Что такое "Breakpoint distance”Планирование и оптимизация сетей GSM

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G@nzzza
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Что такое "Breakpoint distance”

Сообщение G@nzzza »

Народ, может кто объяснить более понятным языком что такое "Breakpoint distance”. В книге "Radio Interface System Planning for GSM,GPRS,UMTS" есть такой кусок текста:

"Notice
however that the propagation slope is not constant over the BTS–MS link
even if the propagation environment is constant. Close to the base station
the propagation slope follows the inverse square law according to the tworay
equation, excluding fading dips. Thus, the propagation slope near the
transmitting antenna is lower than the propagation slope at greater
distances. The distance of the propagation slope change is called the
“breakpoint distance” and it can be calculated by using the equation

B=4*(Hbts*Hms)/длина волны

where is the height of antenna 1 (BTS) and is the height of the
other antenna (MS).
The existence of the propagation slope breakpoint is an important
element that should be taken into account in cellular radio network
planning. The idea is to plan the radio network in such a way that a mobile
station (MS) connected to a certain BTS experiences a lower propagation
slope to the serving BTS and a greater propagation slope to any interfering
BTS"

В принципе все понятно, но не очень, почему все таки "propagation slope near the transmitting antenna is lower than the propagation slope at greater distances". И что это за закон "according to the tworay
equation"???

Понять досконально немогу.
optimizer
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Сообщение optimizer »

Вот что пишут относительно BP зарубежом:

Base station antenna height affects on the propagation signal near the base station antenna. Until certain distance, the propagation near the base station antenna happens with propagation slope of 20 dB/dec. This distance where the propagation slope changes is called breakpoint distance. After this point, the propagation slope is determined by the
environment.
optimizer
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Сообщение optimizer »

А так же:

For efficient computation, an algorithm for the multiple diffraction calculation is derived using a matrix formulation. Forward-scattering processes are considered heuristically [75] using a two-ray approach. This two-ray approach yields an additional path loss of 20 dB/decade if the distance between Tx and Rx exceeds a so-called breakpoint distance.
G@nzzza
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Сообщение G@nzzza »

Интересно как профи этого форума используют его в практике?
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