コダニティブ無線は周波数資源の枯渴問題に対する解決法として有望である.コグニティブ無線で必要とされる電波の利用状況監視には，広い帯域で様々な電界強度の信号を同時にかつ正確に検出できるスぺクトル検出器が必要であり，これらを高いレベルで満足するために二段階検出方式が提案されている.しカゝし，スぺクトル検出器の非線形性および量子化雑音による誤検出が生じる事でダイナミックレンジが狭く制限されてしまう.本稿では，誤検出率を十分に抑えられるダイナミックレンジを計算機シミュレーションにより評価する.また，このダイナミックレンジにおける二段階検出方式の空きスぺクトル検出成功確率および検出時間を計算機シミュレーションによる定量的に評価する.その結果，二段階検出方式は，誤検出率を十分に抑えられる最小のダイナミックレンジにおいても，十分高い空きスぺクトル検出成功率を保持しつつ，検出時間の短縮が可能であることがわかり，二段階検出方式の有用性が示される.%Cognitive radio is considered as the highly promising solution to the shortage problem of the frequency resource. A spectrum detector that can detect signals of a variety of electric field strength at the same time is necessary to observe whether the specified frequency spectrum is occupied by the other system or vacant. The two-stage detecting method is proposed for these requirements. But, because of error detection by a detector having non-lineriy and quantization noise, a dynamic range is limited. In this report, we evaluate that a dynamic range can have low error detection probability by the computer simulation. In addition, with this dynamic range, the success probability of detecting the vacant frequency spectrum and the detection time of it of the two-stage detecting method are evaluated by computer simulation. As a result, the computer simulation result shows two-stage detecting method can achieve the high successful probability of detecting vacant frequency spectrum as well as the short detection time. Therefore, the proposed two-stage detection method can be expected to establish the super high speed spectrum detection in cognitive radio.
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