An integrated space/terrestrial cellular architecture with different priority schemes for global mobile communications

A multiple hierarchical cellular structure is proposed to handle the teletraffic load resulting from different user densities. In the lowest hierarchical level, microcells serve the highest teletraffic density, while overlaying macrocells serve both calls from areas that are difficult to be covered by microcells, as well as overflow traffic from microcells. At the highest hierarchical level, nongeostationary satellites focus their spotbeams to serve satellite-only users sparsely distributed and act as teletraffic relief for the terrestrial segment. At each hierarchical level different priority schemes are used to privilege handoff requests. A reserved channel scheme (RCS) is applied in the microcell layer, both RCS and a sub-rating scheme (SRS) are used in the macrocell layer, while in the spotbeam cell layer, RCS, SRS, and a queuing priority scheme (QPS) are implemented. An analytical teletraffic model is developed to evaluate the proposed architecture. Numerical results are presented and discussed for the new call blocking, handoff failure, forced termination and noncompletion probabilities.