If the AT&T cell booster 4g LTE light is blinking, what does that mean?

@Julysangel69  The Cell Booster is an open system. In other words, you can not restrict who has access to your Cell Booster. If there is an AT&T phone within range of the Cell Booster they have the potential of connecting and using that connection for cellular calls. That's why you may see the 4G/LTE light flashing when you are not using your phone.

AT&T's Cell Booster is a femtocell, not a cellular booster. The naming is purely a marketing decision on AT&T's part. Most people have a vague understanding of what a cellular booster is but have not a clue what a femtocell is. The Cell Booster only uses a cellular signal from the closest tower for location verification, handing off, and the occasional maintenance check. It does not connect to the tower. The Cell Booster will broadcast an LTE signal that your phone registers to and then uses that connection thru your internet service to reach the AT&T Mobility Servers. A cellular booster actually takes the incoming cellular signal and "boosts" it to useable levels within your home. It requires and outdoor antenna (usually on your roofline) to capture the signal and transfers that to an indoor antenna for propagation throughout your home, and then vice versa.

If the outside cellular signal fluctuates a lot then that can affect the Cell Booster because your phone will want to connect to the strongest signal it can detect. So, if the outside cellular signal increases or decreases as you move about your home, your phone may drop the Cell Booster signal and attempt to use the outside cellular signal, which can cause call quality issues or dropped calls. The same is true for the Cell Booster signal as you move thru your home. Ideally, if you had a consistent 1 bar of incoming cellular signal, the Cell Booster should work very well for you.

Ideally, WiFi-C (WiFi Calling) is the preferred method for improving in-home coverage. But that is dependent on the phone (some work better than others) and the strength/reliability of your WiFi signal. WiFi-C is similar to the Cell Booster in that it too uses your internet connection to reach the AT&T Mobility Servers. And, it is a more secure connection than the Cell Booster because only you can use WiFi-C in your home because your WiFi is password protected.

Read my Cell Booster Tech Guide. The link (first link) is in my sig line. Typically, if the 4G/LTE light is flashing that means the Cell Booster is being accessed/used. Otherwise, it stays a solid color.

Thank you for your reply. I wondered why it was blinking when I wasn't on the phone actively using it. But, am thankful it seems to be boosting my signal. 

@Julysangel69  Keep in mind that the Cell Booster (which does not boost the signal as it is not a cellular booster) will show activity even if you are not using it because it is open to anyone with an AT&T phone who is close enough to connect. It could be a neighbor or someone on the street in front of your house. It all depends on how far the signal is propagating.

Wow, I had no idea others outside my home or neighbors could benefit from it.  Happy it extends to my yard outside however.  Now I'm a bit confused by your statement

"(which does not boost the signal as it is not a cellular booster)". I had been told there must be a slight cellular signal before the AT&T booster can boost signal off of my modem/router through an ethernet connection.  Without it I barely have 1 bar on my phone, with it I get 5 bars usually. I did find it puzzling the last few days however, as my internet signal stopped working, but my cellular signal is still 5 bars. Cable service provider comes in a couple days.  Thanks for your prompt reply,  hope others can learn from your help as well.