trouble with bluetooth

I have got a radios Cd Alpine 125 BT with bluetooth, and I have got an iPhone 4s, and no work well bluetooth, connecting but then disconnecting all the time same problem. I have Make everything with iPhone, don´t work and my Alpine bluetooth work correctly with another mobiles, so, the problem is in iPhone

I need help

I have restore red. Restore iPhone and I can´t looking for a solution