How far must I be from a tower to get excellent coverage from the MicroCell?

In the MicroCell Informational Document, it states that if your local tower is far away, you'll probably get excellent coverage in-home from the MicroCell. I get 1 to 2 bars in my home, and sometimes it says "No Service". If I stay in certain areas of my home, I can hear my callers and my callers can hear me. If I start to walk around the house, the quality drops. I want to make sure that if I buy the MicroCell, it will improve the quality and reliability of my voice calls. I have WiFi so 4G is not an issue more me.