Introduction to basics of wireless networks such as
• Radio waves & wireless signal encoding techniques
• Wireless networking issues & constraints
• Wireless internetworking devices
Introduction to basics of wireless networks such as
• Radio waves & wireless signal encoding techniques
• Wireless networking issues & constraints
• Wireless internetworking devices
Understanding RF Fundamentals and the Radio Design of Wireless NetworksCisco Mobility
This advanced session focuses on deep-dive understanding of the often overlooked Radio Frequency part of designing and deploying a Wireless LAN Network. It discusses 802.11 radio MIMO APs and antennas placements when to use a DAS system antenna patterns. It covers the main environments such as carpeted offices campuses and conference centers, providing feedback based on lessons learned from challenging deployments such as outdoor/stadium/rail deployments and manufacturing areas. Learn More: http://www.cisco.com/go/wireless
Wireless Communication and Networking by WilliamStallings Chap2Senthil Kanth
Hai I'm Senthilkanth, doing MCA in Mepco Schlenk Engineering College..
The following presentation covers topic called Wireless Communication and Networking
by WilliamStallings for BSc CS, BCA, MSc CS, MCA, ME students.Make use of it.
Wireless Communication and Networking
by WilliamStallings Chapter : 2Transmission Fundamentals
Chapter 2
Electromagnetic Signal
Function of time
Can also be expressed as a function of frequency
Signal consists of components of different frequencies
Time-Domain Concepts
Analog signal - signal intensity varies in a smooth fashion over time
No breaks or discontinuities in the signal
Digital signal - signal intensity maintains a constant level for some period of time and then changes to another constant level
Periodic signal - analog or digital signal pattern that repeats over time
s(t +T ) = s(t ) -¥< t < +¥
where T is the period of the signal
Time-Domain Concepts
Aperiodic signal - analog or digital signal pattern that doesn't repeat over time
Peak amplitude (A) - maximum value or strength of the signal over time; typically measured in volts
Frequency (f )
Rate, in cycles per second, or Hertz (Hz) at which the signal repeats
Time-Domain Concepts
Period (T ) - amount of time it takes for one repetition of the signal
T = 1/f
Phase () - measure of the relative position in time within a single period of a signal
Wavelength () - distance occupied by a single cycle of the signal
Or, the distance between two points of corresponding phase of two consecutive cycles
Sine Wave Parameters
General sine wave
s(t ) = A sin(2ft + )
Figure 2.3 shows the effect of varying each of the three parameters
(a) A = 1, f = 1 Hz, = 0; thus T = 1s
(b) Reduced peak amplitude; A=0.5
(c) Increased frequency; f = 2, thus T = ½
(d) Phase shift; = /4 radians (45 degrees)
note: 2 radians = 360° = 1 period
Sine Wave Parameters
Time vs. Distance
When the horizontal axis is time, as in Figure 2.3, graphs display the value of a signal at a given point in space as a function of time
With the horizontal axis in space, graphs display the value of a signal at a given point in time as a function of distance
At a particular instant of time, the intensity of the signal varies as a function of distance from the source
Frequency-Domain Concepts
Fundamental frequency - when all frequency components of a signal are integer multiples of one frequency, it’s referred to as the fundamental frequency
Spectrum - range of frequencies that a signal contains
Absolute bandwidth - width of the spectrum of a signal
Effective bandwidth (or just bandwidth) - narrow band of frequencies that most of the signal’s energy is contained in
Frequency-Domain Concepts
Any electromagnetic signal can be shown to consist of a collection of periodic analog signals (sine waves) at different amplitudes, frequencies, and phases
The period of the total signal is equal to the period of the fundamenta
Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use radio
Understanding RF Fundamentals and the Radio Design of Wireless NetworksCisco Mobility
This advanced session focuses on deep-dive understanding of the often overlooked Radio Frequency part of designing and deploying a Wireless LAN Network. It discusses 802.11 radio MIMO APs and antennas placements when to use a DAS system antenna patterns. It covers the main environments such as carpeted offices campuses and conference centers, providing feedback based on lessons learned from challenging deployments such as outdoor/stadium/rail deployments and manufacturing areas. Learn More: http://www.cisco.com/go/wireless
Wireless Communication and Networking by WilliamStallings Chap2Senthil Kanth
Hai I'm Senthilkanth, doing MCA in Mepco Schlenk Engineering College..
