Design And Implementation Of CMMB-based Data Service System

With the development of economy and the change of people's life style,China has the largest number of mobile terminals. The increasing number of people who own mobile devices demands the multimedia information service to support mobile information receiving. There are some mobile multimedia broadcast standards. However,the complicated topography of China leads to the problem of coverage and efficiency. The large number of users leads to the cost and information security problem. Besides,using foreign standards demands a huge sum of patent fee. China Mobile Multimedia Broadcasting (CMMB) System is independently innovated to solve the problems mentioned above. Currently,the application of CMMB system is mainly to provide mobile television programs. The data service broadcasting needs further development.This paper analyzes the background of the research and development of CMMB technology and illustrates the standard architecture. According to the feature of data service broadcasting and functional demands,a CMMB-based data service system is presented. The system consists of the data generation and encapsulation subsystem,the conditional access subsystem and the multiplexing subsystem. The system implements the file slicing,encapsulation,entitlement control,multiplexing,transmission,demultiplexing,decryption and restoring of various types of data services. The framework of the system and the designs of all the functional modules are expounded. The key technologies,such as data file slice transmission packet encapsulation,the generation of file attribute table,extensible protocol encapsulation,data scrambling protection,encryption entitlement control,electronic service guide and multiplexing,are explained in detail.Experiments show that the system has achieved the goal and is up to the CMMB standards. The feasibility of the design is verified. The CMMB data service system is able to provide various types data broadcasting services,expanding the scope of mobile multimedia broadcasting services and satisfying people's needs for different kinds of information.