I believe what Veera is asking is, if you were to complete an entire flow and resolve a case [potentially] offline, and then you go to sync the case to "submit the application" what is the minimum network strength required.
I feel as though Pega does not have any set/defined minimums and this question may be more of a low level networking/OS sort of question. But I could be wrong, and will need Mobile SMEs to weigh in here.
I imagine we might fall under the philosophy that this question is somewhat N/A in the sense that offline mobility is supposed to handle this. Even with poor or spotty connections, the inherent design is to ensure no data loss and complete the sync once [better] networking connectivity is restored.
But that is just my read on the question and how the product is designed.