Real-time Access Research Of Industrial Wireless Sensor Networks

With the development requirements of industrial wireless technology, the combinative advantages of wireless sensor networks and industrial technology are increasingly obvious. We can use the low-cost, easy-to-use, and perceptive features of wireless sensor networks to realize comprehensive monitor to the industry process with a lower investment and using cost. Also, we can obtain the important industrial process parameters, which traditionally do not monitored on line because of cost reasons, to implement optimal control and achieve the goal of enhancing the product quality, reducing the accients during the industrial production process the and improving the energy efficiency.In the industrial environment, Real-time has a vital role. Industrial applications are divided into security, control and monitoring three different applications, and different applications have different needs for time.Among the IEEE802.11, IEEE802.15.1, IEEE802.15.4 and other standards, IEEE802.15.4 standard is strongly supported by the SP100, Honeywell, GE Global Reseach, Emerson and other international research institutions and commercial organizations, which fully demonstrates that the IEEE802.15.4 standard has the tremendous development potential in the industrial wireless sensor networks.When IEEE802.15.4 is applied to the industrial environment, its GTS real-time is a very important topic. This paper analyzes the existing real-time technology, and uses the GTS delay analysis model to summarize three key factors of GTS: scheduling mechanisms, distribution mechanism, using mechanisms. To use the three key factors research the existing inadequacies of GTS real-time in the IEEE802.15.4. Also, as the response to the inadequacies, the paper makes a corresponding improvement on the GTS scheduling method, request method and bandwidth application method.The paper profoundly understands the key technology of MAC layer in the IEEE802.15.4 standard. And we use the simulation software OPNET to simulate the GTS work of beacon-enabled IEEE802.15.4 standard. Further more, we bulds the simulation system architecture and the interface between modules, and describes the process model, state design and timer design of every module. Finally, we depict the main GTS news interactive process used in the real-time performance evaluation.The simulation results show that, by improving the mechanisms of GTS, IEEE802.15.4 real-time in different applications of industrial environment has significant enhancement in the aspects of GTS delay, energy consumption and bandwidth utilization compared with original GTS.