Big data is the buzzword of the year. Especially in the field of telecommunications, telecom operators have been put to the test of mobile big data because it has huge, varied and complex structure with challenges to store and analysis. However, big data also has potential big value. Revealing hidden information and making further processes in mobile big data, telecom operators could depict user behaviour to improve average–revenue–per–user (ARPU) and detect real–time device information to prevent potential equipment failure. An overview of mobile big data's content, scope, methods, challenges and samples is presented in this paper. The paper also discusses the current process and analysis on mobile big data and introduces a mobile data infrastructure (MDI) and a mobile data lifetime management (MDLM) model. Finally, a mobile big data system will be described.