Iphone turns off when data is in use

My iphone 4s on iOS 8.4, even when 100% charged, turns off after only about 5 minutes or sometimes less when I turn data/3g on. It says it is out of battery so I wait 5 minutes, turn the phone on and it turns on and still states the phone is on 100%. If I continue to have data turned on, it will then shut down again but if I put it on airplane mode, it usually lasts. This suggests it just an issue with data??