On the coverage and power allocation for downlink in heterogeneous wireless cellular networks

This paper investigates downlink performance of a heterogeneous wireless cellular network (HWCN) consisting of multi-tier cells operating within various indoor and outdoor propagation environment models. The coverage probability of the practical HWCN is derived using stochastic geometry modeling. The derived expressions not only characterise the effects of building infrastructures and transmission environment on the coverage region in practice but also enable us to propose an optimal power allocation at cells in different tiers. Specifically, a heuristic algorithm is developed for the power allocation at the tiered cells within various propagation models to minimise the total power consumption. The proposed scheme is shown to achieve a lower total power consumption saving up to 45% for a given target coverage probability of a specific region when compared to the equal power allocation technique.