In the simplest formula for path loss of land propagation is Lp=Ad^(alpha) ; which value does the propagation constant (alpha) usually take in a typical urban area?

In the simplest formula for path loss of land propagation is Lp=Ad^(alpha) ; which value does the propagation constant (alpha) usually take in a typical urban area?

a. 1~2
b. 2~3
c. 3~4
d. 4~5


Answer: c

Calculate the change in received signal power Pr (in dB) in free-space propagation condition at two different distance points when the second distance point is ten times the distance of the first point (d2=10d1)

Calculate the change in received signal power Pr (in dB) in free-space propagation condition at two different distance points when the second distance point is ten times the distance of the first point (d2=10d1)

a. -3dB
b. -5dB
c. -6dB
d. -20dB



Answer: d

Calculate the change in received signal power Pr (in dB) in free-space propagation condition at two different distance points when the second distance point is twice the distance of the first point (d2=2d1)

Calculate the change in received signal power Pr (in dB) in free-space propagation condition at two different distance points when the second distance point is twice the distance of the first point (d2=2d1)

a. -3dB
b. -5dB
c. -6dB
d. -20dB



Answer: c

The "fast fading" seen in mobile communications is caused by ______________ waves interfering with direct waves.

The "fast fading" seen in mobile communications is caused by ______________ waves interfering with direct waves.

a. Refracted
b. Reflected
c. Absorbed
d. Diffracted


Answer: b

Cellular phone systems rely on:

Cellular phone systems rely on:

a. high power
b. repeaters
c. the radio horizon
d. the reuse of frequencies


Answer: d

A 20-dB reduction in the strength of a radio wave due to reflection is called:

A 20-dB reduction in the strength of a radio wave due to reflection is called:

a. fading
b. diffraction
c. frequency diversity
d. spatial diversity



Answer: a

Sky waves cannot be "heard":

Sky waves cannot be "heard":

a. close to the transmitter
b. far from the transmitter
c. in the "silent" zone
d. in the "skip" zone



Answer: d

Sky waves:

Sky waves:

a. are line-of-sight
b. "bounce" off the ionosphere
c. are same as space waves
d. are radio waves used for satellite communications


Answer: b

Space waves are:

Space waves are:

a. line-of-sight
b. reflected off the ionosphere
c. same as sky waves
d. radio waves used for satellite communications


Answer: a

Radio waves would most strongly reflect off:

Radio waves would most strongly reflect off:

a. a flat insulating surface of the right size
b. a flat metallic surface of the right size
c. a flat dielectric surface of the right size
d. a flat body of water


Answer: b

Radio waves sometimes "bend" around a corner because of:

Radio waves sometimes "bend" around a corner because of:

a. reflection
b. refraction
c. diffusion
d. diffraction



Answer: d

Ground waves are most effective:

Ground waves are most effective:

a. below about 2 MHz
b. above about 20 MHz
c. at microwave frequencies
d. when using horizontally polarized waves


Answer: a

The attenuation of free space is due to

The attenuation of free space is due to 

a. losses in the characteristic impedance of free space
b. losses due to absorption in the upper atmosphere
c. the decrease in energy per square meter due to expansion of the wavefront
d. the decrease in energy per square meter due to absorption of the wavefront


Answer: c

In free space, radio waves travel at a speed of

In free space, radio waves travel at a speed of 

a. 3 x 106 meters per second
b. 3 x 106 miles per second
c. 300 x 106 meters per second
d. 300 x 106 meters per second


Answer: a

What is Doppler Effect in mobile radio propagation?

What is Doppler Effect in mobile radio propagation?

a. The received signal is unchanged when the wave source is moving
b. The received signal is reflected
c. The change in frequency of a wave (or other periodic event) for an observer moving relative to its source
d. The change in frequency of a wave is interval


Answer: c

When a cell phone is used in the elevator, why is the signal weak or not in service?

When a cell phone is used in the elevator, why is the signal weak or not in service?

a. The elevator is closed
b. EM wave are absorbed or reflected
c. EM wave is strong
d. The elevator is moving


Answer: b

GSM is a digital system with an over-the-air bit rate of _________

GSM is a digital system with an over-the-air bit rate of _________

a. 9.6 kbps
b. 56 kbps
c. 144 kbps
d. 270 kbps



Answer: d

8 Location Area is an area covered by ______.

8 Location Area is an area covered by ______.

a. BTS
b. BSC
c. MSC
d. Operator


Answer: c

Bluetooth is a _______ technology that connects devices (called gadgets) in a small area.

Bluetooth is a _______ technology that connects devices (called gadgets) in a small area.

a. wired LAN
b. wireless LAN
c. VLAN
d. Sensor Networks



Answer: b

IEEE has defined the specifications for a wireless LAN, called _______, which covers the physical and data link layers.

