Integration interval and decision threshold issues were investigated for improved transmitted reference pulse cluster （iTRPC-） ultra-wideband （UWB） systems. Our analysis shows that the bit error rate （BER） perfo...Integration interval and decision threshold issues were investigated for improved transmitted reference pulse cluster （iTRPC-） ultra-wideband （UWB） systems. Our analysis shows that the bit error rate （BER） performance of iTRPC-UWB systems can be significantly improved via integration interval determination （IID） and decision threshold optimization. For this purpose, two modifications can be made at the autocorrelation receiver as follows. Firstly, the liD processing is performed for autocorrelation operation to capture multi-path energy as much as possible. Secondly, adaptive decision threshold （ADT） instead of zero decision threshold （ZDT）, is used as estimated optimal decision threshold for symbol detection. Performance of iTRPCUWB systems using liD and ADT was evaluated in realistic IEEE 802.15.4a UWB channel models and the simulation results demonstrated our theoretical analysis.展开更多
Continuous-variable quantum key distribution(CV QKD)using optical coherent detectors is practically favorable due to its low implementation cost,flexibility of wavelength division multiplexing,and compatibility with s...Continuous-variable quantum key distribution(CV QKD)using optical coherent detectors is practically favorable due to its low implementation cost,flexibility of wavelength division multiplexing,and compatibility with standard coherent communication technologies.However,the security analysis and parameter estimation of CV QKD are complicated due to the infinite-dimensional latent Hilbert space.Also,the transmission of strong reference pulses undermines the security and complicates the experiments.In this work,we tackle these two problems by presenting a time-bin-encoding CV protocol with a simple phase-error-based security analysis valid under general coherent attacks.With the key encoded into the relative intensity between two optical modes,the need for global references is removed.Furthermore,phase randomization can be introduced to decouple the security analysis of different photon-number components.We can hence tag the photon number for each round,effectively estimate the associated privacy using a carefully designed coherent-detection method,and independently extract encryption keys from each component.Simulations manifest that the protocol using multi-photon components increases the key rate by two orders of magnitude compared to the one using only the single-photon component.Meanwhile,the protocol with four-intensity decoy analysis is sufficient to yield tight parameter estimation with a short-distance key-rate performance comparable to the best Bennett-Brassard-1984 implementation.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 61271262,61473047 and 61572083in part by Shaanxi Provincial Natural Science Foundation under Grant 2015JM6310in part by the Special Fund for Basic Scientific Research of Central Colleges,Chang’an University 310824152010 and 0009-2014G1241043
文摘Integration interval and decision threshold issues were investigated for improved transmitted reference pulse cluster （iTRPC-） ultra-wideband （UWB） systems. Our analysis shows that the bit error rate （BER） performance of iTRPC-UWB systems can be significantly improved via integration interval determination （IID） and decision threshold optimization. For this purpose, two modifications can be made at the autocorrelation receiver as follows. Firstly, the liD processing is performed for autocorrelation operation to capture multi-path energy as much as possible. Secondly, adaptive decision threshold （ADT） instead of zero decision threshold （ZDT）, is used as estimated optimal decision threshold for symbol detection. Performance of iTRPCUWB systems using liD and ADT was evaluated in realistic IEEE 802.15.4a UWB channel models and the simulation results demonstrated our theoretical analysis.
基金Engineering and Physical Sciences Research Council(project EP/T001011/1)Shenzhen-Hong Kong Cooperation Zone for Technology and Innovation(HZQB-KCZYB-2020050)+7 种基金Hong Kong Research Grant Council(R7035-21)Army Research Office(W911NF-23-1-0077)Multidisciplinary University Research Initiative(W911NF-21-1-0325)Air Force Office of Scientific Research(FA9550-19-1-0399,FA9550-21-1-0209)National Science Foundation(OMA-1936118,ERC-1941583,OMA-2137642)NTT ResearchDavid and Lucile Packard Foundation(2020-71479)Marshall and Arlene Bennett Family Research Program。
文摘Continuous-variable quantum key distribution(CV QKD)using optical coherent detectors is practically favorable due to its low implementation cost,flexibility of wavelength division multiplexing,and compatibility with standard coherent communication technologies.However,the security analysis and parameter estimation of CV QKD are complicated due to the infinite-dimensional latent Hilbert space.Also,the transmission of strong reference pulses undermines the security and complicates the experiments.In this work,we tackle these two problems by presenting a time-bin-encoding CV protocol with a simple phase-error-based security analysis valid under general coherent attacks.With the key encoded into the relative intensity between two optical modes,the need for global references is removed.Furthermore,phase randomization can be introduced to decouple the security analysis of different photon-number components.We can hence tag the photon number for each round,effectively estimate the associated privacy using a carefully designed coherent-detection method,and independently extract encryption keys from each component.Simulations manifest that the protocol using multi-photon components increases the key rate by two orders of magnitude compared to the one using only the single-photon component.Meanwhile,the protocol with four-intensity decoy analysis is sufficient to yield tight parameter estimation with a short-distance key-rate performance comparable to the best Bennett-Brassard-1984 implementation.
