The fourth-generation Telecommunication communication system is base on LTE technology . LTE Evolved High-Speed ​​Packet Access networks (HSPA) and to achieve higher data rates, greater compatibility with heterogeneous networks and more uniform network architecture is presented. LTE version of the standard release 8, 3GPP is. One of the goals of LTE and wireless systems is providing integrated handover and fast from one cell (source cell) to another cell (target cell) . The process defined in Version 8 supports LTE handover mobility are provided, but not suitable for all modes of mobility and even compared to 2nd and 3rd generation systems, may be user dissatisfaction. This paper, first we defined LTE network architecture and its Vulnerabe. Then handover related concepts in LTE network and recent actions in this area have been investigated.