This document discusses using signal strength and path loss data from 208 reports and OSS to identify hardware faults in cells. Case studies show how comparing path loss between transmit-receive channels within sectors can expose problems like loose cables or connectors. For example, much higher path losses (>20 dB difference) for some channels in a sector indicate a combiner issue. Differences only in uplink path loss between channels suggest a receiver cable problem. The document recommends using pivot tables to flag cells with over 10 dB variation in downlink or uplink path losses between channels for further 208 report analysis to identify worst performing cells needing attention.

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1 © 2005 Nokia V1-Filename.ppt / yyyy-mm-dd / Initials
208 Report Analysis

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Case1: Jumper from TRX 4 to combiner
loose (check connectors at both ends)
Case2: Jumper from Duplexer to TRX 4
(check connectors at both ends)
Case3: Check common feederline from
Top of cabinet to Antenna port ( loose
connector’s at either end or High VSWR problem, TRX 2&4 in
this case use the same feeder)
In this case, the Path imbalance (DL-UL) varies between +1.6 to
-4dB which doesn’t tell much
BUT DL pathloss variations between TRX’s is from 112.8 to
136dB
& UL pathloss variations between TRX’s is from 111.2 to 140dB
DEFINITELY A PROBLEM!

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Use OSS Data to identify & pinpoint HW faults
faster
Sector A
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
>70dBm 70-80dBm 80-90 90-100dBm <100dBm
Downlink Signal Strength
TRX3
TRX4
TRX5
TRX6
Sector B
0.00
20.00
40.00
60.00
80.00
100.00
120.00
>70dBm 70-80dBm 80-90 90-100dBm <100dBm
Uplink Signal Strength
TRX3
TRX4
TRX5
Path Balance Reports help understand any imbalance between
UL and DL
Whereas
Eg.Pathloss comparisons between TRX’s of same sector can
help identify loose cables or hardware faults, taking other TRX’s
as reference case
Eg. In Sector A:TRX 3 &4 have only 20% of DL SS samples <-
100dBm whereas TRX 5 & 6 have 70% of their DL SS samples
<-100dBm.
Prob:1 Combiner Faulty
In Sector B TRX 5 clearly had a difference in signal strength
only in Uplink.
Prob: Rx cable found to be loose
The same faults can also be seen using
Rxlevel statistics from OSS shown in this
slide, but 208 is faster for analysis!

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How to identify the worst cells in your network?
• Import DL & UL pathlosses for all TRX’s
of all cells into separate columns
• Use a pivot table to get Min and Max
values of dL and Ul pathlosses in a cell
• Identify all cells with DL TRX pathloss
variatons >10dB(for a NW with huge TI
quality issues , sstart with 15dB)
• The same can be done for UL also
• A combined analyses for DL& UL with
>10dB diff gave a list of 58 cells for
UP(West) attached below.
• Go back to 208 report for detailed analysis