Joint deployment of macrocells and microcells over urban areas with spatially non-uniform traffic distributions

Abstract

For the efficient accommodation of exploding wireless users, many studies have been published but little concern has been taking in coping with the existing conditions of today``s large urban areas, which include spatial and temporal traffic distributions, geographical characteristics, user mobility patterns, different quality of service (QoS) requirements, and so on. This problem is caused by the simple system modeling and the analytical tractability. However, in order to obtain a useful knowledge about the deployment and operation of multi-tier cellular overlays, we must deal with the above conditions carefully. In this thesis, we provide an algorithmic approach for the joint deployment of macrocells and microcells over today``s large urban areas. We assume a macro-micro cellular overlay in which the radio frequency spectrum is divided orthogonally between layers and each layer uses a CDMA technique. First, we identify several issues related to the optimal design of macro-micro cellular overlays, taking into account the previous studies on multi-tier cellular overlays and cell planning strategies. Next, based on a novel characterization of spatial traffic distribution and user mobility, we propose an algorithm that determines a cost-effective set of macrocells and microcells. In order to evaluate the resulting macro-micro cellular overlays, we resort to carefully devised event-driven simulations. We inspect the resulting cell deployments in terms of the number of deployed cells, radio resource utilization, call blocking and dropping probabilities, etc. The numerical results by extensive event-driven simulations, show that the resulting macro-micro cellular overlays successfully cope with the existing conditions of today``s large urban areas, such as spatial and temporal traffic distributions and user mobility characteristics. Finally, we discuss the practical guidelines for designing macro-micro cellular overlays in the existing large urban areas.