Teletraffic performance of a hierarchical microcell/macrocell PCS architecture

In this work, teletraffic performance of a hierarchically overlaid microcel l and macrocell structure in a PCS environment is presented. In this system , each group of N microcells is overlaid exclusively by one macrocell. The microcell tier is dedicated to low-mobility users and tile macrocell tier i s dedicated to both hish-mobility users and overflowed low-mobility users f rom microcells. In general, forced termination is considerably undesirable from the user's viewpoint compared with the occurrence of call blocking. Th erefore. handoff calls are given access priority to channels at the macroce ll tier. As a priority scheme at the macrocell tier: a partial buffer shari ng (PBS) scheme is proposed. As performance measures, call blocking probabi lity, forced termination probability, and carried traffic are derived. Effe cts of the sizes of a macrocell and of hierarchical cell structure on syste m performance are discussed. The performance of the PBS scheme is also comp ared with those of the no priority scheme (NPS) and the first-come-first-se rvice (FCFS) queueing scheme. Numerical results show that the PBS scheme gi ves the best performance for handoff traffic among the three schemes.