Power control is essential for uplink multi-user access of Long Term Evolution (LTE). It guarantees that the received uplink power is kept within reasonable dynamic range such that the weak signals from large distance users do not get lost due to limited resolution of the eNB's Analog-to-Digital Converter (ADC). Capacity optimization of the open loop power control (OLPC) parameter P0 is applicable cell-individually for Macro deployments but fails in combination with small cells using the same frequency carrier, i.e. in heterogeneous networks (HetNet). In this paper, we show that an autonomous cell-individual Self-Optimizing-Network (SON) algorithm using cell internal optimization criteria like power headroom (PHR) reports and receive power dynamic range to increase P0 leads to good performance in macro-only layout. However, for co-channel HetNet deployment with embedded pico cells the inter-cell interference among the layers must be taken into account by means of propagation information exchange. We present a novel enhanced HetNet SON approach for P0 optimization where P0 value for a pico is calculated based on network configuration and the path loss of the weak macro cell-edge User Equipments (UEs) L _max . The results show that approach can limit the P0 at safe level when pico cell could cause too much inter-cell interference to macro cell and on the other hand has higher limits when pico cell UEs are not interfering macro cell. This method offers a simple way to boost uplink capacity in macro and HetNet layouts while taking the uplink dynamic range and inter-cell interference into account.