This sort of exists but there is no network element as you’ve described. These are called off-route mines. They’re far cheaper than guided missiles but you need

This sort of exists but there is no network element as you’ve described. These are called off-route mines. They’re far cheaper than guided missiles but you need to accurately predict where the target will be. You’d also need to be much closer than you’d typically be with a rocket or missile. Also see IEDs with EFPs, but I wouldn’t want to have a cell phone emitting on a battlefield.