Call admission control in the microcell/macrocell overlaying system

Call admission control can significantly affect the performance of a cellular system by adding additional bandwidth to a wireless network. In this paper, we show how call admission control can be used to optimize the performance of a hierarchical cellular system. The hierarchical system we study is based on a novel frequency planning scheme, whereby both the micro and macro layers can share the same spectrum and a hard partition of the frequency spectrum is not needed. The original analysis of the hierarchical system showed that a significant capacity gain can be achieved by the scheme. However, this capacity is gained at the expense of the carrier-to-interference ratio (C/I) performance of the macrocells. In this paper, we show that call admission control can be used in hierarchical cellular systems to achieve a capacity gain without sacrificing the C/I performance of the macrocells