Unlike the other generations which are designed to provide users with moderate bandwidths, the next generation mobile system will be design in such a way that it integrates all the already existing networks and new emerging networks, services and terminals (Rao, K.R.; Bojkovic, Z.S. and Milovanovic, D.A.; 2009). Designing a heterogeneous wireless and mobile network for all-IP network has gained a lot of attention in the mobile Telecommunication sector. The major challenge is to connect between different technologies such as GSM, 3G, Wi-Fi, WiMAX, LTE, Femto and TETRA to support each other by providing end-to-end communication. The two concepts of wireless and cellular network has different radio access technologies; the cellular system which gave birth to current wireless technologies divides the area into a geographical region called cells and the base station which has an antenna installed at the centre of the cell. Hence, they are called a wide area networks (WANs) which provide high data. The wireless network on the other hand provides a wide range of coverage. This implies that complementing these technologies (networks) through the provision of interactions between the heterogeneous networks will provide a next generation network which will support high mobility at high data rates.
Also the existing wireless network depends on such infrastructure s as base stations, gateways etc. of their services limits the availability of the network in some areas. But because next generation mobile networks are meant to provide services anytime and anywhere, the system allows for the integration of an ad hoc network which is an infrastructure less network into the system.
Many researchers have proffer ways of integrating heterogeneous networks using interworking solutions. Park, H. et al (2012) has proposed gateway service which is provided through message encapsulation with MIH protocol header. Nithyanandan, L., and Parthiban, I. (2012) suggested a heterogeneous network through gateway relocation.
Zhou, W.; Arslan, T.; Benkrid, K.; El-Rayis, A.O.; and Haridas, N.; (2013); presents a novel miniaturized reconfigurable and switchable feeding network to cover GSM, GPS, 3G and LTE. It was made up of four individually reconfigured conventional Wilkinson power dividers. The dividers are reconfigured using PIN diode switches and by controlling the bias voltage of the PIN diodes, the operating frequency of the feeding network can be converted between four different bands in order to accommodate the above mentioned networks. These are: 600MHz-900MHz to satisfy the application of LTE US which uses 700MHz, LTE UK (800MHz), and GSM which uses 850MHz and 900MHz; 1.2GHz-1.6GHz for GPS L1 (1.575GHz) and GPS L2 (1.227GHz); 1.8GHz-2.2GHz which targets different GSM (1800MHz, 1900MHz) and 3G standards; and 2.4GHz-2.6GHz which is used to cover LTE Europe which uses 2.6GHz and Wi-Fi (2.45GHz).
The design which was implemented on FR4 substrate can be applied to commercial multiband communication systems and hence “forms an important step towards realizing a truly global mobile phone” (Zhou, W.; Arslan, T.; Benkrid, K.; El-Rayis, A.O.; and Haridas, N.; 2013).
Chen, Y-C.; Yang, C-C.; Tseng, S-C.; and Hu, Y-B.; (2011); proposed the Advanced Vertical Handoff Translation Centre (Advanced VHTC) architecture for Wi-Fi/WiMAX heterogeneous wireless networks with the aim of improving QoS through packet format translation and MIH based mechanism for vertical handover. This in turn minimizes the time for handover and improves quality and persistent connection service.
The framework provides a good integrated network which allows MTs to have a seamless roaming in the heterogeneous wireless networks and exchange data conveniently.

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