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The Hata model is a radio propagation model for predicting the path loss of cellular transmissions in exterior environments, valid for microwave frequencies from 150 to 1500 MHz. It is an empirical formulation based on the data from the Okumura model , and is thus also commonly referred to as the Okumura–Hata model . [ 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.
From the figure the received line of sight component may be written as = {() /}and the ground reflected component may be written as = {() (+ ′) / + ′}where () is the transmitted signal, is the length of the direct line-of-sight (LOS) ray, + ′ is the length of the ground-reflected ray, is the combined antenna gain along the LOS path, is the combined antenna gain along the ground-reflected ...
The free-space path loss (FSPL) formula derives from the Friis transmission formula. [3] This states that in a radio system consisting of a transmitting antenna transmitting radio waves to a receiving antenna, the ratio of radio wave power received P r {\displaystyle P_{r}} to the power transmitted P t {\displaystyle P_{t}} is:
Path loss, or path attenuation, is the reduction in power density (attenuation) of an electromagnetic wave as it propagates through space. [1] Path loss is a major component in the analysis and design of the link budget of a telecommunication system. This term is commonly used in wireless communications and signal propagation.
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).
The example above is the simplest kind of contingency table, a table in which each variable has only two levels; this is called a 2 × 2 contingency table. In principle, any number of rows and columns may be used. There may also be more than two variables, but higher order contingency tables are difficult to represent visually.
Friis' original idea behind his transmission formula was to dispense with the usage of directivity or gain when describing antenna performance. In their place is the descriptor of antenna capture area as one of two important parts of the transmission formula that characterizes the behavior of a free-space radio circuit. [2]