A practical and cost-effective cyclic pulse synchronization system using IEEE 802.11 wireless LAN

Timing synchronization is important for collaborating machines. For various reasons concerning practicability, some machines cannot have cables to synchronize them. To synchronize wirelessly connected machines, this paper proposes a practical and cost-effective cyclic pulse synchronization system. The proposed system consists of a master machine with an IEEE 802.11 wireless LAN AP and slave machines with wireless LAN STAs. The master machine outputs a cyclic pulse to the AP. Then the STAs can reproduce synchronized cyclic pulses for the slave machines. Thus the machines can synchronize their work timing using the cyclic pulses. All functions to synchronize the pulses are implemented in a wireless LAN chip as user software applications without additional hardware. We evaluated the pulse synchronization precision of our system in the case of the peak network load. The proposed system achieves approximately 200 μs precision for the maximum pulse edge delay of STA output pulse to AP input pulse.