Basic RF introduction for newbies eng.ppt

© USI proprietary and confidential
ASE Group
Prepared by : Milin
Date : July – 2012
Essential Intro to RF and Wireless

© USI proprietary and confidential 2
自我介绍
姓名: 宓霖
目前职务: M&N上海研发部硬件课副理
学历: 工学硕士
经历: 1998～2005 东南大学无线电工程系；
2005~now，环旭电子股份有限公司；先后参与IP STB，
VOIP，Wi-Fi AP/Router等产品的开发工作；
公司分机: 81267
MIAL: Lin_mi@usish.com

© USI proprietary and confidential 3
Content
• Essential Intro to RF and Wireless: Fundamentals, RF
hardware and system – easy way to learn about
• Part 1. RF Fundamentals
• Part 2. RF Hardware
• Part 3. RF system technologies – Wireless Networks
Reference Book:
The Essential Guide to RF and Wireless , 2nd Editon,
by Carl J.Weisman

• Part 1. Fundamentals
• 1. Basic Concepts:
• 1) RF: Radio Frequency, let’s think of RF as an electrical signal that is
on the move.
• 2) Prefixes: milli(m), kilo(k), Mega(M), Giga(G).
• 3) Transmitters and Receivers:
4
T R
Current on a
conductor
Current on a
conductor
Airborne waves

• 4) Analog Signals: sine wave
5
A
B
C
D
E
Signal
intensity
Time

• 5) Frequency
Radio Frequency(RF) (≤1GHz)
Microwave Frequency (≥1GHz,≤40GHz)
Millimeter wave frequency (≥40GHz)

• 6) Digital Signals:
7
High level
Low level
Rising edge Falling edge
Signal
intensity
Time

• 2. RF behavior:
• 1) Loss and Gain: All components (active or passive) exhibit one of
these two properties;
• Loss/Attenuation: Any signal that passes through a device exhibiting
loss is said to experience attenuation or is attenuated.
• Gain: If the signal coming out is bigger than the signal going in, the
device exhibits gain, and such device is called amplifier.
8
Power supply
Active
device
exhibiting
gain
Input
signal
Output
signal
Heat
Passive
device
exhibiting
loss
Input
signal
Output
signal
Thermal
impedance

• 2. RF behavior:
• Multiple Gain Stages:
• Insertion Loss: The loss of signal power resulting from the insertion of
a device in a transmission line or optical fiber.
9
Gain of 10
Signal Strength of 100
Signal Strength of 1 Signal Strength of 10
Gain of 10

• 2. RF behavior:
• 2) DECIBELS
• Let’s recall: 10 x log10(Power out/Power in).
• +3dB means 2 times bigger (multiply by 2)
• +10dB means 10 times bigger (multiply by 10)
• Or : -3dB means 2 times smaller (divide by 2)
• -10dB means 10 times smaller (divide by 10)
10
1 2
Input
signal
Output
signal
A 3 4 B
-2 dB 30 dB -7 dB -1 dB
20dB
The world of RF only deals in dB, so all you will ever have to do is add or
subtract dBs at any point in the system to figure out what is going on.

• 2. RF behavior:
• 3) BANDWIDTH
• Example: If a device can accommodate all frequencies between 75MHz
and 125MHz, what is its band width and percentage bandwidth?
• 125MHz – 75MHz = 50MHz;
• 50MHz ÷ [(125MHz + 75MHz) ÷ 2] × 100% = 50%
• Octaves bandwidth example: 100MHz ~ 200MHz
• Decades bandwidth example: 100MHz ~ 1GHz
• 4) WIDEBAND AND NARROWBAND
• For example: narrowband – bandwidth < 50%; wideband – bandwidth >
50%
• Key: the wider the bandwidth of a component, the more frequencies it
can accommodate, but the more it costs and the worse it performs.
11

• 2. RF behavior:
• 5) RF IN THE ENVIRONMENT
• Signal behavior
• Skin Effect: When an RF signal is on a conductor, it only hangs out on
the surface of the metal object itself.
• Free Space Loss: RF signal suffers from something when it flies
around in the air
• Power Density: Imagine the volume of water
as RF signal energy, and the area of flowerpot
is 1m2, then power density will be?
• And What if move the flowerpot closer to
the nozzle?
12
Transmitter
Receiver

