BRANCH: ELECTRONICS AND COMMUNICATION ENGINEERING SEMESTER: VIII SUBJECT: MOBILE COMMUNICATION - ELECTIVE IV

VINAYAKA MISSION’S UNIVERSITY, SALEM

V. M. K. V ENGINEERING COLLEGE

DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING

COMMON TO ECE & ETCE

QUESTION BANK

BRANCH: ELECTRONICS AND COMMUNICATION ENGINEERING

SEMESTER: VIII

SUBJECT: MOBILE COMMUNICATION  -  ELECTIVE IV

                       

 MOBILE COMMUNICATIONS

Unit –I

Part – A :

1.      Define Roamer.

2.      Mention the parts available in basic cellular system.

3.      Define common air interface and mention the channels present in common air interface.

4.      Write any two differences between Cellular phone and paging system.

5.      Define Paging system.

6.      What is meant by Control channel?

7.      What is meant by MIN and define the term.

8.      Define Mobile station.

9.      Define Mobile switching centre.

10.  What is meant by Forward channel and Reverse channel?

11.  Define EDGE.

12.  State example of half duplex and full duplex.

13.  Classify mobile radio transmission systems.

14.  State example of simplex system.

15.  What is base station?

16.  What is full duplex?

17.  What is half duplex?

18.  Define MSC.

19.  What are the standards used in mobile communication?

20. What is the use of RSSI ?
21. Give the equation which illustrates the relation between capacity of a system and cluster size.
22. Classify the mobile radio transmission systems.
23. State the operations performed by control channel
24. Define cluster.
25. State the different classifications of channel assignment strategies

Part – B :

1.      Explain briefly about the evolution of Mobile radio systems.

2.      Discuss briefly about the cellular systems.

3.      Explain in detail about the various trends in personal wireless communication systems.

4.      Explain in detail about WLL Systems and LMDS.

5.      Narrate wireless communication systems with the help of paging system.

6.      Write short notes on: (i) EDGE Standard

(ii) IS-95B Standard

7. Write short notes on  (i) cordless telephone system

                                              (ii) Cellular telephone system

8. (a) Write short notes on  Satellite systems

(b) Compare various wireless communication systems.

9. Explain briefly about 3G wireless networks.

10. With the help of timing diagram, explain the process of call initiation in a cellular system.          

Unit –II

Part – A :

1.      why hexagonal shape is selected for cell?

2.      Define the term ‘Frequency Reuse’

3.      What is mean by ‘cell’?

4.      What is meant by ‘blocked calls cleared’ and give its equation?

5.      Define handoff and give its types.

6.      Define the term ‘Trunking’

7.      What is meant by Grade of service?

8.      What are the types of system generated cellular interference? And define their types.

9.      Define Traffic intensity.

10.  What is meant by Cell cluster?

11.  Define Co-channel reverse ratio.

12. What is cell splitting?
13. What is grade of service?
14. What is co channel interference?
15. What is sectoring?
16. State the different techniques used for improving coverage and capacity in cellular systems
17. Define modulation.
18. What is frequency planning?
19. What is trunking efficiency?
20. State the basic constituents of a cellular system.
21. what is Micro cell zone
22. What is TDMA?
23. What is FDMA?
24. What is CDMA?
25. What are the types of multiplexing access schemes available?

Part – B :

1.      Describe briefly about Frequency reuse concept in cellular systems.

2.        (a)     Explain in detail about channel assignment and handoff in cellular systems.

(b)  A Hexagonal cell within a four-cell system has a radius of 1.387 km. A total of 60 channels are used within the entire systems. If the load per user is 0.029Erlangs,and      =1 call/hour, compute the following for an Erlang c systems that has 5% probability of a delayed call;

(i)                 How many users per square kilometer will this system support?

(ii)               (ii)   What is the probability that a delayed call will have to wait for    more than 10s?

3.      Discuss briefly about Interference and system capacity in cellular systems.

4.      Write short notes on

a)      Channel Planning for wireless systems.

b)      Adjacent channel interference.

5.      Explain in detail about trunking and grade of service in cellular systems

6. Explain in detail about the various Multiple Access Schemes.
7. Explain in detail about the handoff strategies with suitable diagram.
8. Explain in detail about the umbrella cell concepts.
9. Discuss briefly about Improving channel capacity in cellular systems.

10.  Explain in detail about Co-channel interference and system capacity.

Unit –III

Part – A :

1.      Define Multipath waves.

2.      Mention three important small scale fading effects.

3. State the two different types of fading
4. Define Rayleigh fading.
5. Define the term coherence bandwidth.
6. What is direct wave path?
7. State the different analog modulation schemes
8. State the different modulation schemes.
9. Define amplitude modulation

10.  List some parameters of mobile multipath channels.

11.  Define Doppler spread.

12.  Define Coherence time.

13.  What are Time dispersion parameters and write the expression for any one of the dispersion parameters.

14.  Define large scale fading model.

15.  Define Small scale fading model.

16.  Write down the expression for received power delay profile in a local area in impulse model of a multipath channel.

17.  State the techniques used for SSB generation.

18. State the advantages of digital modulation schemes.
19. Define bandwidth efficiency.
20. Define Power efficiency.
21. State the different types of line coding.
22. State the types of modulation schemes used in mobile communication.
23. What is coherent detector?
24. What is CPFSK?
25. Define Fraunhofer region.

