  We consider a topology control problem in which we are given a set of $n$
sensors in the plane and we would like to assign a communication radius to each
of them. The radii assignment must generate a strongly connected network and
have low receiver-based interference (i.e., we minimize the largest in-degree
of the network). We give an algorithm that generates a network with $O(\log
\Delta)$ interference, where $\Delta$ is the interference of a uniform-radius
ad-hoc network. We then adapt the construction to the case in which no sensor
can have a communication radius larger than $R_{\min}$, the minimum value
needed to obtain connectivity. We also show that $\log \Delta$ interference is
needed for some instances, making our algorithms asymptotically optimal.
