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Saturday, 18 April 2015

Wireless and mobile communication-Model question paper for Diploma/B.E/B.Tech

1(a) Why is PSTN required for wireless communication? (4 Marks)
(b) What is TDMA? Explain its advantage and disadvantage over FDMA. (6 Marks)
(c) Explain packed radio using ALOHA techniques. (4 Marks)
(d) Why is CDMA most secure than other multiple access techniques? Explain basic operation of CDMA. (6 Marks)
2(a) Explain the differences between wireless and fixed telephone networks. (4 Marks)
(b) Explain characteristics and functions of SS-7 network and protocol. (8 Marks)
(c) Write a note on cellular digital packet data. (4 Marks)
(d) Mention some advantages of packet switching. (4 Marks)
3(a) Explain frequency reuse concept. How it is used to increase cellular system capacity? Explain using a suitable example. (8 Marks)
(b) Write a note on umbrella cell approach. (4 Marks)
(c) Derive formula for signal-to-interference ratio. (4 Marks)
(d) If a service provider had a 10.5 MHz band in each direction (up-link and down-link) and it would install 20 antenna sites to provide its services, what would be the maximum number of simultaneous users that the system called support in all cells? Neglect the channels that are used for control signaling. (4 Marks)
4(a) Explain using a block diagram, first generation basic cellular radio network. (8 Marks)
(b) Describe three subsystems in the GSM architecture. (6 Marks)
(c) Write a note on identification codes in AMPS. (6 Marks)
5(a) What is GPRS? Explain its architecture and services it provides. (8 Marks)
(b) What are the reasons to perform handoff? (6 Marks)
(c) What is location management system? What is the difference between registration and call establishment? (6 Marks)
6(a) Mention some advantages and disadvantages of WLAN compared to Wired LAN. (6 Marks)
(b) All current WLAN products fall into one of the three categories. Explain. (6 Marks)
(c) What is ad-hoc networking? (4 Marks)
(d) Distinguish between LLC and MAC. (4 Marks)
7(a) Explain the difference between piconets and scotternets. With reference to this, explain Bluetooth architecture. (8 Marks)
(b) Write a note on RFCOMM protocol. (4 Marks)
(c) Write a note on Bluetooth security. (4 Marks)
(d) What is the difference between the MAC protocol of the Bluetooth and the IEEE 802.11? (4 Marks)
8(a) Explain microcell zone concepts. (6 Marks)
(b) Explain spectrum allocation. Explain the difference between analog and digital cellular systems. (8 Marks)
(c) Distinguish between Hata model and Walfisch-Bertoni model. (6 Marks)

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