Fig. 17

Interference ratio according to E[on] ratio. Compares the actual interference ratio according to the ratio of E[on] with the proposed method and the general sensing optimization method. If the sensing and transmission intervals are alternating, there is no way to recognize the PU during data transmission. Therefore, even if the idle is detected in the sensing interval, the interference ratio is high because the PU occurs in the data transmission interval. As the E[on] increases, the probability of the PU of the sensing interval continuing to the data transmission interval is high and the interference ratio decreases. Both proposed methods considerably lower the interference ratio than the conventional method, and the second method shows a lower interference ratio because the data transmission is immediately stopped using the narrow band as soon as the PU is detected