Signal Diffraction

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Knife-edge diffraction is the propagation mode where radio waves are bent around sharp edges. For example, this mode is used to send radio signals over a mountain range when a line-of-sight path is not available. Aug 06, 2011 Both diffraction and refraction involve change of direction of waves. When a wave encounters an obstacle, bending or spreading occurs, which we call diffraction. On the other hand, waves refract when they travel from one medium to another.

Reflection vs Diffraction-difference between Reflection and Diffraction

X-ray Diffraction Signal

This page compares Reflection vs Diffraction and mentions difference between Reflection and diffraction of EM (Electro-Magnetic) wave.

These terms are associated with Non Line of Sight (NLOS) Communication path.When a signal propagates between transmitter and receiver, it willgo through many obstacles. More over it gets reflected, diffracted andgets penetrated due to objects/obstacles along the path.

DiffractionSignal diffraction effectDiffraction of light definition


The multipath reflection using wide beam antennas is essential in mobilebroadband communication. It is difficult to achieve single pathreflection due to unavailability of object which can provide necessary angle ofincidence to obtain desired propagation.The figure-1 depicts reflection of EM signal along the path from transmitter to thereceiver.


When electromagnetic wave hits edge of building or large object along thepath diffraction occurs. It is also referred as bending.The loss to the EM signal due to this depends on frequency of EM waveand sharpness of the bend.The figure-2 depicts diffraction of EM signal along the path from transmitter to thereceiver.

Refer Wireless Propagation Modes which mentions groundwave,skywave and LOS wave propagations.


Following are matlab codes for channel models viz. SUI channel model, ITU-T channel model as per wimax 802.16e standard, JTC channel model as per 802.11b/11g, UWB channel model as per 802.15.3 and 802.15.4 standard specifications.
types of channel models
802.11a WLAN channel model matlab files
802.11b 11g JTC WLAN channel model matlab files
802.15.3 UWB channel model matlab files
802.15.4 UWB channel model matlab files
802.16d SUI WiMAX channel model matlab files
802.16e ITU-T channel model matlab files
Rayleigh channel model matlab files
Rician channel model matlab files

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
Bluetooth vs zigbee
Fixed wimax vs mobile

Signal Anomalous Diffraction

RF and Wireless Terminologies

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