Two-Step Channel Observation Scheme Considering Spread of Observation Results in Dynamic Spectrum Sharing

Dynamic Spectrum Sharing (DSS), in which multiple wireless systems share the same radio resource, has been studied to improve frequency utilization efficiency. In DSS, the channel occupation ratio (COR), the usage of radio resources (channels) used by other wireless systems, is measured. The wireless system dynamically selects the channel with the lowest COR for communication. A long observation time is required to measure the COR with high accuracy. However, as the number of observed channels increases, the observation time per channel becomes shorter. Since the shorter observation time, the degradation of the accuracy of observed COR is a problem. This paper proposes a two-step channel observation scheme considering the spread of observed results. In the first observation, the proposed scheme measures all channels and excludes channels with high COR, considering the spread due to the error in the observed results. Only remaining channels are observed in the second observation, so the observation time can be relatively long. Computer simulation results show that the proposed scheme with 200 ms or more of first observation can improve communication reliability compared to the conventional scheme.