@article{zaim_perros_rouskas_2003, title={Computing call-blocking probabilities in leo satellite constellations}, volume={52}, ISSN={0018-9545}, url={http://dx.doi.org/10.1109/tvt.2003.811219}, DOI={10.1109/TVT.2003.811219}, abstractNote={We present an analytical model for computing call-blocking probabilities in a low Earth orbit (LEO) satellite network that carries voice calls. Both satellite-fixed and Earth-fixed constellations with interorbit links and handoffs are considered. We assume a single beam per satellite. Also, we assume that call arrivals are Poisson with a fixed arrival rate that is independent of the geographic area. The model is analyzed approximately by decomposing it into subsystems. Each subsystem is solved in isolation exactly using a Markov process and the individual results are combined together through an iterative method. Numerical results demonstrate that our method is accurate for a wide range of traffic patterns. We also derive an upper and lower bound for the link-blocking probabilities that can be computed efficiently. These bounds can be used for constellations of realistic size where each satellite has multiple beams.}, number={3}, journal={IEEE Transactions on Vehicular Technology}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Zaim, A.H. and Perros, H.G. and Rouskas, G.N.}, year={2003}, month={May}, pages={622–636} }
 @article{zaim_rouskas_perros_2002, title={Computing call-blocking probabilities in LEO satellite networks: The single-orbit case}, volume={51}, ISSN={["1939-9359"]}, DOI={10.1109/25.994809}, abstractNote={We study the problem of carrying voice calls over a low-Earth-orbit satellite network and present an analytical model for computing call-blocking probabilities for a single orbit of a satellite constellation. We have devised a method to solve the corresponding Markov process efficiently for orbits of up to five satellites. For orbits consisting of a larger number of satellites, we have developed an approximate decomposition algorithm to compute the call-blocking probabilities by decomposing the system into smaller subsystems and iteratively solving each subsystem in isolation using the exact Markov process. Our approach can capture blocking due to handoffs for both satellite-fixed and Earth-fixed constellations. Numerical results demonstrate that our method is accurate for a wide range of traffic patterns and for orbits with a number of satellites that is representative of commercial satellite systems.}, number={2}, journal={IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY}, author={Zaim, AH and Rouskas, GN and Perros, HG}, year={2002}, month={Mar}, pages={332–347} }