Line of sight
![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d6/FresnelSVG.svg/400px-FresnelSVG.svg.png)
The term line of sight ( direct wave , English: line-of-sight , LOS for short ) is used in communications technology for radio transmission with direct visual contact between the transmitter and receiver . In contrast to the no line of sight (NLOS) there is no obstacle in the first Fresnel zone .
A line of sight should be aimed for for the best possible radio connection, since the technical effort and the transmission power can be reduced compared to a non-line of sight connection .
The advantage of the line of sight is that through the use of parabolic antennas with very narrow opening angles , the effect of multipath ( multipath ) and interference minimized or can be excluded. In addition, the laws of wave propagation and free space attenuation apply . All these factors must be taken into account when developing a communication concept and when installing a radio transmission link.
literature
- Ralf Gessler, Thomas Krause: Wireless networks for the local area. Embedded radio systems, 2nd edition, Springer Fachmedien, Wiesbaden 2015, ISBN 978-3-8348-1239-1 .
- Jörg Eberspächer (Ed.): DFG Priority Program Mobile Communication. Herbert Utz Verlag, Munich 2000, ISBN 3-89675-937-X .
- Armin Schöne: Measurement technology. Springer Verlag, Berlin / Heidelberg 1994, ISBN 978-3-540-54629-0 .