EC-803-A Wireless Networks - Jun 2025 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
   aHow does IEEE 802.16 mobile differ from the fixed standard, and what are the key enhancements introduced to support mobility?
   How to answer

   • Distinguish IEEE 802.16 fixed (802.16-2004) vs mobile (802.16e-2005)
   • Key mobility enhancements: handover, power saving, OFDMA scalability
   • PHY/MAC changes for Doppler, frequency, subchannelization
2. 7 Marks
   bWhat are the key components of a UMTS network architecture, and how do they interact to provide mobile services?
   How to answer

   • Components: UE, UTRAN (Node B, RNC), Core Network (CS/PS domains)
   • Role of HLR, MSC, SGSN, GGSN
   • Interaction flow to provide voice and packet mobile services
3. 7 Marks
   aWhat are the key functions performed by the Medium Access Control (MAC) Layer in IEEE 802.11 WLANs. Discuss
   How to answer

   • MAC functions: channel access, framing, QoS, reliability
   • DCF/CSMA-CA, PCF/HCF coordination
   • Association, authentication, power management, fragmentation
4. 7 Marks
   bDescribe the key components of E-UTRAN architecture and their roles in facilitating wireless communication.
   How to answer

   • E-UTRAN nodes: eNodeB, UE, MME, S-GW, P-GW
   • Interfaces X2, S1 and flat architecture
   • Roles in radio resource, mobility, bearer setup
5. 7 Marks
   aWhat do you understand by SISO and MIMO systems? Discuss the advantages of MIMO systems over SISO systems
   How to answer

   • Define SISO: single antenna Tx/Rx, limits
   • Define MIMO: multiple antennas, spatial multiplexing/diversity
   • Advantages: capacity, reliability, spectral efficiency, range
6. 7 Marks
   bHow does OFDM-MIMO address the challenges of channel variability and inter-symbol interference in wireless communication environments?
   How to answer

   • Challenges: frequency-selective fading, ISI, channel variability
   • OFDM role: subcarriers, cyclic prefix against ISI
   • MIMO addition: diversity and multiplexing gain in fading
7. 7 Marks
   aWhat is topology management in WSNs and why is it essential for ensuring network efficiency and robustness?
   How to answer

   • Define topology management in WSN
   • Need: energy efficiency, connectivity, coverage
   • Robustness against node failure and load balancing
8. 7 Marks
   bDescribe the architecture of an Underwater Wireless Sensor Network. Give their main applications and use cases?
   How to answer

   • Architecture: surface buoys, underwater nodes, AUVs, acoustic links
   • Communication challenges: acoustic propagation, delay
   • Applications: ocean monitoring, disaster, military, oil exploration
9. 7 Marks
   aExplain the advantages and limitations of proactive (table-driven) and reactive (on-demand) routing protocols in WSNs.
   How to answer

   • Proactive: table-driven, low latency, overhead; e.g. DSDV, OLSR
   • Reactive: on-demand, low overhead, route delay; e.g. AODV, DSR
   • Comparison on energy, scalability in WSN
10. 7 Marks
    bHow does the exposed terminal problem influence medium access in wireless networks, and what techniques are used to mitigate its effects?
    How to answer

    • Define exposed terminal problem with example topology
    • Effect: reduced spatial reuse, unnecessary deferral
    • Mitigation: RTS/CTS tuning, directional antennas, MAC schemes
11. 7 Marks
    aDiscuss the process of data forwarding when a mobile node is away from its home network and communicates with a correspondent node.
    How to answer

    • Mobile IP entities: home agent, foreign agent, correspondent node
    • Tunneling, care-of-address registration steps
    • Triangular vs route-optimized forwarding
12. 7 Marks
    bHow does mobile TCP adapt to the challenges of wireless and mobile networks, including high packet loss, variable latency and frequent handovers?
    How to answer

    • Wireless challenges: loss, latency variation, handovers misinterpreted as congestion
    • Adaptations: split connection, snooping, explicit notification
    • Examples: I-TCP, M-TCP, Snoop TCP, freeze TCP
13. 7 Marks
    aCompare and contrast the characteristics of Bluetooth piconet and scatternet in terms of topology, scalability, coverage area, and device interaction.
    How to answer

    • Piconet: star, 1 master 7 slaves, small coverage
    • Scatternet: interconnected piconets via bridge nodes
    • Compare scalability, coverage, device interaction
14. 7 Marks
    bWhat is GPS-Aided GEO Augmented Navigation (GAGAN), and what is its purpose in global navigation systems?
    How to answer

    • GAGAN definition: ISRO-AAI SBAS augmentation
    • Working with GPS + GEO satellites for correction
    • Purpose: aviation accuracy, integrity for navigation
15. 14 Marks
    Write a short note on any two :

    1. a)Mobility Management
    2. b)Security in WSN
    3. c)3GPP
    4. d)Wireless ATM
    How to answer

    • Select any two topics with definition and key points
    • Explain architecture/features and relevance to wireless networks
    • Conclude with applications/limitations