Call admission control in hierarchical cellular networks

Call admission control can significantly impact the performance of a cellular system by adding additional bandwidth to a wireless network. 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. The analysis assumed that the C/I (carrier to interference ratio) of the macrocells can be lowered as we migrate toward digital networks. Since analog macrocellular systems may still exist for some time to come, additional schemes are needed in order to apply the architecture and still maintain the same C/I performance of macrocells. We show how this is done using call admission control