Name:
ID:
Faculty of Information Engineering & Technology
The Communications Department
Course: Wireless Communications [NETW 701]
Group:
Quiz (1)
Problem (1):
Choose the correct answer
1- The effect of obstacles on the attenuation of signal strength due to distance is termed
a. Lognormal Shadowing
b. Distance Path-loss
c. Small-scale Fading
d. Attenuation Variance
2- The wireless channel characteristic that has very low variation over distances that are compared to signal
wavelength is
a. Large-Scale Path-loss
b. Small-scale fading
c. Both (a) and (b)
d. Neither (a) nor (b)
3- Given that
a.
b.
c.
d.
a signal received power is -90 dBm. The power in W is
1 micro Watt
1 nano Watt
1 pico Watt
Other
4- Suppose the power transmitted from a source is 0 dBm and the received power at a distance d is -100
dB. The path loss is:
a. 100 dBm
b. 100 dB
c. 70 dBm
d. None of the above
5- The equation PTGT/4πd2 depicts the equation for
a. Power received at a distance d
b. Flux intensity at a distance d
c. Flux density at a distance d
d. Free Space Pathloss
6- In which of the models below that it is possible for the received power across a certain distance d would
be larger than that received in the case of line of sight model calculated using Friis equation
a. Two ray model
b. Knife-edge diffraction model
c. Both (a) and (b)
d. Neither (a) nor (b)
Problem (2):
Consider the system shown below where a receiver is simultaneously receiving signal from two transmitters A
and B. From transmitters A and B the receiver receives a line of sight signal in addition to a signal reflected
form the ground (Assume Γperp=-1). Assume the transmission power from transmitter A and transmitter B is
1W. Let the carrier frequency be 2 GHz. For both transmitters GT=8dB and GR=3dB.
Derive an exact expression for the amount of received power and calculate such power using the derived
expression.
B
A
50m
20m
Receiver
1.5 Km
1.5m
1.5 Km
Problem (3):
A company owns two offices towers in a city and wants to set up a 4-GHz microwave link between them. The
two towers have heights of 100 m and 80 m, respectively and are separated by 2 Km. In the line of sight
(LOS) and midway between the two towers is a third tower of height 100 m. Calculate the diffraction loss due
to the existence of the middle tower.
Fresnel zone diffraction parameter
 h
2  d1  d 2 
 d1d 2

2d 1 d 2
  d1  d 2 