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arXiv 2021年

作者： Hu, Xiao-Min Huang, Cen-Xiao Sheng, Yu-Bo Zhou, Lan Liu, Bi-Heng Guo, Yu Zhang, Chao Xing, Wen-Bo Huang, Yun-Feng Li, Chuan-Feng Guo, Guang-Can CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China Institute of Quantum Information and Technology Nanjing University of Posts and Telecommunications Nanjing210003 China College of Mathematics & Physics Nanjing University of Posts and Telecommunications Nanjing210003 China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing210003 China

High quality long-distance entanglement is essential for both quantum communication and scalab.e quantum networks. Entanglement purification is to distill high-quality entanglement from low-quality entanglement in a noisy environment and it plays a key role in quantum repeaters. The previous significant entanglement purification experiments require two pairs of low-quality entangled states and were demonstrated in table-top. Here we propose and report a high-efficiency and long-distance entanglement purification using only one pair of hyperentangled state. We also demonstrate its practical application in entanglement-based quantum key distribution (QKD). One pair of polarization spatial-mode hyperentanglement was distributed over 11 km multicore fiber (noisy channel). After purification, the fidelity of polarization entanglement arises from 0.771 to 0.887 and the effective key rate in entanglement-based QKD increases from 0 to 0.332. The values of Clauser-Horne-Shimony-Holt (CHSH) inequality of polarization entanglement arises from 1.829 to 2.128. Moreover, by using one pair of hyperentanglement and deterministic controlled-NOT gate, the total purification efficiency can be estimated as 6.6 × 103 times than the experiment using two pairs of entangled states with spontaneous parametric down conversion (SPDC) sources. Our results offer the potential to be implemented as part of a full quantum repeater and large scale quantum network. Copyright © 2021, The Authors. All rights reserved.

关键词： Quantum communication

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Noiseless linear amplification for the single-photon entanglement of arbitrary polarization–time-bin qudit

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Chinese Physics B 2019年第1期28卷 210-217页

作者： Ling-Quan Chen Yu-Bo Sheng Lan Zhou School of Science Nanjing University of Posts and TelecommunicationsNanjing 210003China College of Electronic and Optical Engineering&College of Microelectronics Nanjing University of Posts and TelecommunicationsNanjing 210003China Key Laboratory of Broadband Wireless Communication and Sensor Network Technology(Ministry of Education) Nanjing University of Posts and TelecommunicationsNanjing 210003China Institute of Signal Processing Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China

Single-photon entanglement(SPE) is an important source in quantum communication. In this paper, we put forward a single-photon-assisted noiseless linear amplification protocol to protect the SPE of an arbitrary polarization–time-bin qudit from the photon transmission loss caused by the practical channel noise. After the amplification, the fidelity of the SPE can be effectively increased. Meanwhile, the encoded polarization–time-bin features of the qudit can be well preserved. The protocol can be realized under the current experimental conditions. Moreover, the amplification protocol can be extended to resist complete photon loss and partial photon loss during the photon transmission. After the amplification, we can not only increase the fidelity of the target state, but also solve the decoherence problem simultaneously. Based on the above features, our amplification protocol may be useful in future quantum communication.

关键词： single-photon entanglement noiseless linear amplification polarization–time-bin qudit complete and partial photon loss

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Optimization of grant-free NOMA with multiple configured-grants for mURLLC

arXiv

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arXiv 2021年

作者： Liu, Yan Deng, Yansha Elkashlan, Maged Nallanathan, Arumugam Karagiannidis, George K. The Key Laboratory of Ministry of Education in Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing210003 China School of Electronic Engineering and Computer Science Queen Mary University of London London United Kingdom Department of Engineering King’s College London London United Kingdom Department of Electrical and Computer Engineering Aristotle University of Thessaloniki Thessaloniki54 124 Greece

Massive Ultra-Reliable and Low-Latency communications (mURLLC), which integrates URLLC with massive access, is emerging as a new and important service class in the next generation (6G) for time-sensitive traffics and has recently received tremendous research attention. However, realizing efficient, delay-bounded, and reliable communications for a massive number of user equipments (UEs) in mURLLC, is extremely challenging as it needs to simultaneously take into account the latency, reliability, and massive access requirements. To support these requirements, the third generation partnership project (3GPP) has introduced enhanced grant-free (GF) transmission in the uplink (UL), with multiple active configured-grants (CGs) for URLLC UEs. With multiple CGs (MCG) for UL, UE can choose any of these grants as soon as the data arrives. In addition, non-orthogonal multiple access (NOMA) has been proposed to synergize with GF transmission to mitigate the serious transmission delay and network congestion problems. In this paper, we develop a novel learning framework for MCG-GF-NOMA systems with bursty traffic. We first design the MCG-GF-NOMA model by characterizing each CG using the parameters: the number of contention-transmission units (CTUs), the starting slot of each CG within a subframe, and the number of repetitions of each CG. Based on the model, the latency and reliability performances are characterized. We then formulate the MCG-GF-NOMA resources configuration problem taking into account three constraints. Finally, we propose a Cooperative Multi-Agent based Double Deep Q-network (CMA-DDQN) algorithm to balance the allocations of the channel resources among MCGs so as to maximize the number of successful transmissions under the latency constraint. Our results show that the MCG-GF-NOMA framework can simultaneously improve the low latency and high reliability performances in massive URLLC. Copyright © 2021, The Authors. All rights reserved.

