WIRELESS COMMUNICATIONS Flashcards

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1
Q

The most prevalent wireless technology

A

Cellphones

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2
Q

The WLAN uses a device called

A

Access point

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3
Q

Transfer rate for broadcast radio channel

A

upto 4Mbps

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4
Q

Transfer rate for microwave radio

A

45Mbps

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5
Q

Transfer rate for satellite radio channel

A

50Mbps

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6
Q

Transfer rate for cellular radio channel

A

9600bps to 14.4kbps

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7
Q

Transfer rate for infrared channel

A

1 to 4 Mbps

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8
Q

___________ Transmission is when the original signal such as a voice, or digital signal is put directly into the medium

A

Baseband transmission

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9
Q

This high frequency is added to the baseband signal so that it can radiate well in space

A

Carriers

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10
Q

It is the process of adding the carrier signal to the baseband signal and then modulated to be amplified and then sent to the antenna

A

Broadband transmission

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11
Q

when was the first LAN established?

A

1971

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12
Q

The experiment in which the first LAN was established

A

ALOHANET

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13
Q

The type of topology the ALOHANET used

A

Star topology network

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14
Q

Give the wireless technology for Wireless Ethernet LAN

A

Wi-Fi 802.11

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15
Q

Give the wireless technology for short-range wireless (commonly used in audio)

A

Bluetooth

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16
Q

Give the wireless technology for home/industrial monitoring control

A

ZigBee 802.15.4

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17
Q

Give the wireless technology for high speed and short-range for computer peripherals and video connections

A

Ultrawideband

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18
Q

Give the wireless technology for MAN broadband wireless

A

WiMAX 802.16

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19
Q

Give the wireless technology for wireless barcode used for tracking and ID

A

RFID

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20
Q

Give the wireless technology for ultrashort range for smart cards and ID

A

NFC

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21
Q

Give the wireless technology for mixed-used unlicensed short-range telemetry and control

A

ISM

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22
Q

Give the wireless technology for optical wireless for control and data

A

IR

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22
Q

Give the wireless technology for wireless telemetry and control and internet access

A

White space radio

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23
Q

It is the interconnection between nodes

A

Communication link

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24
Q

A type of network that covers a large geographical area

A

WAN

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25
Q

Type of network that covers a city, town, or village

A

MAN

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26
Q

The smallest type of network

A

LAN

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27
Q

A short-range wireless network

A

PAN (Personal Area Network)

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28
Q

The generic term which refers to the IEEE 802.11 communications standard for WLAN

A

Wireless Fidelity (Wi-Fi)

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29
Q

WiFi radios that work with the 802.11b and 802.11g standards transmit up to _______

A

2.4GHz

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30
Q

The ISM Band for 802.11a

A

56GHz

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31
Q

radios used for WiFi have the ability to _______ frequencies

A

Change frequencies

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32
Q

It is a method of transmitting signals by rapidly switching the carrier between different frequency channels

A

Frequency Hopping

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33
Q

The advantage of this method is that it is more immune to interference and can allow dozens of WiFi cards to talk simultaneously

A

Frequency Hopping

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34
Q

It is the group of radio bands that are intentionally reserved for these radio frequency energy intended for scientific, medical and industrial requirements rather than for communications

A

ISM (Industrial, Scientific, Medical)

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35
Q

In this frequency band, interference occurs a lot

A

ISM (Industrial, Scientific, Medical)

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36
Q

The earliest useful and most widely adopted version of 802.11 standard

A

802.11b

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37
Q

The access method used in 802.11b

A

Direct Sequence Spread Spectrum (DSSS)

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38
Q

The 802.11b has ___ channels and ___ non-overlapping channels

A

11, 3

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39
Q

ISM Band for 802.11b

A

2.4GHz

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40
Q

the total bandwidth for 802.11b

A

83.5MHz

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41
Q

The maximum data rate for 802.11b

A

11 Mbps

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42
Q

The back-off rates for 802.11b

A

1, 2, 5.5 Mbps

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43
Q

The maximum distance at the maximum data rate of 802.11b

A

100m

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44
Q

The channels in 802.11b are spaced ____ apart over the spectrum

A

5MHz

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45
Q

Each channel in 802.11b is ___ wide, which is why they overlap

A

22MHz

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46
Q

a modulation technique used to achieve faster rates such as 11Mbps and 5.5Mbps

A

CCK (Complementary Code Keying)

