1. BY:
Manish Srivastava

2.  In simple language
Wireless telecommunications
is the transfer of information
between two or more points
that are not physically
connected.
 Here distances can be
short, such as a few metres
for television remote
control, or as far as thousands
or even millions of kilometres
for deep-space radio

3. Wireless operations permit
services, such as long range
communications, that are
impossible or impractical to
implement with the use of
wires.
It use some form of energy
(e.g. radio
frequency (RF),acoustic
energy, etc.) to transfer
information without the use
of wires.

4. DIAGRAM OF MICROWAVE
J C BOSE IN ROYAL
INSTITUTION, LONDON WITH HIS RECEIVER AND TRANSMITTER
TRANS-RECEIVER APPARATUS, FROM BOSE'S
1897 PAPER.

5.  A communication channel, or channel, refers
either to a physical transmission medium such as a
wire, or to a logical connection over
a multiplexed medium such as a radio channel.
 A channel is used
to convey an information signal, for example a
digital bit stream, from one or several senders (or
transmitters) to one or several receivers.

7.  A channel has a certain capacity
for transmitting information, often
measured by its bandwidth in Hz or
its data rate in bits per second
 Bandwidth is limited resources
used by different organization due
to which wide spread use of
wireless network are limited.

8.  The wireless channel (transmission medium) is
susceptible to a variety of transmission impediments
such as path loss, interference, and blockage.
 These factors restrict the range, data rate, and the
reliability of the wireless transmission.
 The extent to which these factors affect the
transmission depends upon the environmental
conditions and the mobility of the transmitter and
receiver.

9.  One of major characteristic in wireless channel
communication is FADING.
 In wireless communications, fading is
deviation of the attenuation affecting a signal
over certain propagation media.
 It is of two types:
(a) large scale fading,
(b) small scale fading.

11.  Large scale fading:
 It occurs due to path loss of a signal as a
function of distance.
 It is shadowing by large objects such as
buildings and hills.
 Small scale fading:
 It happens due to the constructive and
destructive interference of the multiple signal
paths between the transmitter and receiver.

12. MIMO technique for increasing spectral
efficiency
 Increased capacity is achieved
by introducing additional
spatial channels that are
exploited by using space-time
coding in this technology.
 there are certain
environmental factors that
affect MIMO capacity. These
factors include channel
complexity external
interference, and channel
estimation error.

13.  Adaptation brings unique benefits. For
instance, when the throughput required is
low, moving to a narrower channel increases
range and reduces power consumption.
 But in fixed-width systems, these two
quantities are always in conflict.
 Leads to significant improvement to range and
connectivity, low power-consumption, and
capacity.

14.  Limited spectrum available for
communications.
 In addition to security consideration interfering
signals can be generated by other devices
in, for example printers and other
electromechanical devices.
 These devices can temporarily disrupt a
communication link through the noise that
they generate.

15.  Add in a communication device to the system
or remove one from the system without any
disruption to the remainder of the system.
 It is a simple matter to relocate a
communicating device, and no additional cost
of rewiring is associated with such a move

16.  In conclusion it can be said that although wireless
network have several advantages but they also
have their unique difficulties .
 The need for high bandwidth communication is
still relatively new with the rapid growth of the
internet and the place of wireless network in it is
yet to be determined .
 The crucial point could very well be the standards
that define the next mobile phone networks if they
are universally accepted and given the necessary
bandwidth for high speed communication wireless
networks

17. THANK YOU…