Phone doesn't turn wifi off and weirdly transmits data When i wake up my phone(kitkat,cm11) from standby, it always transmits data through wifi and than stops transmitting/recieving data. It gives the feeling it always transmits/recieves while sleeping.   

I turned down all location services in various places, i set wifi to turn on "only when connected to power" , turned of "scanning always availble" , but still no help. 

What is the cause , and how do i track this down?
I've followed Izzi's advice and it worked. Here's what i did:

I used the firewall app, afwall+ ,turned it on( and used whitelist - blocking everything ) , turned logging on. 

made phone sleep. 

Than turned it on - and on the firewall log - i've seen the sources of traffic - all pointing to google, which i can live with - so i didn't continue further.