Multi-layer heterogeneous network layout including small cell base stations are considered to be the key to further enhancements of the spectral efficiency achieved in mobile communication networks. It has been recognized that inter-cell interference has become the limiting factor when trying to achieve not only high average user satisfaction, but a high degree of satisfaction for as many users as possible. Therefore, inter-cell interference coordination (ICIC) lies in the focus of researchers defining next generation mobile communication standards, such as LTE-A.
Building upon our previous white paper, this paper provides an overview over the background calling for ICIC in heterogeneous LTE-A networks. It outlines techniques standardized in Rel. 10 of LTE-A, discusses them showing their benefits and limitations by means of system-level simulations and motivates the importance of self optimizing network (SON) procedures for ICIC in LTE-A.