Research Of MP3 Decoder Modeling And Simulation Based On Ptolemy Ⅱ

As embedded system is widely applied in various fields, the complexity of embedded systems is also increasing, As the result, the work of analysis and design phase in developing embedded system has become more and more burdensome. So it is necessary to reduce the workload of the design phase by the embedded system modeling. However, since embedded system is typically heterogeneous, the existing modeling methods in the design of embedded system become invalid. Therefore, research based on Ptolemy II platform for a design strategy of modeling to effectively solve the heterogeneousness of embedded system is necessary and significant in the design of embedded system.PtolemyⅡprovides modeling and simulation platform for distributed real-time embedded system. It uses hierarchically heterogeneous modeling idea of actor-oriented, solves the heterogeneousness of embedded system by providing rich computing models and achieves the function of embedded systems. In this paper, modeling and simulation of a typical embedded system-MP3 decoder is achieved based on PtolemyⅡto illustrate the validity of this modeling design strategy. The key to MP3 decoder is to enhance the decoding speed and achieve real-time decoding. The current solution strategy is to improve the decoding algorithm of hardware chip. However, the efficiency of parallel execution is promoted in the process of decoding software by using an improved real-time scheduling algorithm. The validity and effectiveness is verified by modeling and simulation of MP3 decoder. The main research work is as follows:1.In this paper, the research background and significance of the topic are introduced, the principle and the decoding process of MP3 decoder are introduced to provide a technical basis for the later modeling and simulation, the characteristics of current modeling and simulation platform are analyzed, the advantages of PtolemyⅡmodeling and simulation platform are illustrated in detail, and the PtolemyⅡactor-oriented design idea of hierarchically heterogeneous modeling of simulation platform is also expounded.2.Actors in the library of PtolemyⅡcan not meet the needs of MP3 decoder modeling, for this reason, the structure of actors in PtolemyⅡis elaborated, the ports, parameters and design strategy of public methods are studied, customized actors are added to the Vergil actor library, and the FrequencyInverter actor is designed to meet the needs of MP3 decoder modeling.3. In order to enhance the parallelism of system implementation to meet the needs of real-time decoding of MP3 decoder, the existing real-time scheduling algorithm is improved and new scheduling algorithm based on PTIDES implementation strategy is proposed.4. Based on the actor-oriented PtolemyⅡdesign method of heterogeneous hierarchy, following the decoding process of MP3 decoder, and for the demand of real-time decoding, MP3 decoder system model is achieved by improving the scheduling algorithm respectively in the modeling and simulation platform of PtolemyⅡ. On this basis, the model is simulated and tested; the feasibility of realizing the modeling and simulation of MP3 decoder through the design methodology of PtolemyⅡis illustrated. Compared the decoding time of model before and after the algorithm improvement, the correctness and validity of algorithm are proved.