1. _______ reduces the cell size to increase capacity.
a) Intelligent cell approach
b) Microcell approach
c) Top down approach
d) Bottom up approach
Explanation: The microcell zone concept is used in cellular systems to specifically increase the capacity and coverage in cellular systems. A handoff is not required at MSC when the mobile travels between zones within a cell or when a mobile travels from one zone to another within the cell
2. _________ configuration describes a desktop in an office.
a) Mobile and wired
b) Fixed and wired
c) Fixed and wireless
d) Mobile and wireless
Explanation: Fixed and wired configuration describes a desktop in an office. The device use fixed networks for performance reasons. Neither weight nor power consumption of the devices allows for mobile usage
3. Small scale fading describes the _________ fluctuations of the amplitude, phases of a signal.
a) Rapid
b) Slow
c) Instantaneous
d) Different
Explanation: Small scale fading or simply fading, is used to describe the rapid fluctuations of amplitudes, phases, or multipath delays of a radio signal over a short period of time or travel distance. It ignores the large scale path loss.
4. Fading is caused by interference.
a) True
b) False
Explanation: Fading is caused by interference. It is caused by interference between two or more versions of the transmitted signal which arrive at the receiver at slightly different times
5. Which of the following is not an effect caused by multipath in radio channel?
a) Rapid changes in signal strength
b) Random frequency modulation
c) Power of base station
d) Time dispersion
Explanation: Rapid changes in signal strength over a small travel distance are caused due to multipath. It causes random frequency modulation due to varying Doppler shifts on different multipath signals. Time dispersion is also caused by multipath propagation delays.
6. In urban areas, fading occurs due to height of mobile antenna ________ than height of surrounding structure.
a) Same
b) Smaller
c) Greater
d) Very larger
Explanation: In urban areas, fading occurs because height of the mobile antenna is below the height of surrounding structures. Therefore, there is no single line of sight path to the base station
7. Fading does not occur when mobile receiver is stationary.
a) True
b) False
Explanation: The received signal may fade even when the mobile receiver is stationary. It is due to the movement of surrounding objects in the radio channel. The multipath components combine vectorially at the receiver antenna and cause signal to distort or fade.
8. Apparent shift in frequency in multipath wave is caused due to relative motion between________
a) Base station and MSC
b) Mobile and surrounding objects
c) Mobile and MSC
d) Mobile and base station
Explanation: Due to relative motion between mobile and base station, each multipath wave experiences an apparent shift in frequency. This shift in received signal frequency due to motion called Doppler shift.
9. Doppler shift is directly proportional to __________
a) Velocity
b) Height of antenna
c) Power of receiving antenna
d) Power of transmitter
Explanation: The shift in received signal frequency due to motion is called Doppler shift. It is directly proportional to the velocity and direction of motion of mobile with respect to the direction of arrival of the received multipath wave.
10. Which of the following factor does not influence small scale fading?
a) Multipath propagation
b) Power density of base station
c) Speed of mobile
d) Speed of surrounding objects
Explanation: Many physical factors in radio channel influence small scale fading. Multipath propagation, speed of mobile, speed of surrounding objects, transmission bandwidth of the signal influences small scale fading in a large way.