Radio Frequency Engineering

RF Planning and Optimization VIVA question part-1

  1. What is link Budget Analysis used for in GSM?

  • Answer:
    Link budget analysis is used for the path balance between both up-links (Transmitter)
    Down-link(Receiver) part of the network. Imbalance in up-link and down-link causes a frequent call drop and decreases the Call Complete Success Rate (CCSR).
  • 2. How is path loss taken into calculation ?

  • This is the total path loss occurred due to multipath propagation of the signal between transmitted signal and the received signal level.

Few important reasons for path loss:
  • Reflection
  • Deflation
  • Scattering
  • Rain fading etc.
3. What is capacity planning?
  • Answer:
  • This is process of increasing traffic by adding Transceivers (TRXs) traffic channels and proper use of frequency reuse pattern. By adding new BTSs.
  • 4. How is site selection done for planning and site acquisition?
  • Answer:
  • After nominal cell planning with the geographical coordinates identifying best site candidate in a geographical area is the process of site selection. Selecting best sites depends on number of issues:
    • Site distance from nominal.
    • Site availability.
    • Major obstacle.
    • Type of site Rooftop (RT), Greenfield (GF), Greenfield rooftop (GFRT), here rooftop will be top prioritized.
    • 24/7, 365 site access permits or not.
    • Site distance from car access able road.
    • Lift avail ability in rooftop (RF) sites etc.

    5. What is optimization? What are the tools used for optimization?

  • Once GSM network is integrated in order to achieve proper planning prediction
    RF parameters Optimization is done.
    Drive test tool, Planning tool and Post processing tools are used for optimization.
    Drive Test Tools:
    • Tems investigation data collector.
    • Tems route analyzer.
    • Nemo
    • Actrix
    • Cell planner
    • Mapinfo
    • Google map.
    6. What is system information?
  • Answer: System information is from BTS sent to Mobile for the idle mode and dedicated mode of the call for call management.
  • 7. What is bench marking in GSM ?
  • Answer:
    Bench Marking used for comparing performance of different network for quality and call performance parameters.
  • 8. What is Erlang table?
  • Answer:
    This is the table for calculating Traffic in erlang for number of channels. To calculate Erlang we often consider blocking probability is a constant value, but in practice it’s not, It varies on Traffic and other KPI issues.
  • 9. How do you optimize a network using OMCR performance data?
  • Answer: Proper increase in call success, and increase in handover success performance and drop call reduction performance, error log analysis etc.
  • 10. What is daily report and traffic?
  • Answer:
    This is the report obtained in OMC for the performance of all BTS about traffic and resource utilization.

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