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Mark

Mobile Communications - examination paper (set A)

1	Complete the diagram so that it explains call setup sequence from PSTN/ISDN to MS.		Explain acronyms that you use to annotate the diagram:
2	How path attenuation in the two-ray model depends on the distance d? What properties of the ground are typically assumed in this model, and how phase and amplitude of the wave reflected from it change?
3	In free space there is a transmitting and a receiving antenna, both with gain GT = GR = 0 dBi. The antennas are located d = 1000 km one from another. Transmit power is PT = 1 W and carrier frequency f = 30 MHz. What is the received power in W, dbW, dBm?
4	Sketch the GSM normal burst. Name its components, duration, and number of bits.
5	Explain GSM authentication procedure. Draw a suitable diagram.
6	Explain timing advance technique:
7	First NMT450 system was launched in: ð 1970 ð 1976 ð 1981 ð 1983	If VSWR = 0.5 then reflection coefficient r =: ð 0.2 ð 12 ð 1.5 ð 0.1		If ERP = 30 dBm then EIRP = ð 27.85 dBW ð 30.15 dBm ð 27.85 dBm ð 30.15 dBm
8	Calculate the minimum number of cells in a cluster to achieve the C/I ratio of 9 dB for the path attenuation exponent n=4. Consider two cases, i.e. with and without 120º sectorisation. Use simplified formulas for C/I ratio.
9	Which techniques used in the GSM allow to save energy in Mobile Stations:

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