A new generation of ultra wideband (UWB) communication transceivers are becoming available which support both positioning and communication tasks. Transceiver manufacturers envision that communication and positioning features are used separately. We believe that this is an unnecessary restriction of the available hardware and that positioning and communication tasks can be active concurrently. This paper presents and investigates a medium access control (MAC) protocol which combines communication and positioning functions. Our experiments show that the existing data communication of a network can be exploited to gather position information efficiently.