You may be in a fringe area, as lte on every network has pockets. However, Verizon is also in the process of upgrading every single one of their lte towers to lte advanced for volte in preparation for launch next year. During this process your signal may weaken.
And so you know, those bars lie for signal strength. Go into settings ->about phone ->status and scroll down to the area where it says signal strength. That displays your true signal, the closer to zero the dbm is, the higher your signal. Anything 110 and above is a fringe signal. With asu, the farther it is from zero, the better the signal.
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