Robust and Soft: handover design for high-tier Mobile ATM systems

Mobile/Wireless ATM is a rapidly developing field of research and standardization. The ATM Forum’s Wireless ATM specification version 1.0 is expected to be released by the end of 1999. It will cover the issues of wireless access to the ATM network and the network signaling and control functions for basic support of mobile virtual circuit ATM connections. While at the moment, WATM system are envisaged for LAN or fixed wireless access solutions with very low or even no mobility requirements, research projects (like e.g. ACTS SAMBA) are under way to demonstrate the feasibility of future broadband radio access networks based on cellular ATM technology. These high-tier Mobile ATM systems will offer full-scale mobility paired with ATM service capabilities comparable to those of fixed ATM networks. In this paper, we present extensions to the TIHH-BR handover scheme based on in-slot signaling for supporting a broad range of handover classes in these future Mobile ATM systems. Handover classes include hard and soft, backward and forward, lossless and non lossless handover. These handover mechanisms can be flexibly chosen from, depending on radio conditions and QoS requirements, to enhance handover performance and robustness.