Chapter 16 Flashcards
Absorption
The loss of energy in an
electromagnetic signal as it
passes through a medium.
TDMM.* Page 16-9
AGC
Automatic Gain Control
A circuit arrangement used to
automatically sense variations in
the received signal levels and
adjust the gain of the receiver
amplification stages to
provide a constant output.
TDMM.* G-14
Amplitude
The size or magnitude of a
voltage or current waveform.
TDMM.* Page 16-6
Access Point (AP)
Access Point
Stand-alone hardware device or
a computer wireless adapter
with software that acts as a
wireless communication hub for
users of wireless devices to
connect with each other and to
bridge those devices to the
cabled portion of the network.
TDMM.* Page G-4
BSS
Basic Service Set
A single wireless LAN (WLAN)
access point (AP) and its
associated clients, loosely
equivalent to a wireless
collision domain.
TDMM.* Page G-19
DAS
Distributed Antenna System
A network of spatially separated
antenna nodes connected to a
common system source via
transport medium that provides
wireless service within a
geographic area or structure.
(HetNet Forum)
TDMM.* Page G-60
Diffraction
The bending of sound, radio, or
light waves around an object,
barrier, or aperture edge.
TDMM.* Page 16-9
Dispersion
The loss incurred by an RF
signal due to the natural
broadening of the wave front.
TDMM.* Page 16-12
ERRCS
Emergency Responder Radio
overage Systems
An implementation of distributed
antenna system (DAS) designed
for use by first responders or
public safety officials. These
systems re-transmit fire and police
radio sianals from outside of a
the building’s interior
allowing for continuous
communication even within
structures whose construction
greatly attenuates outside
radio signals.
TDMM: Page G-68
Extended Service Set
(ESS)
Extended Service Set
A collection of access points (APS) that are tied together by a wired backbone in a single collision domain, or by virtual LANs (VLANs) to allow Layer 2 data link layer) roaming.
TDMM.* G-73
Frequency
A measure of the rate at which a
periodic function repeats. It is
the number of cycles or events
per unit of time. For
electromagnetic signals,
frequency is expressed
in hertz (Hz).
TDMM.* Page 16-6
IBSS
Independent Basic Service Set
A group of stations in a wireless
LAN (WLAN) that communicate
directly with each other (without
the use of a central access point
[AP]). This type of network is
also called an ad hoc network.
TDMM: Page G-95
IR (Standard)
Infrared (Standard)
An inexpensive
telecommunications standard
based on the use of the
IR light spectrum.
TDMM: Page 16-66
LoS
Line of Sight
The imaginary line that connects
the observer’s eye with the
object the observer is looking at.
TDMM.* G-110
NIC
Network Interface Card
The circuitry in a device that
provides the means to connect,
via cabling or wireless to a
network.
TDMM.* Page G-129
OS
Operating System
The system software that
controls the execution of all
programs and the use of
resources on a device
such as a computer.
TDMM.* Page G-134
PTP
Point to Point
A direct connection established
between two specific locations,
as between two buildings
or devices.
TDMM.* Page G-144
Reflection
The abrupt change in direction
of a wave front at the interface
between two dissimilar media
such that the incident wave front
returns into the medium from
which it originated.
TDMM.* Page 16-9
Refraction
The abrupt change in direction
of a wave front at the interface
between two dissimilar media as
the incident wave front enters
the second medium.
TDMM.* Page 16-9
QoS
Quality of Service
1 .A commitment to
performance, based on
predefined service pararneters.
2.A measure of the level of
service provided on a network.
TDMM: Page G-156
Scattering
A change in the level, direction, frequency, or polarization of incident radiation when it encounters small particles or inhomogeneous particles whose size is similar to or smaller than the wavelength of the incident radiation.
TDMM.* Page 16-9
Wavelength
The distance between points of
a corresponding phase of one
complete cycle of a wave. In
electromagnetic systems,
wavelength is typically
measured in meters.
TDMM.* Page 16-6
WLAN
Wireless Local Access Network
A LAN that functions wirelessly
between the client and a
wireless access point (WAP).
Most modern WLANs are based
on IEEE 802.11 standards,
marketed under the Wi-Fi name.
TDMM.* Page G-209
Name 3 technological
considerations in
wireless design.
