How works client android: when don't have internet it remembers points to send when will connect to internet ???

My wife connect 3g internet every 3 - 4 hours.
I need to know when again connecting internet the client will sent all points of coordinates to the server ?????
I need set interval time 900 seconds (15 min).
If this client doesn't work as I need then which client hidden will work as I described ????
Please help me.
Thanks a lot.

It already works like you described.

Thanks for repply
I tested yesterday and find settings for work as described.
work very good.