Part – B:

1.      Explain in detail about the three basic propagation mechanisms.

2.      Write short notes on

a.       Factors influencing small scale fading.

b.      Doppler Shift.

3.      Explain in detail about impulse response model of a multipath channel.

4.      a. Determine the proper spatial sampling interval required to make small scale propagation measurement which assume that consecutive samples are highly correlated in time. How many samples will be required over 10m travel distance if fc=1900MHz and v=50m/s. How long would it take to make these measurements, assuming they could be made in real time from a moving vehicle? What is the Doppler spread B_D for the channel?

b. Discuss briefly about the fading effects due to multipath time delay spread.

5. Describe the parameters of mobile multipath channels.
6. Explain in detail about ground reflection model.
7. Explain in detail about knife edge diffraction model
8. Explain in detail about Radar cross section model.
9. Explain in detail about log -distance path loss model
10. Explain in detail about outdoor propagation model.

Unit –IV

Part – A :

1.      What are the techniques used to improve the radio link performance in communication system?

2.      Define Adaptive Equalizer.

3.      Define Diversity.

4.      What is meant by Frequency Diversity and Time Diversity?

5.      What are the basic types of error correction and detection codes?

6.      Define Sub-band Coding

7.      What is meant by channel vocoders?

8.      Mention the methods of generating an FM signal and define any one method.

9.      Define the term Quantization.

10.  Define Coding Gain.

11. What is a diversity receiver?
12. Expand PCS, PLMR, NLOS and DECT.
13. Mention the three partially separable effects of radio propagation.
14. Mention the basic propagation mechanisms, which impact propagation in mobile communication
15. What is reflection?
16. What is diffraction?
17. What is scattering?
18. Define Brewster angle?
19. We use 1mi intercept for mobile communication? Why
20. What are the possible conditions in a point-to-point prediction model?
21. What are the merits of point-to-point model?
22. What is a smart antenna?
23. Define inter symbol interference.
24. What is meant by RAKE receiver?
25. What is the need of equalization?

Part – B :

1.      Explain with neat diagram the performance of RAKE receiver.

2.      Explain in detail about the performance of digital modulation in slow flat fading channels.

3.      Discuss briefly about frequency domain coding of speech.

4.      Discuss briefly about Vocoders.

5.      Discuss briefly about the types of equalization techniques, and explain any two.

6.      Explain any two diversity techniques, in detail.

7.      Draw the block diagram of LPC coding system and explain the different types of LPC used for wireless systems?

8.      Explain LMS algorithm for adaptive equalization, in detail.

9.      Explain RLS algorithm for adaptive equalization, in detail.

10.  Explain digital modulation.

Unit –V

Part – A :

1.      Write any 2 differences between FDD and TDD.

2.      List the features of FDMA.

3.      Write down the expression for number of channels simultaneously supported in a FDMA system.

4.      If a US AMPS cellular operator is allocated 12.5MHz for each simplex band,and if Bt is 12.5MHz,Bguard is 10KHz,and Bc is 30KHz,Find the number of channels available in an FDMA system.

5.      Define TDMA.

6.      Define frame efficiency in TDMA  system.

7.      List some of the features of CDMA.

8.      Write any 2 differences between wireless and fixed telephone networks.

9.      List some of the limitations in wireless networking.

10.  What is the objective of personal communication systems?

11. What is PHP?
12. Define near-far problem in CDMA.
13. Write down the applications of PHP?
14. List out the features of PHP?
15. What are the logical channels that the control channel consists?
16. What is BCCH?
17. What is CCCH?
18. What is SIM?
19. Mention the disadvantages of FDMA.
20. What are main subsystems of GSM architecture?
21. What are the channel types of GSM system?
22. What is broadcasting?
23. Define wideband system.
24. Write the formula for spectral efficiency of FDMA.
25. Write the non-linear effects in FDMA.

Part – B :

1.                  Explain in detail about the frequency division multiple access technique.

2.                  Explain cellular Packet –switched architecture in personal communication service with neat diagram.

3.                  Discuss briefly about the traffic routing in wireless networks.

4.                  Explain spread spectrum multiple access technique, discuss in detail about any one type.

5.                  What is meant by CDMA? Explain the features of CDMA and also discuss the capacity of cellular CDMA.

6.                  What is meant by TDMA? Explain the features of TDMA.

7.                  What is meant by FDMA? Explain the features of FDMA.

8.                  Discuss briefly about the wireless networks.

9.                  Compare TDMA,FDMA and CDMA

1. 10.              Explain about Personal Access Communication Systems