Problem 1 (Count as 2 problems) Satellite TV Transmission
•
A signal is transmitted at 10 GHz (
meter
03
.
0
=
λ
) from an orbit 30,000 km above the earth. The
transmitter gain is 20 dB. In bad weather, the signal may suffer an absorption loss of 2 dB per km
through thunderstorm rain 3 km depth. The receiver dish is 0.4 m in diameter. Account for the following
losses and gains
Distance loss =
Transmitter gain plus receiver gain =
Absorption loss by rain =
Net loss =
•
Assume thermal noise
Hz
W
N
/
10
4
21
0

×
=
. We transmit HDTV at 10 Mbps at 100
W
power.
Calculate
Received power (
W
) =
:
The energy per bit =
The subsequent
0
/
N
E
b
=
•
If we need
dB
N
E
b
10
/
0
, is the above
0
/
N
E
b
satisfactory? Suppose we use a rate ½ Hamming
distance = 14 convolutional encoder. Calculate the coding gain. Is the result satisfactory now?
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View Full DocumentProblem 2
Cellular communications
•
Draw the cellular pattern for
N
=13 (with
1
,
3
=
=
j
i
). Draw a pattern with 13 cells numbered, plus one
more layer of cells (numbered also) surrounding the pattern.
•
What is the signal to interference for this cellular system, assuming fade exponent
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 Spring '09
 Hui
 Amplifier, Hertz, Satellite television, Rayleigh fading, Transmitter power output

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