An Approximation Algorithm for the Euclidean Bottleneck Steiner Tree Problem

Consider a wireless communication network with n stations, each station has a limited power so that it can only communicate with stations within a limited range, and suppose that, in order to make the network connected and due to budget limits, one is only allowed to put at most k new stations in given potential locations in this network. Clearly, one would like to select locations such that distance between stations as small as possible.