Elevation angle dependent Markov model for LEO satellite communication systems

Most low Earth orbit (LEO) satellite communication systems provide multiple satellite visibility in order to reduce call dropping due to the shadowing effect. When a satellite communicating with a mobile terminal (MT) is shadowed or when the coverage area of a satellite moves out of range of an MT, a handoff occurs. The handoff problem of LEO satellite communication systems is analyzed. The shadowing process of each satellite is modeled as an elevation angle dependent two-state continuous time Markov model. The probability distribution of multiple satellite visibility, which is used in the analysis, is also analytically obtained. The performance of the proposed model is evaluated in terms of the call blocking probability and the average number of handoffs during a call.