3.2 Peer-to-Peer networks: In this system,           wireless and mobile networks,

every device is both a transceiver and a             Next-generation multimedia support: fast

router/repeater for other devices in the             speed and large volume data transmission at

network, elimination of a single node does           a lower cost than today.

not disable the network. 4G can be defined
as       "wireless     ad       hoc   peer-to-peer   MIMO techniques : The benefit of array or

networking."                                         multiple antennas for spatial diversity has
                                          4G WIRELESS NETWORKS

long been realized. Yet only recently were          line network fails.7. Possible Architectures
they combined      with     advanced      coding    on 4G
techniques to from extremely efficient                       One      of     the    most    challenging
MIMO (Multiple Input Multiple Output)               problems        facing     deployment       of    4G
systems.                                            technology is how to access                   several
Wireless access technologies: OFDMA                 different.
(Orthogonal Frequency – Division Multiple           7.1 Multimode devices (Fig2):
Access ) and MC-CDMA (Multiple Carrier              A single physical terminal with multiple
CDMA) are the main contender for the                interfaces to access services on different
future system.                                      wireless networks. The multimode device
                                                    architecture may improve call that a
   Another more radical access scheme for           completion and expand effective coverage
the downlink, yet better in terms of                area. It should also provide reliable wireless
throughput, is a single queue packet based          coverage in case of network, link, or switch
system                                              failure. The device itself incorporates most
                                                    of    the    additional        complexity     without
6. Future applications                              requiring wireless network modification or
Sensors on public vehicles Cameras in               employing inter-working devices. Each
traffic lights                                      network can deploy a database that keeps
Tele-medicine: a paramedic assisting a              track of user location, device capabilities,
victim of a traffic accident in a remote            network conditions, and user preferences.
location could access medical records (e.g.,        The handling of quality-of-service (QoS)
x-rays) and establish a videoconference so          issues remains an open research question.
that a remotely-based surgeon could provide
"on-scene" assistance.
Crisis-management applications: In case              D                                                            D
                                                     B                                                            B
of any natural disasters where the entire                                                  INTE
communications           infrastructure      has
collapsed, restoring communications quickly
is essential. With 4G networks it can be set
up in a matter of hours. In comparison, it                                                            network
may take days or even weeks to re-establish
communications capabilities when a wire
                                             4G WIRELESS NETWORKS

  mobile        and   wireless   networks.    Three    universal access points. These UAPs in turn
  possible architectures: using a multi-mode           select     a     wireless     network       based   on
  device, an overlay network, or a common              availability, QoS specifications, and user-
  access protocol.                                     defined choices. A UAP performs protocol
                                                       and       frequency          translation,      content
                                                       adaptation,         and       QoS       negotiation-
           Fig 2 A multimode device lets the           renegotiation on behalf of users. The overlay
  user,    rs    modification    or   interworking     network, rather than the user or device,
  devices. device, or network initiate handoff         performs handoffs as the user moves from
  between networks without the need for                one UAP to another. A UAP stores user,
  network        modification    or   interworking     network,          and       device      information,
  devices.                                             capabilities, and preferences. Because UAPs
                                                       can keep track of the various resources a
  7.2 Overlay mode (Fig 3) :                           caller uses, this architecture supports single
           In this architecture, a user accesses       billing and subscription. Satellite network
  an overlay network consisting of several             Fixed wireless network.


                                                              Fig 3. An overlay network—consisting
                                         network       of several universal access points (UAPs)
                                                       that     store    user,     network,    and    device
                                                       information—performs a handoff as the user
                                                       moves from one UAP to another.
                                         4G WIRELESS NETWORKS

     7.3 Common access protocol (Fig4):
            This protocol becomes viable if
     wireless networks can support one or two
     standard access protocols. One possible
     solution, which will require interworking
     between different networks, uses wireless                 Fig 4. A device capable of automatically
     asynchronous transfer mode. To implement            switching between networks is possible if
     wireless ATM, every wireless network must           wireless networks can support a common
     allow transmission of ATM cells with                protocol to access a satellite-based network
     additional headers or wireless ATM cells            and another protocol for terrestrial networks.
     requiring changes in the wireless networks.
                                                            Fig 5 shows the real scenario of how 4G
                                                         can    really   mingle    with   the    present
                                                         technology and scale upward to give more
                                                         bandwidth and lower the cost. Security will
            One or more types of satellite-based         be a major issue when several networks will
     networks might use one protocol while one           be connected together.
     or more terrestrial wireless networks use
     another protocol. Wireless LAN Cellular             7.4 Generation of Wireless Technology:
     network                                                      The first generation of wireless
                                                         mobile communications was based on
                                                         analog      signalling.   Analog       systems,
DB                                                  DB
                                                         implemented in North America, were known
                                                         as Analog Mobile Phone Systems (AMPS),
                                                         while systems implemented in Europe and
                                                         the rest of the world were typically
                                                         identified as a variation of Total Access
 Wireless                               network          Communication Systems (TACS). Analog
 LAN                                                     systems were primarily based on circuit-
                                                         switched technology and designed for voice,
                                                         not data.
                  Tunable adapter
                                   4G WIRELESS NETWORKS