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47
Q

This type of modulation technique improves the performance of the signal under noise and multipath conditions due to their unique codes and properties that make them easier to identify and decode

A

CCK(Complementary Code Keying)

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48
Q

The equivalent isotropic radiated power for 802.11b is

A

1 W

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49
Q

when did the IEEE 802 Executive Committee establish the 802.11 working group to create a WLAN standard?

A

1990

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50
Q

UNII meaning

A

Unlicensed National Information Infrastructure band

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51
Q

when did 802.11a come out?

A

1991

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52
Q

What is the ISM band for 802.11a?

A

5GHz

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53
Q

The three authorized frequency segments of 802.11a

A

5.15 GHz to 5.25 GHz - 50mW power
5.25 GHz to 5.35 GHz - 250mW power
5.725 GHz to 5.825 GHz - 1W max power

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54
Q

maximum power for 5.15 GHz to 5.25 GHz 802.11a frequency segment?

A

50mW power

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55
Q

maximum power for 5.25 GHz to 5.35 GHz 802.11a frequency segment?

A

250mW power

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56
Q

maximum power for 5.725 GHz to 5.825 GHz 802.11a frequency segment?

A

1W max power

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57
Q

The access method for the 802.11a standard?

A

Orthogonal Frequency Division Multiplexing (OFDM)

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58
Q

Compared to 802.11b, this standard offers a wide range of data rates. The highest is 54 Mbps

A

802.11a

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59
Q

Channels for 802.11

A

23 (nonoverlapping)

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60
Q

Each channel in the 802.11a standard carries an OFDM signal made up of __ subcarriers, ____ for data, and other _____ for error corrections.

A

52 subcarriers
48 for data
4 for error corrections

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61
Q

Each subcarrier in the 802.11a standard is ____ wide

A

300khz

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62
Q

The maximum data rate for 802.11a standard

A

54 Mbps

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63
Q

The back-off rates for 802.11a standard

A

48 Mbps, 36 Mbps, 24 Mbps, 18 Mbps, 12 Mbps, 9 Mbps, 6 Mbps

64
Q

The maximum distance at the maximum rate of 802.11a standard

A

50m

65
Q

The downside of 802.11a standard

A

short-range (the maximum distance is only 50m)

66
Q

The modulation technique used in 802.11a standard with 6Mbps data rate

A

BPSK (Binary Phase-Shift Keying)

67
Q

The modulation technique used in 802.11a standard with 12Mbps data rate

A

QPSK (Quadrature Phase-Shift Keying)

68
Q

The modulation technique used in 802.11a standard with 24Mbps data rate

A

16- QAM (Quadrature Amplitude Modulation)

69
Q

The modulation technique used in 802.11a standard with 54Mbps data rate

A

64-QAM 9(Quadrature Amplitude Modulation)

70
Q

What access method is used in 802.11g that enables it to provide a maximum data rate of 54Mbps at 100ft indoors?

A

OFDM (Orthogonal Frequency Division Multiplexing)

71
Q

The 802.11g is fully ______ compatible with 802.11b

A

backwards-compatible

72
Q

The ISM band for 802.11g

A

2.4 GHz

73
Q

This access method is used because it reduces multipath issues

A

OFDM (Orthogonal Frequency Division Multiplexing)

74
Q

The channels for 802.11g

A

11 channels (3 non-overlapping)

75
Q

The maximum data rate for 802.11g

A

54Mbps

76
Q

The maximum distance at the maximum data rate in 802.11g is

A

100 ft

77
Q

This standard uses Multiple Input Multiple Output antenna systems to improve the reliability of the link

A

802.11n

78
Q

The access point for 802.11n uses _____ transmit antennas and ____ receive antennas

A

two or more transmit
three or more receive

79
Q

This arrangement of 802.11n permits data range in the 100-600 Mbps range at a distance of up to 100m

A

MIMO (Multiple Input, Multiple Output), where multiple antennas are used for both transmitting (Tx) and receiving (Rx) signals.

