Call admission control for non-geostationary orbit satellite networks and other capacity-varying networks

Many networks, such as non-geostationary orbit satellite (NGOS) networks an d networks providing multi-priority service using advance reservations, hav e capacities which vary over time for some or all types of calls carried on these networks. For connection-oriented networks, call admission control ( CAC) policies which only use current capacity information may lead to exces sive and intolerable dropping of admitted calls whenever the network capaci ty decreases. Thus novel CAC policies are required for these networks. We p resent the admission limit curve (ALC) and prove it is a constraint limitin g the conditions under which any causal CAC policy may admit calls and stil l meet call dropping guarantees on an individual call basis. The ALC also l eads to a lower bound on the call blocking performance achievable by any ca usal CAC policy which provides dropping guarantees to individual calls. Als o, we introduce a new CAC policy which uses knowledge of future capacity ch anges to provide dropping guarantees on an individual call basis and which achieves blocking performance close to the lower bound. Copyright (C) 2000 John Wiley & Sons, Ltd.