Design And Implementation Of The Task Controller Merged With Petri Nets In Telecom Billing System

Along with the stable development of 3G and the advent of the era of 4G, competition between operators becomes more intense and requirements for the billing system are increasing. Online Charging System solved the high risk of arrears of the traditional billing methods and the problem of unable to respond quickly to new business by using online charging method pushing mainly by operators. However, the billing system involved huge business and need to be classified by so many services, How to achieve a unified control of the service and establish a unified message handling mechanism to enable communication between the services was the key.Petri net is a theory with rigorous mathematical foundation, Clear interface display and the ability to perform powerful analysis and a powerful tool to achieve process control. This paper, combining with the theory techniques of Petri nets, designed and implemented a task controller. It received messages sent by all services, dealt with messages classify, played a role of transport hub between the services. The task controller established various business models and kept contact on business between services by using the technology of Petri nets. The main contents were as follows.Firstly, this paper introduced the basic theory of Petri nets, including the definition, properties and methods of analysis of Network System for lading the theoretical foundation of creating and analyzing the model of Petri nets.Secondly, this paper introduced the process framework of OCS system, the relationships of task controller with other modules and the overall implementation process of task controller and analyzing the function of Petri nets in task controller. It realized the instantiation of the elements of Petri nest.Thirdly, this paper realized the function of each part of the task controller, introduced details of the part of Petri nets and the part of timer to generate messages. It established two models of Petri nets, one was the same with the general Petri which had initial marking and start place and was mainly used in the system monitoring, the other one made some changes on the traditional Petri for business which generated initial marking by initial transition and was mainly used in scheduled task. Then, this paper analyzed the properties of examples of the two models of Petri nets by solving the correlation matrix, invariants, reachability graph.Finally, the Petri nets model of timing tasks and several types of message processing in the task controller were tested in a production environment, which verified the practicality of the Petri nets functions and the overall control of operations such as start and stop for each service in the task controller.After the OCS system was commercially, we discovered that the merge of Petri nets and task controller made the system more user-friendly and brought convenience for the developer and maintenance personnel. We can quickly solve business process problems by Petri nets model. It laid a good foundation for the development of the follow-up of new business.