1 .Scalability of the network
2. Compatibility of the overall network
3. ImpIementation of a wireless network based around standards
TDMM.* Page 16-2
Name 3 factors that
define the reliability of
a wireless network.
1 .Accessibility
2.Continuity
3.Consistency of service
TDMM.* Page 16-3
Name 4 factors that affect
the throughput of a
wireless system.
1 .AppIication requirements
2.Number of users
3.Future requirements
4.Capabilities of the products
used in the design
TDMM.* Page 16-3
What type of impact do
radio communications
towers have on the
footprint of a facility?
They have a limited impact on
the footprint (physical
environment), but the towers
may have a high impact on the
visual environment.
TDMM.* Page 16-4
Name 3 reasons the rooftop of a tall building may be an unsuitable location for a cellular system.
- Difficult to get signal to street level
- Increased potential for interference
- Reduced frequency reuse capabilities
TDMM.* Page 16-4
Name 3 methods for
evaluating the environment
in which a wireless network
will be used.
1 .Site survey
2.Propagation analysis
3.ModeIing
TDMM.* Page 16-4
Name 5 environmental
factors that can affect
wireless communications.
1 .Materials
2.Vegetation
3.0bjects
4.Local geography
5.Atmosphere
TDMM.* Page 16-4
What 2 considerations
does a QOS program
attempt to balance?
1 .End user expectations
2.Wireless network performance
TDMM.* Page 16-4
What term is used to describe
the size or magnitude of a
voltage or current waveform?
Amplitude
TDMM.* Page 16-6
What term is used to
describe the number of
cycles or events per
unit of time?
Frequency
TDMM.* Page 16-6
What unit of measure is
used to express the
frequency of an
electromagnetic signal?
Hertz (Hz)
TDMM.* Page 16-6
What does one hertz equal?
One cycle per second
TDMM.* Page 16-6
What term is used to
describe the distance
between two points of a
corresponding phase of
one complete cycle
of a wave?
Wavelength
TDMM.* Page 16-6
What unit of measure is
typically used for
wavelengths in an
electromagnetic system?
Meters
TDMM.* Page 16-6
What term is used to
describe the motion of
waves through or along
a medium?
Propagation
TDMM.* Page 16-7
Define line of sight in terms
of propagation.
A propagation in which the
radiation from the transmitter to
the receiver is unobstructed
TDMM.* Page 16-7
Name 2 types of
LOS propagation.
1 .Visual
2.Radio frequency (RF)
TDMM.* Page 16-7
What is visual LOS?
The visual observation of one
point to another as seen by the
observer’s eye
TDMM.* Page 16-7
What is RF LOS?
The line of sight LOS between
the receiving and transmitting
antennas
TDMM.* Page 16-7
What are Fresnel zones?
A series of concentric ellipsoids
surrounding the path
TDMM.* Page 16-8
How is the first
Fresnel zone used?
As a nominal unit to measure
certain distances in terms of
their effect on the frequency
involved rather than in terms of
meters (feet)
TDMM.* Page 16-8
What is the minimum
clearance requirement for
reliable wireless service
(expressed in Fresnel zones)?
60 percent of F1 clearance
TDMM.* Page 16-8
Name 2 categories of barriers
and obstructions that impede
electromagnetic waves.
1 .Natural
2.Man-made
TDMM.* Page 16-9
What is free space loss?
The signal attenuation that
would result if all reflection,
refraction, scattering, diffraction,
and absorption influences
were removed
TDMM.* Page 16-9
What term refers to the
abrupt change in direction
of a wave at the interface
between two dissimilar
media such that the
incident wave front returns
into the medium from
which it originated?
Reflection
TDMM.* Page 16-9
What term is used to
describe abrupt change in
direction of a wave at the
interface between two
dissimilar media such that
the incident wave front
enters the second medium?
Refraction
TDMM.* Page 16-9
What term describes the
change in the level,
direction, frequency, or
polarization of incident
radiation when it
encounters small particles
or inhomogeneous
particles whose size is
similar to or smaller than
the wavelength of the
incident radiation?
Scattering
TDMM: Page 16-9
What term is used to
describe the bending of
sound, radio, or light waves
around an object, barrier, or
aperture edge?
Diffraction
TDMM.* Page 16-9
What term is used to
describe the loss of energy
in an electromagnetic
signal as it passes through
a medium?
Absorption
TDMM.* Page 16-9
What is a sky wave?
