How can I stop my Samsung S5 Mini from going into idle mode?

[AC Question]

hi my Samsung S5 mini goes into an

in the "idle" mode calls or sms' do not come through, until i use the phone to make a call or sms, & then it all calls can come through.

 

[B. Diddy]

Re: hi my Samsung S5 mini goes into an

Welcome to Android Central! Does it go into that deep sleep immediately after the screen turns off, or does it take a little while afterwards? Do you have any power saving modes turned on?