This document provides formulas for calculating Ec/Io and converting dBm values to RSSI units.
The Ec/Io formula is expressed as the ratio of the fraction of cell power allocated to the pilot over the sum of the cell power, transmission losses, and noise plus interference.
RSSI units are calculated by taking the dBm value, which is always negative, adding 130, and dividing by 0.78125. This converts the dBm measurement to a unit that can be represented by 7 binary bits ranging from 0 to 127.
This document provides formulas for calculating Ec/Io and converting dBm values to RSSI units.
The Ec/Io formula is expressed as the ratio of the fraction of cell power allocated to the pilot over the sum of the cell power, transmission losses, and noise plus interference.
RSSI units are calculated by taking the dBm value, which is always negative, adding 130, and dividing by 0.78125. This converts the dBm measurement to a unit that can be represented by 7 binary bits ranging from 0 to 127.
This document provides formulas for calculating Ec/Io and converting dBm values to RSSI units.
The Ec/Io formula is expressed as the ratio of the fraction of cell power allocated to the pilot over the sum of the cell power, transmission losses, and noise plus interference.
RSSI units are calculated by taking the dBm value, which is always negative, adding 130, and dividing by 0.78125. This converts the dBm measurement to a unit that can be represented by 7 binary bits ranging from 0 to 127.
This document provides formulas for calculating Ec/Io and converting dBm values to RSSI units.
The Ec/Io formula is expressed as the ratio of the fraction of cell power allocated to the pilot over the sum of the cell power, transmission losses, and noise plus interference.
RSSI units are calculated by taking the dBm value, which is always negative, adding 130, and dividing by 0.78125. This converts the dBm measurement to a unit that can be represented by 7 binary bits ranging from 0 to 127.
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Ec/Io CALCULATION
Ec/Io =
Xp * Pc * T(r)
[No Bw]mob + Pc * T(r) * (1+ Y)
Where, T(r) = [Lp (r) + Gb + Gm] Xp = Fractional Cell Power Allocated to the Pilot ~ 15% = 34.77 dBm Pc = Cell Output Power ~ 20 Watts = 43 dBm Gb = Cell Antenna Gain including Cable Losses = 6 dB Gm = Mobile Antenna Gain including Cable Losses = 0 dB Lp (r) = Maximum Path Loss = 110 dB [No Bw]mob = Thermal Noise at the Mobile ~ - 185 dBm T(r) = Maximum Transmission Loss = -116 dB Yp = Ioc/Io = Other Cell / Serving Cell interference power spectral density ~ 2.5 dB Putting the values @ 110 dB Max Path Loss we get, Ec/Io = 34.77 + 43 - 116 + 185 - [116 + 43 + 3.5] Ec/Io = -15.73
RSSI UNITS CALCULATION
RSSI Units = dBm + 130 0.78125 Where, dBm always express with negative sign in the formula. For dBm = -55
RSSI Units = -55 + 130
0.78125 RSSI Units = 96 Note: In the cell site, receive signal strengths at the input to the voice radio are measured in terms of RSSI units. The conversion example is explained above.The constant value ".78125" is obtained by dividing 100 by 128. 128 is the true constant and is the number of possible values represented in the range 0-127 which can be represented by seven binary bits.