80
Q

This technology in 802.11 greatly mitigates multipath problems and helps extend the range and reliability of the wireless link

A

MIMO (Multiple Input, Multiple Output)

81
Q

What standard dominates the Wireless LAN space today?

A

802.11n

82
Q

What wireless technology is commonly available in laptops, smartphones, and tablets?

A

802.11n

83
Q

it is the wireless technology of all hot spots and access points, including the millions of home wireless routers

A

802.11n

84
Q

The 802.11n is backward compatible with _____ and _____

A

802.11a
802.11b
802.11g

85
Q

The access method for 802.11n

A

OFDM (Orthogonal Frequency Division Multiplexing)

86
Q

The maximum data rates for 802.11n

A

100 to 600Mbps

87
Q

The maximum distance at the maximum data rate for 802.11n

A

100 m

88
Q

This standard is one of the newest versions of 802.11

A

802.11ac

89
Q

The ISM band for 802.11ac

A

5GHz

90
Q

The 802.11ac uses ____ technology and ____ access method

A

MIMO (Multiple Input Multiple Output) antenna systems
OFDM (Orthogonal Frequency Division Multiplexing)

91
Q

As the bandwidth increases in 802.11ac, the number of OFDM subcarriers also increases to a maximum of ____ at 160MHz bandwidth

A

512

92
Q

It is a wireless LAN transceiver or “base station” that can connect one or many wireless devices simultaneously to the internet

A

Access Point (AP)

93
Q

They accept the wireless signal and relay information

A

Wi-Fi cards

94
Q

They are the firewalls and antivirus software, which protect the networks from uninvited users and keep information secure

A

Safeguards

95
Q

A wifi hotspot is created by installing a/an ______ to an internet connection

A

Access Point

96
Q

A single access point can support up to ____ users and can function within a range of ____ to ____ indoors and up to ____ outdoors

A

30 users
100-150 ft indoors
300 ft outdoors

97
Q

Many access points can be connected to each other via ____ to create a single large network

A

Ethernet Cables

98
Q

A computer’s ____ translates data into a radio signal

A

wireless adapter

99
Q

A _____ receives the signal from the wireless adapter and decodes it

A

wireless router

100
Q

The wireless router sends the information received from the adapter to the internet via ________

A

physical wired ethernet connection

101
Q

Wi-Fi radios transmit frequencies of ____ and _____

A

2.4 GHz to 5 GHz

102
Q

Wi-Fi radios can transmit on any three frequency bands or they can _____ rapidly between bands

A

frequency hop

103
Q

This helps reduce interference and lets multiple devices use the same wireless connection simultaneously

A

Frequency Hopping

104
Q

in this Wi-Fi topology, the client communicates through the access point

A

AP-based topology (infrastructure)

105
Q

The RF coverage is provided by an AP

A

Basic Service Area (BSA)

106
Q

This extends the coverage network by combining two or more BSA

A

ESA (Extended service area)

107
Q

The ESA (extended service area allows 10-15% overlap to allow _____

A

roaming

108
Q

In this topology, access points are not required

A

Peer to Peer topology (Ad-hoc mode)

109
Q

In this topology, client devices within a cell can communicate directly with each other.

A

Peer to Peer topology (Ad-hoc mode)

110
Q

This topology is useful for setting up a wireless network quickly and easily

A

Peer to Peer topology (Ad-hoc mode)

111
Q

This network topology is used to connect a LAN in one building to LANs in the other buildings even if the buildings are miles apart

A

Point to Multipoint bridge topology

112
Q

The Point to Multipoint bridge topology creates a ____ between buildings

A

Line of Sight

113
Q

This wifi configuration network is designed for small businesses and individuals operating within limited physical workspaces such as homes or small offices

A

Home/ SOHO (Small Office Home Office) network

114
Q

This wifi network configuration is used for small public hotspot

A

Simple Wireless Network

115
Q

This wifi network is used in homes and offices in which the hub, router, and Wi-Fi AP are all in a single device

