A wireless industrial networks protocol stack with time synchronization and node positioning

According to the characters and requirements in industrial field, a protocol stack structure in WIN (wireless industrial networks) is proposed and presented comparing with OSI reference model. After that, an MAC (Medium Access Control) protocol based on virtual token mechanism is proposed to meet the real-time requirement. Afterwards, an improved time synchronization method and a new node positioning algorithm combined within the proposed protocol are introduced respectively. At last, an experiment implemented on the amended GAINS (Global Actable Intelligent Networks) platform demonstrates that the proposed protocol ensures the impartiality of channel medium access, the throughput is ca.5% higher than that in CSMA/CA and has a smaller transmission delay. The time offset after the synchronization can be reduced to 1.25 ms.