关键词： Deep learning

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Experimental three-state measurement-device-independent quantum key distribution with uncharacterized sources

arXiv

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arXiv 2020年

作者： Zhou, Xing-Yu Ding, Hua-Jian Zhang, Chun-Hui Li, Jian Zhang, Chun-Mei Wang, Qin Institute of quantum information and technology Nanjing University of Posts and Telecommunications Nanjing210003 China " Broadband Wireless Communication and Sensor Network Technology" Key Lab of Ministry of Education NUPT Nanjing210003 China "Telecommunication and Networks" National Engineering Research Center NUPT Nanjing210003 China

The measurement-device-independent quantum key distribution (MDI-QKD) protocol plays an important role in quantum communications due to its high level of security and practicability. It can be immune to all side-channel attacks directed on the detecting devices. However, the protocol still contains strict requirements during state preparation in most existing MDI-QKD schemes, e.g., perfect state preparation or perfectly characterized sources, which are very hard to realize in practice. In this letter, we investigate uncharacterized MDI-QKD by utilizing a three-state method, greatly reducing the finite-size effect. The only requirement for state preparation is that the state are prepared in a bidimensional Hilbert space. Furthermore, a proof-of-principle demonstration over a 170 km transmission distance is achieved, representing the longest transmission distance under the same security level on record. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum cryptography

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280-km experimental demonstration of quantum digital signature with one decoy state

arXiv

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arXiv 2020年

作者： Ding, Hua-Jian Chen, Jing-Jing Ji, Liang Zhou, Xing-Yu Zhang, Chun-Hui Zhang, Chun-Mei Wang, Qin Institute of quantum information and technology Nanjing University of Posts and Telecommunications Nanjing210003 China "Broadband Wireless Communication and Sensor Network Technology" Key Lab of Ministry of Education NUPT Nanjing210003 China "Telecommunication and Networks" National Engineering Research Center NUPT Nanjing210003 China

Quantum digital signature (QDS) guarantee the unforgeability, nonrepudiation and transferability of signature messages with information-theoretical security, and hence has attracted much attention recently. However, most previous implementations of QDS showed relatively low signature rates or/and short transmission distance. In this paper, we report a proof-of-principle phase-encoding QDS demonstration using only one decoy state. Firstly, such method avoids the modulation of vacuum state, thus reducing experimental complexity and random number consumption. Moreover, incorporating with low-loss asymmetric Mach-Zehnder interferometers and real-time polarization calibration technique, we have successfully achieved higher signature rate, e.g., 0.98 bit/s at 103 km, and to date a record-breaking transmission distance over 280-km installed fibers. Our work represents a significant step towards real-world applications of QDS. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum theory

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Resource Allocation for Outage Probability Minimization in Cognitive wireless Powered communication networks

Resource Allocation for Outage Probability Minimization in C...

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International Conference on communication technology (ICCT)

作者： Qun Li Ding Xu Key Lab of Broadband Wireless Communication and Sensor Network Technology Ministry of Education Nanjing University of Posts and Telecommunications Nanjing China

This paper considers a cognitive wireless powered communication network (CWPCN) consisting of a cognitive base station (CBS) and a set of secondary users (SUs) sharing spectrum with a primary user (PU). The transmission time is assumed to be divided into two parts, where the CBS transfers energy in the downlink during the first time part, and the SUs use the harvested energy to transmit in the uplink based on the time-division multiple access (TDMA) during the second time part. We investigate the problem for minimizing the average outage probability of the SUs by jointly optimizing the time allocation and the downlink transmit power allocation under the interference power and the transmit power constraints and propose a heuristic algorithm to solve it. Simulations show that the proposed algorithm greatly outperforms the benchmark algorithms.

关键词： Resource management wireless communication Interference Power system reliability Probability wireless sensor networks Downlink

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Moving Object Distance Estimation Method Based on Target Extraction with a Stereo Camera

Moving Object Distance Estimation Method Based on Target Ext...

