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In telecommunications, the free-space path loss (FSPL) (also known as free-space loss, FSL) is the attenuation of radio energy between the feedpoints of two antennas that results from the combination of the receiving antenna's capture area plus the obstacle-free, line-of-sight (LoS) path through free space (usually air). [1]
The log-distance path loss model is a radio propagation model that predicts the path loss a signal encounters inside a building or densely populated areas over long distance. While the log-distance model is suitable for longer distances, the short-distance path loss model is often used for indoor environments or very short outdoor distances.
The path loss in other frequency bands (medium wave (MW), shortwave (SW or HF), microwave (SHF)) is predicted with similar methods, though the concrete algorithms and formulas may be very different from those for VHF/UHF. Reliable prediction of the path loss in the SW/HF band is particularly difficult, and its accuracy is comparable to weather ...
where is the large-scale (log-normal) fading, is a reference distance at which the path loss is , is the path loss exponent; typically =. [ 1 ] [ 2 ] This model is particularly well-suited for measurements, whereby P L 0 {\displaystyle PL_{0}} and ν {\displaystyle \nu } are determined experimentally; d 0 {\displaystyle d_{0}} is selected for ...
This model is the combination of empirical and deterministic models for estimating path loss in an urban area over frequency range of 800 MHz to 2000 MHz. [ 2 ] COST (COopération européenne dans le domaine de la recherche Scientifique et Technique) is a European Union Forum for cooperative scientific research which has developed this model ...
The Egli model is a terrain model for radio frequency propagation. This model, which was first introduced by John Egli in his 1957 paper, [1] was derived from real-world data on UHF and VHF television transmissions in several large cities. It predicts the total path loss for a point-to-point link.
The Longley–Rice model (LR) is a radio propagation model: a method for predicting the attenuation of radio signals for a telecommunication link in the frequency range of 40 MHz to 100 GHz. [ 1 ] Longley-Rice is also known as the irregular terrain model (ITM).
In physics, coherence length is the propagation distance over which a coherent wave (e.g. an electromagnetic wave) maintains a specified degree of coherence. Wave interference is strong when the paths taken by all of the interfering waves differ by less than the coherence length. A wave with a longer coherence length is closer to a perfect ...