High Precision Industrial Wireless LAN System with Asynchronous Communication

In this paper, we propose an industrial Wireless Local Area Network (iWLAN) system compatible with asynchronous communication for industrial robots (iRBs) control in factory automation (FA) environments. The design of our media access control layer is synchronous multi-user round-robin transmission protocol. Low overhead Packet Division Multiple Access (PDMA) scheme is utilized for Multi-user Downlink transmission up to 80 MHz, while Frequency Division Multiple Access (FDMA) is employed for the uplink transmission. The system is developed based on a fast and deterministic communication featuring the synchronous multi-user system. In general, the iRBs are not only controlled by synchronous communication but also by asynchronous communication via this iWLAN system. In this paper, we present the Field-programmable gate array (FPGA) implementation are carried out to confirm that our iWLAN system by asynchronous communication can control up to four motors. Based on the result of FPGA implementation, the time synchronization of the proposed system in high accuracy from 40 to 100 ns is also captured by an oscilloscope.