SDCCH DRop is around 9% !! That’s not what I’d call normal 🙂
What I see is:
High TCH drop
High SDCCH drop
Then, Call success % is excellent and HO success are good too. That proves that the way Ericsson are computing their indicators is very obscure ! (for me, at least)
Could you please state also the average duration of the SDCCH and TCH in the cells ? If it is very short, then that confirms my suspicion…
With such bad QoS I must suspect a hardware failure, or most probably a wrong configuration of the equipments or interfaces. I would investigate if the drops happen on some TRX only, or even on some TS only. I would check also what is the cause of the drops (with indicators, or with drivetest)
If there is a random pattern, then the failure is probably located further up in the core network (Ater ? TC ? A interface ? MSC ???). My instinct is leaning towards A and Ater misconfiguration, or a board failure somewhere.