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U
Æ
Increases power by 0.5 dB (fine adjustment)
C
Æ
Decreases TX power by 0.5 dB (fine adjustment)
Cu
Æ
Increases power by 5 dB (course adjustment)
Cd
Æ
Decreases TX power by 5 dB (course adjustment)
o
Between each adjustment observe the RSSI and MCS value at the
CPE RX until the desired value is achieved.
o
The following commands can be used to read the transmitter
configuration:
Gettxstatus : Will show the TX power as well as the value of the
TXattenuator. The TX attenuator cannot be accessed using the
User Interface but is provided for diagnostic purposes.
\
Note: If the User tries to increase the TX power beyond the maximum power
for which the device has been certified, the software will not allow the TX
power to be increased beyond the maximum permissible value.
Furthermore, for some links it may not be possible to achieve an RSSI of -75
dBm, at which point the link should be set to transmit at the maximum
permissible power to get the best RSSI and hence SNR.
8.1.2 Point to Multi-Point Link
The power control for a point to multi-point link can be performed in a similar manner
with a few small but important differences. The Uplink power control should be
performed first to ensure that signals from the 2 or more CPE’s arrives at the BTS
at a similar power. This will prevent the creation of a near far issue for the BTS
which can severely degrade throughput. For the Downlink power control, the BTS
TX power should be decreased until the CPE with the weakest signal has an RSSI of
about -75 dBm. If the furthest CPE cannot achieve an RSSI of -75 dBm when the
BTS is transmitting at full power, then the BTS should be configured at full power in
order to provide a reasonable level of service to the furthest CPE.
It is important to ensure we do not have a very large spread of RSSI’s on the uplink,
from the multiple CPE’s. Acceptable values are from Senstivity ( -100 dBm to about
-70 dBm). The presence of a strong signal , > -60 dBm will actuate the RX AGC of
the BTS and will degrade the quality of the connection for CPE’s which are arriving
at low powers near sensitivity. If the Uplink power control is performed properly, the
signals from all CPE’s should be between -100 dBm and -70 dBm and no near far
issue will be present. Ideally, the signal from all CPE’s should be received by the
BTS at about -75 dBm.
8.1.2.1 Configure the link:
•
Telnet into the BTS and each of the CPE’s.
•
From the telnet session type “monitor”