A sky wave is a wave that is
usable due to reflection and
refraction in the ionosphere.
TDMM.* Page 16-10
What is the ionosphere?
The portion of the Earth’s upper
atmosphere where ions and
electrons are present in
quantities sufficient to affect the
propagation of radio waves
TDMM.* Page 16-10
Normally, the ionosphere extends ___ to ___ above the Earth.
Normally, the ionosphere extends 48 km (30 mi) to 1000 km (621 mi)
above the Earth.
TDMM.* Page 16-10
What causes the distance
to the radio horizon to
exceed the optical horizon
within the troposphere?
Within the troposphere, bending
of radio waves by refraction
makes the distance to the radio
horizon exceed the distance to
the optical horizon.
TDMM.* Page 16-10
At what distances does
tropospheric refraction
typically affect received
signals?
At distances beyond
the radio horizon
TDMM.* Page 16-10
What is a direct wave?
A direct wave is an RF wave that
travels directly from the
transmitting antenna to the
receiving antenna.
TDMM.* Page 16-70
How can the LOS distance
be extended in terrestrial
communications?
By increasing the height of the
transmitting antenna and/or the
receiving antenna
TDMM.* Page 16-10
What is a ground wave?
A ground wave is a wave that
travels along a surface or an
interface between two mediums
that have different refraction
indexes.
TDMM.* Page 16-10
What is the maximum
range of a surface path
when high-powered
transmitters and efficient
antennas are used?
=500 km (310 mi) at 2 MHz
TDMM.* Page 16-11
What is the relationship
between the range of a
surface path and
frequency?
The surface path range
decreases as frequency
increases.
TDMM.* Page 16-11
What is isotropic gain?
The ratio of actual signal
strength at the antenna in a
given direction relative to an
ideal isotropic radiator that
uniformly distributes the signal
in all directions
TDMM.* Pag 16-12
What is fading?
The variation (with time) of the
amplitude or relative phase, or
both, of one or more of the
frequency components
of a signal
TDMM.* Page 16-13
Name the 2 types of fading.
1 .Multipath fading
2.Delay spread
TDMM: Page 16-13
Name 4 possible outcomes
of multipath.
1 .lntersymbol interference (data
corruption)
2.Cancellation of signal (nulling)
3.Decrease of signal strength
(downfade)
4.1ncrease of signal strength
(upfade)
TDMM.* Page 16-13
What is modulation?
The process of altering the
amplitude, frequency, or phase
of a carrier signal in a measured
way, which allows for other
signals such as voice, data, and
video to be added to it
TDMM.* Page 16-14
Name 4 types of
modulation.
1 .Amplitude modulation
2.Frequency modulation
3.Phase modulation
4.PuIse modulation
TDMM.* Pages 16-14 to 16-17
What is amplitude
modulation?
The method of superimposing a
signal (e.g., voice, data) on a
carrier wave in which the
amplitude of the carrier
envelope (carrier and sidebands)
is varied in relation to
the signal strength
TDMM.* Page 16-14
What is frequency
modulation?
The method of superimposing a
signal (e.g., voice, data, video)
on an RF carrier wave in which
the instantaneous frequency of
the carrier wave is varied in
relation to the signal strength
TDMM.* Page 16-15
What is phase modulation?
The method of superimposing a
signal (e.g., voice, data, video)
on a carrier wave in which the
phase of the carrier wave is
varied in relation to the
signal strength
TDMM.* Page 16-16
What is pulse modulation?
The method of superimposing a
series of pulses carrying the
signal (e.g., voice, data, video)
on a carrier wave in which the
carrier wave is varied in relation
to the signal strength
TDMM.* Page 16-17
Which modulation
technique uses two
different phase angles that
are usually out of phase by
180 degrees?
Binary phase-shift keying (BPSK)
TDMM.* Page 16-18
Which modulation
technique uses four
different phase angles that
are usually out of phase by
90 degrees?
Quadrature phase-shift keying
(QPSK)
TDMM.* Page 16-18
What is complementary
code keying (CCK)?
A standard adopted by the IEEE
802.11 standards committee as
the basis for the high-rate
physical layer extension to
deliver data rates of
11 Mb/s at 2.4 GHz
TDMM.* Page 16-18
Describe how the QAM
modulation technique
works.
Two carriers at the same
frequency are independently
amplitude modulated and
combined for transmission.
