Design For EPA Wireless-based Wireless Access Gateway

Wireless technology is quickly developed for industrial application in recent time, working as an extension of wired industrial network.Since there is no obvious tend for wireless employed as a replacement for traditional wired communications,it is worth focusing on their integration with popular industrial wired solutions,such as EPA standard.In order to achieve efficiency and performance for the overall networked system,wireless access gateway plays an important role in these interconnections.For wireless integration with EPA wired network,we developed a set of technologies based on EPA wireless gateway.1.A bridge protocol is proposed between network layer and transport layer in this thesis,achieving protocol transformation between wired and wireless communication.There are two main functions of this bridge protocol:Map IP addresses for EPA Wirelss devices,built up information list for each wireless device and dealing with packets pass through the two different networks.2.A TDMA based link layer schedule scheme for EPA wireless communication is also present in this thesis,which can coordinate with the EPA communication schedule management entity(CSME) with unified embedded module.In EPA wireless, communication macro-cycle is divided into two periods:Cycle period and Non-cycle period,which are specially designed for cycle process data for real-time transmission and non-cycle data triggered by process events separately.Further more,non-cycle data are classified into multiple priorities to satisfy their different real-time requirements.3.Under the above communication schedule structure,timeslot assignment algorithm for non-cycle period is proposed along with the macro-cycle calculation method.Therefore,the timeslot length of the macro-cycle is determined and non-cycle data transmission schedule between different nodes in wireless network is achieved.Packet lost rate is reduced to 0.1‰by combining these two method.4.Parameter configurations for application layer both for wired and wireless devices are actualized.In the process,wireless gateway is map into two visual devices: a wired EPA device in wired network and a EPA wireless device,with two IP addresses assigned.