Detection of multiple primary systems using DAA UWB-IRs

Underlay ultra wideband (UWB) systems have to be able to detect the presence of primary systems operating in the same band for detect-and-avoid (DAA) operation. In this paper, the performances of joint and independent detection of multiple primary systems are investigated assuming that the primary systems are potentially dependent (e.g., frequency division duplex uplink-downlink communications). Joint detection is performed based on generating the maximum a posteriori (MAP) decision variables at the receiver, where some bias terms are used with these variables in order to achieve a desired trade-off between the detection and false alarm probabilities. Independent detection is performed based on the Neyman-Pearson (NP) test, which optimizes system threshold values individually in order to achieve the best detection probability for a given false alarm probability value. When the two detection schemes are compared, it is shown that the gain of joint detection depends on the joint system activity values and the considered receiver operating characteristic (ROC) region, where the complementary ROC curves illustrate the trade-off between missdetection and false alarm probabilities.