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Measurement of transmission loss can be in terms of decibels. Mathematically, transmission loss is measured in dB scale and in general it can be defined using the following formula: TL = 10 log 10 | W i W t | {\displaystyle 10\log _{10}\left\vert {W_{i} \over W_{t}}\right\vert } dB
(3) Conversion to scientific notation: = (), for instance = =. The scientific notation example shows that the graph for the interval from 0 to 10 suffices for calculating quick approximations for any argument value.
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 1/10 (approximately 1.26) or root-power ratio of 10 1/20 (approximately 1.12). [1] [2]
is the reference distance, usually 1 km (or 1 mile) for a large cell and 1 m to 10 m for a microcell. [1] is the path loss exponent. is a normal (Gaussian) random variable with zero mean, reflecting the attenuation (in decibels) caused by flat fading [citation needed]. In the case of no fading, this variable is 0.
A simple link budget equation looks like this: Received power (dBm) = transmitted power (dBm) + gains (dB) − losses (dB) Power levels are expressed in , Power gains and losses are expressed in decibels (dB), which is a logarithmic measurement, so adding decibels is equivalent to multiplying the actual power ratios.
Like the decibel, the neper is a unit in a logarithmic scale.While the bel uses the decadic (base-10) logarithm to compute ratios, the neper uses the natural logarithm, based on Euler's number (e ≈ 2.71828).
The electric field strength at a specific point can be determined from the power delivered to the transmitting antenna, its geometry and radiation resistance. Consider the case of a center-fed half-wave dipole antenna in free space, where the total length L is equal to one half wavelength (λ/2).
Unit: decibel (dB) L FSL = The free space loss. Unit: decibel (dB). A MU = Median attenuation. Unit: decibel (dB). H MG = Mobile station antenna height gain factor H BG = Base station antenna height gain factor K correction = Correction factor gain (such as type of environment, water surfaces, isolated obstacle etc.)