Trouble Shooting Guide

Axxcelera Broadband
Troubleshooting-Installing an RF link - 33 - Issue: 5.3.x
Rev 2
10.1.14 Actual TX power
Actual TX power is the actual power level (dBm) being transmitted from the SU radio. The difference
between the actual and actual (AP) TX powers represents the amount by which the SU transmit power can
increase before it is capped. A small difference indicates that if the RSSI drops then the SU may not be
able to transmit at the correct level, and the signal from this SU may be too weak when it arrives at the AP
receiver. This is likely to cause RF problems. Because the actual TX power is calculated from calibration
data, the accuracy of the actual TX power calculation is dependent on the accuracy of the calibration data.
10.1.15 Rssi at SU
The RSSI at the SU is the Received Signal Strength Indicator which measures the strength of the signal
received at the SU, and is displayed in dBm. The SU transmit power is derived from the strength of the
received signal.
10.1.16 Path loss to AP
Path loss to the AP is an estimate of the free space path loss between the SU and the AP. This is calculated
from the SU’s RSSI, and the actual (AP) TX power (which is the SU’s best guess at the AP’s transmit
power). The path loss is calculated for the downstream direction, and is then used to calculate the SU’s
required transmit power.
10.1.17 Valid rssi range at AP
Valid rssi range at AP is the valid range for the estimated RSSI at AP. This is the same for all SUs and is
between -78dBm to -71dBm. You should typically see a value of -74dBm to -76dBm (see section 10.1.19).
10.1.18 Offset to fix uplink cell errors
Offset to fix uplink cell errors will display +3dB or -3dB if the SU detects that there is problem with the
uplink. If it displays 0dB then it hasn’t had to make any adjustments. These adjustments are based on the
modem txoffset, which will display why a correction was made.
10.1.19 Estimated RSSI at AP
Estimated RSSI at AP is estimated RSSI at the AP for this SU. The estimate is based on the SU’s actual
TX power and the calculated path loss to AP. The accuracy of this calculation is dependent on the
accuracy of the calibration data. A low value here may arise because of a very high path loss between the
AP and SU, i.e. the units are badly aligned and the SU’s transmit power is capped below the ideal power
level.