IEEE has defined the specifications for a wireless LAN, called _______, which covers the physical and data link layers.

a. IEEE 802.3
b. IEEE 802.5
c. IEEE 802.2
d. IEEE 802.11


Answer: d

Which networks are wireless but not mobile?

Which networks are wireless but not mobile?

a. Mobile network
b. Wireless LAN
c. Microwave backbone network
d. GPS



Answer: c

What is a sensor network often used for?

What is a sensor network often used for?

a. Defense and civilian applications
b. Cellular phones
c. Telesystems
d. Home devices


Answer: a

How is an ad hoc network different from a cellular network?

How is an ad hoc network different from a cellular network?

a. No base station
b. Simple base station
c. Unlimited range
d. Need a fixed infrastructure



Answer: a

What are the challenges for wireless networking? (Many choices can be selected)

What are the challenges for wireless networking? (Many choices can be selected)

a. Cost and power
b. Network size
c. Mobility
d. No lines


Answer: ab

The three groups of wireless technologies are

The three groups of wireless technologies are

a. fixed wireless, mobile wireless, IR wireless
b. wired wireless, mobile wireless, IR wireless
c. wired wireless, mobile wireless, wired IR
d. fixed wireless, mobile wireless, wired wireless


Answer: c

Find the reuse distance if radius of each cell is 2 km and a cluster size is 7

Find the reuse distance if radius of each cell is 2 km and a cluster size is 7

a. 6.2 km
b. 7.2 km
c. 8.2 km
d. 9.2 km



Answer: d

If each user keeps a traffic channel busy for an average of 6% time and an average of 60 requests per hours is generated, what is the offered traffic load (in Erlangs)?

If each user keeps a traffic channel busy for an average of 6% time and an average of 60 requests per hours is generated, what is the offered traffic load (in Erlangs)?

a. 2.6 Erlangs
b. 2 Erlangs
c. 3.6 Erlangs
d. 5 Erlangs



Answer: c

The reuse distance increases with the cluster size, more precisely

The reuse distance increases with the cluster size, more precisely

a. with the square root of the cluster size
b. proportional to cluster size
c. with the square of the cluster size
d. with the logarithm of the cluster size



Answer: b

The cluster size of the frequency reuse pattern of a hexagonal cellular system can only take on a particular values. Namely

The cluster size of the frequency reuse pattern of a hexagonal cellular system can only take on a particular values. Namely

a. 1,3,5,7,9,...
b. 1,4,9,16,25,..
c. 1,3,4,7,9,11,...
d. 1,3,4,6,7,9,10,..



Answer: c

The cell having the same number in the adjacent cluster using the same set of RF channels are termed as

The cell having the same number in the adjacent cluster using the same set of RF channels are termed as

a. Adjacent cell
b. Co channel cell
c. Macro cell
d. Selective Cell


Answer: b

Which cell size is sometimes used in instances such as those where a heavily used road crosses an area where there are microcells

Which cell size is sometimes used in instances such as those where a heavily used road crosses an area where there are microcells

a. Microcell
b. Macrocell
c. Picocell
d. Umbrella cell


Answer: d

Which cell size is generally used for covering very small areas such as particular areas of buildings, or possibly tunnels

Which cell size is generally used for covering very small areas such as particular areas of buildings, or possibly tunnels

a. Microcell
b. Macrocell
c. Picocell
d. Umbrella cell



Answer: c

Densely populated areas which may have a diameter of around 1 km will be covered by

Densely populated areas which may have a diameter of around 1 km will be covered by

a. Microcell
b. Macrocell
c. Picocell
d. Umbrella cell


Answer: a

The remote and sparsely populated areas will be covered by

The remote and sparsely populated areas will be covered by

a. Microcell
b. Macrocell
c. Picocell
d. Umbrella cell



Answer: b

What is the process of subdividing congested cells into smaller cells each with its own base stations and a corresponding reduction in antenna height and transmitter power

What is the process of subdividing congested cells into smaller cells each with its own base stations and a corresponding reduction in antenna height and transmitter power

a. Sectoring
b. Cell splitting
c. Blocked call delay system
d. Frequency reuse


Answer: b

What is technique for decreasing co-channel interference and thus increasing the system performance by using directional antennas.

