Hi, I just noticed that on my iphone4 my wifi connection is always active even after the screen is locked. My 3g and cell data are disabled. I always get whatsapp messages when im on wifi and when i turn on my iphone the wifi logo is on. My dad got a 3gs with the same Os version and the wifi connection is always lost after the screen is locked so he cant use push and when i turn on hes phone it always takes 4-5 secondes till the wifi logo appears. why is there a difference between 3gs and 4?? thanks!!