Ericsson RBS 2106 Reference Manual page 374

Self Test and Supervision
Preconditions and Initiation
Initiates when the signalling multiplexing application is started in the
CMRU and when the corresponding application handling the signalling
endpoints on the DMRUs, are started.
Description
The relation between the reflected power and the output power can be
described by the voltage standing wave ratio (VSWR). The more
reflection the higher value of the VSWR. At no reflection at all the
value of VSWR will be equal to 1 and at total reflection the value of
VSWR will be very large. The higher value of the VSWR the higher
value of the return loss.
There are two kinds of return loss the Tx feeder return loss and the Tx
feeder normal return loss. The Tx feeder Return loss, that is, the RF
attenuation between the RBS cabinet and the antenna (the cable and
cable connections) including an ALNA/TMA shall be in the interval 0-
4 dB. The Tx feeder normal Return loss, that is the total attenuation
from the RBS cabinet and to the antenna and back to the cabinet (that is,
the attenuation at the cable to the antenna and from the antenna, cable
connections, ALNA/TMA, and the antenna). The attenuation should be
≤-14dB if the Tx feeder loss is ≤ 2dB and ≤-18dB if the Tx feeder loss
> 2dB. If VSWR is too high a message is sent to the fault handling. It
is possible to set two disturbance parameters from the OMT.
The two disturbance VSWR levels are in the range of 1.5-2.8. Allowed
alarm level VSWR values are: 1.5, 1.6, 1.7, 1.8, 2.0, 2.2, 2.5, 2.8. The
transmitter at the TRU measures the VSWR signal and if the signal is
to high it may be harmful to the power amplifier. If the VSWR signal
is too high the transmitter may reduce or turn off its output power.
46.4.7 Receiver Antenna
This is described within the context of Diversity Supervision
46.4.8 Layer 2 Data Link Transmission
Purpose
To check the number of aborted and erroneous frames received by the
CMRU from the DRMUs.
Preconditions and Initiation
Initiated when the signalling multiplexing application is started in the
CMRU and when the corresponding application handling the signalling
endpoints in the DMRUs is started.
Description
Signal messages between the CMRU and the endpoints of the DMRUs
are supervised by the following events and conditions:
•
•
372 (485)
Number of aborted frames received
Number of error frames received
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EN/LZT 720 0008 P2A
2001-11-28