Question:

a) An antenna is an electrical conductor or system of conductors that sends and receives radio signals. Explain the omni-directional and the directional antennas.

b) Radiations after leaving an antenna are propagated by using one of the three modes of propagation. List down and explain the different signal propagation behaviours that radio waves exhibit.

c) Explain two major differences between the first generation and second generation of cellular based mobile systems?

d) Describe the following subsystems that form part of the GSM (Global System for Mobile Communication) architecture:

i. Radio Subsystem
ii. Network and Switching Subsystem
iii. Operational Subsystem

e) GPRS (General Packet Radio System) is considered as a transition phase from 2G to 3G. Describe the main characteristic that differentiates GPRS with GSM?

f) Briefly explain the main features of a popular fourth generation system.