IF365 - MOBILE COMMUNICATION

[aruljothi]

IF365 - MOBILE COMMUNICATION

Time:   Three Hours                   Maximum:   100 Marks

Answer All The Questions
Part – A (10 x 2 = 20 Marks)

1.   Explain cellular frequency reuse concept?
2.   How does cell splitting technique import the capacity of cellular system?
3.   What is the effect of base band Gaussian Pulse shaping in the transmitted spectrum of GMSK signal?
4.   Draw the power spectral density of MSK and QPSK signals and give your comments.
5.   What are the loss producing mechanisms in a wireless channel?
6.   What are the features of a smart antenna system?
7.   What are the criteria for choosing speech codec for mobile communication?
8.   How are different channels within the forward link in an IS – 95 system identified?
9.   List the applications of Low Earth Orbiting satellite and Geostationary satellite?
10.   Explain why a minimum of four satellite must be visible at an earth location of GPS system for position determination?

PART – B (5 x 16 = 80 Marks)

11.   Discuss the channel assignment and Hand off strategies employed in the design of cellular mobile system.

12.a)i)   Explain GMSK transmitter and receiver with the help of a neat block diagram.

ii)   Find the 3-dB band width for a Gaussian Low pass filter used to produce 0.25 GMSK with a channel data rate of 270 kbps. What is the 90% power bandwidth in the RF channel.

(OR)

12.b)   Compare the bit error rate performance and spectral efficiency of Binary PSK and OPSK. Also explain OPSK receiver.


13.a)   Explain Okumura model for outdoor propagation and any one model for indoor propagation model.

(OR)

13.b)i)   What are the advantages of diversity techniques in mobile radio communication.

ii)   Explain time, frequency, space and polarization diversity techniques and compare them.

14.a)   Discuss in detail about GSM system architecture, channel types and frame structure.

(OR)

14.b)   Explain the following multiple access techniques. Compare their performances.
i) FDMA  ii) TDMA  and iii) CDMA

15.a)   Explain the following satellite services
          i)    Very small Aperture Terminal System
         ii)     Global Positioning System

(OR)

15.b)   Write notes on the following:
        i)    Orbcommunication System
           ii)    Direct Broadcasting System.

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