Signal problem with Samsung Galaxy Y GT-S5630 mobile

I am using Samsung Galaxy Y GT-S5630 phone with IDEA network provider. I am having signal loss problems many times a times. When I try to make a call, it says "Network unavailable". I though this might be the problem IDEA network, but it was not. I tried checking the same sim card in another mobile and it's working fine, this issue is being observed mostly for every 4-5 minutes. How can I resolve this?