What could cause IRAT preparation failures to unknown target RNC on a site?


#1

Hi guys, i am observing IRAT preparation failures due to Unknown target RNC on one site. IRAT preparation failures are with co-located 2G cells and one neighbor site.
I have checked nbr definitions in 3G dump, its ok no issue observed. Whats else could be the reason?

Vendor is ZTE


#2

Target RNC or BSC? 2G frequencies are clean? BSIC verification is on?


#3

I had irat preparation fail 3g to 2g for two 2g cells; Reason was wrong MNC, normally mcc-mnc 286-02; there were write 286-002. You should Check inconsistency for Target cells


#4

Yes that’s true


#5

Cause is unknown target RNC. 2g freq are clean, BSIC is also ok


#6

Check on external definition of 2g cells on Rnc, this defination have ci, basic, bsc, bcch, lac of the target 2g cells


#7

Already done no issue observed. All definitions are ok


#8

Hmmm, great will check this, Today deleted & added relations again. Will observe tomorrow.


#9

Is there congestion in 2g site?


#10

Yes there is, but if its due to 2g cell congestion then the failure cause would be different like “fails due to physical channel”


#11

U might check cell definition on CN… This as well might cause interrat problems


#12

Ok we also think this because every 3g cell is degraded with that 2g site


#13

Check LK license at RNC… this will resolve the Unknown target RNC