Conservative Soft Handoff for Heterogeneous Wireless Networks

Seamless handoff between different wireless technologies is a vital requirement for the next generation mobile networks (NGMN). The soft handoff (SHO) method provides seamless roaming, but makes heavy use of battery and radio resources. In this paper, we propose a conservative soft handoff (cSHO) which maintains the benefits of SHO and reduces the consumption of resources. Instead of using both radio interfaces during the handoff period, the mobile station (MS) activates and deactivates its radio interfaces and switches between them to maintain the best possible radio connection. Since multimedia packets are already duplicated in the network and buffered in the base stations, fast switching between interfaces is possible. We investigate the performance of our proposed scheme by simulation and compare the performance of the cSHO scheme with the SHO and hard handoff (HHO) mechanisms.