MC - calls dropping on IPhone then 3G light blinking

Just adding my experience to the list out there…

PROBLEM:   

While on a call on our IPhone, the call will suddenly go silent, we get a “Call Failed” message on Iphone which lasts for maybe 10-15 seconds until we can use the phone again.  Immediately upon the “Call Failed”, the 3G light on the MC starts blinking, and our IPhones lose their M-Cell signal and switch to the AT&T cell tower signal.  The green 3G light on the MC blinks for maybe 15 seconds, then it goes solid again and the IPhones regain their M-Cell signal.   And all is well until next dropped call.   

It doesn’t happen to EVERY call (no pattern noticed) and it can happen after just a minute or after 10 minutes (no pattern noticed).

This happens with the Iphones anywhere from 2 feet from the MC to 20 feet away.  (No pattern)

The other lights on the MC remain steady green (good GPS and Ethernet signals).

I’d estimate about 80% of our calls are dropped this way. Because of this we cannot depend on our cell phones.  Considering the switch to a different carrier if we can find one that gives us better signal in our house. 

NOTES: 

We got the Microcell because we only get 1 bar inside our house.  With the MC, we get a full 5 bars.

This is the 2nd Microcell we’ve tried with same problem occurring on both.  Tried the first one back in January and the 2nd one just the last couple weeks.

We have CenturyLink internet service, a Westell 7500 modem/router. 

We use an Iphone 4 and an Iphone 5. 

I have disable the "Automatic Handout" option in AT&T's MC settings. 

I've talked at length to AT&T support and CenturyLink support with no resolution.  AT&T support said their conclusion is it’s the internet/router settings.  The CenturyLink support person went over all the settings with me and said they all seem to be correct as far as she could tell. 

I've spent many, many hours trying to figure this out, but I'm not a techie so a lot of this stuff is Greek to me…especially all the settings for the network setup & modem/router. 

Frankly, when the MC works, it works very well.  I know people that do not have this problem, so I want to be optimistic that there is a “fix” for us, but I just don’t know enough about this stuff to figure it out.