I'll copy and paste my post from another thread and this might help you out. I never had this issue with a 3G phone and with a 4G phone, a tower far away is "pulling" my phone and it is connecting to that tower, rather than the 4G tower 1/2 a mile from me. I am convinced this is Tower issues, I was even bouncing from tower to tower the other night when I was talking to AT&T and I was sitting in my chair in my living room, not driving through the city. I'm surrounded by 4, 4G towers, in the best coverage they have, but one tower 4 miles away is overriding 3 towers that are W/E/S of me and they are 1 mile away on both sides of me and 1/2 a mile away behind me and yet, my phone and many others in this neighborhood are going to the one 4 miles north. There are several microcells in my area but there shouldn't be any, because like I said, we are in the best coverage area, right in the middle of it, not even on the line. This is what I am doing:
I would suggest opening a network ticket with 611, then after the ticket is opened and they give you the number, call 888-343-7992. That is a very small department, they can look at everything and every tower your phone has connected to, they can tell you how many dropped calls, not connected calls, etc and they can tell you what your phone is doing in real time.
You have to open a network ticket first, for them to check towers. Of course going through 611, they are going to want to "troubleshoot" your device, even though you have replaced it, that is their script at 611 and they must do that first. If they don't go ahead and open a network ticket, they will send you to Tier 2 and they might want to troubleshoot it again, but if you explain about exchanging the phone and the SIM card, chances are good they will open the network ticket for you and that ticket will go to Tier 3, then call the number I gave you and they can give you a ton of info then what is going on with your calls and the towers and they will add that info to your network ticket. Those are the people that get to the engineers, because this is most likely a 4G/LTE Tower issue. I'm having an issue myself, not with the dropped calls, I've only had 4, but my phone is connecting to the wrong tower far away and sometimes my phone doesn't ring, I just suddenly have a voicemail.
Now I have also found if you go through these steps and still are having an issue and call Samsung, they will take your phone and check it out completely (I'm assuming it is under the 1 year warranty) for free and then fix it for free if they find an issue.
This department can and will also tell you real time if there is any minor or major issue with a specific tower.