TDMM.* Page 16-18
Describe how the OFDM
modulation technique
works.
A large number of closely
spaced orthogonal sub-carriers
are combined into parallel
streams.
TDMM.* Page 16-18
How does the OFDMA
modulation technique
achieve a more efficient
use of airtime?
By scheduling the transmissions
from the clients so they do not
clash with each other
TDMM.* Page 16-18
What are harmonics?
The multiples of an alternating
current’s fundamental frequency
TDMM.* Page 16-19
What is the first harmonic?
The fundamental frequency
TDMM.* Page 16-19
What is the second
harmonic?
Twice the fundamental
frequency
TDMM.* Page 16-19
What is harmonic
distortion?
The presence of unwanted
harmonic frequencies
TDMM.* Page 16-20
Name 4 types of
harmonic filters.
1 .High-pass filter
2. Low-pass filter
3.Band-pass filter
4.Band-stop filter
TDMM.* Page 16-20
What term describes an
increase in an RF signal’s
power?
Gain
TDMM.* Page 16-20
Name 2 sources of gain.
1 .External power sources
2.Passive sources
TDMM.* Page 16-20
What term describes a
decrease in signal
strength?
Loss
TDMM.* Page 16-20
Name the 2 main sources
of loss in a wireless
system.
1 .lmpedance of cables and
connectors
2.During signal propogation that
absorbs, reflects, refracts,
scatters, or destroys
TDMM.* Page 16-20
What unit provides an
absolute measurement
of power?
Watt
TDMM.* Page 16-21
What unit provides a
measurement of the
relative gain or loss of
power?
Decibel
TDMM.* Page 16-27
What rule is commonly
used to calculate isotropic
gain for antennas?
The 6 dB Rule
TDMM.* Page 16-21
Name 8 types of
information that should
be gathered before the
wireless network
is designed.
1 .Bandwidth requirement
2.Number of users
3.Growth and expandability
4.Existing data network considerations
5.User environment
6.EM and RF noise
7. Topography, terrain, and building materials
8.Climate
TDMM.* Pages 16-22 to 16-24
Name the 2 primary types
of wireless networks.
1 .Licensed
2.Unlicensed
TDMM.* Page 16-25
What is the frequency
range for P T P licensed
wireless networks?
6 GHz to 40 GHz
TDMM.* Page 16-25
What frequencies are used
primarily for public safety
applications?
6 GHz to 11 GHz
TDMM.* Page 16-25
What frequencies are
primarily used in the
private sector for P TP
applications?
18 GHz and above
TDMM.* Page 16-25
What frequencies are the
most prevalent for wireless
deployments for the
unlicensed spectrum?
2.4 GHz and 5 GHz
TDMM.* Page 16-25
What frequency range
is used by amateur
radio operators?
2.4 GHz and below
TDMM.* Page 16-25
How does licensing provide
a higher level of
interference protection
than what is found in
unlicensed systems?
By limiting the use of any
frequency to a single user
in any one area
TDMM.* Page 16-26
What is path loss?
The loss of the RF signal power
from its originating point to the
ultimate end point
TDMM.* Page 16-26
Name 5 factors that
contribute to path loss.
1 .Frequency of RF signal
2. Transmission power
3.Distance between the transmit
and receive antenna
4.0bstructing materials (type and
density)
5. Terrain
TDMM.* Page 16-26
Name 5 factors used to
select the proper antenna
for an application.
1 .Required gain
2.AIlowable wind load
3.Frequency
4.Aesthetics
5.Zoning
TDMM: Page 16-27
What is the purpose of a
radome cover for a
parabolic antenna?
To keep ice and snow from
accumulating on antennas and
causing additional weight
and wind load
TDMM.* Page 16-27
How does a radome cover
affect an RF signal?
It causes some loss as the
signal passes through the cover.
TDMM.* Page 16-27
What is the common
path loss when using
radome covers?
0.5 dB isotropic
TDMM.* Page 16-27
Name 2 problems
associated with
oversizing antennas.
1.Interference
2.Damage to the radio equipment
TDMM.* Page 16-27
Name the 2 basic
measurements used in
analyzing radio waves and
other wave forms.
1 .Frequency
2.Amplitude
TDMM.* Page 16-28
Name the 3 categories of
wireless transceivers.
1 .Half-duplex
2.Frequency division duplex
3. Time division duplex
TDMM.* Page 16-28
What type of transceiver is
incapable of transmitting
and receiving signals at the
same time?
