3GPP LTE标准即将冻结，其应用变得指日可待。分析了LTE协议栈RRC层功能，并描述了RRC子层的状态，各状态下的任务以及状态间的转换，重点研究了RRC连接重新建立的原因和过程。研究表明，更好地完善RRC连接重建过程的处理方法对于重配置信令无线承载SRB1和恢复相应的数据传输有着极其重要的作用，这也是LTE通信系统中需要研究的方向之一。

With the completion of 3GPP LTE standard，the commercial application of LTE can be expected soon．The paper gives a Functional Model of the RRC sub layer in LTE system and pays more attention to the assignment of the RRC sub-layer and the state transitions between them．There is a detailed description of the causes and processes for RRC connection reestablishment in this paper．In addition，it also includes the study of RRC Connection Reestablishment．Researches show that it plays an important role for reconfigure SRB1 and resumes data transfer only for this RB．