I've asked the following question on Network Engineering and Android Enthusiasts, where it was closed as off-topic.
Network Engineering said questions about hosts are off-topic, and Android Enthusiasts said they disallow questions which are Android-independent. I expect Ask Different will say the same thing.
Do mobile devices vary transmission power based on signal strength?
Do mobile devices typically vary transmission power according to the reception strength?
e.g. Will my phone use more battery if I'm far from my router?