Performance Evaluation & SON Aspects of Vertical Sectorisation in a Realistic LTE Network Environment

The advent of Active Antenna Systems has provided new ways and features for increasing the capacity of mobile networks in order to cope with the ever increasing traffic demand. One such feature is the vertical sectorisation (VS) technique where a cell is divided into an inner and an outer sector by using a second downtilted beam from one antenna. The two sectors use the same spectrum resources but share the electrical power available. The limitation in available power per sector, raises the question whether there is gain in using VS, and if so, how much and under which circumstances. This paper presents some new numerical results on the performance gains of VS in a realistic LTE network environment, especially for the case of independent activation of the feature across cells in the network. We also present a framework for the design of a SON controller enabling the smart (de) activation of the feature based on the estimated/observed traffic distribution. The controller design follows two steps: first the functional form of the controller is derived based on analytical modelling, and then this functional form is calibrated using realistic measurements in a statistical learning fashion.