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Please tell me what is the reason behind the Link imbalance……
Thanks for advance
Well there could be a number of reasons.if not due to bad planning.
First check if the link balance is degraded for all the TRXs / All the TRXs belonging to a zone.
if all the TRXs then the issue might be with the antenna system / associated feeder cables check for VSWR and any sharp turns or connectors may be loose / feeder faulty or in rare cases antenna faulty.
Else if all the TREs of a zone then check the VSWR / combiner / antenna if seperate or associated cables
else if one / two indipendent TREs
check VSWR issue may be
1. Faulty TRE / associated cables.
2. associated cables.
3. TRE slot.
4. Combiner port.There are three different possible known sources of Link imbalance:
−Invalid or inaccurate TX/BAY CAL
o If the radio is a new spare it comes with default CAL data and must be TX and RX offset calibrated within the slot it will function in
o If the radio was swapped from one slot to another and preserve bay level cal feature is not enabled, a recalibration of the TX and RX is necessary to achieve more accurate PB stats
o If an expansion cabinet is added to the configuration it might be necessary to recalibrate the TX and RX
o If external combining, filtering or amplification is added to the configuration a TX or RX calibration is required. In some cases this might be impossible
−HW/Connection problem with the cabinet slot/cabling/antenna:
An element in the received path might have failed, or might not be used or installed correctly: backplane, cabling, bad connectors, a bad duplexer …
−HW problem with the DRI:
A HW component of the transceiver (CTU or CTU2) can have failed which results in abnormal noise in the transceiver or loss of output power.Thanks Mania and Yasin
please i need to know which value we can say that the link imbalance is good or bad
Hi Andreas,
Which vendor are you working for as the value is shifted for different vendors like motorola the value should be close to 110 give or take 5HI Mania, Thx for your answa, i m working on ericsson system rbs 2116, please i need to know more about this issue.
Hi Andreas,
Sorry don’t have any direct experiance on erricson so don’t know the details but for a live network I heard they had a mean value of 103 on the cells. Hope its helpful.
Those experianced with Erricson say that they normally view the indipendent differnece between UL and DL and if its 15dB or above there might be cable swap or such issues.
For motorola we used to see variation of more than 8 max.
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