Wireless sensor networks (WSN) have received significant attention over the last few years as they afford a growing number of applications in various fields. At the same time, these networks provide numerous challenges due to their constraints, primarily related to energy scarcity. To overcome energy waste caused by collisions and contention based algorithm, the channel assignment mechanisms, like TDMA, seem to be an effective way for scheduling node transmissions. To solve channel assignment problems, graph coloring theory has been exploited in many research works, primarily in order to assure collision-free communications. In this paper, we present a novel distributed coloring algorithm for WSNs taking into account constraints of a real WSN environment. Our collision aware coloring algorithm assures a 2 hop nodes coloring, in a deterministic time execution, without requiring a neighborhood discovering phase. Performance evaluation results have shown the effectivness of our algorithm in terms of exchanged control packets per node as well as the number of colors used.