Half-duplex
TDMM.* Page 16-28, Table 16.2
How does a frequency division
duplex transceiver operate?
Transmits and receives
simultaneously with transmitter
and receiver operating on a
separate pair of frequencies or
duplex channel assigned in
accordance with a band plan
TDMM.* Page 16-28, Table 16.2
How does a time division
duplex transceiver operate?
Transmits and receives at RF
alternately in sequential time
slots on a single frequency
TDMM.* Page 16-28, Table 16.2
Define antenna.
A means for coupling RF energy
from a transmitter onto the
transmission medium and from
the transmission medium
to a receiver
TDMM.* Page 16-29
What will happen if the
wrong connector is
selected and implemented
in a radio system?
Selecting the wrong connector
will cause degradation and
failures in the radio system.
TDMM.* Page 16-30
Name 5 considerations for
implementing an outdoor
P TP solution.
1 .Distance
2. Terrain
3.Climate
4.Physical obstructions
5.Cabling attenuation
TDMM.* Page 16-31
What is a jinpole?
A rigging tool that is used to
hoist sections up the tower
TDMM.* Page 16-32
What is the benefit of using
jumpers to connect the RF
media to the antenna and
the equipment?
Using jumpers to connect the RF
media to the antenna and the
equipment allows the system to
be serviced without damaging
any part of the system.
TDMM.* Page 16-33
What is the weakest part of
the antenna system?
The antenna connector
TDMM.* Page 16-33
What is the purpose of a
voltage injector?
To power electronic equipment
located away from a convenient
source of power
TDMM.* Page 16-35
Name the 2 major types of
voltage injectors.
1 .Coaxial
2.Power over Ethernet (POE)
TDMM.* Pages 16-35 to 16-36
How far above the roof
should RF media be
supported?
At least 38mm (1.50 in)
TDMM: Page 16-37
What is a distributed
antenna system?
A system that transmits and
receives or relays RF signals
within buildings, structures,
tunnels, or other areas where
wireless services cannot be
provided because of lack of
signal penetration from outdoor
networks or where no suitable
outdoor network exists
TDMM.* Page 16-38
Name 7 components
of a DAS.
- Transmitters
2.Receivers
3.Amplifiers - Converters
5.Cabling
6.Connectors
7.Antennas
TDMM.* Page 16-38
Name 5 types of cable that
are commonly recognized
for DAS cabling
distribution.
1 .Singlemode optical fiber cabling
2.Multimode optical fiber cabling
3.Hybrid optical fiber cabling
4.Balanced twisted-pair cabling
5.Coaxial cable
TDMM.* Page 16-47
What category/class of
balanced twisted-pair
cabling is recommended
for DAS cabling
distribution?
Category 6A/Class EA
TDMM.* Page 16-47
Excluding the base station
hardware, what is the most
expensive part of a DAS?
The antenna network
TDMM.* Page 16-42
Name the 4 types of
antennas used in a DAS.
1 . Omnidirectional
2. Directional
3. Radiating cable
4. Combination of all three
TDMM.* Page 16-42
What type of antenna
broadcasts equally in all
directions of only one cross
section of its toroidal
(doughnut-shaped)
three-dimensional
radiation pattern?
Omnidirectional
TDMM.* Page 16-42
What type of antenna
concentrates the radiated
signal in one direction more
than in another or receives
a signal more readily from
one direction than from
another?
Directional
TDMM.* Page 16-43
Why is a radiating coaxial
cabling useful in combined
systems?
Because it has a wide
bandwidth, allowing operation
from 70 MHz to more than
2.4 GHz (with some limitations)
TDMM.* Page 16-43
True or False
A radiating cable should be
placed in a metal conduit
for protection.
False. A radiating cable cannot
be placed in a metal conduit
because it would block the
radiating signal from the cable.
For this reason, the cable must
conform to the environmental
flame spread and fire code
requirements.
TDMM.* Page 16-44
Name 5 common types of
active DAS equipment.
- Transceivers
- Bidirectional amplifiers
- Unidirectional amplifiers
- Repeaters
- Power supply units
TDMM.* Page 16-47
What is a transceiver?
A device that uses many of its
components to transmit and
receive RF signals
TDMM.* Page 16-47
What function is typically
performed by the power
supply unit?