• 2. RF behavior:
• 5) RF IN THE ENVIRONMENT
• Signal behavior
• Absorption: The insertion loss exhibited by nature things which
“absorb” the RF signal, including air, rain, glass, wood, etc.
• Reflection: Some things that RF waves encounter send the RF signal in
another direction
• The amount of reflection depends on two things: the frequency of the
RF and the material of the object
13
An RF signal is radiated inside the
microwave oven at a frequency that
water really likes to absorb.
Solid Object Solid Object
Direct reflection Angular reflection

• 2. RF behavior:
• 6) MATCH
• What Is Match?
• The Meaning of 50 Ohms
• Imagine if two garden hoses(conductors) are exactly not the same size,
no doubt some of the water(RF signal) leaks out
• The better the match, the less the leaking
• To make their lives easier, engineers in the RF world have standardized
the size of the hose they all agree to use – 50ohms
14
As far as cable is concerned, 75ohms
performs better(less attenuation), it is
for the world of video.

• 2. RF behavior:
• 6) MATCH
• What Is Match?
• VSWR: Voltage Standing Wave Ratio, one measure of match
• A format of X : 1, Vr means reflected wave, and Vf means forward wave
• Return Loss: Another measure of match
• VSWR versus Return Loss:
15
Ignore
these if
you’re not
interested
VSWR Return Loss (dB) Meaning
1.0 : 1 ∞ Perfect match, no leaking
1.4 : 1 15.6 Excellent match, very little leaking, often a design goal
2.0 : 1 9.5 Good match, acceptable amount of leaking
10 : 1 1.7 Horrible match
∞ : 1 0 Total reflection
A perfect open or short can make this

• 2. RF behavior:
• 6) MATCH
• Consequences of an Imperfect Match
• In reality, when mismatch happens, the RF energy heads back down in
the direction from which it came (reflection )
• Impedance Matching
• Quite often in the world of RF circuit design an engineer is forced to
connect two things (a conductor to a component) with a bad match
• A graphical representation of a matching circuit
16
Conductor with 50 ohm
impedance
Component with 100 ohm
impedance
Matching circuit

• 3. Basic System Components:
• 1) BLOCK DIAGRAMS
17
Receiver
Airborne waves
in at 900MHz
Electrical signal
out at 400MHz
Antenna
LNA Filter
RF IF
Mixer
LO
500MHz
OSC
Filter
Amplifier
Transmitter
Electrical signal
in at 400MHz
Airborne waves
out at 900MHz
Amplifier
OSC
IF RF
LO
500MHz
Filter
High Power Amplifier

• 2) ANTENNAS
• Block Diagram
• Every wireless system has an antenna
• Most antennas work equally well in both directions
• Antenna Characteristics
• Active and Passive: Active antennas are nothing more that passive
antennas with amplifiers inside of them
• Sizes and Shapes
• Depends on three things:
• A) The lower frequency the antenna must handle, the larger the size
• B) All directions, or Omnidirectional, the antenna will have a certain
shape versus directional antennas
• C) The higher the power, the larger the antenna
18
Airborne waves
in
Electrical signal out

• 2) ANTENNAS
• Antenna Characteristics
• Signal Strength and Direction
• If an omnidirectional antenna is used, all of the RF energy must be
evenly divided in all directions
• Since the directional antenna has to divide its energy over a smaller
area, that area receives more energy.
19

• 2) ANTENNAS
• How Antennas Work
• Wavelength
• The higher the frequency, the shorter the wavelength
• Antennas begin to radiate RF energy (as waves) when the RF signal’s
wavelength becomes similar to the antenna itself, vice versa
• A hint to radiation: If the object is much smaller than the wavelength it
will not radiate RF energy at all, and if the object is much bigger than
the wavelength, the object will radiate some RF energy, but not very
efficiently
20

