EC-803-A Wireless Networks - May 2023 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
   aDraw the protocol Architecture of WLAN (802.11). Explain the Physical layer and MAC management layer of 802.11
   How to answer

   • Protocol architecture diagram of IEEE 802.11 showing PHY, MAC, MAC management, station management
   • Physical layer functions: FHSS/DSSS/OFDM, modulation, carrier sensing
   • MAC layer and MAC management: DCF/PCF, framing, authentication, association, power management
2. 7 Marks
   bDescribe in detail the Universal Mobile Telecommunication System (UMTS).
   How to answer

   • UMTS as 3G system evolution from GSM/GPRS
   • Network architecture: UE, UTRAN NodeB/RNC, Core Network CS/PS domains
   • Interfaces Uu, Iub, Iur, Iu and W-CDMA, services and significance
3. 7 Marks
   aGive and explain the simple architecture for Wireless ATM network. What are the biggest research challenges in wireless ATM networks?
   How to answer

   • Simple Wireless ATM reference architecture with mobile terminal, base station, ATM switch/network
   • Protocol layers and wireless extensions, handover support
   • Research challenges: mobility, QoS, error control, handover, bandwidth, power
4. 7 Marks
   bWith neat block diagram explain the OFDM Transmitter and receiver.
   How to answer

   • Neat block diagram of OFDM transmitter: serial-parallel, mapping, IFFT, cyclic prefix, DAC/RF
   • Block diagram of OFDM receiver: RF, ADC, CP removal, FFT, demapping
   • Function of orthogonal subcarriers and ISI mitigation
5. 7 Marks
   aGive the E-UTRAN architecture and explain in detail.
   How to answer

   • E-UTRAN flat architecture: eNodeB, UE, MME, S-GW, P-GW
   • Interfaces: LTE-Uu, X2, S1 and functions
   • Significance for LTE: reduced latency, scalability
6. 7 Marks
   bWhat is Multi-Input Multi-Output (MIMO) system? Explain with suitable diagram?
   How to answer

   • Definition of MIMO using multiple antennas at transmitter and receiver
   • Suitable diagram: SISO/SIMO/MISO/MIMO configurations
   • Benefits: spatial multiplexing, diversity, capacity gain
7. 7 Marks
   aDraw and explain the WSN Architecture with suitable diagram.
   How to answer

   • WSN architecture diagram: sensor nodes, cluster head, sink, base station
   • Layered/protocol components and topologies
   • Data flow from sensing to gateway
8. 7 Marks
   bWrite a note on security issues in Wireless Sensor Network (WSN).
   How to answer

   • Threats: eavesdropping, spoofing, DoS, node capture, routing attacks
   • Constraints: limited energy/computation making security hard
   • Countermeasures: encryption, authentication, secure routing
9. 7 Marks
   aWrite the different types of applications of Wireless sensor network.
   How to answer

   • Categories: military, environmental, health, industrial, home automation
   • Examples of monitoring, tracking, surveillance applications
   • Brief function of each application type
10. 7 Marks
    bExplain in detail about Traditional TCP and its significance.
    How to answer

    • Traditional TCP mechanisms: slow start, congestion avoidance, ACK
    • Assumptions of wired networks and performance degradation in wireless
    • Significance and need for wireless-adapted TCP variants
11. 7 Marks
    aImage the following scenario. Japanese and a German meet at a conference on Hawaii. Both want to use their Laptops for exchange data, both run mobile IP for mobility support. Explain the optimizations used in this mobile IP network.
    How to answer

    • Mobile IP entities: mobile node, home agent, foreign agent, care-of-address
    • Scenario with two mobile nodes away from home networks in Hawaii
    • Optimizations: route optimization, tunneling, binding updates to avoid triangular routing
12. 7 Marks
    bGive the comparison between TCP Tahoe, Reno, New-Reno and Vegas.
    How to answer

    • Congestion control evolution: Tahoe slow-start/fast-retransmit, Reno fast-recovery
    • New-Reno improvement for multiple losses, Vegas delay-based estimation
    • Tabular comparison on loss detection, throughput, fairness
13. 7 Marks
    aDiscuss in detail the architecture of IoT with a neat sketch.
    How to answer

    • IoT layered architecture: perception, network, middleware, application/business
    • Neat sketch showing devices, gateway, cloud, applications
    • Functions of each layer and data flow
14. 7 Marks
    bGive and explain the interface between 802.11 and Bluetooth.
    How to answer

    • Need for interworking between WLAN 802.11 and Bluetooth
    • Interface approaches: coexistence, bridging, dual-mode devices
    • Protocol adaptation and interference handling
15. 14 Marks
    Write a short note on any two:

    1. i)CSMA/CD
    2. ii)OFDM-MIMO
    3. iii)Under water WSN
    4. iv)IEEE 802.15 WPAN
    How to answer

    • Select any two topics from i-iv
    • For each: definition/principle, diagram/operation, applications
    • Comparison or significance in wireless networks