In case your cell is Multiband, check if drops are high on 1800. Modify tilts accordingly. Sometimes if OL is uptilted too much it drags calls (as its SS is good) but when it HOs to the UL subcell (on which tilts were somewhat aggressive and it had low SS) the call gets dropped.
Check your LOL settings too. Are these open area cells?
If the drop reason is Low SS Uplink, then perhaps your path balance is disturbed. You can confirm this via MRR.
Oh, so much information is needed and so much can be done.