• 2) ANTENNAS
• Antenna Performance
• Antenna Patterns
• Is a tool for antenna design, birds-eye view of the RF energy radiating
out from an antenna
• Antenna Gain
• To understand antenna gain, need to know a thing
called isotropic antenna, which is a single point in
space that radiates RF energy out in all directions,
and its 3D pattern is a sphere with the antenna as a point at the center
21
Omnidirectional
Directional
3D
2D
2D

• 2) ANTENNAS
• Antenna Performance
• Antenna Gain
• Since the directional antenna sends the same amount RF energy
further than the isotropic antenna, the directional antenna could be
considered to have “gain” relative to the isotropic antenna. This is
directional gain, not a power gain.
• The units of measure antenna gain is dBi, where the “i” stands for
isotropic
• When the antenna gain is used to determine a transmitter’s output
power, the output power is given a very special name: effective
isotropic radiated power or EIRP
22
Where PT is power of transmitter, Lc is cable
loss, Ga is antenna gain
EIRP = PT – Lc + Ga

• 2) ANTENNAS
• Polarization
• Vertical, Horizontal, and the combination is
called Circular Polarization
• 3D movie: Each side of the glasses lets only
one type of polarization pass, which causes each eye to see a different
image, tricking you into thinking you see an image with depth
23

• 2) ANTENNAS
• Antenna Dimensions
• Two most basic One-Dimension Antennas are the monopole and dipole
• Monopole : λ/4
• Dipole : λ/2
24
The monopole
antenna and its
image form a dipole
that radiates only
upward.
Folded dipole antenna
UHF–Half–Wave Dipole,
1.0–4 GHz Mast radiator monopole antenna used
for broadcasting. AM radio station WARE,
Warren, Massachusetts, USA.

• 2) ANTENNAS
• Antenna Dimensions
• Two-Dimension Antennas
• Patch antennas
• An array antenna
• Smart antenna: Save RF energy,
reduce interference
• Two types: Switched beam and
adaptive array
25
Microstrip Array Antenna
Patch Antenna
Aperture array antenna
Base station antenna
Ruckus VF2825

• 3) AMPLIFIERS
• Block Diagram
• Fundamental Properties of Amplifiers
• Gain: A measure of how much bigger the output signal is than the input
signal, in dB
• Three main categories: Low noise(LNA), high power, other
• Noise Figure: The fundamental property of LNA, in dB, to measure LNA’s
quietness; The lower the NF, the smaller the signal that LNA can hear,
thus the greater the range of the telecom devices
• Output Power: The bigger the signal, the farther it travels and the greater
the range, expressed in dBm; {?dBm = 10xlog10(1000x?Watt)}
26
Big signal out
Small signal in
Power in Watts 0.1 mW 1 mW 1 watt 1000 watts
Power in dBm -10 dBm 0 dBm 30 dBm 60dBm

• 3) AMPLIFIERS
• Fundamental Properties of Amplifiers
• Linearity: A measure of how much the amplifier distorts the shape of the
signal; It is much simper to think the P1dB point of an amplifier as the
highest power the amplifier can put out and still be in the linear region
27
OP1dB
Input power
IP1dB
Output power
1 dB
Linear
region
Non-linear or
Saturation region

• 3) AMPLIFIERS
• The 3rd order intercept point: The higher the intercept point, the more
linear the amplifier, measured in dBm
• Ip3 – Referred to as amplifier’s dynamic range
• Ip3 is 10dB greater than its P1dB point
28
OP1dB
Input power(dBm)
IP1dB
Output
power(dBm)
OIP3
IIP3
Pout(f1)
Pout(3f1)
1
1
3
1

• 3) AMPLIFIERS
• How Amplifiers Work: The input RF signal acts to control another type of
power called DC power through a controller called transistor
• We used Driver(RF signal), Car(PA), Steering wheel(Transistor), and
Tires(DC power)
• In an amplifier, the RF input signal tells the transistor to “shape” the DC
power to exactly reflect the shape of the input signal
29
DC power
PA
Transistor
RF signal

