UPTU Old Year Papers B
Tech 8th Semester
Wireless Communication 2006-07
Notes : (i) Attempt all questions
(ii) All questions carry equal marks.
(Hi) Assume data suitably if missing.
1 Attempt any four parts of following :
(a) A radio link can be modelled as “Radomly varying propagation path”. Justify. Determine maximum Doppler spread in a 2.4 GHz mobile system, if maximum allowable speed of received unit is 150 kM/h.
(b) What are the three partially separable effects of radio propagation in mobile environments ? Explain in brief.
(c) Determine the maximum communication range of a wireless system having transmitted power of 1 Watt, and receiver sensitivity of -90 dBm for a specified threshold BER=3 x 10″2, Assume d0=7m for this indoor wireless system applications and transmitting carrier frequency being 2.48 GHz. Assume ideal transmitting and receiving omnidirectional antenna.
(d) Define the following :
(i) Power delay profile
(ii) First arrival delay
(iii) Mean excess delay
(e) Show that free space propagation loss for ideal omnidirectional transmit and receive antenna, the received power (relative to transmitted power) decreased by 6dB for every doubling of distance and also for every doubling of radio frequency.
(f) How the delay spread can be measured ? Draw the block diagram of the setup and explain its working.
2. Attempt any four parts of the following :
(a) What do you mean by access method ? Describe various access techniques in brief.
(b) Define and discuss the use of outage and margin in cellular engineering.
(c) Define elementary spectral efficiency with respect to space, frequency and time respectively.
(d) A telephony connection has a duration of 25 minutes and connection is maintained continuously at a bit rate of 9600 b/s. Calculate the amount of traffic, in Erlangs, for this link.
(e) What are the factors that are taken into consideration while deciding the area of unit cell within a cellular region ?
(f) What are different modulation techniques used for base band transmission in cellular system ? Describe one of them.
3. Attempt any two parts of the following :
(a) What is the price paid for error correction ?
What do you meant by block coding ? Discuss block coning with its merits and demerits.
(b) Compare Block Coding with convolution coding and explain convolution coding system with the help of suitable block diagram.
(c) Discuss the standards of CDMA mobile cellular system.
4. Attempt any two parts of the following :
(a) Describe IEEE standard for WLAN.
(b) What do you mean by Wireless multimedia ? Describe Wireless multimedia system and application.
(c) Write short note on Wireless local loop.
5. Attempt any two parts of following :
(a) Describe third generation cellular system. Also mention the services of 3G system.
(b) What do you meant by GEO, LEO and MEO ? Describe how these satellites can be used for mobile communication.
(c) Write short note on universal mobile telecommunication system.