Mobile and wireless networks have made remarkable development in the last few years. At the present time many mobile phones have also a WLAN adapter. One may expect that near soon many mobile phones will have Wax adapter too, besides their 3G, 2G, WLAN, Bluetooth etc. adapters. We are using IP for both generations, 2.5G or 3G Public Land
Mobile Networks (PLMN) on one side and WLAN on the other, raised study on their integration. Concerning the 4G, its focus is towards flawless incorporation of cellular networks such as GSM and 3G. Multi mode consumer terminals are seen as must have for 4G, but special security mechanisms and special operating system support in special wireless technologies remain a test. Nevertheless, integration among different wireless networks (e.g. PLMN and WLAN) is implemented in practice even nowadays. Although, different wireless networks from a sole terminal are used absolutely, that is, there is no combining of different wireless access technologies for a same session (e.g., FTP download). The anticipated Open Wireless Architecture (OWA) in is targeted to offer open baseband processing modules with open interface parameters. The OWA is related to MAC/PHY layers of future (4G) mobiles.[3] The 5G terminals will have software defined radios and modulation scheme and new error-control schemes can be downloaded from the Internet The enhancement is seen towards the consumer terminals as a focus on the 5G mobile networks. The 5G mobile terminals will have access to different wireless technologies at the same time. The 5G mobile terminal should be capable to merge special flows from different technologies. The network will be dependable for managing user-mobility.The 5G terminal will make the ultimate selection among different mobile access
network providers for a specified service. The paper gives the concept of intelligent Internet [13] phone where the mobile
can prefer the finest connections. [14]