• 3) AMPLIFIERS
• Special Amplifiers
• Limiting Amplifiers: To protect the components following it by limiting the
output power
• Balanced Amplifiers: A for high reliability; B for better match (lower
VSWR)
• Variable Gain Amplifiers, or VGA
30
Big signal out
Small signal in
Balanced Amplifier VGA

• 4) FILTERS
• Block Diagram
• The Filter’s function: Filters out all the signals that are not wanted
• Filter types:
• Filter Performance
• Frequency Response
• Special Filters
• Duplexers, or diplexer, a fancy device that combines two filters into a single components
• SAW Filters: Surface Acoustic Wave
• RF signal -> sound signal -> back to RF, 10MHz ~3GHz
• Superconducting Filters
• Very little insertion loss, Large, Staying cold
31
f1
f2
f3
f2
Low pass High pass Band pass Band reject

• 5) MIXERS
• Block Diagram
• The Mixer’s Function: To change the frequency of a signal while hopefully
keeping everything else about the signal the same
• Other names: Up-converters for transmitter and Down-converters for
receiver
• An Example of Changing Frequencies:
32
f1 +f2
f1 - f2
f1
f2
When you talk you create 2
kHz sound waves
Voice is changed to 900MHz
frequency signals by cell
phone

• 5) MIXERS
• How Mixers Work: Three ports
• Conversion Loss: Insertion loss in a mixer is called Conversion Loss (CL)
• Mixer Configurations
• Two-Stage Mixers
• Frequency Doublers: The output frequency of
a frequency doubler is twice that of its input
33
LO1 LO2
RF IF Baseband
Local oscillator

• 6) SOURCE
• How Oscillators Work: Active devices, a power supply is connected and,
out comes a perfect sine wave signal at a predetermined frequency, the
“Source” of the RF
• Different Kinds of Oscillators
• Synthesizers: An oscillator plus some other circuitry that employs
feedback to make a more perfect sine wave
• Phase-Locked Loops(PLLs): When synthesizers perform this feedback
activity they are sometimes referred to as PLLs. One of the functions a
synthesizer can perform is frequency programmability
34
Output
signal
Acronym Oscillator Use
VCO Voltage-Controlled Oscillator Variable frequency
VCXO Voltage-Controlled XO Very accurate and variable
XO Crystal Oscillator Very accurate
Frequency
Out
Voltage in
OSC VCO

• 4. Other Components:
• 1) SWITCHES
• Block Diagram:
• Switch Function and Performance: To consider about lower insertion
loss(path A) and higher isolation(path B)
• Types of Switches: Electromechanical Switches switching speed is in the
order of “mS”, bigger signal
• Solid State Switches, level of “nS”, smaller signal, by diodes(lower loss)
or transistors(faster)
35
N
A
B
Single-pole, double-throw

• 1) SWITCHES
• System Use:
• 2) ATTENUATORS
• Block Diagram
• Types of Attenuators: Fixed-, Voltage Variable-,
and digital attenuator
36
N
A
B
T/R switch
Receiver
Transmitter
Attenuator
Fixed Attenuators Digital Attenuator Agilent 11713A
2dB 4dB 8dB 16dB
RF in RF out
A B C D
Control inputs

• 3) DIVIDERS AND COMBINERS
• Divider: Signals shape stays the same, but power is reduced to half
• Combiner: Flipped-over divider
• 4) COUPLERS
• Block Diagram
• How Couplers Work: RF signal goes from A to C, a tiny fraction of the
signal is siphoned off and brought out at sample port B; Couplers are
often used as part of feedback circuits in RF systems; Couplers are
passive devices; Key performance parameter: coupling accuracy
• Type: Directional, Bidirectional, Quadrature
37
N
A
B
Two-way power divider
A
A directional coupler
C
B
Input Output1
Output2
A Quadrature Coupler A directional coupler

• 5) CIRCULATORS AND ISOLATORS
• Block Diagram
• How Circulators Work: Microwave or radio frequency power entering any
port is transmitted to the next port in rotation
• How Isolators Work: A passive 2 ports
device, where power is transmitted in one
direction and absorbed in the other direction
• System Use:
38
3 ports Circulator 4 ports Circulator
Energy flow in an isolator
Receiver
Transmitter
A circulator between an antenna, a
receiver, and a transmitter
Load
PA
An isolator between a power
amplifier and an antenna
Energy dissipated
as heat

