Wireless and Mobile Communication Networks
Communication without being physically tied-up to wires has always been of interest and mobile and
wireless communication networks promise that. The last few years have witnessed unprecedented growth
in wireless communication networks. Significant advancements have been made in the technologies that
support wireless communication environment and there is much more to come in the future. The devices
used for wireless communication require certain features that wired communication devices may not
necessarily need. These features include low power consumption, light weight, and worldwide communication
ability.
In wireless and mobile communication networks, the access to a communication network is wireless
so that the end users remain free to move. The rest of the communication path could be wired, wireless, or combination of the two. In general, a mobile user, while communicating, has a wireless connection with
a fixed communication facility and rest of the communication path remains wired. The range of wireless
communication is always limited and therefore the range of user mobility is also limited. To overcome this
limitation, the cellular communication environment has been devised. In a cellular communication environment,
a geographical region is divided into smaller regions called cells, thus the name cellular. Each
cell has a fixed communication device that serves all mobile devices within that cell. However, as a mobile
device, while in active communication, moves out of one cell and into another cell, service of that connection
is transferred from one cell to another. This is called the handoff process [7,16].
The cellular arrangement has many attractive features. As the cell size is small, the mobile devices do
not need very high transmitting power to communicate. This leads to smaller devices that consume less
power. In addition, it is well known that the frequency spectrum that can be used for wireless communication
is limited and can therefore support only a small number of wireless communication connections
at a time. Dividing communication regions into cells allows the use of the same frequency in different cells
as long as they are sufficiently far apart to avoid interference. This increases the number of mobile devices
that can be supported. Advances in digital signal processing algorithms and faster electronics have led to
very powerful, smaller, elegant, and versatile mobile communication devices. These devices have tremendous
mobile communication abilities including wireless Internet access, wireless e-mail and news items,
and wireless video (though limited) communication on handheld devices. Wireless telephones are already
available and operate in different communication environments across the continents. The day is not far
when a single communication number will be assigned to every newborn and will stay with that person
irrespective of his/her location.
Another field that is emerging rapidly is the field of ad hoc wireless communication networks. These
networks are of a temporary nature and are established for a certain need and for a certain duration. There
is no elaborate setup needed to establish these networks. As a few mobile communication devices come in
one another’s proximity, they can establish a communication network among themselves. Typical situations
where ad hoc wireless networks can be used are in the classroom environment, corporate meetings, conferences,
disaster recovery situations, etc. Once the need for networking is satisfied, the ad hoc networking setup
disappears.

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