NAME: B.OBULIRAJ
BRANCH: B. E COMPUTER SCIENCE AND ENGINEERING
E-MAIL: obuliraj.avl@gmail.com
4G WIRELESS NETWORKS
Abstract :
The Third-Generation
(3G) wireless technologies offer wireless web, SMS, MMS, EDGE, WCDMA, GPRS etc.
4G is a packet switched technology, uses
bandwidth much more efficiently, allowing each user's packets to compete for
available bandwidth. It solves the non-standardization problems associated with
3G. Data transfer rate will be 20 to 100 Mbps, which is 10 to 50 times than 3G
and 10-20 times faster than ADSL. Operating
frequency range will be 3 to 10 GHz and the IPv6 protocol will be used. In this
paper, fundamentals of 4G and their various proposed architectures are
explained. In India
it can be used to network rural and urban areas, reduce cost of communication,
flourish educational activities, facilitate research and development, faster
internet connectivity, more cellular options, real time information systems,
crisis management, Tele-medicines and many more. The present 3G networks need
not to be discarded, and can be used in conjunction with 4G technology. There
are various architectures proposed that can be used to deploy 4G.
4G Wireless Networks
1.
Introduction
The fourth-generation wireless (4G)
technology implements designs that will take the wireless telecommunication
industry beyond 2010. The infrastructure of the 4G will function on top of the
current existing CDMA, GSM and TDMA. It extends the 3G capabilities These technical opportunities
strengthen the user mobility and encourage the deployment of the mobile
technologies for the development of various (mobile) applications providing
information, orientation (routing) and other helpful services.
Fig1.
INCREMENTAL PROGRESS OF WIRELESS TECHNOLOGY
It will deliver superior quality video and data, in addition to voice. It
also solves the non-standardization problems associated with 3G networks for
voice, video and data transmission. The data transfer rate is 20 to 100 Mbps,
which will be 10 to 50 times those offered by 3G links and 10-20 times faster
than standard ADSL (Asymmetric Digital Subscriber Line) services. The operating frequency
ranges between 3 to 10 GHz and the IPV6 protocol used will be used.
High-definition television programming through wireless broadband connections,
Internet-based multi-channel video and higher mobile Internet will become a
reality. The Defense Advanced Research Projects Agency (DARPA) in the US
originally conceived of 4G.
2. Need of 4G:
- 3G performances insufficient to meet high performance future needs.
- Multiple incompatible standards. Global mobility and service portability required.
- Need for hybrid networks for both WLAN and cellular network design.
- Technology to utilize newly found modulation methods.
- Need for All IP network with converged voice and data capability.
- Wider bandwidth.
3. Characteristics
3.1
End-to-End Internet Protocol (IP):. It will
provide access through a collection of radio interfaces, seamless
roaming/handover and the best-connected service, combining multiple radio
access interfaces (such as WLAN, Bluetooth and GPRS) into a single network that
subscribers may use. It allows any mobile device to seamlessly roam over
different wireless technologies automatically, using the best connection
available for the intended use. Users will have access to different services,
increased coverage, the convenience of a single device, one bill with reduced
total access cost, and more reliable wireless access even with the failure or
loss of one or more networks.
3.2
Peer-to-Peer networks: In this system,
every device is both a transceiver and a router/repeater for other devices in
the network, elimination of a single node does not disable the network. 4G can
be defined as "wireless ad hoc peer-to-peer networking."
4. Significance of 4G
In 4G
networks, users joining the network add mobile routers to the network
infrastructure. Network capacity and coverage is dynamically shifted to
accommodate changing user patterns. Wherever the concentration of people is
more in one area, additional routes are created, thus enabling additional
access to network capacity. Users will automatically hop away from congested
routes to less congested routes. This permits the network to dynamically and
automatically balance capacity and increase network utilization. As number of
users increases, the service improves for all users.
5. Features of 4G
High
speed: 100 Mbps in stationary mode with an average of
20 Mbps when traveling.
High
network capacity: Should be at least 10 times
that of 3G systems.
Fast/seamless
handover across multiple networks: 4G
wireless networks should support global roaming across multiple wireless and
mobile networks,
Next-generation
multimedia support: fast speed and large volume data transmission
at a lower cost than today.MIMO techniques
: The benefit of array or multiple antennas
for spatial diversity has long been realized. Yet only recently were they
combined with advanced coding techniques to from extremely efficient MIMO
(Multiple Input Multiple Output) systems.