• 6) TRANSFORMERS
• Block Diagram
• The Transformer’s Function: a device that transfers electrical energy
from one circuit to another through inductively coupled conductors—the
transformer's coils; It is used to connect two devices whose impedances
are horrible mismatching, or to “transform” impedances
• Impedance Ratio: If the impedance ratio is specified as 2:1, then the
transformer will “transform” 100Ω to 50Ω
• 7) DETECTORS
• The Detector’s Function:
A Power(A) to Voltage(B) converter,
from RF system to test equipments who
can only handle an electrical voltage
39
RF in RF out
A Detector
C
B
A
RF in Voltage out

• 8) PHASE SHIFTERS
• Block Diagram
• The Phase Shifter’s Function:
• 9) PHASE DETECTORS OR COMPARATOR
• The Phase Detector’s Function: To
converts the difference in phase between two sine waves into an
equivalent voltage
40
A Phase Shifter
RF in RF out
Ф
Zero-degree phase shift 90-degree phase shift
0
0 0
0
A Phase Detector
RF in
Voltage out
Phase
Detector
RF in
A
B
C

• 9) REVIEW OF COMPONENTS
41
Component Active/Passive Primary Function Component Active/Passive Primary Function
Antenna Both Convert to and from
airborne waves
Combiner Passive Add signals together
Amplifier Active Make signals bigger Coupler Passive Split up or add 2 signals in unequal
proportion
Filter Passive Separate signals by
frequency
Circulator Passive Control signal flow among 3
components
Mixer Both Increase/decrease a
signal’s frequency
Isolator Passive Protect adjacent components from
signal reflection
Oscillator Active Create a perfect sine
wave
Transformer Passive Change impedance
Switch Active Change the direction a
signal travels
Detector Passive Convert an RF power signal to its
equivalent voltage
Attenuator Both Make signals smaller Phase shifter Both Change the phase of 1 sine wave
with respect to another
Divider Passive Split up a signal Phase detector Passive Produce a voltage proportional to
the difference in 2 phases

• 5. Circuits and Signals:
• 1) SEMICONDUCTORS
• Materials and Devices
• Liquid State Technology
• Vacuum Tubes: big, expensive than semiconductors
• Wireless communications take off with the development of
semiconductor technology(=Solid state technology)
• Silicon(Si，硅) and Gallium Arsenide(GaAs，砷化镓): GaAs works at
higher frequency, while it is more expensive than Si
• Silicon Germanium(SiGe，锗化硅): Driving force is PA of handheld mobile
phones; It has better linear performance and more efficient than GaAs,
the latter leads to longer battery life; Inexpensive
• Indium Phosphide(InP，磷化铟): Best low noise performance at millimeter
wave frequencies(>40GHz), relative expensive to manufacture
42
Vacuum tubes

• Two basic semiconductor building blocks: Diodes and Transistors
• Diode types: PIN(high power), Schottky(fast), Gunn(>10GHz),
Impatt(>100GHz), Tunnel(>10GHz), Varactor(in VCO); Diodes are primarily
used in Switches, Mixers, and Voltage Variable Attenuators (VVA)
• Transistor Types: MOSFET & MESFET, Bipolar, HBT, HEMT & PHEMT,
JFET, LDMOS
• Bipolar Junction Transistors (BJT), made by Silicon;
Field Effect Transistors (FETs);
• Heterojunction Bipolar Transistor (HBT), made by GaAs;
43
Bipolar
transistor
nFET pFET

• Transistor Usage:
• a) If there is gain, there is at least one transistor
• b) Metal Oxide Semiconductor Field Effect Transistor(MOSFET) (<1GHz,
by silicon, used in HPAs)
• c) When>1GHz: silicon BJTs are less expensive and produce high power
while GaAs Metal Semiconductor Field Effect Transistors(MESFETs) cost
more, but work better at higher frequencies while delivering lower noise
figures
• High Electron Mobility Transistors (HEMTs), or Pseudomorphic HEMT
are suited to high-frequency, low-noise applications
44
HEMT

