Identifying MIMO wireless devices based on radiometric signatures

Maximum performance in networks of cognitive radios requires careful coordination among the nodes desiring spectrum access. One part of this coordination that is becoming increasingly important is the authentication of nodes requesting network access. Prior work on this topic has shown that unique imperfections in the waveform transmitted by a device, referred to as radiometric features, can be used to identify devices with relatively high accuracy. This paper experimentally quantifies the authentication accuracy improvements achieved when applying such techniques to multiple-input multiple-output systems. It further studies an information theoretic technique for determining which radiometric features are most effective in discriminating different devices.