Wireless Communication (EC-802 (B)) - Important Questions

Discuss the history and evolution of wireless communication from early systems to 1G-5G and explain the technical and economic requirements driving development.

Explain and compare the narrowband, wideband and directional channel models, their architecture, implementation and applications.

Explain the key technical challenges in wireless communications, including effects of multipath propagation and user mobility.

Define the WSSUS model with neat diagram, explain its condensed parameters and discuss its importance for system-theoretic description of wireless channels.

Explain the time-variant two-path channel model and differentiate between time-invariant and time-variant models with suitable mathematical representation.

Derive and discuss the Doppler spectrum and explain its relation to mobile velocity and temporal dependence of fading.

What is channel sounding? Explain the time-domain channel sounding measurement technique with block diagram and discuss its limitations.

Describe the frequency-domain channel sounding method and compare its advantages and disadvantages over time-domain measurement techniques.

Sketch and explain the block diagram / structure of a wireless communication link / transceiver and explain the role and impact of modulation and demodulation.

Compare the performance of BPSK, QPSK and QAM in terms of spectral efficiency, power efficiency and suitability for fading channels.

Define diversity in wireless communication, differentiate between microdiversity and macrodiversity including simulcast, and explain how diversity improves reliability and signal reception.

What is transmit diversity? Explain Alamouti's space-time block coding (STBC) scheme and its significance in modern MIMO wireless systems.

Differentiate reflection, diffraction and scattering as propagation mechanisms and explain wave guiding and the effect of rough surfaces on scattering.

Explain the importance of equalizers in wireless devices and classify / compare different equalizer structures with suitable examples.

Write short notes on any two of the following: (a) Antennas for mobile stations (b) Antennas for base stations (c) TDMA system (d) CDMA system.