to solve some of the main challenges that 4G is facing. The main challenges of 4G are described below
Multimode user terminals 4G: In order to access different kinds
of services and technologies, the user terminals should be able
to configure themselves in different modes. This eliminates the
need of multiple terminals. Adaptive techniques like smart
antennas and software radio have been proposed for achieving
terminal mobility.
Wireless system discovery and selection 4G: The main idea
behind this is the user terminal should be able to select the
desired wireless system. The system could be LAN, GPS, GSM
etc. One proposed solution for this is to use software radio
approach where the terminal scans for the best available
network and then it downloads the required software and
configure themselves access the particular network using 4G.
Terminal Mobility 4G: This is one of the biggest issues the
researchers are facing. Terminal mobility allows the user to
roam across different geographical areas that uses different
technologies. There are two important issues related to terminal
mobility using 4G. One is location management where the system has to
locate the position of the mobile for providing service. Another
important issue is hand off management. In the traditional
mobile systems only horizontal hand off has to be performed
where as in 4G systems both horizontal and vertical hand off
should be performed. As shown in figure 1, horizontal hand off
is performed
Personal mobility 4G: Personal mobility deals with the
mobility of the user rather than the user terminals. The idea
behind this is, no matter where the user is located and what
device he is using, he should be able to access his messages.
Security and privacy 4G: The existing security measures for
wireless systems are inadequate for 4G systems. The existing
security systems are designed for specific services. This does
not provide flexibility for the users and as flexibility is one of
the main concerns for 4G, new security systems has to be
introduced.
Fault tolerance 4G: As we all know, fault tolerant systems are
becoming more popular throughout the world. The existing
wireless system structure has a tree like topology and hence if
one of the components suffers damage the whole system goes
down. This is not desirable in case of 4G. Hence one of the
main issues is to design a fault tolerant system for 4G.
Billing System 4G: 3G mostly follows a flat rate billing system
based where the user is charged just by a single operator for his
usage according to call duration, transferred data etc. But in 4G
wireless systems, the user might switch between different
service providers and may use different services. In this case, it
is hard for both the users and service providers to deal with
separate bills.
