Abstract
In order to move into the fourth generation of wireless networks, heterogeneous wireless networks (HWNs) like WLAN, WiMAX, and UMTS must be coupled. In order to function better in such heterogeneous networks, algorithms for these networks must be devised, particularly handoff algorithms. In order to make intra-technology handoff (horizontal handoff) switching in each network and inter-technology handoff (vertical handoff) by interworking between two HWNs, a number of projects with various network types were implemented and simulated in various case studies provided by OPNET simulation. The findings of the OPNET simulation demonstrate the higher performance of WiMAX on the WLAN and UMTS networks. WiMAX throughput outperforms other networks by more than thirty percent. Additionally, the simulation results demonstrate the effective deployment of WLAN into WiMAX and UMTS networks via the use of numerous network interfaces. It was discovered in this study that the vertical handoff between WLAN-WiMAX and WLAN-UMTS is very difficult to do without meticulously and precisely building the WLAN network because it highlights the basic differences in HWNs.