Dynamic user association and eICIC management in heterogeneous cellular networks

Abstract

In heterogeneous cellular networks, users are sometimes forcibly redirected into a low power base station (BS) for the purpose of data offloading. In order to guarantee an acceptable performance for such users, who suffer from severe inter-tier interference, enhanced inter-cell interference coordination (eICIC) was proposed. Using this technique, macro BSs periodically mute their data transmission by using an almost blank subframe (ABS). In this paper, we formulate a joint optimization problem incorporating user association and ABS portion tuning to increase network-wide utility. In the development of our algorithms, we particularly consider the time-varying characteristics of wireless propagation channels in order to reflect practical signal transmission environments, and we derive a throughput estimation equation that is compatible with the eICIC operation. Based on this analysis, we separately develop algorithms for user association and ABS tuning, and the performance enhancement achieved by our proposed methods is verified through extensive system-level simulations.