How to keep apps active while in blank screen mode

[Android Question]

I trying to run an android app on a Samsung Galaxy Rush phone. App works great when phone is active, however when phone goes to sleep (or blank scree mode) the app stops working and can not receive or send data.

Is there a way to keep the phone out of blank screen mode and always active? OR is there a way to keep apps active during the blank screen mode.

Phone uses andrioid 4.1 jelly bean


thank for the help