Lingaya’s University
M.Tech. 1st Year (Term – II)
(Full Time)
Examination – Feb 2011
Wireless Communication (EC - 507)
[Time: 3 Hours] [Max. Marks: 100]
Before answering the question,
candidate should ensure that they have been supplied the correct and complete
question paper. No complaint in this regard, will be entertained after
examination.
Note:
– Attempt five questions in all. All questions carry equal marks. Question no.
1 (Section A) is compulsory. Select two questions from Section B and two
questions from Section C.
Section – A
Q-1. Part – A
Select the correct answer of the following multiple choice questions. [10x1=10]
(i) The capacity of the wireline system can be increased
(a) By TDMA (b) By random access
(c) By increasing the number of wires
(d) By all of the above methods
(ii) Which of the following happen when the transmission bandwidth is greater than the coherence bandwidth?
(a) Frequency selective fading (b) Flat fading
(c) Large scale fading (d) Small scale fading
(iii) Doppler effect is nothing but
(a) A tone received with delay
(b) A tone received reduced amplitude
(c) A tone received with spectrum spread
(d) Motion of the mobile
(iv) Direct (LOS) component is not considered in
(a) Rician fading (b) Nakagami fading c) Rayleigh fading (d) All of above
(v) The chip duration of PN code
(a) Can be anything
(b) Must be much less than the message bit duration
(c) Must be equal to the message bit duration
(d) Must be much larger than the message bit duration
(vi) If two different PN codes are correlated, then
(a) Their cross correlation should be high
(b) Their cross correlation should be less
(c) Their autocorrelation should be high
(d) None of the above is true
(vii) In which of the following multiple access schemes, a user can use only a part of the total bandwidth?
(a) TDMA (b) FDMA
(c) CDMA (d) SDMA
(viii) Synchronous TDM is called synchronous because
(a) Synchronous transmission is used
(b) Time slots are preassigned to sources and fixed
(c) Preamble is transmitted
(d) None of above
(ix) The frequency reuse
(a) Maintains spectrum efficiency
(b) Increases spectrum efficiency
(c) Decreases spectrum efficiency
(d) Does not effect spectrum efficiency
(x) The modulation method for GSM is
(a) GMSK (b) GFSK
(c) MSK (d) FSK
Q-1. Part – B
(a) Write short note on frequency reuse factor. [5]
(b) Explain the term Coherence bandwidth and Coherence time. [5]
Section – B
Q-2. (a) Write short note on Rayleigh fading distribution and Ricean distribution. [10]
(b) How do you improve the coverage and capacity of cellular system? [10]
Q-3. (a) What are different generations of wireless networks? Compare these generations. [10]
(b) Draw and explain GSM architecture with placement of BTS, BSC and MSC. [10]
Q-4. (a) Explain various microscopic diversity techniques. [10]
(b) Explain the Raised Cosine Rolloff Filter. [5]
(c) Find the far-field distance for an antenna with maximum dimension of 1 m and operation frequency of 900 MHz in case of free propagation model. [5]
Section – C
Q-5. (a) Write short note on Rake receiver. [10]
(b) What do you understand by spread spectrum? Enlist its merits and demerits. [10]
Q-6. (a) Write short note on antennas at cell site. [10]
(b) Explain various types of mobiles antennas. [10]
Q-7. (a) Differentiate TDMA and CDMA. [10]
(b) Write a note on co-channel interference and how does it affect the cellular system. [10]
Q-8. (a) Explain the design parameter at mobile unit. [10]
(b) Write short note on Micro cell zone concept. [10]
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