  We present a novel quantum clock synchronization(QCS) scheme of multiple
parties which uses operation as the trigger to start the evolution of the
initial state, where existing QCS protocols use measurement to start the
evolution. Since the trigger is the unitary operation, we have protected
entanglement of remote nodes, and after concentration of the qubits to the
center node, general measurements of the total state is possible. We show that
our protocol links the QCS problem to a multiple phase estimation problem. We
use the Fisher information to give the precision of the synchronization, and
explicitly show that the Heisenberg scale of synchronization is achieved in the
two party case. We also show that our protocol is very efficient in
synchronizing a clock to the average time of other clocks. The precision has an
$O(\sqrt{d})$ advantage of the precision of the average time's estimation over
the best possible strategy using measurement triggered QCS. The precision is
also Heisenberg scale.