The following presentation covers topic called Wireless Communication and Networking
by WilliamStallings for BSc CS, BCA, MSc CS, MCA, ME students.Make use of it.
Wireless Communication and Networking
by WilliamStallings Chapter : 2Transmission Fundamentals
Chapter 2
Electromagnetic Signal
Function of time
Can also be expressed as a function of frequency
Signal consists of components of different frequencies
Time-Domain Concepts
Analog signal - signal intensity varies in a smooth fashion over time
No breaks or discontinuities in the signal
Digital signal - signal intensity maintains a constant level for some period of time and then changes to another constant level
Periodic signal - analog or digital signal pattern that repeats over time
s(t +T ) = s(t ) -¥< t < +¥
where T is the period of the signal
Time-Domain Concepts
Aperiodic signal - analog or digital signal pattern that doesn't repeat over time
Peak amplitude (A) - maximum value or strength of the signal over time; typically measured in volts
Frequency (f )
Rate, in cycles per second, or Hertz (Hz) at which the signal repeats
Time-Domain Concepts
Period (T ) - amount of time it takes for one repetition of the signal
T = 1/f
Phase () - measure of the relative position in time within a single period of a signal
Wavelength () - distance occupied by a single cycle of the signal
Or, the distance between two points of corresponding phase of two consecutive cycles
Sine Wave Parameters
General sine wave
s(t ) = A sin(2ft + )
Figure 2.3 shows the effect of varying each of the three parameters
(a) A = 1, f = 1 Hz, = 0; thus T = 1s
(b) Reduced peak amplitude; A=0.5
(c) Increased frequency; f = 2, thus T = ½
(d) Phase shift; = /4 radians (45 degrees)
note: 2 radians = 360° = 1 period
Sine Wave Parameters
Time vs. Distance
When the horizontal axis is time, as in Figure 2.3, graphs display the value of a signal at a given point in space as a function of time
With the horizontal axis in space, graphs display the value of a signal at a given point in time as a function of distance
At a particular instant of time, the intensity of the signal varies as a function of distance from the source
Frequency-Domain Concepts
Fundamental frequency - when all frequency components of a signal are integer multiples of one frequency, it’s referred to as the fundamental frequency
Spectrum - range of frequencies that a signal contains
Absolute bandwidth - width of the spectrum of a signal
Effective bandwidth (or just bandwidth) - narrow band of frequencies that most of the signal’s energy is contained in
Frequency-Domain Concepts
Any electromagnetic signal can be shown to consist of a collection of periodic analog signals (sine waves) at different amplitudes, frequencies, and phases
The period of the total signal is equal to the period of the fundamenta
Wireless communication is the transfer of information between two or more points that are not connected by an electrical conductor.
The most common wireless technologies use radio
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Normal Labour/ Stages of Labour/ Mechanism of LabourWasim Ak
Normal labor is also termed spontaneous labor, defined as the natural physiological process through which the fetus, placenta, and membranes are expelled from the uterus through the birth canal at term (37 to 42 weeks
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
2. Course objective
At the end of the semester, the learner
will be able to:
• Explain the principles of a
communication systems
• Discuss the nature of information,
different types of signals involved and
their characteristics
• Determine the need of modulation and
differentiate various type of modulation
techniques
2
3. 3
“How do you want to send
data/information to someone
who is far from you?”
4. COMMUNICATION OVER LONG DISTANCES IS NO LONGER A PROBLEM.
4
Communication : To transfer information from one
place to another
5. Communication System HistoryCommunication System History
• 1837 – Samuel Morse invented telegraph.
• 1858 – First telegraph cable across Atlantic (Canada – Ireland)
• 1876 – Alexander Graham Bell invented telephone.
• 1988 – Heinrich Hertz introduce electromagnetic field theory.
• 1897 – Marconi invented wireless telegraph.
• 1906 – Radio communication system was invented.
• 1923 – Television was invented.
• 1938 – Radar and microwave system was invented for World
War II.
