This paper presents a simulation platform that exploits the scalability properties of network simulator-2 (ns-2) for the discrete-event simulation of a telecommunication network, and adopts the open source tool Octave for the discrete-time implementation of adaptive antenna arrays. The physical antenna system, the beamforming algorithm, and the multipath statistic are modeled in detail to accurately estimate the Signal to Interference Ratio (SIR) at each receiving node. This study describes the methods that can be used to interface Octave with ns-2 and compares the developed solution to an existing one, based on the proprietary tool MATLAB, discussing the advantages and disadvantages that characterize the two platforms.