Through deploying additional low-power nodes (LPNs) under the coverage area of a macrocell, heterogeneous network (HetNet) or multi-layered network deployments could be critical for operators to boost system capacity (per unit area). In order to extent the coverage region of open access LPNs and hence offload more traffics from macrocells, cell range expansion (CRE) strategy is suggested to apply in HetNets. However, when macrocells and LPNs share the same spectrum, the total network throughput could actually decrease due to CRE if the inter-layer interference couldn't be effectively managed. In this paper, we propose an inter-layer interference coordination scheme on the downlink side for an OFDMA co-channel macro-pico HetNet that carries out CRE technique. The idea of the proposed method is to coordinate frequency and power resources among macrocells and picocells with a set of resource allocation rules. Simulation results show that the proposed method can bring a significant increase in overall system capacity as well as reduce the user outage rate in the system, especially when aggressive CRE is applied.