WIRELESS COMMUNICATION By: G. Swetha Arjun college of technology and sciences 2/4 ECE
B. Samuel Kumar Arjun college of technology and sciences 2/4 ECE
ABSTRACT
microwave and millimeter wave circuits and
.Wireless communication is becoming an ever-growing part of human life with new services and products being released every month. Wireless communications brings huge benefits to the user or users and is therefore becoming a must for
industry. The report looks into the
possibility of installing mobile devices (PDA’s) integrated with a wireless network into a hospital. Hospitals are information intensive and need the
speed
and
easiness
of
wireless
communications. Issues raised through this report include the types of wireless networking technologies available, the effects of electro-magnetic
radiation
on
hospital
equipment and peoples’ health, the use and benefits of personal digital assistants (PDA’s), security covering aspects such as encryption, authentication, data protection act and the Health Insurance Portability and Accountability Act (HIPAA) and finally, system design, an area that illustrates how a System might function based on examples of systems currently being tested. Wireless communication has led to an explosive growth of emerging consumer and military applications
of
radio
frequency
(RF),
systems. Future personal (hand-held) and ground communications systems as well as communications satellites necessitate the use of highly integrated RF front-ends, featuring small size, low weight, high performance and low cost. Continuing chip scaling has contributed to the extent that off-chip, bulky passive RF components, such as high-Q inductors, ceramic and SAW filters, varactor diodes and discrete PIN diode switches, have become limiting.
CONTENTS
Introduction
Definition
Need for study
Theory
Applications
Advantages/disadvantages
Conclusion
References/bibliography
INTRODUCTION
DEFINITION
The birth of wireless communications dates
Transmitting/receiving
from 1800’s, when M.G. Marconi did the
using electromagnetic waves in open space
Pioneer
first
is known as wireless communication. The
successful radio between a land-based
information from sender to receiver is
station and a tugboat. Since then, wireless
carrier over a well defined frequency band.
communication
been
Each channel has a fixed frequency band
developing and evolving with a furious
width and capacity. Different channels can
pace. The number of mobile subscribers has
be used to transmit information in parallel
been growing tremendously in the fast
and independently.
work
establishing
systems
the
have
voice
and
data
decades. The early wireless systems consist of a base station with a high power transmitter and served a larger geographic area. Each of base station would serve a small number of users and was costly as well. The systems were isolated from each other and only a few of them communicated with
the
public
switched
telephone
networks. Today the cellular system consists of a cluster of base stations with low power
NEED FOR STUDY
radio transmitters. Each base station serves a small cell with in a large geographic area. The total number of users served is increased because of channels reuse and also larger frequency bandwidth. The cellular systems connect with other via mobile switching and directly access the public switched telephone networks. The most advantage of wireless communication is that a mobile user can make a phone call anywhere anytime.
Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. The term is commonly used in the telecommunications industry to refer to telecommunications systems (e.g. radio transmitters and receivers, remote controls, computer networks, network terminals, etc.) which use some form of energy to transfer information without the use of wires.
Information is transferred in this manner
VLF - Very Low Frequency.
over both short and long distances. Why we use wireless communication?
THEORY
Freedom from wires
Types of Wireless
No cost of installing wires or rewiring and
Communications are
no bunches of wires running here and there.
Mobile
Cellular
Phones
(GSM
/
Global Coverage
Communications can reach where writing is
cdma2000.1x)
infeasible or costly, e.g., rural areas, old
Portable
buildings, battlefield, vehicles, outer space
IEEE 802.11b (WiFi),
(through Communication Satellites)
IEEE 802.15.3 (UWB)
Stay Connected
Fixed
Roaming allows flexibility to stay connected
IEEE 802.16 (WirelessMAN)
anywhere and anytime.
The typical frequencies are
Flexibility
FM Radio ~ 88 MHz
Services reach you wherever you go
TV Broadcast ~ 200 MHz
(Mobility). E.g, you don’t have to go to your
GSM Phones ~ 900 MHz
lab to check your mail. Connect to multiple
GPS ~ 1.2 GHz
devices simultaneously,
PCS Phones ~ 1.8 GHz
Bluetooth ~ 2.4 GHz
WiFi ~ 2.4 GHz
The propagation characteristics are different in each frequency band. EHF - Extreme High Frequency SHF - Super High Frequency UHF - Ultra High Frequency VHF - Very High Frequency HF - High Frequency
Types of Wireless Communication are
Radio Transmission
Easily generated, omni-directionally travel long distances, easily penetrate buildings. The problems are frequency-dependent, relative
low
bandwidth
for
data
communication tightly licensed by the government.
Microwave Transmission
MF - Medium Frequency
Widely
used
for
long
distance
LF - Low Frequency
communication and gives a high S/N ratio,
relatively inexpensive. The problems are
Current wireless communication systems are
they don’t pass through buildings well,
Cellular Systems
weather and frequency-dependent.
Wireless LANs
Satellite Systems
Wireless PANs (bluetooth, UWB)
Cellular Systems The geographic region divided into cells. Frequencies/timeslots/codes
Infrared and Millimeter Waves
reused
at
spatially separated locations.
