关键词：通信；认知无线电网络；协作通信；频谱感知
摘 要：In this scheme,the spectrum sensing slot is divided into four equal sub-slots.In the first and third sub-slots,the SS and SRs detect the PU by themselves.Then,in the second sub-slot,if the SRs that detect the PU during the first sub-slot are more than or equal to a prespecified quantity,the corresponding SRs will send their flag signals (FSs) to the SS while the others keep quiet,where the FS is narrowband and indicates that the PU is present.Otherwise,if the SRs that detect the PU during the first sub-slot are less than the prespecified quantity,all the SRs will keep quiet in the second sub-slot.Meanwhile,the SS detects the PU based on the received signals from the PU and SRs.And,the SS uses the same method as employed in the second sub-slot to detect the PU in the last sub-slot wherein the SRs send their FSs based on their detections made during the third sub-slot.Finally,an ultimate decision is made by the OR ruler based on the SS detection results obtained during the spectrum sensing slot. In the end,simulation and numerical results show that our proposed scheme can achieve better performance than the non-cooperative method and an existing cooperative spectrum sensing method.