Real-time communication in WIA-PA industrial wireless networks

Wireless communication technologies can bring great benefits to industrial automation systems. But because of the high data losses and transmission errors caused by channel fading and interference, the hard real-time and reliability requirements of industrial automatic control are more difficult to be guaranteed. WIA-PA is the new Chinese industrial wireless communication standard for process automation. Its protocol is introduced and the real-time problems are analyzed. To provide required real-time communication services in WIA-PA, resource reservation, priority-based CSMA/CA and queuing mechanisms are put forward for predefined periodic and non-periodic automatic tasks to access the MAC layer channel and to transmit network layer packets. Congestion control is used to prevent the network from collapse in heavy traffics. The performance analysis shows the modified WIA-PA can satisfy the real-time requirements of automatic field monitoring and control in process industry