Alvarion BREEZEACCESS SW VERSION 5.1 - Manual (Page 151)

Menus and Parameters
Operation and Administration
119
4.2.5.3.1 Continuous Average SNR/RSSI Display
The Continuous Average SNR Display option displays continuously updated
information regarding the average quality of the received signal, using Signal to
Noise Ratio (SNR) and Received Signal Strength Indication (RSSI) measurements.
The average RSSI is calculated using the formula:
NewAvgRSSI = (PrevAvgRSSI*HistWeight) + CrtRSSI*(1 – HistWeight ), where:
„ NewAvgRSSI = New Average RSSI
„ PrevAvgRSSI = Previous Average RSSI
„ CrtRSSI = RSSI of the current packet
„ HistWeight = History Weight
The History Weight is given by the next formula:
HistWeight = 0.9 / ( PastTime / 2 SNR_Memory_Factor + 1 ), where
PastTime = time between the current packet and previous packet, in seconds
SNR_Memory_Factor = the Average SNR Memory Factor configurable parameter
(see Average SNR Memory Factor on page 186.
The SNR_Memory_Factor can be -1 in this case the history is not used and the
Average RSSI is the RSSI of the current packet.
The same formula is used also for calculating Average SNR (SNR values are used
instead of RSSI values).
Click the Esc key to abort the test.
4.2.5.3.2 Continuous Noise Floor Display
The Continuous Noise Floor Display option displays continuously updated
information regarding the average noise floor in the wireless link.
Click the Esc key to abort the test.
4.2.5.3.3 Continuous UpLink Quality Indicator Display
The Continuous UpLink Quality Indicator Display option displays continuously
updated information regarding the average quality of the wireless link to the AU,
using the dynamically updated average modulation level measurements. The Link
Quality Indicator (LQI) calculation is performed using the formula:
LQI = (0.9 x ”Previous LQI”) + (0.1 x ”Last Successful Modulation Level”).