Physical Cell Identity Assignment in Heterogeneous Networks

In order to meet the ever increasing demands for capacity in mobile networks, several technological solutions are being sought and one of them is heterogeneous networks. In heterogeneous networks, the pre-planned, relatively regular placed macro base stations are complemented with several low-powered base stations that might be deployed in a relatively unplanned fashion for both capacity and coverage enhancements. This can result in a large number of cells within a given area, making it difficult to assign non-conflicting cell identities from the limited number of available sets. In this paper, we analyze this problem in realistic deployment scenarios in a 3GPP LTE network that is enhanced with low power pico nodes. System level simulation results show that for deployment densities that can meet the anticipated traffic demands for up to 2020, the 504 cell identity limit in LTE is quite sufficient and cell identities can be reused efficiently among the pico nodes.