WiFi
(Wireless Fidelity) -. Wi-Fi is the short
form for Wireless Fidelity. Wi-Fi is a simple, cost-effective way to connect to
the Internet, to other Computers and to other Wi-Fi-enabled devices (such as
high-end Mobile Phones), without the need to physically connect wires between
the two Computers/ devices. WiFi is working on unlicensed spectrum at 2.4 GHz. In today's wired WiFi
has a lot of advantages. Wireless networks are easy to set up and inexpensive. It
do not need for long Network Cables, it also does not need a Network Socket for
every Computer. There is less implementation cost. The disadvantages are cant
go more distance with in wifi zone and three are lot security factors.
Microwave Links - Microwave
links are fixed-wireless broadband systems and were around long before the term wireless
broadband was coined. It is the point-to-point LOS wireless transmission
method for up to 155 Mbps with
a range of up to 50 km. Basic advantages of microwave links are no cables needed,
multiple channels available and can have wide bandwidth. And disadvantages are
Line-of-sight will be disrupted if any barrier, such as new buildings, signal
absorption by the atmosphere, microwaves suffer from attenuation due to
atmospheric conditions and towers are expensive to build.
WiMAX – WiMAX is called as Worldwide Interoperability for Microwave Access. And
it is
the latest wireless broadband technology which is designed to deliver WiFi type
connectivity over a much greater range and thereby
compete as a point-to-multipoint last-mile broadband wireless access solution.
It provides capacity up to 40 Mbit/s. The current WiMAX is based upon IEEE
Std 802.16e-2005. advantages of Wimax is single station can serve hundreds of
users, Much faster deployment of new users comparing to wired networks, speed of 10Mbps at 10 kilometers with
line-of-sight, and also It is
standardized and the same frequency equipment should work together. And
disadvantages are Line of sight is needed for longer
connections, Weather conditions like rain could interrupt the signal, other
wireless equipment could cause interference and multiplied frequencies are
used. WiMAX is very power intensive technology and requires strong electrical support
and big installation and operational cost.
Direct Broadcast Satellite (DBS) – Direct Broadcast Satellite is a normal satellite
system used for communication. The satellite s which is position in same space
station related to the earth. Direct Broadcast Satellite (DBS) services also provide two-way
high-speed data transmission services.
Satellites are operating in the Ku band with a 12 GHz
downlink and a 14 GHz uplink. Major drawback is that satellites being 22,300 km from
the earth’s surface introduce a 250 ms delay into the network.
In this method companies mainly supply satellite TV for users with more choice. And the advantages are rural availability,
high capacity, and reliable service and can get digital picture & sound.
FSO (Free Space Optics) - This is the technology uses the light
propagating in free space to transmit data between two points. This system
uses infra-red sources or lasers to support free-space data transmission rates of between 10Mbps and 1.25Gbps between a transmitter and a receiver
over distances of up to 4km. The main advantages of FSO systems are the low installation costs and
avoidance of radio spectrum licensing requirements as FSO systems use a light signal
instead of a radio wave. The disadvantages are beam
dispersion; atmospheric absorption of the signal, if there is a rain hard to
transmit and opens the signal to environmental disturbances (Rain, Fog and
Snow).
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