     The second generation (2G) of the       technologies. HSCSD is one step towards
wireless mobile network was based on low-    3G wideband mobile data networks.
band digital data signalling. The most           Figure 2 shows the protocols used in
popular 2G wireless technology is known as   BTS, BSC, SGSN, GGSN, and mobile
Global Systems for Mobile Communications     handsets:
Figure 1 shows a GPRS network.

      Today, GSM systems operate in the
900MHz and 1.8 GHz bands throughout the
world with the exception of the Americas          3G wireless technology represents the
where they operate in the 1.9 GHz band.      convergence     of   various   2G   wireless
2G+ technology that is packet-based and      telecommunications systems into a single
increases the data communication speeds to   global system that includes both terrestrial
as high as 384kbps.                          and satellite components. One of the most
    Another one is 2G+ systems are based     important aspects of 3G wireless technology
on the following technologies: High Speed    is its ability to unify existing cellular
Circuit-Switched Data (HSCSD), General       standards, such as CDMA, GSM, and
Packet Radio Service (GPRS) and Enhanced     TDMA, under one umbrella.
Data Rates for Global Evolution (EDGE)           Figure 3 shows the 3G wireless network
                                     4G WIRELESS NETWORKS

     The existing core technology used in
mobile networks is based on traditional
circuit-switched technology for delivery of
voice services. However, this traditional
technology is inefficient for the delivery of
multimedia services. The core switches for
next-generation of mobile networks will be
based on packet-switched technology which
is better suited for data and multimedia

                                                                 Televison satellite
                       educational                                     \tellite

                                                4G          4G
            RAILWAYS                      GOVERNMENT        DB
                               NN                                                 OP
                                  4G WIRELESS NETWORKS

                                            7.5 The proposed Architecture for 4G:

 Legend used in the diagram:                      Fig 6. Several networks can be
                                            converged with the 4G networks providing
            Bi-directional block arrow      all kinds of services to the users.

                                                   A legal subscriber can view various
              Antenna                       television networks in his/her handset,
                                            browse through to the internet at a very high
                                            speed connectivity, send e-mails remotely,
              Rectangle                     reserve train or air tickets from any part of
                                            the country, stay connected with their
                                            professors and many more things at a very
              Cylinder                      reduced cost.
                                                  Repeaters will give mobile Internet at
                                            a speed of 20mbps; optical cables can also
                                            contribute   to    the   data    transmissions.
                                         4G WIRELESS NETWORKS

Different organizations can stay connected          general    public.   Equally   as   important,
with each other and their customers,                industry must ensure that expectations are
                                                    realistic and that services meet and exceed
                                                    those expectations. If all goes according to
                                                    what the industry envisions, it may be
                                                    sooner, rather than later that we will see
         4G is the next upcoming wireless
                                                    wireless    communications     evolve.   This
technology. It holds a lot of promises in
                                                    evolution will give the general public as
solving today’s problems and tomorrows
                                                    well as the public safety community
needs.      4G will also make worldwide
                                                    amazing functionality from the convenience
roaming using a single handheld device. 4G
                                                    of a single handheld device.
networks may eventually deliver on all the
promises.     At    times,   it    seems     that
technological advances are being made on a
daily basis. These advances will make high-
speed        data/voice-over-Internet-protocol
(VoIP) networks a reality. In the meantime,
it is important for industry to develop a
strong 3G offering that is palatable for the

        International forums on 4G mobile,
         By : Lucant technologies, bell labs
        Fraunhofer    Institute   for     Secure
         Telecooperation (SIT) August 02.
        Information   Raining     for Mobile
         Hotspots in 4G Wireless Networks :
         Shahrokh Valaee , Department of
         Electrical and Computer Engineering
         ,University of Toronto, Toronto,
         Ontario,       Canada,            Email:

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