• 1956 – First telephone cable was installed across Atlantic.
• 1960 – Laser was invented
• 1962 – Satellite communication
• 1970 – Corning Glass invented optical fiber.
• 1985 – Facsimile machine.
• 1988 – Installation of fiber optic cable across Pacific and
Atlantic.
• 1990 – World Wide Web and Digital Communication.
• 1998 – Digital Television.
5
6. • The words "tele", "phon", and "graph" are derived from Greek.
– Tele – means ‘at a distance’
– Phon – means sound or speech
– Graph - means writing or drawing
• Therefore, telecommunication means communication at a distance. This can be
done through wires called transmission lines or through atmosphere by a radio
link. Other examples include:
– Telephone – speaking at a distance
Television – seeing at a distance
Telegraph – writing at a distance
6
7. 7
Basic Communication SystemBasic Communication System
Transmitter
Transmission
Medium Receiver
Input
Transducer
Output
Transducer
Noise
wired / wireless
mtx(t)
s(t) r(t)
ptx(t)
n(t)
mrx(t)prx(t)
s(t) – Input signal; audio, video, image, data etc.
mtx(t) – Modulating signal; input signal that has been converted to electrical signal.
ptx(t) – Modulated signal transmit by the transmitter.
n(t) – Noise signal.
prx(t) – Modulated signal receive by the receiver.
mrx(t) – Modulating signal at the receiver.
r(t) – Output signal.
8. 8
• Input Transducer – convert input signal, s(t) in electrical forms. eg:
microphone.
• Transmitter – involve modulation process – convert modulating signal, mtx(t)
to modulated signal, ptx(t). And finally transmit the signal.
• Transmission medium – connecting the transmitter and the receiver that
enable the modulated signal, ptx(t) propagate through the medium.
• Receiver – receive the modulated signal, prx(t) and then convert the signal to
modulating signal, mrx(t) through the process called demodulation.
• Output Transducer – convert the modulating signal, mrx(t) to its original forms
(output signal), r(t) that is useful to the users. eg: loud speaker.
Component Function in BasicComponent Function in Basic
Communication SystemCommunication System
10. Coaxial Cable
•First type of
networking media
used
•Available in
different types (RG-
6 – Cable TV,
RG58/U – Thin
Ethernet, RG8 –
Thick Ethernet
•Largely replaced by
twisted pair for
networks
11. Unshielded Twisted Pair
Advantages
Inexpensive
Easy to terminate
Widely used, tested
Supports many
network types
Disadvantages
Susceptible to
interference
Prone to damage
during installation
Distance
limitations not
understood or
followed
12. Glass Media
• Core of silica, extruded glass or plastic
• Single-mode is 0.06 of a micron in diameter
• Multimode = 0.5 microns
• Cladding can be Kevlar, fibreglass or even steel
• Outer coating made from fire-proof plastic
Advantages
Can be installed over long distances
Provides large amounts of
bandwidth
Not susceptible to EMI RFI
Can not be easily tapped (secure)
Disadvantages
Most expensive media
to purchase and install
Rigorous guidelines for
installation
14. CHAPTER 1
INTRODUCTION TO COMMUNICATION SYSTEMS
WHAT IS BASEBAND ?
Data
(nonelectrical)
Electrical
Waveform
Without any shift in the range of frequencies of the signal
The signal is in its
original form, not changed by modulation.
Baseband is the original information that is to be Sent.
15. Modulation
Continuous wave Pulse
PAM
PPM
PWM
PCM
Digital Analog
ASK
FSK
PSK,
etc
Linear Exponential
AM
DSB-
SC
SSB
VSB
FM
PM
Based on
the type of
carrier
wave
Based on
the type of
modulating
signal
Based on the
relationship
between
modulating
and
modulated
signal
16. TYPE OF MODULATION
Amplitude Modulation (AM)
Frequency Modulation (FM)
Phase Modulation (PM)
16
18. ANALOG AND DIGITAL SIGNAL
The information can be in term of :
Analog form such as Human Voice or Music
Digital form such as binary-coded number.
