[This paper contains SIX questions printed on THREE pages ...

SCHOOL OF COMPUTER TECHNOLOGY
EXAMINATION FOR BSC (HONS) INFORMATION TECHNOLOGY
SPECIALISATION IN NETWORKING, YEAR 3
ACADEMIC SESSION 2009, SEMESTER 8 & 9
CCB3304: SATELLITE COMMUNICATION
MARCH 2009
TIME: 2 HOURS
INSTRUCTIONS TO CANDIDATES
Answer any FOUR <strong>questions</strong>.
All <strong>questions</strong> carry equal marks.
Candidates must write in blue or black INK when writing in the answer booklet.
All answers must be written in the answer booklet provided. At the end of the
examination, answer booklets and answer sheets must be fastened together.
Only non – programmable calculators are allowed (if applicable).
Question <strong>paper</strong>s must NOT be removed from the exam hall.
[<strong>This</strong> <strong>paper</strong> <strong>contains</strong> <strong>SIX</strong> <strong>questions</strong> <strong>printed</strong> on THREE pages]

Question 1 (25 marks)
a) Provide FIVE different types of satellites that were launched
between the years 1957 to 1967.
b) Briefly define the following Kepler’s law:
i. First Kepler’s Law
ii. Second Kepler’s Law
iii. Third Kepler’s Law
(5 marks)
(2 marks)
(2 marks)
(2 marks)
c) Briefly explain the following types of satellites:
i. The Low Earth Orbit (LEO) satellite
ii. The Medium Altitude Orbit (MEO) satellite
(7 marks)
(7 marks)
Question 2 (25 marks)
a) An earth station is located in Washington DC and the
Geosynchronous satellite (GOS) is located at 97°W. The
following are the parameters of the earth station and the
satellite:
Earth Station:
Latitude (L E ) = 39°N = +39
Longitude (I E ) = 77°W = -77
Altitude = H = 0 km
GOS Satellite:
Latitude (L S ) = 0° (Inclination angle = 0)
Longitude (I S ) = 97°W = -97
Find the followings based on the information given in figures Q2
(a) and Table Q2 (a) :
i. The range, d
ii. The Elevation angle, θ
iii. The azimuth angle, φ z
(8 marks)
(3 marks)
(7 marks)
CCB3304: Satellite Communication
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(March 2009)

) A Low Earth Orbit (LEO) satellite is in a circular orbit 322 km
above the earth. Assume the average radius of the earth is 6378
km and the earth eccentricity is 0.
i. Determine the orbital velocity of the satellite in m/sec
ii. What is the orbital period, in minutes, of the LEO
satellite?
(3 marks)
(4 marks)
Question 3 (25 marks)
a) Briefly explain the following functions in a satellite system:
i. Tracking
ii. Telemetry
iii. Command
b) Calculate the following antenna parameters:
i. The gain in dBi of a 3m parabolic reflector antenna at
frequencies of 6 GHz and 14 GHz;
ii. The gain in dBi and the effective area of a 30m parabolic
antenna at 4 GHz
(5 marks)
(5 marks)
(5 marks)
(6 marks)
(4 marks)
Question 4 (25 marks)
a) Consider a satellite link that operates in ‘KU-Band’ and the
parameters are shown in figure Q4 (a). The transmit power is 10
watts, and both the transmitter and receiver parabolic antennas
have a diameter of 3 m. The antenna efficiency is 55% for both
antennas. The satellite is in a GSO location, with a range of 35
900 km. The frequency of operation is 12 GHz. These are typical
parameters for a moderate rate private network VSAT uplink
terminal.
Determine:
i. The received power (pr)
ii. The power flux density (pfd) for the link
(10 marks)
(5 marks)
Figure Q4 (a)
b)
CCB3304: Satellite Communication
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(March 2009)

c
Briefly explain the concepts of using Carrier to Noise Density ( ) n
e b
and ( ) Energy Per-bit to Noise Density in measuring the Radio
n 0
Frequency (RF) link performance in satellite communications.
(10 marks)
Question 5 (25 marks)
a) A satellite at 40,000 km transmits 2W of power. The antenna gain
is 17 dB. Calculate:
i) The flux density on the earth’s surface
ii) The power received by the antenna with effective aperture of
10m 2
iii) The gain of the receiving antenna
i) The receiver Carrier to Noise ratio C/N, assuming system
temperature (Ts) is 152 K, and bandwidth (BW) is 500 MHz
b) Briefly explain the influence of cloud and fog attenuations in a
satellite communication system.
(4 marks)
(4 marks)
(3 marks)
(4 marks)
(10 marks)
Question 6 (25 marks)
a) Why is it that Beam Diversity and Power Control techniques do
not alter basic signal format in the process of restoring the
communication link?
b) Frequency Division Multiple Access (FDMA) was the first Multiple
Access (MA) technique to be implemented on satellite systems
and is the simplest in principle and operation. Sketch a design to
show the function of the FDMA process, which features an
example of three ground stations accessing a single frequency
translation (FT) satellite transponder.
(12 marks)
(13 marks)
~ END OF PAPER ~
CCB3304: Satellite Communication
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(March 2009)