In this paper we propose the enhancement of routing metrics through a more complete view of the physical channel. Using cross-layer optimizations, we develop the distribution based expected transmission count (DBETX), which improves the performance of the network in the presence of varying channels. Through observations of the wireless link, nodes estimate how the wireless link behaves. The proposed metric exploits this estimation to increase routing efficiency. The proposed metric is shown to outperform the conventional ETX metric in the presence of fading. The improvement over ETX increases with the network density because connectivity increases and more routing options become available. Results show a reduction of up to 26% in the Average Number of Transmissions per link and an increase of up to 32% in the end-to-end availability.