Analysis of Downlink Heterogeneous Cellular Networks with Frequency Division: A Stochastic Geometry Way

As cells are getting smaller, more random and chaotic in future heterogeneous cellular networks (HCNs), mitigating interference to enhance coverage performance has become one of the key challenges. To elucidate the coverage and throughput performance of downlink HCNs, a tractable framework with frequency division (FD) scenario is provided. Coverage probability and average cell throughput expressions are carried out to further understand how FD effects system performance with the stochastic geometry treatment. Furthermore, with some plausible assumptions, we derive the specific closed-form expressions in some special cases. Simulation results show that the coverage performance is effectively improved by using FD comparing with conventional frequency sharing (FS) scenario, which are firmly consistent with our theoretical derivation. The analytical results of the present work also demonstrate that although some throughput will be lost compared to FS, it is still acceptable since UEs could choose any tier which offers greatest performance under FD scenario, hence this work further provides mobile operators a guideline for resource allocation schemes in future chaotic multi-tier networks.