Fast Time Synchronization Strategy for Mitigating Collision of Initial Entry Message over Link-16

TDL (Tactical Data Link) is a communication technology that can be a base technique to allow all platforms used in the battlefield to communicate with each other. To operate smoothly, synchronizing network time over TDL is necessary. Most TDLs use GPS (Global Positioning System) for time synchronization. GPS is vulnerable to jamming attacks because the power of the GPS signal is low. Link-16 has a GPS independent time synchronization method. This method is performed when new nodes attempt to join a certain network. Synchronized nodes in the network transmit IEM (Initial Entry Message) sent by broadcasting to the same slot. This causes a problem with collisions on the entry node side. If the entry node does not receive the IEM, it waits for another IEM in the next frame to synchronize with a reference node roughly. In this paper, we propose a method to acquire coarse synchronization with a reference node by overhearing messages sent by other nodes. Our proposed method can be used to acquire coarse synchronization instead of IEM when entry nodes cannot receive IEM because of the collision. Simulation results show that the proposed scheme provides lower time for synchronization than Link-16.