In cognitive relay networks, the transmission of Secondary Users （SUs） suffers from the activity of Primary Users （PUs） and wireless channel fading. Therefore, how to achieve robust transmission for cognitive rela...In cognitive relay networks, the transmission of Secondary Users （SUs） suffers from the activity of Primary Users （PUs） and wireless channel fading. Therefore, how to achieve robust transmission for cognitive relay networks is a challenging task. In this paper, we propose a relaying transmission scheme which exploits robust beamforming at the physical layer and rateless codes at higher layers. We derive the optirml beamforng weight vector and analyze the perforrmnce of the pro- posed scheme when the channel estirmtion is not accurate between two SU nodes. We also study how the anaount of channel information between SU and PU impacts the system perforroance. Sinlation results validate our theoretical analysis and demonstrate that the proposed scheme can signifi- cantly enhance the system throughput.展开更多
基金Acknowledgements The authors would like to thank the editor and anonymous reviewers for their detailed reviews and constructive comments, which have helped to greatly improve the quality of this paper. This work was supported by the National Natural Science Foundation of China under Grants No. 60832008, No. 60902001 Beijing Natural Science Foundation Program and Scientific Research Key Program of Beijing Municipal Commission of Education under Grant No. KZ201010009009 the Tsinghua National Laboratory for Infomation Science and Technology （TNList） Cross-discipline Foundation.
文摘In cognitive relay networks, the transmission of Secondary Users （SUs） suffers from the activity of Primary Users （PUs） and wireless channel fading. Therefore, how to achieve robust transmission for cognitive relay networks is a challenging task. In this paper, we propose a relaying transmission scheme which exploits robust beamforming at the physical layer and rateless codes at higher layers. We derive the optirml beamforng weight vector and analyze the perforrmnce of the pro- posed scheme when the channel estirmtion is not accurate between two SU nodes. We also study how the anaount of channel information between SU and PU impacts the system perforroance. Sinlation results validate our theoretical analysis and demonstrate that the proposed scheme can signifi- cantly enhance the system throughput.
