COS-based inter-switch handoffs in wireless ATM: pitfalls and solutions

Handoff in a wireless ATM network is an important and challenging problem. Previous research on this topic suggested using a cross-over switch (COS) for inter-switch handoffs. One overlooked problem with COS based handoff schemes is the possible disjointed connection for a mobile-to-mobile communication. Although one may argue that this may occur only occasionally, it does present a serious design flaw and should be corrected. We propose a general approach and a permission based inter-switch handoff protocol for mobile-to-mobile connection in wireless ATM networks. The proposed approach/protocol takes advantages of the ATM PNNI hierarchical information to detect potentially “unsafe” handoffs. Analysis shows that our approach/protocol avoids disjointed connection for mobile-to-mobile connections while keeping the overhead low