What is NLOS communication?
Non-Line-of-Sight (NLOS) is a term often used in radio communications to describe a radio channel or link where there is no visual line of sight (LOS) between the transmitting antenna and the receiving antenna.
What is the difference between line of sight LOS and beyond line of sight BLOS communications?
Non-LOS (NLOS) and beyond-LOS (BLOS) are other cases of propagation that can be successfully dealt with to provide a robust and secure link. Line of sight is exactly what it states; the transmitter can see the receiver, or at least, the antennas of each can see each other. It is the visual line of sight.
What is non line of sight Internet?
NLOS – Near, or Non Line of sight, is a common wireless bridge terminology which is used to describe a situation where perfect observable line of sight, without obstructions is not present.
What is line of sight propagation in wireless communication?
Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation which means waves travel in a direct path from the source to the receiver. The farthest possible point of propagation is referred to as the “radio horizon”.
How can NLOS situations be overcome?
Non-line of sight can be overcome with the use of antennas and other such communication devices. Distance also plays a significant role in lowering the receiving power of a signal, leaving a poor transmission system.
What is Los operation?
Line of sight (LoS) is a type of propagation that can transmit and receive data only where transmit and receive stations are in view of each other without any sort of an obstacle between them. FM radio, microwave and satellite transmission are examples of line-of-sight communication.
Is HF a BLOS?
HF radio is the only realistic BLOS alternative and to maximise the utility of HF Radio as a fall back to SATCOM, it is important to utilise the modern HF developments and applications discussed below. It is also important to train in a C2D2E environment.
Is WiMAX line-of-sight?
In this mode, WiMAX uses a lower frequency range — 2 GHz to 11 GHz (similar to WiFi). There is line-of-sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it’s able to send a lot of data with fewer errors.
What is antenna and propagation?
About Antenna and Propagation An antenna or aerial, is an electrical device which converts electric power into radio waves, and vice versa. Radio propagation is the behaviour of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere.
What is the Fresnel zone and why is it important?
The Fresnel Zone is the area around the visual line-of-sight that radio waves spread out into after they leave the antenna. You want a clear line of sight to maintain signal strength, especially for 2.4 GHz wireless systems. This is because 2.4 GHz waves are absorbed by water, like the water found in trees.
Which instrument is used for viewing objects normally out of direct line-of-sight?
A periscope is popular as the instrument useful for observing over and around some surface like sea surface for the submarines. It is also applicable to view through some obstacle or object which may be prevented by the direct line of sight.
What is optical horizon?
Optical horizon is the locus of points at which a straight line from the given point becomes tangential to the earth’s surface. 1 shows the relationship between the optical horizon distance and radio horizon distance.
What is the difference between NLOS and Blos?
If, instead, a large building was constructed in the path making it NLOS, the channel may be impossible to receive. Beyond line-of-sight ( BLOS) is a related term often used in the military to describe radio communications capabilities that link personnel or systems too distant or too fully obscured by terrain for LOS communications.
How to deal with NLOS conditions on wireless computer networks?
Currently, the most common method for dealing with NLOS conditions on wireless computer networks is simply to circumvent the NLOS condition and place relays at additional locations, sending the content of the radio transmission around the obstructions.
What is the frequency range of the NLOS network?
Frequencies that are affected by ionospheric propagation range from approximately 500 kHz to 50 MHz but the majority of such NLOS links operate in the ‘short wave’ or high frequency (HF) frequency bands between 3 MHz and 30 MHz.
What are the obstacles to the propagation of NLOS?
Obstacles that commonly cause NLOS propagation include buildings, trees, hills, mountains, and, in some cases, high voltage electric power lines.
