Preliminary experimental results on the spectrum sensing performances for UWB-Cognitive Radios for detecting IEEE 802.11n systems

In this paper we present the spectrum sensing performance for detecting the IEEE 802.11n Wi-Fi terminals for ultrawideband (UWB) based cognitive radio (CR) systems. The 802.11 n WiFi system lies in the 5 GHz un-licensed frequency band and is subjected to interferences from the UWB transmissions. The UWB based CR terminals perform secondary communications by opportunistically utilizing the available spectrum when no legacy users such as the 802.11n WiFi systems are present in the environment. Therefore, the CR nodes need to sense the spectrum to detect the presence of any legacy users in the surroundings. Here, we study the commonly known spectrum sensing technique, the energy based method, on experimentally obtained signal data for the IEEE 802.11n WiFi system, and analyze the detection performances for detecting the legacy user. We present the time-frequency measurements obtained from the experimental data, and also compute the probabilities of missed detection and false alarm for detecting the legacy user by performing post analysis on the experimental data. The results can then be used to determine the detection threshold based on the required detection criteria.