Wireless propagation modes
This page describes wireless propagation modes. It provides difference between Ground wave propagation, Sky wave propagation and Line-of-Sight propagation.
Frequencies up to about 2MHz fall in this category of propagation. Here waves follow contour/curvature of the Earth, this is due to EM waves induce current in the earth's surface. This causes wavefront to bend towards the earth and follow/propagate earth's surface. Typical applications include AM radio broadcasting,direction finding,submarine communication,home control systems,analog telephone lines,long range navigation and more.
Frequencies between 2 MHz and 30 MHz fall in this category of propagation. Here ionosphere above earth's surface reflect the transmitted wave and hence it gets propagated due to reflection. Typical applications include amateur radio,CB radio, international broadcasting,military communication and long range aircraft/ship communication.
Frequencies above 30 MHz fall in this category of propagation. Here signal above 30MHz are not reflected by ionosphere and here it is transmitted based on line-of-sight concept. For satellite application,it is transmitted from earth station antenna to the satellite antenna. for ground based wireless link, communication happens when both the transmit(Tx) and receive(Rx) antennas are in the line of sight of each other. Typical applications include VHF/UHF television,FM broadcast,optical communication,Infrared LANs,terrestrial wireless link, radar,cellular telecom,PCS,WLL and more.
What is Difference between
difference between FDM and OFDM
Difference between SC-FDMA and OFDM
Difference between SISO and MIMO
Difference between TDD and FDD
Difference between 802.11 standards viz.11-a,11-b,11-g and 11-n
OFDM vs OFDMA
CDMA vs GSM
Bluetooth vs zigbee
Fixed wimax vs mobile