Handover Initiation in 3G/WLAN Integrated Networks

Next generation wireless network is envisioned as a convergence of different wireless access technologies providing the user best connection any where any time to improve the systems resource utilization. In such converged systems, the heterogeneous co-existence of access technologies with largely different characteristics results in handoff asymmetry that differs from traditional intra-network handoff (horizontal handoff) problem. The seamless and efficient handoff between different access technologies (vertical handoff) is essential and remains a challenging problem. The parameters measured to determine handoff are received signal strength, signal to noise ratio and bit error rate. In this paper, an analytical framework to evaluate the performance of vertical handover between wireless access networks in terms of received signal strength, is validated by simulation. It is likely that WLAN will become an important complementary technology to 3G cellular systems and typically used to provide hotspot coverage where there is a high density of users.