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It is the most often cited of the COST 231 models (EU funded research project ca. April 1986 – April 1996), [1] also called the Hata Model PCS Extension. 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.
Path loss normally includes propagation losses caused by the natural expansion of the radio wave front in free space (which usually takes the shape of an ever-increasing sphere), absorption losses (sometimes called penetration losses), when the signal passes through media not transparent to electromagnetic waves, diffraction losses when part of the radiowave front is obstructed by an opaque ...
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 ]
This is based on either close-in measurements or calculated based on a free space assumption with the Friis free-space path loss model. [1] is the length of the path. is the reference distance, usually 1 km (or 1 mile) for a large cell and 1 m to 10 m for a microcell. [1]
Free-space loss increases with the square of distance between the antennas because the radio waves spread out by the inverse square law and decreases with the square of the wavelength of the radio waves. The FSPL is rarely used standalone, but rather as a part of the Friis transmission formula, which includes the gain of antennas. [3]
(a) the electric field strength at a given point in space, due to the operation of the transmitter; and (b) the distance of that point from the transmitter's antenna". [9] It relates to AM broadcasting only, and expresses the field strength in "microvolts per metre at a distance of 1 kilometre from the transmitting antenna". [8]
For example, a "2 by 4" wood stud wall with drywall on both sides results in about 6 dB loss per wall at 2.4 GHz. [2] Older buildings may have even greater internal losses than new buildings due to materials and line of sight issues. Experience has shown that line-of-sight propagation holds only for about the first 3 meters.
In antenna theory, radiation efficiency is a measure of how well a radio antenna converts the radio-frequency power accepted at its terminals into radiated power. Likewise, in a receiving antenna it describes the proportion of the radio wave's power intercepted by the antenna which is actually delivered as an electrical signal.