TS asking about cellular issue. What you posted is wifi signal issue. Both are different problem and using different chip and antennae.

And how is that even a common issue? I have been using iphone since 3G and never heard of this problem or this way of resolving signal issues. I would advise TS to do more research on this method before doing it. Cause heating and freezing anything generally is not a good idea. Heat will expand the molecules in a substance and then frozen rapidly will shrink the molecules which can cause cracking of the substance.

Not saying that it won't work but read more about this before doing it. It's possible that the cellular chip is faulty or the antennae connection is faulty. Anyway, good luck on fixing.