Title: power assignment problem in wireless networks. Abstract. Assigning power levels (corresponding to transmission ranges) to the transceivers of a radio network, such that the total power consumption is as low as possible, is often an extremely important issue. Let $\P$ be a set of $n$ points in the plane, representing $n$ transceivers. We need to assign transmission ranges to the transceivers in $\P$, so that (i) the resulting communication graph is strongly connected; that is, the graph over $\P$ in which there exists a directed edge from $p$ to $q$ if and only if $q$ lies within the transmission range $r_p$ assigned to $p$, should contain a directed path from any transceivers $p \in \P$ to any other transceiver $q \in \P$, and (ii) the total power consumption (i.e., the cost of the assignment of ranges) is minimized, where the total power consumption is a function of the form $\sum_{p \in \P} r_p^{\alpha}$, where $r_p$ is the range assigned to transceiver $p$ and $\alpha > 0$ is a constant typically between 2 and 5. The talk will be focus in three topics of the power assignment: 1. The case where only two power levels are available. 2. A new cost measure, namely, minimum area. 3. Finally, The power assignment with fault-tolerance problem.