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International Conference on Image, Vision and Computing (ICIVC)

作者： Jingyi Zhang Jianxin Chen Qingyu Lin Liming Cheng Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Ministry of Education Nanjing China

ISBN: (纸本)9781728123264

Real-time distance estimation with high accuracy is crucial to robot applications such as navigation and obstacle negotiation. However, considering the truth that high accuracy brings huge computation, the previous work either accelerates the distance estimation process through hardware, or only estimates the static objects, or sacrifices accuracy to realize real-time. In order to improve the trade-off between speed and accuracy, in this paper we propose a stereovision-based method that integrates the object detection and tracking into stereo matching. We utilize kernelized correlation filter (KCF) to track the moving object, and then extract target regions from image pair as input images to compute disparity map. In addition, we update each pixel's disparity by a simple but effective approach to further refine disparity map. Eventually, distance is calculated with disparity by triangulation. Experimental results show that our proposed method is suitable for dynamic environment, the extraction method improves the speed of the entire system, and the average accuracy of distance estimation can achieve over 95% from 88 cm to 300 cm when baseline is 151 mm.

关键词： Distance estimation Stereo vision KCF tracking Target region extraction Disparity refinement Triangulation Stereo cameras triangulation Stereoviews extraction of object Object detection object distance Static objects

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QoE Optimization for Traffic Offloading from LTE to WiFi

QoE Optimization for Traffic Offloading from LTE to WiFi

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IEEE Global Conference on Consumer Electronics (GCCE)

作者： Feng Tian Yue Yu Dapeng Li Jingwu Cui Yue Dong Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Ministry of Education Nanjing China

ISBN: (数字)9781728135755

ISBN: (纸本)9781728135762

In this paper, a novel QoE (Quality of Experience) optimization mechanism is proposed for the coexistence between LTE and WiFi networks, where traffic offloading is enabled from LTE to WiFi. Firstly, the throughput models of LTE and WiFi are analyzed, respectively. And then the users' satisfaction function is introduced to measure QoE. An optimal problem that maximizing the QoE of LTE network with guaranteeing the QoE of WiFi network, is formulated and solved by transformation and simplification. Simulation results indicate that traffic offloading can greatly improve the QoE of LTE network.

关键词： wireless fidelity Long Term Evolution Quality of experience Optimization Throughput wireless communication Interference

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Geometry Based LM of Robot to Imitate Human Motion with Kinect

Geometry Based LM of Robot to Imitate Human Motion with Kine...

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International Conference on Image, Vision and Computing (ICIVC)

作者： Wei Guo Jianxin Chen Ming Zhang Zhaolai Pan Ministry of Education Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Nanjing China

ISBN: (纸本)9781728123264

Humanoid robots are easily accepted by people because they have a body shape and appearance close to human. Humanoid robots have many application scenarios and great application potentials. Nevertheless, it is not easy to realize robot simulation due to the different physical structures of human bodies and robots. In this paper, we propose a geometry based LM algorithm for the robot to imitate the human motion of upper limb in real time. This method greatly improves the joint angle similarity under the premise of ensuring the similarity of the end trajectories. We designed a comprehensive and unrestricted motion simulation experiment to verify this method.

关键词： Kinect Inverse kinematic Nao Levenberg-Marquardt Geometry game player geometry Robot Human motion Humanoid robots Human Body

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A Reliable Hand Tracking Method Using Kinect

A Reliable Hand Tracking Method Using Kinect

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International Conference on Image, Vision and Computing (ICIVC)

作者： Qinyu Lin Jianxin Chen Jiangyi Zhang Ling Yao Ministry of Education Key Lab of Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and Telecommunications Nanjing China

ISBN: (纸本)9781728123264

Hand tracking has been focused over years in the field of human-computer interaction. But there are still some challenges such as reliability and accuracy due to the highly articulated and deformable of hand. In this paper we propose a real time hand tracking method with the depth information of the Kinect sensor. In this method, we preprocessed the depth information with a pixel filter to deal with the noise. Then we isolated the hand region from the depth image by using the KCF (Kernelized Correlation Filters) to the confined minimum depth area, which can release the limitation of hand movement range. Then the forearm region is segmented with assistance of PCA (Principle Component Analysis). And, to accurately locate the fingertip position, we integrate the maximum geodesic distance to hand centroid into EIC (Extended Inscribed Circle). And by lab.lling each finger to avoid mistaken fingertip determination. Experimental results verify the accuracy and reliability of our solution.

关键词： Real-time systems Human computer interaction Tracking Covariance matrices Principal component analysis Wrist Reliability

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