Analysis of a hierarchical cellular system with reneging anddropping for waiting new and handoff calls

摘要

We analyze a hierarchical cellular system with finite queues fornnew and handoff calls. Both the effect of the reneging of waiting newncalls because of the callers' impatience and the effect of the droppingnof queued handoff calls as the callers move out of the handoff area arenconsidered, besides the effect of the guard channel scheme. Wensuccessfully solve the system by adopting the multidimensional Markoviannchain and using the transition-probability matrix and the signal-flowngraph to obtain the average new-call blocking probability, the forcedntermination probability, and the average waiting time of queued new andnhandoff calls. We further investigate how the design parameters of thenbuffer sizes and guard channel numbers in macrocell and microcellsnaffect the performance of the hierarchical cellular system. The resultsnshow that provision of a buffering scheme and guard channel scheme canneffectively reduce the new call blocking probability and the forcedntermination probability in the hierarchical cellular system, and theneffectiveness is more significant in the macrocell than in thenmicrocells