The power supply unit converts
the commercial ac power to dc
operating voltages.
TDMM.* Page 16-47
What is the primary
headend device?
Master control unit (MCU)
TDMM.* Page 16-48
Name 3 suitable
locations for an MCU.
1 .Main equipment room (ER)
2. Telecommunications room (TR)
3.Penthouse near the roof
TDMM.* Page 16-50
Where is DAS backend
equipment typically
located?
In the TR
TDMM.* Page 16-51
Name 6 examples of DAS
backend equipment.
- Slave processors
- Power supplies
- Host ports
- Amplifiers and transceivers
- Antenna ports
- Antennas
TDMM.* Page 76-51
Name the 3 primary means
used by active DAS to
transport radio signals.
- Analog modulation of RF
signals onto an optical carrier - Down conversion of RF
signals to IF - Digital sampling of RF signals
TDMM.* Page 16-52
What is an advantage of
analog modulation?
The ability to modulate a large
portion of the radio spectrum
over one optical path
TDMM.* Page 16-52
What is a major problem
associated with analog
systems?
The direct dependency of the
modulation and recovery of the
RF signal to the optical transport
TDMM: Page 16-52
What is the primary
medium used for DAS
analog systems?
Singlemode optical fiber
TDMM.* Page 16-52
How do DAS analog
systems compensate for
the dependency on optical
losses?
By using an automatic gain
control (AGC) as a feedback
loop to maintain constant
optical strength over the optical
fiber plant
TDMM: Page 16-52
How is passive distribution
equipment in a DAS
defined?
As equipment that does not
require external power input
TDMM.* Page 16-54
What is a
directional coupler?
A linear device that uses
induction or another method to
differentially split downlink
power from an input connector
to two or more output
connectors
TDMM.* Page 16-54
What piece of passive DAS
equipment combines dc
power with the ac RF signal
on a coaxial cable and taps
it off at the other end?
Bias tee
TDMM.* Page 16-54
What piece of passive DAS
equipment is used to
combine two wireless
bands to a single antenna
feed or distribution cable?
Hybrid coupler
TDMM.* Page 16-54
Which piece of passive
DAS equipment accepts an
input signal and delivers
multiple output signals with
specific phase and
amplitude characteristics?
Power splitter
TDMM.* Page 16-54
Name 3 characteristics
of output signals in
power splitters.
- Equal amplitude
- Zero degree phase
relationship between any two
output signals - High isolation between each
output signal
TDMM.* Page 16-54
Name 2 common
topologies that serve a
DAS within a building
structure.
1 .Star topology
2. Tapped trunk topology
TDMM: Page 16-54
Name 3 factors that may
affect the selection of a
cabling topology for a DAS.
1 .DAS equipment
2.CabIing medium used in a new
installation
3.Legacy cabling system in a
previous installation
TDMM.* Page 16-54
What cabling mediums
may be used in the
installation of a
star topology?
*Balanced-twisted pair
*Coaxial
*Optical fiber
Combination
TDMM. Page 16-55
What types of cabling may
be used to install a tapped
trunk topology?
*Coaxial
Optical fiber
TDMM. Page 16-55
What component is used to
“tap” into the coaxial cable
of a tapped trunk topology?
Splitter or vampire tap
TDMM.* Page 16-55
Name 2 potential problems
associated with using a
DAS to support mobile
communications in
buildings.
1 .Availability and usability of RF
signals in the intended
coverage areas (coverage)
2.Ability to support the demands
of the system users and
recipients (capacity)
TDMM.* Page 16-55
Name the 3 phases
associated with
DAS design.
1.Pre-lnstallation
2.Installation
3.Acceptance/implementation
TDMM.* Page 16-55
What is the purpose of
conducting RF measurements
during an on-site survey of the
radio environment?
To identify existing signals and
their frequency and strength
TDMM.* Page 16-56
Name 2 factors that
determine the overall
usability and capability of
an installed DAS.
1 .Antenna Selection
2.Antenna Location
TDMM.* Page 16-58
What is the link budget
(operating margin)?
The sum of ICT gains and losses
in an ITS, beginning with the
transmitter and continuing to the
receiver, including transmission
line loss and antenna gains
TDMM.* Page 16-59
Name 3 objectives of
diplexing.