What is technique for decreasing co-channel interference and thus increasing the system performance by using directional antennas.

a. Sectoring
b. Cell splitting
c. Blocked call delay system
d. Frequency reuse



Answer: a

The code word with n bits is expressed as: c(x)=c1xn-1 +c2xn-2......+ cn where each coefficient ci (i=1,2,..,n) is either a 1 or 0

The code word with n bits is expressed as:
c(x)=c1xn-1 +c2xn-2......+ cn
where each coefficient ci (i=1,2,..,n) is either a 1 or 0

a. Cyclic Redundancy Check
b. Convolutional Codes
c. Linear Block Codes
d. Cyclic Codes



Answer: d

Both error correction capability and ARQ are used together in a cellular system__________

Both error correction capability and ARQ are used together in a cellular system__________

a. To implement end-to-end error-free transmission.
b. To increase loss and interference
c. To increase the probability of retransmission
d. To decrease error rate



Answer: a

To protect the transmitted data from burst errors, ______is used.

To protect the transmitted data from burst errors, ______is used.

a. Turbo Codes
b. Convolutional Codes
c. Linear Block Codes
d. Interleaver



Answer: d

_____is a technique used to ensure that the information to be transmitted is coded using as few bits as possible to better utilize the available bandwidth.

_____is a technique used to ensure that the information to be transmitted is coded using as few bits as possible to better utilize the available bandwidth.

a. Chanel Coding
b. Line Coding
c. Source Coding
d. Entropy coding


Answer: c

It encodes information stream rather than information blocks and decodes based on Viterbi Algorithm

It encodes information stream rather than information blocks and decodes based on Viterbi Algorithm

a. Cyclic Redundancy Check
b. Convolutional Codes
c. Linear Block Codes
d. Cyclic Codes


Answer: b

What is an error checking code that the transmitter appends an extra n-bit sequence to every frame?

What is an error checking code that the transmitter appends an extra n-bit sequence to every frame?

a. Cyclic Redundancy Check
b. Convolutional Codes
c. Linear Block Codes
d. Cyclic Codes



Answer: a

What kinds of coding if the information sequence is always a multiple of a preselected length k?

What kinds of coding if the information sequence is always a multiple of a preselected length k?

a. Cyclic Redundancy Check
b. Convolutional Codes
c. Linear Block Codes
d. Cyclic Codes


Answer: c

Why channel coding reduces bandwidth efficiency of the link in high signal-to-noise ratio conditions?

Why channel coding reduces bandwidth efficiency of the link in high signal-to-noise ratio conditions?

a. Because of noise
b. It basically adds redundancy to the transmitted bits
c. It carries more signals
d. It harms the deficiencies of the noisy transmission medium



Answer: b

Consider an antenna transmitting at 900 MHz. The receiver is traveling at a speed of 40 km/h. Calculate its Doppler shift.

Consider an antenna transmitting at 900 MHz. The receiver is traveling at a speed of 40 km/h. Calculate its Doppler shift.

a. 33.67 Hz
b. 14.67 Hz
c. 11.11 Hz
d. 0.33 Hz


Answer: a

A receiver is tuned to 1 GHz transmission and receives signals with Doppler frequencies ranging from 10 Hz to 50 Hz when moving at a speed of 60 km/hr. What is the fading rate?

A receiver is tuned to 1 GHz transmission and receives signals with Doppler frequencies ranging from 10 Hz to 50 Hz when moving at a speed of 60 km/hr. What is the fading rate?

a. 444.4 Hz
b. 333.3 Hz
c. 222.2 Hz
d. 111.1 Hz



Answer: d

The receiver is in a distance of 2000 m; the carrier frequency fc = 1 GHz. Express the free space path loss in dB.

The receiver is in a distance of 2000 m; the carrier frequency fc = 1 GHz. Express the free space path loss in dB.

a. 278 dB
b. 38.45 dB
c. 98.45 dB
d. 89.45 dB



Answer: c

Consider an antenna transmitting a power of 10 W at 950 MHz. Calculate the received power at a distance of 5 km if propagation is taking place in free space.

Consider an antenna transmitting a power of 10 W at 950 MHz. Calculate the received power at a distance of 5 km if propagation is taking place in free space.

a. 1.53 x 10-10 W
b. 2.53 x 10-10 W
c. 3.53 x 10-10 W
d. 4.53 x 10-10 W


Answer: b

A wireless transmitter with an effective diameter of 350 cm transmits at a power of 35 mW and a gain of 30 dB. What is the received power if the receiver is 5 km away from the transmitter?

A wireless transmitter with an effective diameter of 350 cm transmits at a power of 35 mW and a gain of 30 dB. What is the received power if the receiver is 5 km away from the transmitter?

a. 0.001 mW
b. 0.002 mW
c. 0.003 mW
d. 0.004 mW


Answer: a

A wireless receiver with an effective diameter of 350 cm is receiving signals at 30 GHz from a transmitter. What is the gain of the receiver antenna?

A wireless receiver with an effective diameter of 350 cm is receiving signals at 30 GHz from a transmitter. What is the gain of the receiver antenna?

a. 30.8 dB
b. 40.8 dB
c. 50.8 dB
d. 60.8 dB


Answer: d