The next generation of heterogeneous wireless access network technologies are  include such as wireless networks (WiFi and WiMax) and cellular networks (such as WCDMA and HSPA and 4G). One of the major issues in heterogeneous wireless network design, support for mobile users is vertically integrated handover. handover process between different wireless technology, called vertical handover. The wireless technology of different features, services, pricing, and offer different regional coverage. Vertical handover can be combined with the benefits of mobile networks to obtain user satisfaction and improve efficiency, can be used. So concepts and review the measures taken are necessary. The main purpose of this article we discribe the basic concepts related to handover, classification, algorithms, protocols, and features favorable factors in handover for Next Generation Networks.

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.