A Cognitive radio communication link is possible to be interrupted easily when its physical channel suffers severe fading. Relay technology is an effective way to mitigate the fading effect of wireless channels in a n...A Cognitive radio communication link is possible to be interrupted easily when its physical channel suffers severe fading. Relay technology is an effective way to mitigate the fading effect of wireless channels in a network. Based on the highest achievable rate of the relay channels, this paper considers a cognitive radio relay network where the secondary transmitter communicates with the receiver through the best relay node under the peak power constraint of a primary receiver. Intuitively, the secondary transmission can benefit from an intermediate relay node chosen from N possible nodes. To quantify this benefit, outage probability of cognitive radio relay networks is derived and also the closed-form expressions for outage capacity and ergodic capacity of cognitive radio relay networks are obtained in Rayleigh fading channels. Numerical simulation results are provided to show that the outage capacity and ergodic capacity benefit tremendously by properly increasing the number of relaying nodes.展开更多
Abstract： This paper focuses on the first-or- der and second-order performance of dual-hop underlay cognitive radio systems with oppor- tunistic relaying （UCR-OR） over indepen- dent and non-identically distributed ...Abstract： This paper focuses on the first-or- der and second-order performance of dual-hop underlay cognitive radio systems with oppor- tunistic relaying （UCR-OR） over indepen- dent and non-identically distributed （i.ni.d） Rayleigh fading channels. For the UCR-OR systems, the tolerable maximum interference power （TMIP） Q at primary users （PUs） and the allowable maximum transmission power limit （AMTP） P at secondary users （SUs） are considered, simultaneously. We first obtain the closed-form solutions to the first-order performance such as outage probability, ave- rage symbol error ratio （SER）, and ergodic capacity （EC）. Secondly, we investigate the second-order statistical performance, i.e., ave- rage outage rate （AOR） and average outage duration （AOD）. With the consideration that in practice implementation the receiver perfor- mance is primarily influenced by the signal- to-noise ratio （SNR） （not the signal envelope）, the second-order statistical performance is investigated based on the equivalent instan- taneous end-to-end SNR. Finally, we present the detailed performance comparison analysis of UCR-OR systems by defining a random variable ,μ=Pmax/Q. The results show that the effect of μ on the first-order and second-or- der performances is different greatly. For the first-order performance, the perlbrmance gap is negligible when the value of// is relatively large. However, for the second-order one, the gap is distinct.展开更多
In this paper,we propose a securityoriented transmission scheme with the help of multiple relays in Cognitive Radio(CR).To maximise the Secrecy Capacity(SC)of the source-destination link in CR,both beamforming and coo...In this paper,we propose a securityoriented transmission scheme with the help of multiple relays in Cognitive Radio(CR).To maximise the Secrecy Capacity(SC)of the source-destination link in CR,both beamforming and cooperative jamming technologies are used to improve the performance of the Secondary User(SU)and protect the Primary User(PU).The effectiveness of the proposed scheme is demonstrated using extensive simulation.Both theoretical analyses and simulation results reveal that the proposed scheme contributes to the secure transmission of the SU with acceptable attenuation of the Signal-to-Noise Ratio(SNR)at the PU receiver,and the upper bound of the SC at the SU receiver is able to exploit the power allocation strategy.展开更多
文摘A Cognitive radio communication link is possible to be interrupted easily when its physical channel suffers severe fading. Relay technology is an effective way to mitigate the fading effect of wireless channels in a network. Based on the highest achievable rate of the relay channels, this paper considers a cognitive radio relay network where the secondary transmitter communicates with the receiver through the best relay node under the peak power constraint of a primary receiver. Intuitively, the secondary transmission can benefit from an intermediate relay node chosen from N possible nodes. To quantify this benefit, outage probability of cognitive radio relay networks is derived and also the closed-form expressions for outage capacity and ergodic capacity of cognitive radio relay networks are obtained in Rayleigh fading channels. Numerical simulation results are provided to show that the outage capacity and ergodic capacity benefit tremendously by properly increasing the number of relaying nodes.
基金supported by the Natural ScienceFoundation of China under Grant 61261015the 973 project 2013CB329104+3 种基金the Natural Science Foundation of China under Grant61372124,61363059,and 61302100the projects BK2011027the Natural Science Foundation of Gansu Province for Distinguished Young Scholars(1308RJDA007)the Foundation Research Funds for the University of Gansu Province:'Massive MIMO channels modeling and estimation over millimeter wave band for 5G'
文摘Abstract： This paper focuses on the first-or- der and second-order performance of dual-hop underlay cognitive radio systems with oppor- tunistic relaying （UCR-OR） over indepen- dent and non-identically distributed （i.ni.d） Rayleigh fading channels. For the UCR-OR systems, the tolerable maximum interference power （TMIP） Q at primary users （PUs） and the allowable maximum transmission power limit （AMTP） P at secondary users （SUs） are considered, simultaneously. We first obtain the closed-form solutions to the first-order performance such as outage probability, ave- rage symbol error ratio （SER）, and ergodic capacity （EC）. Secondly, we investigate the second-order statistical performance, i.e., ave- rage outage rate （AOR） and average outage duration （AOD）. With the consideration that in practice implementation the receiver perfor- mance is primarily influenced by the signal- to-noise ratio （SNR） （not the signal envelope）, the second-order statistical performance is investigated based on the equivalent instan- taneous end-to-end SNR. Finally, we present the detailed performance comparison analysis of UCR-OR systems by defining a random variable ,μ=Pmax/Q. The results show that the effect of μ on the first-order and second-or- der performances is different greatly. For the first-order performance, the perlbrmance gap is negligible when the value of// is relatively large. However, for the second-order one, the gap is distinct.
基金supported by the National Natural Science Foundation of China under Grants No. 61201150, No. 61171097the Fundamental Research Funds for the Central Universities of BUPT under Grant No. 2013RC0202the State Major Science and Technology Special Projects under Grant No. 2012ZX03004001
文摘In this paper,we propose a securityoriented transmission scheme with the help of multiple relays in Cognitive Radio(CR).To maximise the Secrecy Capacity(SC)of the source-destination link in CR,both beamforming and cooperative jamming technologies are used to improve the performance of the Secondary User(SU)and protect the Primary User(PU).The effectiveness of the proposed scheme is demonstrated using extensive simulation.Both theoretical analyses and simulation results reveal that the proposed scheme contributes to the secure transmission of the SU with acceptable attenuation of the Signal-to-Noise Ratio(SNR)at the PU receiver,and the upper bound of the SC at the SU receiver is able to exploit the power allocation strategy.
