Since the QKD network can overcome the distance limitation and expand the point-to-point QKD system to a multi-user key distribution system, some testing QKD networks have been built. However, all of this previous res...Since the QKD network can overcome the distance limitation and expand the point-to-point QKD system to a multi-user key distribution system, some testing QKD networks have been built. However, all of this previous research seldom focused on the routing mechanism of QKD network in detail. Therefore, this paper focuses on the routing issue in trust relaying QKD network, builds a model of the trust relaying QKD network and proposes a secret-key-aware routing method. In our method, a dynamic model for the residual local key is proposed to forecast the residual local key quantity of each QKD link more accurately, and the cost of QKD link and relaying path are defined by multiple affecting factors, e.g. the generation, consumption rate and the local key depletion index. The proposed method is implemented and evaluated in a simulation environment. The simulation results show that our routing method can increase the success rate of key exchange, make all the QKD links participate key exchange with almost equal opportunity to achieve load balance, and trade off the local key generation and consumption of each QKD link. Therefore, our proposed method can contribute to effectively improve the holistic performance of the trust relaying QKD network.展开更多
Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Vi...Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent detection.Simulation results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.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
文摘Since the QKD network can overcome the distance limitation and expand the point-to-point QKD system to a multi-user key distribution system, some testing QKD networks have been built. However, all of this previous research seldom focused on the routing mechanism of QKD network in detail. Therefore, this paper focuses on the routing issue in trust relaying QKD network, builds a model of the trust relaying QKD network and proposes a secret-key-aware routing method. In our method, a dynamic model for the residual local key is proposed to forecast the residual local key quantity of each QKD link more accurately, and the cost of QKD link and relaying path are defined by multiple affecting factors, e.g. the generation, consumption rate and the local key depletion index. The proposed method is implemented and evaluated in a simulation environment. The simulation results show that our routing method can increase the success rate of key exchange, make all the QKD links participate key exchange with almost equal opportunity to achieve load balance, and trade off the local key generation and consumption of each QKD link. Therefore, our proposed method can contribute to effectively improve the holistic performance of the trust relaying QKD network.
基金supported by the National Natural Science Foundation of China(61302095,61401165)the Natural Science Foundation of Fujian Province of China(2014J01243,2014J05076,2015J01262)the Huaqiao University Science Foundation(13Y0384)
文摘Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent detection.Simulation results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.
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.