EC-703-A Cellular Mobile Communication - Dec 2024 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aWhat are the different elements which helps to establish cellular radio system? Briefly explain each one of them.
   How to answer

   • Define cellular radio system concept
   • List elements: mobile unit, cell site, MTSO, trunks, etc.
   • Brief function of each element
   • How elements interconnect to establish system
2. 7 Marks
   bDiscuss about the desired C/I in an Omni directional antenna system. Explore different pathways to achieve the needy conditions.
   How to answer

   • Define C/I ratio in omni-directional cells
   • Desired value and significance for voice quality
   • Factors affecting C/I: reuse distance, cluster size
   • Pathways to achieve: cell splitting, sectoring, power control
3. 7 Marks
   aElaborate general introduction on cell coverage for signal and its traffic conditions.
   How to answer

   • Define cell coverage concept
   • Signal strength vs traffic load considerations
   • Coverage planning basics
   • Relation to capacity and grade of service
4. 7 Marks
   bDiscuss the principle of cell coverage signal propagation over water and flat open area. Also discuss various challenges face by companies to maintain these propagated signals.
   How to answer

   • Principle of propagation over water: reflection, ducting
   • Propagation over flat open area: free-space, ground wave
   • Challenges: fading, multipath, interference
   • Maintenance measures by operators
5. 7 Marks
   aDiscuss all the parameters that supports the antennas of cellular system. Briefly explain all the parameters and derive the necessary equations if required.
   How to answer

   • List antenna parameters: gain, pattern, impedance, polarization, bandwidth
   • Brief explanation of each parameter
   • Relevant equations for gain, radiation resistance etc.
   • Role in cellular system performance
6. 7 Marks
   bDiscuss the gain and pattern relationship of cell site antennas. Give a brief classification of these patterns.
   How to answer

   • Define antenna gain and radiation pattern
   • Relationship between gain, directivity and pattern
   • Omni vs directional patterns
   • Classification of cell-site patterns
7. 7 Marks
   aTry to design a system to serve a predefined area that experiences co-channel interference.
   How to answer

   • Identify co-channel interference problem in area
   • Frequency reuse and cluster size selection
   • Use of sectoring / power control / cell splitting
   • System layout to serve predefined area
8. 7 Marks
   bExplain the different effects on coverage and interference by applying power decrease.
   How to answer

   • Effect of power decrease on coverage radius
   • Effect on co-channel and adjacent channel interference
   • Trade-off between coverage and capacity
   • Examples of power control strategies
9. 7 Marks
   aExplain the differences between the fixed channel assignment and non-fixed channel assignment algorithms.
   How to answer

   • Define fixed channel assignment
   • Define non-fixed / dynamic assignment
   • Comparison on flexibility, blocking, complexity
   • Algorithms examples for each
10. 7 Marks
    bDraw and explain the structure call blocking from the subscribers. What is the practical solution of this problem? Explain.
    How to answer

    • Sketch call blocking structure from subscribers
    • Explain blocking stages / traffic flow
    • Causes of blocking
    • Practical solutions: channel borrowing, queuing, cell splitting
11. 7 Marks
    aWhat are the differences between the cell site handoff and intersystem handoff?
    How to answer

    • Define cell site handoff
    • Define intersystem handoff
    • Differences in control, MTSO involvement, signaling
    • Examples and applications
12. 7 Marks
    bDerive and explain dropped cell rate formula.
    How to answer

    • Define dropped call rate concept
    • Assumptions for derivation
    • Derivation steps of dropped cell rate formula
    • Interpretation and factors affecting it
13. 7 Marks
    aWhat are the various features of GSM Architecture? Explain.
    How to answer

    • Outline GSM architecture components
    • Features: services, interfaces, frequency, security
    • Function of MS, BTS, BSC, MSC etc.
    • Significance of each feature
14. 7 Marks
    bExplain the classification of layer modelling with some practical applications.
    How to answer

    • Define layer modelling concept
    • Classification of layers
    • Function of each layer
    • Practical applications examples
15. 14 Marks
    Write short notes on (any four)

    1. i)TDD systems
    2. ii)Cell splitting
    3. iii)UHF-TV interference
    4. iv)GSM channels
    5. v)Non cellular systems
    How to answer

    • Define each selected topic briefly
    • Key principles and diagrams where relevant
    • Applications / advantages
    • Conclusion for each short note