• Monolithic Microwave Integrated Circuits (MMIC)
• When more than one electrical device is combined onto a single piece of
semiconductor, it is called an IC
• ASIC (Application-specific integrated circuit): Processors, memory blocks
including ROM, RAM, EEPROM, Flash and other large building blocks.
Such an ASIC is often termed a SoC (system-on-chip).
• FPGA: Designers of digital ASICs use a hardware description language
(HDL), such as Verilog or VHDL, to describe the functionality of ASICs.
Lower cost NRE than ASICs.
45

• 2) CIRCUIT TECHNOLOGIES
• Lumped Circuits: Lc << λ, where Lc denotes the circuit's characteristic
length, and λ denotes the circuit's operating wavelength
• Distributed Circuits: Otherwise
• Discrete, Hybrid, and MMIC Circuit Choices
• a) Discrete: Combines semiconductor devices (diodes, transistors and
MMICs) and lumped passive devices as individually packaged discrete
components onto a PCB; Utilizes existing discrete components, fast
design time, superior performance at high power; Takes up a lot of space,
reduced performance at high frequency, expensive in large quantity;
46
Lumped
Distributed

• 2) CIRCUIT TECHNOLOGIES
• Discrete, Hybrid, and MMIC Circuit Choices
• b) Hybrid (MIC, microwave integrated circuit): Combines both packaged
and “chip” semiconductor devices (diodes, transistors, and MMICs), and
passive devices (both lumped and distributed), along with metal traces
onto a ceramic substrate; Smaller and better high-frequency performance
than discrete, cheaper than discrete in large quantity, superior high-
frequency performance; Expensive in small quantity, longer design time
than discrete, more delicate handling and troubleshooting than discrete;
• c) MMIC: Combines semiconductor devices (diodes and transistors) and
distributed passive devices onto a single piece of semiconductor; Smaller
than any other approach, less expensive than any other approach in high
volume; Very expensive in small quantity, very long design time, some
degradation in performance compared to hybrid approach;
47

• 3) MODULATION
• The act of superimposing the information signal onto the RF (carrier)
signal
• Amplitude Modulation (AM): Binary Amplitude Shift Keying
• Frequency Modulation (FM): Frequency Shift Keying
48
Information
signal
RF carrier
Open letter:
“Demodulation”

• 3) MODULATION
• Phase Modulation
49
0⁰
90⁰
180⁰
270⁰
360⁰
Reference Signal
0⁰ phase shift 90⁰ phase shift
180⁰ phase shift 270⁰ phase shift
Acronym Phase Modulation
MSK Minimum Shift Keying
BPSK Bi-Phase Shift Keying
QPSK Quadrature Phase Shift Keying
DQPSK Differential QPSK
GMSK Gaussian Minimum Shift Keying
0⁰ 180⁰ 180⁰ 180⁰
0⁰
0 1 1 0 1
0⁰ 90⁰ 180⁰ 270⁰
180⁰
00 01 10 10 11
BPSK QPSK

• 3) MODULATION
• Quadrature Amplitude Modulation
(QAM)
• Modulators and Demodulators
• MODEM
50
16 QAM
Information Input
RF carrier Input
Modulation output

• 4) GETTING AROUND
• Coaxial Cables: The inner conductor carries
the RF signal and the outer conductor, which
is really a shield, is there to keep the RF signal from escaping
• Coaxial Cable Types and Designations
51
Cable Type Outer Layer Description
Flexible Rubber coating surrounding a
very thin metal shield
Very flexible, the rubber outer
coating is used as protection for
the thin outer shield
Semi-flex Thin metal (braided) shield Less flexible and less durable
than flexible cable, often cheaper
Semi-rigid Thick solid metal shield Less flexible, but more durable,
than semi-flex
RG-58: “Radio Grade”, The cable has a characteristic impedance of either 50 or 52 Ω;

