Computing Call Dropping and Waiting Probabilities in LEO Satellite Systems for Voice Communications

摘要

In this paper we propose and analyze a call management architecture for a cell in a satellite cellular network, where handoff arrivals are prioritized by using a number of guard channels and only new calls are temporarily buffered if necessary. The idea behind this is to avoid any extra delay during handoff procedures, in addition to the intrinsic round trip propagation time, since it might cause severe user dissatisfaction. The analysis is based on a Markov chain model of a single spot (cell) and yields exact expressions for the dropping and waiting probabilities of handoff and new arrivals respectively. Then, we derive an efficient algorithm to evaluate these probabilities, which is based on the well-known Erlang-B formula and its recursion. Finally, we use the expressions for the waiting and dropping probabilities to formulate and solve an optimization problem in the context of network planning. Numerical results are provided.