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Mobile Communications - examination paper (set F)
1 |
Explain multipath propagation. How does it influence the channel impulse response and field strength? Draw suitable plots. |
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2 |
Characterize high frequency methods used in radio wave propagation modelling. When such methods can be used? Which physical phenomena do they take into account?
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3 |
An antenna with VSWR = 1.25 is connected to the transmitter with a flexible cable of attenuation L1=1 dB and reflection coefficient r1 = 0.05 and a main feeder cable of the length l = 50 m, unit attenuation Lu2 = 0.02dB/m, and reflection coefficient r2 = 0.01. Calculate VSWR of this setup.
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4 |
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F(50,50) field strength curves [dBμV/m]. Halfwave dipole at 1kW; land route; frequency 450-1000 MHz; 50% time, 50% locations; h0=10 m; Δh=50 m.
Problem: Calculate field strength at distance d = 100 km at h0 = 10 m, transmitter antenna height 100 m and gain of 12 dBi. The transmit power is 100 W. All other parameter values are as for the curves. |
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5 |
Explain what Subscriber Identity Module is. What type of information does it contain? How its contents can be updated?
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6 |
Explain time-division duplex in GSM. Why is it used?
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