• RF Coaxial Connectors
52
SMA SMB BNC N SC 3mm 1.4mm SMT SMP OSP OSX
SSMA SMC TNC K 7-16 7mm 2.4mm SSMT SSMP OSSP Type 43
SMA male
N type male
Hirose U.FL
SMB male SSMA
BNC adapter

• Waveguides: used either for military or very high power applications
• Circuit Traces: Stripline, Microstrip, and Coplanar Waveguide
53

• Part 3. RF Systems Technologies
• Wireless Networks
• Let’s see the most thing we’re interested in:
54

• 1) WWAN: Wireless Wide Area Network
• Using mobile telecommunication cellular network technologies such as
LTE, WiMAX (often called a wireless metropolitan area network or WMAN),
UMTS, CDMA2000, GSM, WCDMA, TDS-CDMA, cellular digital packet data
(CDPD) and Mobitex to transfer data.
• Also use Local Multipoint Distribution Service (LMDS) or Wi-Fi to provide
Internet access.
• These technologies are offered regionally, nationwide, or even globally
and are provided by a wireless service provider.
• WWAN connectivity allows a user with a laptop and a WWAN card to surf
the web, check email, or connect to a virtual private network (VPN) from
anywhere within the regional boundaries of cellular service. Various
computers can have integrated WWAN capabilities.
55

• 3G Evolution:
56

• LTE: 3GPP Long Term Evolution, usually referred to as LTE, is a standard
for wireless communication of high-speed data for mobile phones and
data terminals. It is based on the GSM/EDGE and UMTS/HSPA network
technologies, increasing the capacity and speed using new modulation
techniques. The standard is developed by the 3GPP (3rd Generation
Partnership Project).
• 3.9G, OFDM, MIMO, 20MHz Bandwidth
• 100Mbps(DL), 50Mbps(UL)
57

• 2) WLAN: Wireless Local Area Network
• Links two or more devices using some wireless distribution method (typically
spread-spectrum or OFDM radio), and usually providing a connection through an
access point to the wider internet.
• This gives users the mobility to move around within a local coverage area and still
be connected to the network.
58

• Wireless Networks - 802.11ac
• Wider channel bandwidths: 80 MHz and 160 MHz channel bandwidths (vs. 40 MHz
max in 802.11n); 80 MHz mandatory for stations (STAs), 160MHz optional
• MIMO spatial streams: Support for up to 8 spatial streams (vs. 4 in 802.11n)
• Modulation: 256-QAM, rate 3/4 and 5/6, added as optional modes (vs. 64-QAM, rate
5/6 maximum in 802.11n)
59

• 3) WPAN: Wireless Personal Area Network
• A network for interconnecting devices centered around an individual
person's workspace - in which the connections are wireless.
• Wireless PAN is based on the standard IEEE 802.15.
• Bluetooth: A specification for short range wireless communications
(developed by Ericsson in Sweden).
• ZigBee: A specification for a suite of high level communication protocols
using small, low-power digital radios, ZigBee is targeted at radio-
frequency (RF) applications that require a low data rate, long battery life,
and secure networking; 802.15.4;
• UWB(Ultra Wide Band): A radio technology that can be used at very low
energy levels for short-range high-bandwidth communications by using a
large portion of the radio spectrum; 3.1~10.6GHz; 802.15.3a;
60

• ZigBee:
• IEEE 802.15.4
• Short range(30~50m), low data rate, low power, long battery life
• Wireless Sensor Network
• working band, data rate, modulation: WW-2.4GHz/250Kbps/O-QPSK,
EU-868MHz/20KHz/BPSK, US-915MHz/40KHz/BPSK
61

• UWB:
• IEEE 802.15.3a
• Short range(10m), high data rate, low power
• working band, data rate: 3.1~10.6GHz, 110~480Mbps,
• Technologies: Impulse Radio, DSSS (Direct Sequence Spread Spectrum),
OFDM (Orthogonal Frequency Division Multiplexing)
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Basic RF introduction for newbies eng.ppt

Basic RF introduction for newbies eng.ppt

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Basic RF introduction for newbies eng.ppt