Dual-Observation Time-Division Spectrum Sensing for Cognitive Radios

The hidden terminal problem of spectrum sensing in dynamic spectrum access is traditionally alleviated by cooperative sensing using multiple cognitive radio (CR) sensors. In this paper, we resolve the hidden terminal problem in spectrum sensing for CRs by a single sensor by applying a unified decision based on heterogeneous information, which enables decisions from multiple heterogeneous observations. Dual-observation time-division (DTD) spectrum sensing is proposed to identify spectrum opportunities for CRs by achieving sensing diversity through a single sensor. The sensor in DTD spectrum sensing simultaneously detects the primary transmitter´s data transmission and primary receiver´s feedback message transmission; thus, DTD spectrum sensing equivalently implements receiving diversity by creating multiple kinds of observations solely from a single terminal/sensor. Performance analysis and simulation results show that DTD spectrum sensing can achieve and transcend the performance of cooperative spectrum sensing, even with a single sensing node. Moreover, DTD spectrum sensing is shown to be robust without sufficient knowledge about the primary system in practical CR operating scenarios.