1 .Maintain proper transmission
limits set by the manufacturer or
regulatory body
2.Provide adequate bandwidth at
each frequency that is diplexed
3.Control and minimize signal loss
TDMM.* Page 16-60
What is duplexing?
Combining the forward and
reverse signal paths into
a single cable
TDMM.* Page 16-60
Name 6 applications where
battery backup for the DAS
is typically required.
1 .Private security services
2.Hospitals and health care facilities
3.Mining and mine operations
4.Government and military installations
5.Financial markets
6.Life safety issues
TDMM.* Page 16-62
Name 6 strategies for
mitigating interference
between a DAS and other
RF frequencies that are in
use in the area.
1.Relocate transmission devices
2.Adjust or reassign transmission frequency
3.Replace receiving antennas
4.Discontinue the use of an interfering frequency
5.Install RF filters or chokes
6.Install RF shielding material
TDMM: Page 16-62
What is a personal area
network (PAN)?
The interconnection of information technology devices within a personal operating space
TDMM.* Page 16-65
What is the typical
radius of a PAN?
-10 m (33 ft)
TDMM.* Page 16-65
Name 3 key factors
for a PAN.
- Lower power consumption
- Low cost
- Superior ease of use
TDMM.* Page 16-65
What is the intent of the
IEEE 802.15 Working Group?
To enhance the Bluetooth
specification and create
a standard
TDMM.* Page 16-65
Which organization
administers the IR
standard?
Infrared Data Association (IrDA)
TDMM.* Page 16-66
True or False
IR is unaffected by RF.
True. IR is unaffected by RF,
but it can be affected by
ambient light.
TDMM.* Page 16-66
True or False
The IrDA standard does
not have any provisions
for security.
True. The IrDA standard does
not have any provisions for
security. Security is left to the
software and firmware
applications utilizing IR
transmission.
TDMM.* Page 16-66
What is the intended
purpose of a public WLAN
or hotspot?
To provide convenient
access to Internet-based
telecommunications and
information to users equipped
with WLAN-capable devices
TDMM.* Page 16-67
Name the 3 categories of
WLAN services based on
access restrictions.
- Unrestricted access
- Established account access
- Temporary account access
TDMM.* Page 16-67
Which IEEE Working Group
is responsible for WLAN
specifications?
IEEE 802.11 Working Group
TDMM.* Page 16-68
Name the 3 types of logical
configurations for WLANs
as defined in IEEE
standards.
- Independent basic service set
(IBSS) - Basic service set (BSS)
- Extended service set (ESS)
TDMM.* Page 16-69
When is an IBSS
WLAN enabled?
When two or more stations
equipped with wireless NICs
communicate with each other
TDMM.* Page 16-69
When is a BSS
WLAN enabled?
When a single AP is used to
manage the communications
between two or more stations
equipped with wireless NICs
TDMM.* Page 16-69
When is an ESS
WLAN enabled?
When two or more
BSS APs are linked
TDMM.* Page 16-69
Which WLAN configuration
transfers messages
directly between devices
without the need for an AP?
IBSS
TDMM.* Page 16-69
What term is used to
describe the requirement to
obtain and install an AP
before enabling wireless
communications for
a BSS WLAN?
Infrastructure mode
TDMM: Page 16-69
How are APs described
when cabling is used to
create a distribution
system for an ESS WLAN?
As portals or gateways
TDMM.* Page 16-69
What is the role of the NIC?
To enable a stand-alone device
to function as a station
on a WLAN (client)
TDMM.* Page 16-72
Which station software
component makes it
possible for the OS to
configure and use the NIC
for all WLAN
communications?
The driver
TDMM.* Page 16-72
What is the role of an
access point (AP)?
To serve as a central point for
communications and
management on a WLAN
TDMM.* Page 16-72
What is the initial
destination of all messages
sent by a station in a
WLAN?
The access point (AP)
TDMM.* Page 16-72
How are bridges used in
both cabled and wireless
network environments?
To link access devices and
extend the physical span or
coverage zone of a network
TDMM.* Page 16-74
What is the role of a
repeating bridge?
To transfer all signals received
from each endpoint to
the other endpoint
TDMM.* Page 16-75
What type of network
device is designed to
centrally manage all
connected APs in a WLAN?
WLAN switch or controller
TDMM.* Page 16-76
Which WLAN component is
used to connect multiple
networks and allow devices
to communicate between
networks?
Gateways
TDMM.* Page 16-77