Wireless
access technologies: OFDMA
(Orthogonal Frequency – Division Multiple Access ) and MC-CDMA (Multiple
Carrier CDMA) are the main contender for the future system. Another more
radical access scheme for the downlink, yet better in terms of throughput, is a
single queue packet based system
6. Future applications
Sensors
on public vehicles
Cameras
in traffic lights
Tele-medicine:
a paramedic assisting a victim of a traffic
accident in a remote location could access medical records (e.g., x-rays) and
establish a videoconference so that a remotely-based surgeon could provide
"on-scene" assistance.
Crisis-management
applications: In case of any natural
disasters where the entire 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 may take days or even weeks to
re-establish communications capabilities when a wire line network fails.
7. Possible Architectures on 4G
One of the most challenging problems
facing deployment of 4G technology is how to access several different mobile
and wireless networks. Three possible architectures: using a multi-mode device,
an overlay network, or a common access protocol.
7.1 Multimode devices (Fig2):
A single physical terminal with multiple
interfaces to access services on different wireless networks. The multimode
device architecture may improve call completion and expand effective coverage
area. It should also provide reliable wireless coverage in case of network,
link, or switch failure. The device itself incorporates most of the additional
complexity without requiring wireless network modification or employing
inter-working devices. Each network can deploy a database that keeps track of
user location, device capabilities, network conditions, and user preferences.
The handling of quality-of-service (QoS) issues remains an open research
question.
Fig 2. A multimode device lets the user, device, or
network initiate handoff between networks without the need for network
modification or interworking devices.
7.2 Overlay mode (Fig 3) :
In this architecture, a user accesses an
overlay network consisting of several universal access points. These UAPs in
turn select a wireless network based on availability, QoS specifications, and
user-defined choices. A UAP performs protocol and frequency translation,
content adaptation, and QoS negotiation-renegotiation on behalf of users. The
overlay network, rather than the user or device, performs handoffs as the user
moves from one UAP to another. A UAP stores user, network, and device
information, capabilities, and preferences. Because UAPs can keep track of the
various resources a caller uses, this architecture supports single billing and
subscription. Satellite network Fixed wireless networks.
Fig
3. An overlay network—consisting 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.
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 asynchronous transfer mode. To implement wireless ATM, every
wireless network must allow transmission of ATM cells with additional headers
or wireless ATM cells requiring changes in the wireless networks. One or more
types of satellite-based networks might use one protocol while one or more
terrestrial wireless networks use another protocol. Wireless LAN Cellular network
Fig
4. A device capable of automatically switching between networks is possible if
wireless networks can support a common protocol to access a satellite-based
network and another protocol for terrestrial networks.
|
7.4 The proposed Architecture for 4G:
Legends used in the diagram:
 |
Bi-directional block arrow Wireless Link
Antenna Repeater
 |
Cylinder Local
Database
Rectangle Organization
Fig 5. Several networks can
be converged with the 4G networks providing all kinds of services to the
users.
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 be a major
issue when several networks will be connected together.
A legal subscriber can view
various television networks in his/her handset, browse through to the internet
at a very high speed connectivity, send e-mails remotely, reserve train or air
tickets from any part of the country, stay connected with their professors and
many more things at a very reduced cost.
Repeaters will give mobile
Internet at a speed of 20mbps; optical cables can also contribute to the data
transmissions. Different organizations can stay connected with each other and
their customers,
8. Conclusion
4G is
the next upcoming wireless technology. It holds a lot of promises in solving
today’s problems and tomorrows needs. 4G
will also make worldwide roaming using a single handheld device. 4G 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 general public. Equally as important, 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 wireless communications evolve. This
evolution will give the general public as well as the public safety community
amazing functionality from the convenience of a single handheld device.
9. References:
- International forums on 4G mobile, By : Lucant technologies, bell labs innovations
- Fraunhofer Institute for Secure Telecooperation (SIT) August 02. [bayarou|rohr]@sit.fraunhofer.de
- Information Raining for Mobile Hotspots in 4G Wireless Networks : Shahrokh Valaee , Department of Electrical and Computer Engineering ,University of Toronto, Toronto, Ontario, Canada, Email: valaee@comm.utoronto.ca
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