Scheduling strategies for HetNets using eICIC

LTE Advanced (LTE-A) small cells (pico cells) allow a smart densification of an existing macro cellular network. They are a means to cope with increasing traffic demands. They cover hotspots and support users in areas with otherwise bad service coverage. As they are surrounded by macro cells with a much higher TX power, higher antenna gain, and a much lower path loss, they offer a high transmission capacity in a relatively small area. The main challenge of small cells embedded into a macro cellular network is to let more users profit from the additional bandwidth introduced into the network. Such a pico cell range expansion can be done based on a bias value, which forces mobiles to perform a handover into the pico cell, even if the received signal strength of the pico cell is comparatively low and, hence, in case of a co-channel deployment the mobile would have a very bad channel quality after the handover. Enhanced Intercell Interference Coordination (eICIC) has been introduced by 3GPP to solve this problem. LTE-A defines measurements to enable eICIC but does not define the scheduling strategy. In this paper we discuss different scheduling strategies for eICIC and analyze the downlink performance for different traffic load scenarios.