There are 2 basic type of communication :
Analog Communication
Digital Communication
18
19. Chapter 1
Introduction to Communication Systems
Example of Analog signal is shown
below:
Analog comes in term of Sinusoid
(Sine or Cosine wave)
Analog signals are continuous
electrical signals that vary in
19
20. Analog Signals
• Human Voice – best example
• Ear recognises sounds 20KHz or less
• AM Radio – 535KHz to 1605KHz
• FM Radio – 88MHz to 108MHz
22. Digital signals
• Represented by Square Wave
• All data represented by binary values
• Single Binary Digit – Bit
• Transmission of contiguous group of bits is a
bit stream
• Not all decimal values can be represented by
binary
1 0 1 0 1 0 1 0
23. Analog or Digital
• Analog Message: continuous in amplitude and
over time
– AM, FM for voice sound
– Traditional TV for analog video
– First generation cellular phone (analog mode)
– Record player
• Digital message: 0 or 1, or discrete value
– VCD, DVD
– 2G/3G cellular phone
– Data on your disk
– Your grade
• Digital age: why digital communication will
prevail
24. Chapter 1
Introduction to Communication Systems
WHAT IS FREQUENCY SPECTRUM ?
IT CONSISTS OF ALL FREQUENCIES CONTAINED IN THE
WAVEFORM AND THEIR RESPECTIVE AMPLITUDE IN
THE FREQUENCY DOMAIN.
24
25.
26. The Bands
VLF LF MF HF VHF UHF SHF EHF
Submillimeter
Range
ELF
3MHz 30MHz300MHz 3GHz 30GHz 300GHz
Far
Infra-
Red
300KHz30KHz 3THz
Radio Optical
3KHz
Near
Infra-
Red
700nm
1PetaHz
R
e
d
O
r
a
n
g
e
Y
e
l
l
o
w
G
r
e
e
n
B
l
u
e
I
n
d
i
g
o
V
i
o
l
e
t
600nm 400nm500nm
UltravioletX-Ray
1500n
27.
28. Frequency SpectrumFrequency Spectrum
28
100MHz
WaveguideCoaxial CableTwisted Pair
Cable
Infrared
Visible
Ultraviolet
Optical Fiber
ExtraHigh
Frequency
EHF
SuperHigh
Frequency
SHF
UltraHigh
Frequency
UHF
VeryHigh
Frequency
VHF
High
Frequency
HF
Medium
Frequency
MF
Low
Frequency
LF
VeryLow
Frequency
VLF
Audio
Line-of-sight
radio
Skywave
radio
Groundwave
radio
Wavelength
Frequency
designations
Transmission
media
Propagation
modes
Representative
applications
Frequency
Laser beam
100km 10km 1km 100m 10m 1m 10cm 1cm 10-6
m
Telephone
Telegraph
Mobilradio
VHFTVandFM
MobilandAeronautical
UHFTV
CBradio
Amateurradio
AMbroadcasting
Aeronautical
Submarinecable
Navigation
Transoceanicradio
BroadbandPCS
Wirelesscommunication
Cellular,Pager
Satellite-satellite
Microwaverelay
Earth-satellite
Radar
Widebanddata
1kHz
10kHz
100kHz
1MHz
10MHz
1GHz
10GHz
1G0Hz
1014
Hz
1015
Hz
30. Chapter 1
Introduction to Communication Systems
WHAT IS BANDWIDTH ?
IT IS THE DIFFERENCE BETWEEN THE HIGHEST
FREQUENCIES AND THE LOWEST FREQUENCIES OF THE
INPUT SIGNAL FREQUENCIES (fB= 2fm).
The bandwidth of a communication signal ≥ bandwidth
of the information signal.
30
31. Chapter 1
Introduction to Communication Systems
EXAMPLE 1:
If human voice frequencies contain
signals between 300 Hz and 3000 Hz,
a voice frequency channel should
have bandwidth equal or greater
than 2700 Hz.
a communication channel cannot
propagate a signal that contains a
frequency that is changing at a rate
greater than the Channel Bandwidth.
