System level performance evaluation of inter-cell interference coordination schemes for heterogeneous networks in LTE-A system

3GPP has recently approved a new work item for LTE-A to support enhanced inter-cell interference coordination (eICIC) for co-channel deployments of heterogeneous networks. The main focus is on the coordination of control and data channel interference between macro and low power nodes, e.g., relay, pico, and femto. Since the femto cells are randomly deployed by consumers with closed access and X2 interface is not available, the femto cell may introduce some excessive interference to the macro cell on the downlink and/or the uplink. In this paper, we aim to clarify the ICIC triggering event to protect a victim user equipment (UE) in the vicinity of an aggressive femto cell and evaluate macro/femto system level performance to show the severity of the downlink dead-zone problem and the benefits of dynamic/static ICIC schemes based on time/frequency silencing.