Wireless Infrared LAN
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Transcript Wireless Infrared LAN
Wireless
Infrared LAN
introduction
INTRODUCTION
Now
a days the telecommunication
principles takes a wide ways and types
can be classified according to the
medium and frequencies used ; IR LANS or
routers is a part that uses the IR
frequencies to transport such a data and
build networks.
INTRODUCTION
INTRODUCTION
The
network
shown can use IR
LANS to connect
the PCs but with
limitations (Line of
sight required to
transport with IR
frequency.
INTRODUCTION
UNLIKE
radio LANS (routers) it can be
transmitted even if LOS is not avaliable (i.e
through walls)
INTRODUCTION
UNLIKE
radio LANS (routers) it can be
transmitted even if LOS is not avaliable (i.e
through walls)
BUT
data ranges and BW is better in IR and
channels can be separated because of
wide frequency range (carrier frequency will
be > 200 THZ and BW easily becomes wider)
INTRODUCTION
UNLIKE
radio LANS (routers) it can be
transmitted even if LOS is not available (i.e
through walls)
BUT
data ranges and BW is better in IR and
channels can be separated because of
wide frequency range (carrier frequency will
be > 200 THZ and BW easily becomes wider)
IR
is more SECURED than radio networks
INTRODUCTION
INTRODUCTION
This
table shows a differences between IR
and radio LANs
INTRODUCTION
This
figure shows a typical topology for IR
Network (for example)
THE WIRELESS IR Channel
THE WIRELESS IR Channel
Non-directed
infrared links, which do not
require alignment between transmitter
and receiver, can be categorized as
either line-of-sight (LOS) or diffuse ; LOS
links means communication with a line
without any object but diffuse can
depends on reflections
THE WIRELESS IR Channel
The
optical signal in a diffuse link can
undergo many reflections and still have
appreciable energy.
THE WIRELESS IR Channel
The
optical signal in a diffuse link can
undergo many reflections and still have
appreciable energy.
Practical
wireless infrared link will use
intensity modulation and direct detection
(IM/DD).
Achieving a High Signal-toNoise Ratio:
Achieving a High Signal-toNoise Ratio:
The
electrical signal-to-noise ratio (SNR) of
IM/DD links is limited by noise from
ambient light sources.
Achieving a High Signal-toNoise Ratio:
The
electrical signal-to-noise ratio (SNR) of
IM/DD links is limited by noise from
ambient light sources.
Since a photodetector produces a
current proportional to the received
optical power, the SNR of IM/DD links is
proportional to the square of the received
optical power.
Bandwidth Reuse in Multi-User
Systems
Evaluations
of the performance of time-,
subcarrier frequency- and code-division
multiple-access (TDMA, FDMA, and
CDMA) schemes for bandwidth reuse,
demonstrating this advantage of infrared
over radio.It appears also possible to
employ space-division multiple-access
(SDMA) with infrared, leading to an even
greater increase in network capacity.
Future Developments
Optical
technology and communication
techniques could enable the realization
of a LAN that employs very high-bit-rate
(up to 100 Mb/s) diffuse infrared links to
access a wired backbone.
Such
a LAN would enable users to run
communication-intensive applications,
including real-time video, on portable
computers.