MOBILE COMMUNICATION (EC-503 (B)) - Important Questions

Explain handoff mechanism, necessity, techniques including MAHO, queuing, and types of handoff (hard, soft, etc.) in cellular mobile systems.

Explain frequency reuse with cellular diagram and draw a 19-cell reuse system locating the co-channel cells.

Explain the cellular concept and describe the basic cellular system with the help of a diagram, including why hexagonal cells are used and its performance criteria.

Explain the merits/advantages of cellular systems and the concept of frequency reuse.

Explain the different generations of wireless network.

Define frequency reuse, explain the frequency reuse concept with diagram, and state its need/requirement and reuse factor.

Explain Clarke's model for flat fading, including fading statistics and level crossing rate.

Explain foliage losses and near-in-distance propagation.

If the coherence bandwidth is calculated as 100 kHz in the given radio channel of 900 MHz frequency, calculate the maximum symbol rate that can be transmitted over this channel that will suffer minimal intersymbol interference.

Explain the ground reflection (two-ray) propagation model for mobile radio propagation.

Discuss the small scale multipath propagation.

Define Doppler spread and coherence time.

What are the dispersion parameters?

For hilly terrain with given heights and path length, calculate the incident angle and slope angle.

What is fading? Explain its classification into slow, fast, flat and frequency-selective fading and the conditions under which each occurs.

Explain coherence bandwidth, Doppler spread and coherence time in detail.

Explain the various techniques/mechanisms used to increase or expand the capacity of a cellular system.

Explain frequency management and channel assignment in cellular systems.

Explain dynamic (non-fixed) channel assignment algorithms and compare advantages and disadvantages with fixed channel assignment.

What are the sources/reasons of co-channel interference and how can it be reduced?

What are cell-site antennas and mobile antennas?

Explain the capacity of a cellular system.

Explain cell splitting and sectoring in cellular systems.

Explain methods to reduce co-channel interference.

Explain cell splitting and the concept of frequency channels.

Describe the antennas used at the cell site and discuss the unique situations of cell-site antennas.

Explain the GSM system architecture with block diagram and functions of each sub-system, including interfaces

Explain frame structure.

Explain GSM traffic channel, control channel and frame structure.

Explain the different multiplexing / multiple access techniques (FDM/TDM/WDM, FDMA/TDMA/CDMA/SDMA).

Numerically find the number of channels available in an FDMA system given total bandwidth, guard bandwidth and channel bandwidth.

Write short note on any two of following.

Explain frequency division multiple access (FDMA).

Explain the multiple access scheme used for GSM.

Explain spread spectrum multiple access in detail.

Describe Code Division Multiple Access (CDMA) including output power limit and power control.

What is CDMA? Explain advantages of CDMA over FDMA / TDMA technologies.

What is frequency hopped multiple access?

Describe / explain CDMA with suitable diagram.

Describe the forward and reverse channels in CDMA.

Numerical on IS-95 CDMA: find bit error probability and processing gain given users, chip rate, data rate, $E_b/N_0$ and PN code length.

Compare slow frequency hopping and fast frequency hopping and describe the working of Frequency Hopped Spread Spectrum (FHSS).

Explain call processing and handoff procedures in CDMA systems.

Write short note on (any two):

Write a short note on any two: