network Coding (NC) is an effective technology to enhance the cooperative system spectral efficiency. However, since it is network-oriented, the existing performance metric of single-user outage can not comprehensivel...
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network Coding (NC) is an effective technology to enhance the cooperative system spectral efficiency. However, since it is network-oriented, the existing performance metric of single-user outage can not comprehensively evaluate its gain and the impact to the entire network, which affect the user fairness. This paper proposes two novel user fair-based adaptive relay power allocation algorithms in single-relay NC cooperative multiple access channels. Firstly, common outage probability is employed as the performance metric, and to minimize it, a specific condition is deduced. On this basis, the instantaneous channel information-based adaptive relay power allocation scheme and the channel statistic information-based one with lower complexity are designed respectively, which make users' signals superimposed at accurately calculated proportion to maintain fairness. Simulation results show that compared with other existing schemes, the proposed schemes can best maintain user fairness, and effectively improve the common outage performance of the whole system, at the expense of small spectral efficiency.
Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is propos...
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Error propagation seriously degenerate the diversity order of Decode-and-Forward (DF) cooperative communication. To address this problem, a novel Log Likelihood Ratio (LLR)-based Link Adaptive Relaying (LAR) is proposed to promote adaption accuracy at relay. The instantaneous Bit Error Probability (BEP) is calculated according to the LLR of the received signals firstly, then based on it, the equivalent Signal-to-Noise Ratio (SNR) is employed to operate dynamic power scaling by relay. It is theoretically proved that the full diversity order can be attained by the scheme. Besides, the power sensitivity is also analyzed. Simulation results show that the proposed scheme outperform the conventional LAR and can achieve full diversity order. Moreover, its strong adaptation to SNR fluctuation is validated.
Quantum key distribution(QKD) allows two legitimate parties, Alice and Bob, to share a series of random bits that are secured by the laws of quantum mechanics. As a remarkable theoretical progress towards longer dista...
Quantum key distribution(QKD) allows two legitimate parties, Alice and Bob, to share a series of random bits that are secured by the laws of quantum mechanics. As a remarkable theoretical progress towards longer distances, the proposal of twin-field QKD(TF-QKD) [1] shows the capability to break a repeaterless bound and provides a key rate in the square-root scale of channel transmittance(i.e.,
Reference-frame-independent quantum key distribution(RFI-QKD)has been proven to be very useful and practical under realistic ***,we present a scheme for one-decoy state RFI-QKD based on the work of Rusca et al.[***.11...
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Reference-frame-independent quantum key distribution(RFI-QKD)has been proven to be very useful and practical under realistic ***,we present a scheme for one-decoy state RFI-QKD based on the work of Rusca et al.[***.112,171104(2018)],and carry out investigation on its performance under realistic experimental *** simulation results show that the one-decoy state RFI-QKD can achieve comparable performance in terms of secret key rate and transmission distance as the two-decoy state correspondence under practical experimental *** contrast,it does not need to prepare the vacuum state in the former case,substantially reducing the experimental complexity and random number ***,our present proposal seems very promising in practical implementations of RFI-QKD.
We present an efficient entanglement concentration protocol（ECP） for the less-entangled W state with some identical conventional polarized single *** the protocol,two of the parties say Alice and Charlie should perf...
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We present an efficient entanglement concentration protocol（ECP） for the less-entangled W state with some identical conventional polarized single *** the protocol,two of the parties say Alice and Charlie should perform the parity check measurements and they can ultimately obtain the maximally entangled W state with a certain success ***,they can obtain another less-entangled W state,which can be reconcentrated into the maximally entangled W *** iterating this ECP,a high success probability can be *** ECP may be an optimal one and it is useful in current quantum information processing.
A Gray code based gradient-free optimization(GCO)algorithm is proposed to update the parameters of parameterized quantum circuits(PQCs)in this *** parameter of PQCs is encoded as a binary string,named as a gene,and a ...
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A Gray code based gradient-free optimization(GCO)algorithm is proposed to update the parameters of parameterized quantum circuits(PQCs)in this *** parameter of PQCs is encoded as a binary string,named as a gene,and a genetic-based method is adopted to select the *** individuals in the offspring are decoded in Gray code way to keep Hamming distance,and then are evaluated to obtain the best one with the lowest cost value in each *** algorithm is performed iteratively for all parameters one by one until the cost value satisfies the stop condition or the number of iterations is *** GCO algorithm is demonstrated for classification tasks in Iris and MNIST datasets,and their performance are compared by those with the Bayesian optimization algorithm and binary code based optimization *** simulation results show that the GCO algorithm can reach high accuracies steadily for quantum classification ***,the GCO algorithm has a robust performance in the noise environment.
Entanglement purification is to distill the high quality entanglement from the low quality entanglement with local operations and classical communications. It is one of the key technologies in long-distance quantum co...
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Entanglement purification is to distill the high quality entanglement from the low quality entanglement with local operations and classical communications. It is one of the key technologies in long-distance quantum communication. We discuss an entanglement purification protocol（EPP） with spontaneous parametric down conversion（SPDC） sources, in contrast to previous EPP with multi-copy mixed states, which requires ideal entanglement sources. We show that the SPDC source is not an obstacle for purification, but can benefit the fidelity of the purified mixed state. This EPP works for linear optics and is feasible in current experiment technology.
作者：
Li, QunXu, DIngMinistry of Education
Nanjing University of Posts and Telecommunications Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing China
We consider a three-node multicarrier network consisting of a source node, a wireless powered full-duplex destination node, and an eavesdropper. The destination node is assumed to adopt the power splitting technique t...
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This paper considers a cognitive wireless powered communicationnetwork (CWPCN) consisting of a cognitive base station (CBS) and a set of secondary users (SUs) sharing spectrum with a primary user (PU). The transmissi...
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作者：
Chun-Hui ZhangChun-Mei ZhangQin WangInstitute of Signal Processing Transmission
Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Lab of Broadband Wireless Communication and Sensor Network TechnologyNanjing University of Posts and TelecommunicationsMinistry of EducationNanjing 210003China
Statistical fluctuations are unavoidable in realistic quantum key distribution (QKD) due to finite-size effect. Based on the four-intensity proposal on measurement-device-independent QKD (MDI-QKD) in [Phys. Rev. A93 (...
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Statistical fluctuations are unavoidable in realistic quantum key distribution (QKD) due to finite-size effect. Based on the four-intensity proposal on measurement-device-independent QKD (MDI-QKD) in [Phys. Rev. A93 (2016) 042324], we particularly analyze the scenario that only three intensities are used, namely a three-intensity decoy-state MDI-QKD with biased basis choice. After performing full parameter optimization method, simulations results demonstrate that this scenario can obtain distinct enhancement compared with the conventional unbiased threeintensity decoy-state method, e.g. Xu et al.’s [Phys. Rev. A 89 (2014) 052333]. Furthermore, results also show that it works more efficiently by using HSPS than using WCS at longer transmission distance.
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