Widely used for short-range communication.
Wireless Local
Unable to pass through solid objects and
WLANs connect “local” computers
used for indoor wireless LANs, not for
(100m range => confined regions)
outdoors.
It breaks data into packets, channel access is
Light wave Transmission
shared (random access).Poor performance in
Unguided optical signal, such as laser,
some applications (e.g. video) and low
connect two LANs in two buildings via laser
mobility.
mounted on their roof. It is unidirectional,
Satellite Systems
easy to install, don’t require license. The
It cover very large areas and very useful in
problems are it is unable to penetrate rain or
sparsely populated areas: rural areas, sea,
thick fog, laser beam can be easily diverted
mountains, etc. different orbit heights,
by
optimized for one-way transmission, Radio
turbulent
air.
.
and movie broadcasting and in expensive base stations (satellites). It is limited-quality voice/datatransmission,traditionalapplication s,
weather
satellite,radio
and
TV
broadcasting. Personal Area Networks (PANs) • Bluetooth It is cable replacement RF technology, Short range (10m, extendable to 100m),2.4 GHz band (crowded),1 Data (700 Kbps) and 3
voice channels,1 Mbps data rate shared
be used anywhere that there is a cellular
between 7 devices, TDD duplex scheme,
telephone site to house the equipment that is
Polling based multiple access, widely
required to transmit and receive the signal
supported by telecommunications, PC, and
that is used to transfer both voice and data to
consumer electronics companies.
and from these instruments.
APPLICATIONS The applications of wireless communication are
Security systems
Cellular
telephone
(phones
and
modems)
Wi-Fi
Wireless energy transfer
Computer interface devices
Wi-Fi Wi-Fi is a wireless local area network that
SECURITY SYSTEMS
enables portable computing devices to connect easily to the internet. Wi-Fi
Wireless technology may supplement or replace hard wired implementations in security systems for homes or office buildings.
approaches speeds of some types of wired ethernet. Wi-Fi hot spots have been popular over the past few years. Some businesses charge customers a monthly fee for service,
CELLULAR TELEPHONE (phones and
while others have begun offering it for free
modems)
in an effort to increase the sales of their goods.
Perhaps the best known example of wireless technology is the cellular telephone and modems. These instruments use radio waves to enable the operator to make phone calls from many locations worldwide. They can
WIRELESS ENERGY TRANSFER Wireless energy transfer is a process whereby electrical energy is transmitted
from a power source to an electrical load
security of wireless keyboards have also
that does not have a built-in power source,
been addressed with the maturation of the
without the use of interconnecting wires.
technology. ADVANTAGES/DISADVANTAGES Wireless communication has the following advantages
Anywhere, Anytime Work
Through working
wireless
communication,
professionals
and
mobile
workers can work and access the Internet just about anywhere, anytime without COMPUTER INTERFACE DEVICES
the hassles of wires and network cables.
Answering the call of customers frustrated with cord clutter, many manufactures of
Enhanced Productivity
computer peripherals turned to wireless
Workers, students, professionals and
technology to satisfy their consumer base.
others need not be constrained by wired
Originally these units used bulky, highly
Internet
limited transceivers to mediate between a
connectivity.
computer and a keyboard and mouse,
connectivity options ensures that work
however more recent generations have used
and assignments can be completed
small, high quality devices, some even
anywhere
incorporating bluetooth. These systems have
productivity of all concerned.
become so ubiquitous that some users have begun complaining about a lack of wired peripherals.Wireless devices tend to have a slightly slower response time than their wired counterparts, however the gap is decreasing.
Initial
concerns
about
the
connections
or
Wireless
and
enhance
dial-up Internet
overall
Remote Area Connectivity
Emergency Alerts
Workers, doctors and other professionals
Through wireless communication, many
working in remote-location hospitals
emergency
and medical centers can keep in touch
situations can be addressed quickly.
with
Help and other assistance can reach
anyone
through
wireless
situations
and
crisis
communication. Non-profit organization volunteers working in remote and underserved areas can stay connected to the outside world with the help of wireless communication.
affected areas quickly through early alerts and warnings provided with the help of wireless communication. The
disadvantages
of
wireless
communication are
Relatively lower bandwidth speed
Ease of access means more security also necessary to protect data
On-Demand
and/or bandwidth, since people can
Entertainment
connect anywhere within range
Bonanza
without seeking network plug. For those unable to keep away from their
daily
soap
operas,
A satellite link is superior to wire for long distances, but is more
reality-
expensive for purely local use
programs, online TV shows and Internet surfing or download activities, wireless
Wireless systems are slower
communication ensures an entertainment
These
bonanza on--demand and anytime.
does
not
offer
performance of wired systems
the
These are harder to supervise.
CONCLUSION Since wireless communication are often application specific, may be intended for unattended over a long period of time. There is great interest in designing their operations to be as efficient as possible so that batteries need to be replaced only infrequently. REFERENCES
books.google.co.in
www.wirelesscommunication.com