Large Scale Cooperation In Cellular Networks With Non-Uniform User Distribution

In conventional wireless cellular networks, each user equipment (UE) is connected to one or a few local base stations (BS). However, the users' distribution in the network area is commonly fluctuating during a day. Especially, if a high density of small cell BSs is available, some user-dense areas or hotspots can be sensed by BSs. When there is some congeries of users in some area, conventional networks waste network resources in sparse areas. To address this issue, we propose a novel cell structuring and clustering to dynamically transfer network resources from sparse cells to crowded cells or hotspots. In our proposed scheme, optimal large cooperative clusters are formed around hotspots and the coverage of BSs are transferred to hotspots by dynamically changing the antennas' beam angles. In this study, a cluster is a group of BSs that cooperatively perform joint transmission (JT) to several UEs. The BSs for each cluster and the antennas' beam angles of each BS are optimized so that the system rate of the network is maximized. Simulation results using 3GPP specifications show that the proposed scheme attains several times higher capacity compared to conventional systems.