It's different and more darker than the alternate ending of the movie. It explains the connection between the Alpha (The antenna) and the Omega (The nexus) much better. The antennas don't have the power to reset time. The nexus does. When an antenna dies (The signal), the nexus resets time. When Cage killed the antenna and got face full of it's blood, Cage became an antenna thereby when Cage dies, the nexus gets the signal to reset time.
The thing I don't get in this plotline is that why is it a requirement to kill all the antennas to stop the time reset? Doesn't killing the antenna triggers the nexus to reset time? Maybe an antenna(Cage) killing an antenna doesn't trigger the signal? And in the ending, how is the time being reset when the nexus is dead? And why is Rita's brain influenced in the time resets as she no longer has the antenna blood in her? *tears hair off* Maybe all of these questions are answered in the book.
As for the movie endings this is what I think.
1. Movie ending; After killing the Omega the time is reset and the mimics are dead. Why and how? Movie magic I guess. I can only speculate that after killing the Omega, it can't revive even with the time reset that magically happened. Since the omega isn't alive after reset, it probably means that Cage can't trigger the signal. Therefore no loops.
Another crazy speculation that I just thought of - Since cage absorbed Omega blood. He
became an Omega! Who was his signal to reset time? That I do not know. But it makes the magical time reset somewhat swallowable.
2. Alternative movie ending; Going by my speculation of requiring an alpha to kill an alpha without resetting time, the normal goon killing an alpha triggered a reset. But why did Cage lose his antenna abilities in the reset? And if he didn't lose it, wouldn't killing him reset time creating a loop? *tears hair off*
Goddamn it Pininfarina
I was happy with my half arsed understanding of the whole thing. But now that I spent far too long thinking about it, there are more questions left unanswered.