Deck 10: Cellular Wireless Networks

Question 1

Cellular technology is the foundation of mobile wireless communications.

Answer 1

True

Question 2

The area to be covered in a cellular network is divided into cells in a pentagonal tile pattern that provide full coverage of the area and equidistant antennas.

Answer 2

False

Question 3

An important design goal for all three generation systems is to limit channel usage to 5 MHz.

Answer 3

True

Question 4

A cellular network uses multiple low power ________.

A)frequencies
B)receivers
C)antennas
D)transmitters

Question 5

A major technical problem for cellular networks is fading.

Question 6

A wireless cellular system limits the opportunity to use the same frequency for different communications because the signals can interfere with one another even if geographically separated.

Question 7

First generation cellular networks ________.

A)were FDDI
B)were digital
C)were analog
D)were based on code division multiple access

Question 8

A technique in widespread use in second generation cellular networks is ________.

A)TCMP
B)CDMA
C)3G
D)HTTP

Question 9

Scattering effects are difficult to predict.

Question 10

The most widely used second generation CDMA scheme is IS-95.

Question 11

Mobile radio communication introduces complexities not found in wire communication or in fixed wireless communication.

Question 12

Second generation cellular networks were analog.

Question 13

One unwanted effect of multipath propagation is that multiple copies of a signal may arrive at different phases.

Question 14

All first and second generation cellular networks provide encryption.

Question 15

Cells in areas of high usage can be split into smaller cells.

Question 16

Affecting not only mobile phones in automobiles,but even a mobile phone user walking down an urban street,________ occurs when there are rapid variations in signal strength.

A)selective fading
B)nonselective fading
C)flat fading
D)fast fading

Question 17

Only one mobile user unit may be active and communicating with the base station at a time.

Question 18

Even though cells are sufficiently distant from each other,they still need to be assigned different frequencies to avoid interference or crosstalk.

Question 19

In a mobile environment one of the two antennas is moving relative to the other,therefore the relative location of various obstacles moves also,so as not to hinder transmission.

Question 20

________ are used to exchange information having to do with setting up and maintaining calls and with establishing a relationship between a mobile unit and the nearest base station.

A)Advanced Mobile Phone Services
B)Mobile initialization units
C)Traffic channels
D)Control channels

Question 21

Each cell in a cellular network is allocated a band of frequencies and is served by a ________ consisting of transmitter,receiver and control unit.

Question 22

The time variation of received signal power caused by changes in the transmission medium is referred to as ________,which is a major technical problem for cellular networks.

Question 23

Each base station is connected to a ________,which serves multiple base stations.

A)mobile telecommunications switching office
B)public telephone network
C)cellular network
D)chain of base stations

Question 24

If there is no clear line-of-sight to the transmitter,such as in an urban area at street level,then diffraction and ________ are the primary means of signal reception.

Question 25

First generation cellular networks made use of ________ multiplexing.

Question 26

A ________ is used to identify the user and register its location.

A)page
B)handoff
C)handshake
D)reflection

Question 27

The number of cells in a repetitious pattern,(each cell in the pattern uses a unique band of frequencies),is termed the ________.

Question 28

________ occurs when an electromagnetic signal encounters a surface that is large relative to the wavelength of the signal.

A)Scattering
B)Diffraction
C)Reflection
D)Termination

Question 29

As the mobile user covers distances well in excess of a wavelength,the urban environment changes as the user passes buildings of different heights,vacant lots, and intersections.Over these longer distances,there is a change in the average received power level about which the rapid fluctuations occur.This is referred to as ________.

Question 30

As the mobile units move they pass from cell to cell,which requires transferring of the call from one base transceiver to another.This process is called ________.

A)frequency reuse
B)a handshake
C)equalization
D)a handoff

Question 31

________ are useful in city streets in congested areas,along highways,and inside large public buildings.

A)Maximum bit rates
B)MTSOs
C)Microcells
D)Control channels

Question 32

The dominant technology for third generation systems is ________.

A)IMT-TC
B)UMTS
C)CDMA
D)TDMA

Question 33

Third generation wireless communication supports ________.

A)voice but not multimedia data
B)multimedia but not voice
C)multimedia and voice
D)voice but not video

Question 34

The ________ connects calls between mobile units,makes connections between a fixed subscriber to the public network and a mobile subscriber to the cellular network,assigns the voice channel to each call,performs handoffs,and monitors the call for billing information.

Question 35

One of the most widely used models to develop guidelines for cell size was developed by ________.

A)Bellman-Ford
B)Jacobson
C)Dijkstra
D)Okumura/Hata

Question 36

________ can be applied to transmissions that carry analog information or digital information and is used to combat intersymbol interference.

A)Forward error correction
B)Diffraction
C)Adaptive equalization
D)Frequency diversity

Question 37

The efforts to compensate for the errors and distortions introduced by multipath fading fall into three general categories: forward error correction,diversity techniques,and ________.

Question 38

________ occurs at the edge of an impenetrable body that is large compared to the wavelength of the radio wave.When a radio wave encounters such an edge, waves propagate in different directions with the edge as the source.Thus,signals can be received even when there is no unobstructed line-of-sight from the transmitter.

Question 39

Nonselective,or ________,is the type of fading in which all frequency components of the received signal fluctuate in the same proportions simultaneously.

A)slow fading
B)fast fading
C)diverse fading
D)flat fading

Question 40

The objective of the ________ of wireless communication is to provide fairly high speed wireless communications to support multimedia,data,and video,in addition to voice.

Question 41

Since the early 1980s the most common first-generation system in North America has been the ________ developed by AT&T.

Question 42

In a multipath environment,if the multiple versions of a signal arrive more than one chip interval apart from each other,the receiver can recover the signal by correlating the chip sequence with the dominant incoming signal.The remaining signals are treated as noise.However,even better performance can be achieved if the receiver attempts to recover the signals from multiple paths and then combine them with suitable delays.This principle is used in the ________ receiver.

Question 43

The key technology for 4G systems is ________.

Question 44

The term ________ refers to the provision of multiple fixed data rate logical channels to a given user,in which different data rates are provided on different logical channels.The traffic on each logical channel can be switched independently through the wireless and fixed networks to different destinations.

Question 45

Second generation systems provide multiple channels per cell,but each channel is dynamically shared by a number of users using time division multiple access or ________.