A

CombinedWireless Network

116
Q

This wireless security standard is the basic security protocol

A

WEP (Wireless Equivalent Privacy)

117
Q

This security standard uses RC4 encryption standard and authentication

A

WEP (Wireless Equivalent Privacy)

118
Q

This security standard may be turned off or on by the user

A

WEP (Wireless Equivalent Privacy)

119
Q

This wifi security protocol has stronger encryption standards

A

Wi-Fi Protected Access
(WPA)

120
Q

The IEEE has a wireless LAN standard that provides the ultimate protection. This standard is ________

A

802.11i

121
Q

This is considered as the most popular PAN

A

Bluetooth

122
Q

It is a digital radio standard that uses frequency-hopping spread spectrum (FHSS)

A

Bluetooth

123
Q

What is FHSS that is used in Bluetooth

A

Frequency-Hopping Spread Spectrum

124
Q

Bluetooth is a digital radio standard that uses frequency-hopping spread system (fhss) in the unlicensed _____ ISM band

A

2.4GHz

125
Q

It is a wireless technology standard for exchanging data over short distances from fixed and mobile devices and building personal area networks

A

Bluetooth

126
Q

when did Ericsson, Nokia, IBM, Toshiba and Intel formed the Bluetooth special interest group (SIG)

A

1998

127
Q

Bluetooth protocol is released in

A

1999

128
Q

in what year did the IEEE adopted the bluetooth standard, 802.15 working group

A

2002

129
Q

It is a network of devices connected in an ad-hoc fashion using bluetooth technology

A

PICONET

130
Q

Piconet can support up to how many devices?

A

8 devices

131
Q

When a piconet is formed, one device acts as a _____ and the others act as __________

A

master
slaves

132
Q

Piconet is sometimes called ____

A

PAN (Personalized Area Network)

133
Q

two or more bluetooth units sharing the same channel form a _____

A

piconet

134
Q

_____ cannot directly transmit data to one another

A

slaves

135
Q

slaves can only have links to ___

A

master

136
Q

____ acts as a switch for the piconet and all the traffic must pass through it

A

master

137
Q

the slaves in a piconet use master’s ___ and ____ to determine the frequency hopping sequence

A

bluetooth device address
clock

138
Q

slaves ____ with master’s clock for duration of the connection

A

synchronize

139
Q

____ also controls when devices transmit data, since ____ can only transmit when scheduled by the master

A

master
slave

140
Q

the _____ controls the total available bandwidth to be distributed to the ____

A

master
slaves

141
Q

It is a group of non-synchronized piconets that share at least one common bluetooth device

A

Scatternet

142
Q

in a scatternet communication, the blutooth device must have a ______ capability

A

point to multipoint

143
Q

how many maximum loaded piconets are there in a scatternet

A

10 loaded piconets

144
Q

it is formed when two or more piconets are interconnected

A

scatternet

145
Q

____ is a standard for tiny radio frequency chips that can be plugged into your device

A

Bluetoooth

146
Q

These chips were designed to take all the information wires normally send and transmit it to a special frequency called the __________

A

receiver bluetooth chip

147
Q

Bluetooth uses _______ to send data

A

packet-switching

148
Q

it is a device in piconet whose clock and sequence are used to synchronize all other devices in the piconet

A

Mater

149
Q

This device carry out paging and connection establishment

A

Master

150
Q

Units within the piconet that are synchronized to the master via its clock and hopping sequence

A

slaves

151
Q
A
152
Q

After connection establishment, slaves are assigned to a temporary 3-bit member address know as __________ to reduce the number of addressing bits required

A

Active Member Address

153
Q

each piconet has a maximum capacity of _____

A

1Mbps

153
Q

It is the interconnection of multiple piconets

A

scatternet

154
Q

the _____ defines a protocol stack to enable heterogenous devices to communicate

A

The Bluetooth Standard

155
Q

_____ includes protocols for the radio layer all the way up to device discovery, service dicovery, etc.

A

Bluetooth stack

156
Q

It is composed of bluetooth protocols to allow bleutooth devices to locate each other and to create, configure, and manage both physical and logical links that allow higher layer protocols and applications to pass data through these transport protocols

A

Bluetooth Protocol Stack