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 [1]. Since the femto cells are randomly deployed by consumers with closed access and X2 interface is not available [2], 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.