Page 17 - GuideFWA

2.1.2.2 Receiver path

Parameter logarith. Description
analog form form
Maximum allowed interfering signal at the RX antenna.
PR (mW) P’R (dBm)
D (ratio) Rise in the Noise Floor (also called “desentization”). It
D’ (dB) is the basic interference threshold assumed in
calculations (see formulae)
RX sensitivity RX’sensitivity
RX sensitivity level to assure a BER < 10-3 performance.
(mW) (dBm) Its value is defined in the corresponding systems
specifications
CIR CIR’ (dB)
Specific C/I ratio defined in system specifications for a
F’margin (dB) system alone (i.e. without external interference). It has
G’rx (dB) been agreed the assumption that this ratio is constant for
G’rxant (dBi) the whole range of received useful signal.
L’rxant (dB)
Fading Margin used in power budget calculations in
L’rxfeeder (dB) normal system deployments. Its value has been agreed
by Experts Group for each system

Gain due to RX antenna system, including feeder
effects. Its value is obtained by calculation (see
formulae)

Isotropic gain of RX antenna. A reference value was
agreed by the Experts group for each system taken into
account actual deployments

Losses due to the directivity of RX antenna. Both
horizontal and Vertical radiation patterns have been
taken into account. Reference values have been agreed
by Experts Group based on actual deployments.

Losses due to the antenna feeder. Reference values have
been agreed by Experts Group based on actual
deployments.

2.1.2.3 Propagation Model

The propagation model used, is the two-slope model, which has been chosen for simplicity.

This model can be expressed as:

L’(dB) = 38 + 20 log (d) , for 1< d < 4htxhrx/? (in meters) (1a)

L’(dB) = 38 - 20 log (4htxhrx/?) + 40 log (d) , for d= 4htxhrx/? (in meters)(1b)

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