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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	Calculate total capacity C of a GSM system assuming: number of frequency pairs L = 48, average cell radius R = 4.37 km, total system area A = 300 000 km^2 , 4-cell clusters.
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	COST-231-Walfish-Ikegami model is suitable for ð urban areas ð rural areas ð satellite links ð hilly terrain		Radius of the n-th Fresnel zone is given by: ð ð ð ð
8	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.
9	Which techniques used in the GSM allow to save energy in Mobile Stations:

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