B.TECH - Semester 8 wireless communications Question Paper 2021 (feb)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- 804 : WIRELESS COMMUNICATIONS (T) (2013 Scheme) Time : 3 Hours Max. Marks : 100 Answer all questions :
- Explain simulcast of paging service.
- List out major functions of Mobile Switching Center.
- Justify the choice of hexagon shaped cell structure in cellular systems?
- What is meant by frequency re-use?
- Determine the number of cells in clusters for the following values $j=4$ and $j=2$ and $j=3$ and $i=3$.
- What is Brewster Angle?
- What is meant by Jamming margin in a CDMA system?
- Describe a technique to generate orthogonal carriers in OFDM.
- Differentiate circuit switching and packet switching.
- Define apogee and perigee. ( $10 \times 2=20$ Marks) P.T.O. Answer any one questions from each Module. Each carries 20 marks.
- (a) Differentiate simplex, half duplex and full duplex systems.
- (b) With the help of timing diagram explain how a cellular telephone call is made. OR
- (a) Compare key features of major 2G systems(GSM and IS95). 10
- (b) Describe (i) Bluetooth, and (ii) Zigbee. 10 ( $1 \times 20=20$ Marks)
- (a) Explain different methods used for improving coverage area of a cellular system.
- (b) If the signal to interference ratio of 15 dB is required for satisfactory forward channel performance of a cellar system, what is the frequency reuse factor and cluster size that should be used for maximum capacity if the path loss exponent (i) $...
- (a) With suitable diagrams explain GSM system architecture. 12
- (b) Explain the hand-off strategies in mobile systeme- ( $1 \times 20=20$ Marks)
- (a) What is meant by fading? List out different types of fading. $\mathbf{1 0}$
- (b) Explain different types of diversity techniques used to combat fading. 10
- (a) With suitable diagram explain the ground reflection model of mobile radio propagation.
- (b) A mobile is located 5 km away from a base station and uses a vertical $\lambda / 4$ monopole antenna with a gain of 2.55 dB to receive cellular radio signals. The E-field at 1 km from the transmitter is measured to be $10^{-3} \mathrm{~V} / \math...
- (i) Find the length and effective aperture of the receiving antenna. (ii) Find the received power at the mobile using the two ray ground reflection model assuming the height of the transmitting antenna is 50 m and the receiving antenna is 1.5 m above...
- (a) Describe the commonly used multiple accessing arrangements (TDMA, FDMA and CDMA) with suitable diagrams.
- (b) Illustrate the X. 25 protocol of wireless networking.
- (a) Write short notes (i) GPRS, (ii) GPS. and (iii) UMTS.
- (b) What are Geo stationary satellites? Explain the functions of a satellite transponder with block diagram.