4G NETWORKS
Kiran Kodali
Department of Computer Science
University of North Texas
Kk0171@unt.edu
ABSTRACT
4G, Fourth Generation communications system is the next
step in wireless communications. With this 4G
technology we will get voice, data and streaming
multimedia on an ‘Anytime’, ‘Anywhere’ basis. 4G is
fully IP based and it is capable of providing a minimum
of 100Mbits/sec speeds both indoors and outdoors, with
good quality and security. It will also be provided at an
affordable cost. I can say 4G is simply an initiative to
overcome the problems and limitations in 3G. Most of the
countries like India, China, Korea are trying to move to
4G technology as the 3G technology has not been found
to be cost effective. According to the vice-president of
research at Telefonaktiebolaget LM Erricson, 4G phones
will be in the shops, Eight years from now. I will be
discussing different aspects about 4G networks in this
paper.
The Evolution Path Of 4G Networks
4G networks are seen as mix or combination of different
existing wireless technologies (e.g. WLAN, WMAN,
MANET, 2G, 2.5G, 3G) and future wireless technologies,
to continuously provide best possible service, by ensuring
Unlimited handovers from one technology to another.
Frequency Division Multiplexing and Time Division
Multiplexing are the two common methods used in
wireless systems. The main challenging issue of the 4G
cellular network is achieving high spectral efficiency and
guaranteed Quality of service for multimedia applications.
Previous generation mobile networks focused mainly on
achieving quality in voice transmission. But now
multimedia is the primary focus in 4G technology. One of
the most interesting applications in this area is Mobile
TV. 4G has its own advantages and challenging issues if
it uses either of the FDD or TDD systems. It is observed
that the Next generation technology will be based on
Orthogonal Frequency Division Multiplexing (OFDMA)
and Multiple Input Multiple Output (MIMO) antenna
technology in order to improve the spectral efficiency and
at the same time offer robust communications over
frequency selective fading channels. With the research
done so far in this field, it is observed that there is more
flexibility and benefit by using TDD system, than an FDD
system.
Features Of 4G Networks
There is much growing interest in 4G wireless networks
because of several interesting features of 4G technology.
4G will provide high network capacity which will allow
more number of users per cell. As there are many
heterogeneous networks existing in the current cellular
technology, 4G will provide smooth handoff’s between
these heterogeneous networks. It will also provide
interoperability between these different existing wireless
standards. It will provide a data rate of atleast 100 Mbps
between any two points in the world. It will solve the
existing roaming issues by providing seamless
connectivity across multiple networks. 4G exceeds the
covering range of 3D by ten times. It is a full IP based
network.
Issues In 4G networks
Deployment of 4G networks is not so far from reality.
Following issues need to be resolved to get this done.
The issues involving the multiple heterogeneous networks
are like handoff, location coordination, resource
coordination to new users, access, Support for
multicasting, support for quality of service, wireless
security and authentication, network failure and backup
and pricing and billing. These issues can be resolved by
implementing the appropriate network architectures. The
three possible architectures would be a multimode device,
an overlay network or a common access protocol. Quality
Of Service is one more important aspect in 4G networks.
Providing Quality Of Service is a challenging issue
because of the factors like varying bit rates, supporting
handoffs between various heterogeneous networks and
fault tolerance. QOS is ensured at various levels namely
User-level, Transaction-level, circuit-level and packetlevel. QOS is provided over the factors like jitter,
throughput and error-rate at Packet –level QOS. The
developers need to modify various existing QOS schemas
to address the problems in providing end-to-end QOS.
CONCLUSION
4G is not far away from its deployment. Although it
offers high bit rates and ability roam across multiple
heterogeneous
networks, several issues like QOS,
Security need much more research and development.
V. REFEREN CES
[1]An Integration Architecture to 4th generation Wireless
Networks , By Xu Yang and John Bigham.
[2]Rise Of the 4G Networks Enabling the Internet
Everywhere Experience ( white paper from Cisco)
[3]The Evolution Path of 4G Networks: FDD or TDD?
By Peter W.C. Chan, Ernest S. Lo, Ray R. Wang, Edward
K. S. Au, Vincent K. N. Lau, Roger S. Cheng, Wai Ho,
Mow, Ross D. Murch, and Khaled Ben Letaief, The Hong
Kong University of Science and Technology.
[4] Issues in Emerging 4G Wireless Networks. By Upkar
Varshney and Radhika Jain.