31
33. PROPAGATION TECHNIQUES
A signal can be propagated in 3 ways:
1. Ground-Wave Propagation
Frequency < 2 MHz
2. Sky-Wave Propagation
Frequency between 2 MHz and 30
MHz
3. Line-of-Sight Propagation
Frequency > 30 MHz
33
37. Types of TransmissionTypes of Transmission
• Simplex
One way transmission
• Half-Duplex
Two way transmission but only one user can transmit the
signal at one time.
• Full-Duplex
Two way transmission, both users can transmit the signal at
the same time.
37
38. Decibel
decibel is a relative unit of measurement used frequently in electronic
communications to describe power gain or loss
Equation 1 is commonly referred to as the power ratio form for dB.
38
(Eq. 2)
(Eq. 1)
(Eq. 3)
People can communicate with other people. This is one unmistakable characteristic that points out the difference between humans and other animals (i.e. the ability to communicate). During the early days, communication among humans was limited by distance. People communicated by natural senses of hearing and sight or by written words. Actual words could be conveyed although the process was very slow. As the distance increased beyond the normal range of vision and hearing it became very difficult or near to impossible to communicate using the above methods. People searched for better ways of communicating faster and over long distances. Smoke signals and flag signaling were used to send messages. These were used for centuries until the nineteenth century when electrical signals came in use. In 1869, the telephone was invented. This marked a real breakthrough. At that time, it seemed like a miracle to be able to talk to someone so many miles away as easily and quickly as they were standing next to you. The arrival of wireless communication nearly three decades after the Telephone, completed the breakthrough
it seemed like a miracle to be able to talk to someone so many miles away as easily and quickly as they were standing next to you.
transmission of a digital or analog signal signaling at its original frequencies.
Phase modulation (PM) is a form of modulation that represents information as variations in the instantaneous phase of a carrier wave.
Unlike its more popular counterpart, frequency modulation (FM), PM is not very widely used. This is because it tends to require more complex receiving hardware and there can be ambiguity problems with determining whether, for example, the signal has 0° phase or 180° phase.
Example:
Telephone voice signal is analog. The intensity of the voice causes electric current variations. At the receiving end, the signal is reproduced in the same proportion. Hence the electric current is a ‘MODEL’ but not one’s voice since it is an electrical representation or analog of one’s voice.
In electronic communication, bandwidth is the width of the range (or band) of frequencies that an electronic signal uses on a given transmission medium. In this usage, bandwidth is expressed in terms of the difference between the highest-frequency signal component and the lowest-frequency signal component.
What is bandwidth?
Bandwidth is the total range of frequency required to pass a specific signal that has been modulated to carry data without distortion or loss of data. The ideal bandwidth allows the signal to pass under conditions of maximum AM or FM adjustment. (Too narrow a bandwidth will result in loss of data. Too wide a bandwidth will pass excessive noise.)
Transmitters and receivers have bandwidths. The &quot;wider&quot; the receiver&apos;s bandwidth is, the more information it can receive on different frequencies.
The term bandwidth is used metaphorically for the carrying ability of Internet carriers. For example, if you can receive information from the Internet over a slow modem, you get less information per second than if you were connected to a fast modem. Thus, you have &quot;low bandwidth&quot; and the Internet appears slower to you.
Modem (from modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems can be used over any means of transmitting analog signals, from driven diodes to radio.
Radio waves in the VLF band propagate in a ground, or surface wave. The wave is connected at one end to the surface of the earth and to the ionosphere at the other . The ionosphere is the region above the troposphere (where the air is), from about 50 to250 miles above the earth.
Ground waves travel between two limits, the earth and the ionosphere, which acts like a duct. Since the duct curves with the earth, the ground wave will follow. Therefore very long range propagation is possible using ground waves.
Sky waves are reflections from the ionosphere.
While the wave is in the ionosphere, it is strongly curved, or refracted, ultimately back to the ground.
From a long distance away this appears as a reflection.
Long ranges are possible in this mode also, up to hundreds of miles.
Sky waves in this frequency band are usually only possible at night, when the concentration of ions is not too great since the ionosphere also tends to attenuate the signal. However, at night, there are just enough ions to reflect the wave but not reduce its power too much.
In the VHF band and up, the propagation tends to straighten out into line-of-sight(LOS)waves. However the frequency is still low enough for some significant effects.