ATM connection handover in LEO satellite networks

There is interest in providing global communications service by using a Low Earth Orbit (LEO) satellite network, resulting in many proposals, the most ambitious of which is Teledesic, and the commercial implementation of constellations including Iridium and Globalstar. Many proposals intend to use ATM or an ATM-like switch fabric, and may also use ATM signaling. LEO satellite networks are mobile with respect to a fixed point on the earth, and therefore require an efficient ATM handover mechanism to provide continuous network connectivity. The Wireless ATM working group of the ATM Forum is standardising wireless extensions to ATM, of which connection handover is a major component. We identify weaknesses in the ATM Forum handover procedure when applied to LEO satellite networks, resulting in degradation of quality of service (QoS) during handover. We also propose a handover procedure, based on the handover framework established by the ATM Forum, which addresses these weaknesses and minimises the QoS degradation during handover.