Figure 5-5: Fresnel Zone Radius Calculation - Alvarion BreezeACCESS LB System Manual

Chapter 5 - Wireless Broadband

Figure 5-5: Fresnel Zone Radius Calculation

Specific FSL formulas are required to deal with this NLOS phenomenon.
There are many NLOS calculations available from established
institutions including the Institute of Electrical and Electronics
Engineers (IEEE) and International Telecommunications Union (ITU),
who are chartered with developing standardized calculations. The
Alvarion Link Budget Tool is built upon these formulas; however, it is
important to bear in mind that the calculations are an estimate only,
with relatively large standard deviations (5-15 dB) depending on the
exact deployment scenario and obstacle characteristics.
The last element to consider in the path calculation is the signal to
noise (S/N) ratio, which is defined as:
S/N = RSL – Smin
Where,
Smin is the receiver sensitivity expressed in dBm.
The Smin is determined by the thermal noise generated by the amplifier
as well as the bandwidth of the filter used in the receiver front end. It
defines the power level at which the receiver is sensitive enough to
properly detect the signal. For the BreezeACCESS LB operating in a
channel spacing of 20 MHz, the Smin is approximately –96 dBm.
BreezeACCESS LB System Manual
5-10